Publications by authors named "Shi Quan"

191 Publications

Diacylglycerols ions as novel marker indicators for the classification of edible oils using ultrahigh resolution mass spectrometry.

Food Res Int 2021 Jul 19;145:110422. Epub 2021 May 19.

Key Laboratory of Agro-food Safety and Quality of Ministry of Agriculture and Rural Affairs, Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing 100081, China.

Diacylglycerols (DAGs) ions, instead of triacylglycerols (TAGs) ions, were established as marker indicators for an improved classification of edible oils using ultrahigh resolution mass spectrometry (UHRMS). DAGs ions can be used not only to identify triacylglycerols (TAGs) and their embedded fatty acids (FAs), but also to distinguish positional isomers of TAGs. In this work, DAGs ions were determined in edible oils by direct infusion atmospheric pressure chemical ionization-ultrahigh resolution mass spectrometry (APCI-UHRMS), where the ultrahigh resolving power up to 500,000 FWHM (full width at half maximum) can provide accurate molecular compositions and detailed fingerprints MS spectra in a minute. A total of 146 samples belonging to 22 species of plant oils and animal fats, were characterized. Chemometric analyses were performed using principal component analysis, partial least square-discriminant analysis and orthogonal partial least squares-discriminant analysis. DAGs ions were proved to be better than TAGs ions as marker indicators in the chemometric analyses. An overall correct rate of 93.40% was achieved for the classification of tested samples. In addition, blend oils and gutter oils were also characterized by this developed method.
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http://dx.doi.org/10.1016/j.foodres.2021.110422DOI Listing
July 2021

Optimal Implantation Site of Orthodontic Micro-Screws in the Mandibular Anterior Region Based on CBCT.

Front Physiol 2021 20;12:630859. Epub 2021 May 20.

The Sixth Medical Center of PLA General Hospital, Beijing, China.

To determine the optimal implantation site of orthodontic micro-screws based on cone beam computed tomography (CBCT) analysis in the mandibular anterior tooth region, provide a theoretical basis for orthodontic implant placement and improve post-implantation stability. Forty patients who underwent CBCT scanning were selected for this study. CBCT scanning was applied to measure the interradicular distance, buccolingual dimension, labial cortical bone thickness and lingual cortical bone thickness between mandibular anterior teeth at planes 2, 4, 6, and 8 mm below the alveolar ridge crest. The data were measured and collected to obtain a comprehensive evaluation of the specific site conditions of the alveolar bone. The interradicular distance, buccolingual dimension and labial cortical bone thickness between the mandibular anterior teeth were positively correlated with the distance below the alveolar ridge crest (below 8 mm). The interradicular distance, buccolingual dimension, labial cortical bone thickness, and lingual cortical bone thickness were all greater than those in other areas between the lateral incisor root and canine incisor root 4, 6, and 8 mm below the alveolar ridge crest. The area between the lateral incisor root and the canine incisor root in planes 4, 6, and 8 mm from the alveolar ridge crest can be used as safe sites for implantation, while 8 mm below the alveolar ridge crest can be the optimal implantation site. An optimal implantation site can be 8 mm below the alveolar ridge crest between the lateral incisor root and the canine incisor root.
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http://dx.doi.org/10.3389/fphys.2021.630859DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8173216PMC
May 2021

Three Gorges Reservoir construction induced dissolved organic matter chemistry variation between the reservoir and non-reservoir areas along the Xiangxi tributary.

Sci Total Environ 2021 Aug 14;784:147095. Epub 2021 Apr 14.

Organic Geochemistry Unit, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China. Electronic address:

As one of the most dynamic and reactive compound pools, DOM plays a crucial part in various biochemical processes such as element cycling and nutrient export. Although the reservoir DOM has been investigated extensively, the variation of DOM between reservoir area and non-reservoir area induced by reservoir construction is not comprehensively assessed. By the combination of a series of complementary techniques including stable carbon isotope, optical spectroscopy, and ultrahigh-resolution mass spectrometry, here we show that hydrological alterations induced by Three Gorges Reservoir (TGR) construction were responsible for the variation in DOM molecular composition between reservoir area and non-reservoir area in Xiangxi tributary. With water intrusion from mainstream induced by reservoir construction and operation, reservoir area had relatively higher terrestrial input and more recalcitrant DOM than those in the non-reservoir area with limited influence of reservoir operation, whereas, relatively more autochthonous source and higher molecular lability of DOM were observed in the non-reservoir area. The water intrusion from mainstream to tributaries induced by reservoir construction is likely the main factor controlling DOM variation between reservoir area and non-reservoir area, and might devote to the organic carbon burial in the reservoir. This research provides new insight into spatial variations of riverine DOM composition induced by reservoir construction, underlining the important role of the reservoir in DOM cycling.
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http://dx.doi.org/10.1016/j.scitotenv.2021.147095DOI Listing
August 2021

The Stratified Distribution of Dissolved Organic Matter in an AMD Lake Revealed by Multi-sample Evaluation Procedure.

Environ Sci Technol 2021 Jun 1;55(12):8401-8409. Epub 2021 Jun 1.

School of Resources and Environmental Engineering, Hefei University of Technology, Hefei, Anhui 230009, China.

As a typical extreme environment, acid mine drainage (AMD) has been extensively studied for its biogeochemical cycle, but little is known about the quality of dissolved organic matter (DOM) in AMD. In this study, DOM molecules in an AMD lake were detected with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and the change of DOM molecules in the stratified water column was analyzed with a multi-sample evaluation procedure. The results demonstrate that DOM quality is highly stratified and can be linked with severe biogeochemical gradients. In the surface layer, DOM molecules can be distinguished by low quantities and intensities, as well as potential photodegradation products. Oxygen-poor and oxygen-rich molecules alternately dominate the chemocline, which can be explained by the redox-dependent adsorption/desorption of DOM on metastable secondary minerals. A rich and abundant DOM pool with a high proportion of heteroatoms exists at the bottom which can be significantly influenced by material exchange with sediments. These findings emphasize the active role of DOM in extreme AMD environments and expand the understanding of the carbon cycle in the hydrosphere.
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http://dx.doi.org/10.1021/acs.est.0c05319DOI Listing
June 2021

Lanthanide-Aromatic Iminodiacetate Frameworks with Helical Tubes: Structure, Properties, and Low-Temperature Heat Capacity.

ACS Omega 2021 Apr 12;6(15):10475-10485. Epub 2021 Apr 12.

College of Chemistry and Chemical Engineering, Dezhou University, Dezhou 253023, P. R. China.

A series of lanthanide coordination polymers [LnL(HO)] [Ln = Pr (), Nd (), Sm (), Eu (), and Gd (), HL = -(4-carboxy-benzyl)iminodiacetic acid] was hydrothermally prepared and structurally characterized. All the five compounds have been confirmed as 3D Ln-CPs with one-dimensional helical tunnels composed of four helical chains, although there are different coordination geometries around Ln. Enantiomeric helixes in , and absolute left-handed and right-handed helical chains in and , respectively, lead to different tunnel spaces. Their conformations can also be featured by different space groups and unit cell dimensions. Photoluminescence measurement on and show characteristic emission peaks of Sm and Eu ions, respectively. The low-temperature heat capacity of has been investigated in the temperature range of 1.9-300 K. Their heat capacity values are nearly equal below 10 K and display a crossover with the value order ( > ( ≈ ( > ( above 10 K. The measured heat capacities have been fitted, and the corresponding thermodynamic functions were consequently calculated based on the fitting parameters. The standard molar entropies at 298.15 K have been determined to be (415.71 ± 4.16), (451.32 ± 4.51), (308.53 ± 3.09), and (407.62 ± 4.08) J·mol·K for , , , and , respectively.
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http://dx.doi.org/10.1021/acsomega.1c01052DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8153764PMC
April 2021

Switching the magnetic hysteresis of an [Fe-NC-W]-based coordination polymer by photoinduced reversible spin crossover.

Nat Chem 2021 May 24. Epub 2021 May 24.

State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian, China.

Magnetic bistable materials that feature magnetic hysteresis are comparable to elementary binary units and promising for application in switches and memory devices. In this work, we report a material that consists of parallel cyanide-bridged [Fe-W] coordination chains linked together through rigid bis(imidazolyl)-benzene ligands and displays multiple magnetic states. The paramagnetic high-spin and diamagnetic low-spin states of the spin-crossover Fe ions can be interconverted by reversible light-induced excited spin state trapping (LIESST) by alternating between light irradiation of 808 and 473 nm. At 1.8 K, under 808-nm-light irradiation, magnetic interactions between the photogenerated paramagnetic high-spin Fe centres and the W centres lead to long fragments that exhibit single-chain magnet behaviour, with a wide magnetic hysteresis and a large coercive field of 19 kOe; under a 473 nm light, isolated Fe-W fragments behave as single-molecule magnets instead. At 3.3 K, the high-spin form still displays magnetic hysteresis, albeit narrower, whereas the low-spin one does not.
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http://dx.doi.org/10.1038/s41557-021-00695-1DOI Listing
May 2021

[Preliminary audiological evaluation of the SoundBite bone conduction devices in adults with single-sided deafness].

Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi 2021 May;56(5):478-486

Department of Dentistry, Chinese PLA General Hospital, Beijing 100853, China.

The auditory deficits of single-sided deafness (SSD) can be treated with a novel intra-oral device, SoundBite, which delivers sound by applying vibratory signal to the teeth. The purpose of this study was to evaluate the efficacy and benefit of the bone conduction device for Chinese adults with SSD. Eighteen patients aged 19-66 yrs with acquired, permanent sensorineural SSD and no current treatment by any other devices for SSD, were recruited in a prospective controlled, nonrandomized, unblinded study. They were requested the continually daily wear of the new device over a 30-day free trial period. The intra-oral hearing device was placed around two maxillary teeth and was similar to a small partial denture or retainer. The audiological tests included pure tone air conduction thresholds, monosyllable word recognition score (WRS) in quiet and sentence reception thresholds in noise (via CMNmatrix test). The benefit was determined with the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Speech, Spatial and Qualities of Hearing Scale (SSQ) questionnaire. The monosyllable WRS and the 50% threshold of signal-to-noise ratio (SNR) were significantly better in all aided conditions. The head shadow effect, assessed by the SNR via CMNmatrix test improved an average of 2.6 dB after 30 days' wearing compared with unaided condition (<0.001). The APHAB scores improved (<0.05) for all subjects for the Global and Ease of Communication, Reverberation, Background Noise subscales. The SSQ scores improved (<0.05) for all subjects for Speech, Spatial and Qualities of Hearing subscales. The SoundBite is a good alternative to the well-established implantable bone conduction devices in patients with SSD. An improvement in listening ability in noise and quiet as well as a decrease of the head shadow effect is validated as the expected.
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http://dx.doi.org/10.3760/cma.j.cn115330-20200602-00465DOI Listing
May 2021

Hydrological management affected dissolved organic matter chemistry and organic carbon burial in the Three Gorges Reservoir.

Water Res 2021 Jul 29;199:117195. Epub 2021 Apr 29.

Organic Geochemistry Unit, Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province, School of Earth Sciences, Zhejiang University, Hangzhou, 310027, China. Electronic address:

With the linkage between dissolved organic matter (DOM) and the characteristics of natural ecosystem assessed extensively, the properties of DOM in reservoirs, the typical human interrupted ecosystems, have been focused on in recent years, which is critical for the understanding of human impacts on watershed ecosystems and carbon cycling. This study aims to analyze the effect of hydrological management on the DOM chemistry and organic carbon burial in Daning River tributary of the world's largest Three Gorges Reservoir (TGR). Based on the application of a combined approach including bulk geochemical analyses, optical spectroscopy, and ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry, various sources of DOM (terrestrial, anthropogenic, and autochthonous sources) were revealed. An increasing trend of terrestrial and recalcitrant DOM was observed along the upstream to downstream transect of Daning River tributary, which was mainly caused by the water intrusion with a higher terrestrial and recalcitrant signature from mainstream to tributary resulted from hydrological management of TGR. Integrated with the analysis of sedimentary organic matter in Daning River tributary in the past decade (after the construction of TGR), our work suggests that organic carbon burial in the reservoir could be enhanced by hydrological management-induced variation in DOM chemistry. Further studies are needed to better constrain the effects of damming reservoirs on carbon cycling considering their booming all over the world.
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http://dx.doi.org/10.1016/j.watres.2021.117195DOI Listing
July 2021

Failure Risk of Short Dental Implants Under Immediate Loading: A Meta-Analysis.

J Prosthodont 2021 May 1. Epub 2021 May 1.

Institute of Stomatology, First Medical Center, Chinese PLA General Hospital, Beijing, China.

Purpose: Currently, there is no clear clinical evidence that short implants are suitable for immediate loading. Therefore, this meta-analysis aims to evaluate whether immediate loading increases the failure risk of short dental implants.

Materials And Methods: This meta-analysis was registered at PROSPERO (CRD 42020195890). PubMed, Embase, and Cochrane Library databases were searched to collect all clinical studies comparing the failure rates of short dental implants (<10 mm) and standard implants (≥10 mm) under the condition of immediate loading and studies comparing the failure rates of short dental implants under immediate loading versus early or delayed loading. All of the clinical studies with available relevant data were eligible for inclusion. The Cochrane Risk of Bias tool was adopted to evaluate the risk of bias for the randomized controlled trial (RCT), while Newcastle-Ottawa Quality Assessment Scale (NOS) was used for the observational studies (OS). The OR value of each included study and its 95% CI were pooled to estimate the failure risk of short dental implants under immediate loading. The heterogeneity among studies was evaluated through Cochran's Q test and I .

Results: Seventeen studies, 5 RCTs and 12 OS studies, with a total of 2461 dental implants were analyzed. Four of the RCT studies were of low risk of bias and one was of unclear risk, while all of the OS studies were of moderate or high quality. Compared with standard implants, short implants did not have an increased failure risk under immediate loading (OR: 1.38, 95% CI: 0.67-2.84, p = 0.997, fixed model). In addition, the OR value of implant failure for short implants under immediate loading compared to that for short implants under early or delayed loading was 1.22 (95% CI: 0.33-4.55, p = 0.104, random model), which was also not significantly different.

Conclusions: There is not enough evidence to show that short dental implants under immediate loading may have higher implant failure risk compared to standard implants under immediate loading and short implants under early or delayed loading. Therefore, an immediate loading protocol may not increase the failure risk of short dental implants.
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http://dx.doi.org/10.1111/jopr.13376DOI Listing
May 2021

Identification of processes mobilizing organic molecules and arsenic in geothermal confined groundwater from Pliocene aquifers.

Water Res 2021 Jun 11;198:117140. Epub 2021 Apr 11.

State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China; School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, China.

Organic matter (OM) has been accepted as an important trigger fueling Fe(III) oxide reduction and arsenic release in the late Pleistocene-Holocene anoxic aquifers, whereas its fates and roles on arsenic mobility in the Pliocene aquifer are unclear. To fill this gap, groundwaters from a confined Pliocene aquifer (CG) and an unconfined Holocene aquifer (UG) were sampled in the Guide Basin, China, to monitor evolutions of groundwater geochemistry and OM molecular signatures along the groundwater flow path. The outcomes showed that groundwater pH, temperature, and arsenic concentrations in the CG samples generally increased along the groundwater flow path, which were much higher than those in the UG samples. The numbers and intensities of recalcitrant molecules (polycyclic aromatics and polyphenols) in the CG samples remarkably increased along the path, but relatively labile molecules (highly unsaturated and phenolic compounds and aliphatic compounds) showed the opposite trends. The arsenic-poor (<10 μg/L) UG samples contained more labile molecules than the arsenic-rich CG samples. High groundwater pH, temperature, and sediment age in the confined aquifers may be responsible for the selective mobilization of the unique polycyclic aromatics and polyphenols. The mobilized recalcitrant organic molecules may enhance arsenic release via electron shuttling, complexation, and competition. Furthermore, high temperature and pH may also facilitate arsenic desorption. The study provides molecular-scale evidences that the mobilization of recalcitrant organic molecules and arsenic were concurrent in the geothermal confined groundwater.
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http://dx.doi.org/10.1016/j.watres.2021.117140DOI Listing
June 2021

Correspondence between DOM molecules and microbial community in a subtropical coastal estuary on a spatiotemporal scale.

Environ Int 2021 Sep 23;154:106558. Epub 2021 Apr 23.

State Key Laboratory for Marine Environmental Science, Institute of Marine Microbes and Ecospheres, College of Ocean and Earth Sciences, Xiamen University, Xiang'an Campus, Xiang'an South Road, Xiamen 361102, China; Fujian Key Laboratory of Marine Carbon Sequestration, Xiamen University, Xiang'an Campus, Xiang'an South Road, Xiamen 361102, China. Electronic address:

Dissolved organic matter (DOM) changes in quantity and quality over time and space, especially in highly dynamic coastal estuaries. Bacterioplankton usually display seasonal and spatial variations in abundance and composition in the coastal regions, and influence the DOM pool via assimilation, transformation and release of organic molecules. The change in DOM can also affect the composition of bacterial community. However, little is known on the correspondence between DOM molecules and bacterial composition, particularly through a systematic field survey. In this study, the spatiotemporal signatures of microbial communities and DOM composition in the subtropical coastal estuary of Xiamen are investigated over one and half years. The co-occurrence analysis between bacteria and DOM suggested microorganisms likely transformed the DOM from a relatively high (>400 Da) to a low (<400 Da) molecular weight, corresponding to an apparent increase in overall aromaticity. This might be the reason why microbial transformation renders "dark" organic matter visible in mass spectrometry due to more efficient ionization of microbial metabolites, as well as photodegradation processes. K- and r-strategists exhibited different correlations with two-size categories of DOM molecules owing to their different lifestyles and responses to environmental nutrient conditions. A comparison of the environmental variables and DOM composition with the microbial communities showed that the environmental/DOM variations played a more important role in shaping the microbial communities than vice versa. This study sheds light on the interactions between microbial populations and DOM molecules at the spatiotemporal scale, improving our understanding of microbial roles in marine biogeochemical cycles.
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http://dx.doi.org/10.1016/j.envint.2021.106558DOI Listing
September 2021

Correcting a major error in assessing organic carbon pollution in natural waters.

Sci Adv 2021 Apr 14;7(16). Epub 2021 Apr 14.

State Key Laboratory of Heavy Oil Processing, China University of Petroleum-Beijing, Beijing 102249, China.

Microbial degradation of dissolved organic carbon (DOC) in aquatic environments can cause oxygen depletion, water acidification, and CO emissions. These problems are caused by labile DOC (LDOC) and not refractory DOC (RDOC) that resists degradation and is thus a carbon sink. For nearly a century, chemical oxygen demand (COD) has been widely used for assessment of organic pollution in aquatic systems. Here, we show through a multicountry survey and experimental studies that COD is not an appropriate proxy of microbial degradability of organic matter because it oxidizes both LDOC and RDOC, and the latter contributes up to 90% of DOC in high-latitude forested areas. Hence, COD measurements do not provide appropriate scientific information on organic pollution in natural waters and can mislead environmental policies. We propose the replacement of the COD method with an optode-based biological oxygen demand method to accurately and efficiently assess organic pollution in natural aquatic environments.
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http://dx.doi.org/10.1126/sciadv.abc7318DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8046372PMC
April 2021

Opportunistic bacteria with reduced genomes are effective competitors for organic nitrogen compounds in coastal dinoflagellate blooms.

Microbiome 2021 03 24;9(1):71. Epub 2021 Mar 24.

State Key Laboratory of Marine Environmental Science, Fujian Key Laboratory of Marine Carbon Sequestration, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, People's Republic of China.

Background: Phytoplankton blooms are frequent events in coastal areas and increase the production of organic matter that initially shapes the growth of opportunistic heterotrophic bacteria. However, it is unclear how these opportunists are involved in the transformation of dissolved organic matter (DOM) when blooms occur and the subsequent impacts on biogeochemical cycles.

Results: We used a combination of genomic, proteomic, and metabolomic approaches to study bacterial diversity, genome traits, and metabolic responses to assess the source and lability of DOM in a spring coastal bloom of Akashiwo sanguinea. We identified molecules that significantly increased during bloom development, predominantly belonging to amino acids, dipeptides, lipids, nucleotides, and nucleosides. The opportunistic members of the bacterial genera Polaribacter, Lentibacter, and Litoricola represented a significant proportion of the free-living and particle-associated bacterial assemblages during the stationary phase of the bloom. Polaribacter marinivivus, Lentibacter algarum, and Litoricola marina were isolated and their genomes exhibited streamlining characterized by small genome size and low GC content and non-coding densities, as well as a smaller number of transporters and peptidases compared to closely related species. However, the core proteomes identified house-keeping functions, such as various substrate transporters, peptidases, motility, chemotaxis, and antioxidants, in response to bloom-derived DOM. We observed a unique metabolic signature for the three species in the utilization of multiple dissolved organic nitrogen compounds. The metabolomic data showed that amino acids and dipeptides (such as isoleucine and proline) were preferentially taken up by P. marinivivus and L. algarum, whereas nucleotides and nucleosides (such as adenosine and purine) were preferentially selected by L. marina.

Conclusions: The results suggest that the enriched DOM in stationary phase of phytoplankton bloom is a result of ammonium depletion. This environment drives genomic streamlining of opportunistic bacteria to exploit their preferred nitrogen-containing compounds and maintain nutrient cycling. Video abstract.
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http://dx.doi.org/10.1186/s40168-021-01022-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7992965PMC
March 2021

Linking the unique molecular complexity of dissolved organic matter to flood period in the Yangtze River mainstream.

Sci Total Environ 2021 Apr 8;764:142803. Epub 2020 Oct 8.

Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province, School of Earth Sciences, Zhejiang University, Hangzhou, China; State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China. Electronic address:

Large rivers transport a significant amount of terrestrially derived dissolved organic matter (DOM) to coastal oceans, consisting of a critical component of the global biogeochemical cycle. Although high flow events usually introduce more terrestrial DOM than baseflow, the underlying molecular complexity and lability of DOM during high discharge are not well constrained, especially in large river ecosystems. By combining ultraviolet and fluorescent spectroscopy, and ultrahigh-resolution mass spectrometry, we found that stronger terrestrial DOM signal was detected during high discharge than normal discharge in the Yangtze River mainstream. The averaged DOC concentration was higher during high discharge than normal discharge. Optical properties confirmed higher aromaticity and relatively higher humic-like fluorescent components in DOM during high discharge. The molecular composition showed significantly higher molecular complexity, averaged molecular weight, aromaticity, relative abundances of polyphenols and highly unsaturated compounds of DOM during high discharge than normal discharge. A large set of unique molecular formulae (up to 4927) was only detected during high discharge. These unique molecular formulae were mostly lignin degradation products, likely due to more intensive soil leaching during high discharge. By comparing with incubation experiments and the Yangtze River mouth and East China Sea DOM molecular composition, some of these unique molecular formulae during high discharge are resistant to both bio- and photo-degradation, and persist during their transport to the East China Sea. Therefore, we suggest that high discharge will additionally introduce a relatively recalcitrant pool of DOM into the Yangtze River mainstream and persist during its journey to the ocean. Considering the projected increase of flood frequency, this study provides a preliminary foundation for further studies to better assess the underlying mechanisms how hydrology affect the biogeochemical cycling of DOM in large rivers.
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http://dx.doi.org/10.1016/j.scitotenv.2020.142803DOI Listing
April 2021

Comprehensive Composition, Structure, and Size Characterization for Thiophene Compounds in Petroleum Using Ultrahigh-Resolution Mass Spectrometry and Trapped Ion Mobility Spectrometry.

Anal Chem 2021 Mar 18;93(12):5089-5097. Epub 2021 Mar 18.

State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, People's Republic of China.

Thiophene compounds are the main concern of petroleum desulfurization, and their chemical composition and molecular configuration have critical impacts on thermodynamic and kinetic processes. In this work, atmospheric pressure chemical ionization (APCI) was employed for effective ionization of thiophene compounds in petroleum with complex matrix, in which carbon disulfide was used for generating predominant [M] ions without the need of derivatization as for electrospray ionization. APCI coupled with ultrahigh-resolution mass spectrometry (UHRMS) was successfully applied to the composition characterization of thiophene compounds in both a low boiling petroleum fraction and a whole crude oil. APCI coupled with trapped ion mobility spectrometry (TIMS) was developed to determine the shape and size of thiophene compounds, providing configuration information that affects the steric hindrance and diffusion behavior of reactants in the desulfurization reaction, which has not been previously reported. Moreover, the comprehensive experimental structural data, expressed as the collision cross section (CCS) of the ions as surrogates of molecules, provided clues to the factors affecting the desulfurization reactivity of thiophene compounds. Further exploration showed that not only qualitative analysis of thiophene compounds can be achieved from the correlation between / and CCS, but also molecular size was found to be correlated with CCS that can be used as structural analysis. Overall, the molecular composition and dimension analysis together can provide substantial information for the desulfurization activity of thiophene compounds, facilitating the desulfurization process studies and catalyst design.
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http://dx.doi.org/10.1021/acs.analchem.0c04667DOI Listing
March 2021

The unfavorable role of titanium particles released from dental implants.

Nanotheranostics 2021 10;5(3):321-332. Epub 2021 Mar 10.

Shanxi Medical University School and Hospital of Stomatology, Taiyuan 030001, China.

Titanium is considered to be a metal material with the best biological safety. Studies have proved that the titanium implanted in the bone continuously releases titanium particles (Ti particles), significantly increasing the total titanium content in human body. Generally, Ti particles are released slowly without causing a systemic immune response. However, the continuous increased local concentration may result in damage to the intraepithelial homeostasis, aggravation of inflammatory reaction in the surrounding tissues, bone resorption and implant detachment. They also migrate with blood flow and aggregate in the distal organ. The release of Ti particles is affected by the score of the implant surface structure, microenvironment wear and corrosion, medical operation wear, and so on, but the specific mechanism is not clear. Thus, it difficult to prevent the release completely. This paper reviews the causes of the Ti particles formation, the damage to the surrounding tissue, and its mechanism, in particular, methods for reducing the release and toxicity of the Ti particles.
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http://dx.doi.org/10.7150/ntno.56401DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7961127PMC
May 2021

Chemodiversity of water-extractable organic matter in sediment columns of a polluted urban river in South China.

Sci Total Environ 2021 Jul 1;777:146127. Epub 2021 Mar 1.

State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China. Electronic address:

Dissolved organic matter (DOM) in sediments of polluted rivers significantly contributes to oxygen consumption and river blackening and odorization. However, the chemodiversity of DOM at different depths or river reaches is poorly known. Here, we studied the storage and molecular-level signatures of water-extractable organic matter (WEOM) in the sediment column (0-100 cm) of the upper, middle, and lower mainstream of Maozhou River (a polluted river in Shenzhen, China, with 40 years of urbanization) using optical spectroscopy and Fourier transform ion cyclotron resonance mass spectrometry. The sediment WEOM level increased from upstream to downstream. The relative abundances of sulfur-containing surfactants in all sediment WEOM were higher than those previously reported for surface water DOM. The WEOM in surface sediment had higher aromaticity, molecular size, and nominal oxidation state of carbon and greater signals from anthropogenic inputs than did deep sediment at the upper and middle mainstream sites. However, these characteristics varied little between surface and deep sediments at the lower mainstream site, probably due to intensive surface water and pore water interactions. The sediment WEOM at 0-40 cm in the middle mainstream showed a greater anthropogenic signature (e.g., more surfactant and dissolved black carbon contributions) than any other sediment. We demonstrate strong anthropogenic impacts on the surface sediment over decades of urbanization.
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http://dx.doi.org/10.1016/j.scitotenv.2021.146127DOI Listing
July 2021

Microbial transformation of distinct exogenous substrates into analogous composition of recalcitrant dissolved organic matter.

Environ Microbiol 2021 May 18;23(5):2389-2403. Epub 2021 Apr 18.

State Key Laboratory of Marine Environmental Science and College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361005, China.

Oceanic dissolved organic matter (DOM) comprises a complex molecular mixture which is typically refractory and homogenous in the deep layers of the ocean. Though the refractory nature of deep-sea DOM is increasingly attributed to microbial metabolism, it remains unexplored whether ubiquitous microbial metabolism of distinct carbon substrates could lead to similar molecular composition of refractory DOM. Here, we conducted microbial incubation experiments using four typically bioavailable substrates (L-alanine, trehalose, sediment DOM extract, and diatom lysate) to investigate how exogenous substrates are transformed by a natural microbial assemblage. The results showed that although each-substrate-amendment induced different changes in the initial microbial assemblage and the amended substrates were almost depleted after 90 days of dark incubation, the bacterial community compositions became similar in all incubations on day 90. Correspondingly, revealed by ultra-high resolution mass spectrometry, molecular composition of DOM in all incubations became compositionally consistent with recalcitrant DOM and similar toward that of DOM from the deep-sea. These results indicate that while the composition of natural microbial communities can shift with substrate exposures, long-term microbial transformation of distinct substrates can ultimately lead to a similar refractory DOM composition. These findings provide an explanation for the homogeneous and refractory features of deep-sea DOM.
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http://dx.doi.org/10.1111/1462-2920.15426DOI Listing
May 2021

Circ_0061012 contributes to IL-22-induced proliferation, migration and invasion in keratinocytes through miR-194-5p/GAB1 axis in psoriasis.

Biosci Rep 2021 Jan;41(1)

Department of Dermatology, Hubei Provincial Hospital of Traditional Chinese Medicine, Hubei Province Academy of Traditional Chinese Medicine, Wuhan, Hubei, China.

Psoriasis is a chronic inflammation-associated skin disorder featured by excessive proliferation and abnormal differentiation of keratinocytes. Here, we intended to investigate the role of circular RNA 0061012 (circ_0061012) in psoriasis progression. The expression of circ_0061012, SLMO2-ATP5E readthrough (SLMO2-ATP5E) messenger RNA (mRNA), microRNA-194-5p (miR-194-5p) and GRB2 associated binding protein 1 (GAB1) mRNA was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation and metastasis were analyzed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and transwell assays. Western blot assay was used to measure the protein levels of Ki67, matrix metallopeptidase 9 (MMP9) and GAB1. Dual-luciferase reporter assay and RNA immune co-precipitation (RIP) assay were used to verify the interaction between miR-194-5p and circ_0061012 or GAB1. Circ_0061012 abundance was significantly enhanced in lesional skin samples from psoriasis patients than that in normal skin specimens from healthy volunteers. Interleukin-22 (IL-22) treatment increased the expression of circ_0061012 in a dose-dependent manner. Circ_0061012 silencing alleviated IL-22-induced promoting effects in the proliferation, migration and invasion of HaCaT cells. Circ_0061012 interacted with miR-194-5p, and miR-194-5p knockdown counteracted circ_0061012 silencing-mediated influences in IL-22-induced HaCaT cells. GAB1 was a target of miR-194-5p in HaCaT cells, and miR-194-5p hampered proliferation and metastasis which were induced by IL-22 partly through targeting GAB1. Circ_0061012 elevated the expression of GAB1 through sponging miR-194-5p in HaCaT cells. Circ_0061012 accelerated IL-22-induced proliferation and metastasis in HaCaT cells through enhancing GAB1 expression via sponging miR-194-5p in psoriasis.
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http://dx.doi.org/10.1042/BSR20203130DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7809556PMC
January 2021

Synthesis of Surface-Active Heteropolyacid-Based Ionic Liquids and Their Catalytic Performance for Desulfurization of Fuel Oils.

ACS Omega 2020 Dec 25;5(48):31171-31179. Epub 2020 Nov 25.

Beijing Key Laboratory for Chemical Power Source and Green Catalysis, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, 100081 Beijing, China.

Surface-active heteropolyacid-based ionic liquids with varying alkyl carbon chains were synthesized, which were subsequently analyzed. The desulfurization of fuels was investigated utilizing various surface-active heteropolyacid-based ionic liquids, and acetonitrile was used as the extractant for the coupling of ODS and EDS. The influences of the alkyl group, surface activity, and hydrophobicity of ionic liquids on sulfur removal were studied. The results suggested that the ionic liquids were stable. Among these ionic liquids, [CImBS][PWO] exhibited the best catalytic performance. Using [CImBS][PWO] as the catalyst, the influences of the catalyst amount, aqueous hydrogen peroxide amount, and reaction temperature on the sulfur removal were explored. Under the optimum conditions, the sulfur removal could achieve 100% efficiency. The recycle experiments also proved that the ionic liquid could be reused.
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http://dx.doi.org/10.1021/acsomega.0c04398DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7726930PMC
December 2020

Molecular Characterization of Lignite Extracts of Methanol and Carbon Disulfide/-Methyl-2-pyrrolidone by High-Resolution Mass Spectrometry.

ACS Omega 2020 Dec 27;5(48):31085-31091. Epub 2020 Nov 27.

State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China.

CS/-methyl-2-pyrrolidone (NMP) could extract much more substance from coals than any other solvents. Investigation on the molecular composition of CS/NMP extracts from lignite is significant for the understanding of high extraction yield and the clean utilization of coal. The methanol-soluble portions from lignites and CS/NMP extracts of lignites were characterized by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. The yield of CS/NMP extracts from lignite was quite higher than that of methanol extracts. Furthermore, the yield of methanol-soluble portions from CS/NMP extracts was far more than that of methanol extracts from lignite. At the level of molecular composition, the relative content of heteroatom compounds with more oxygen atoms, longer side chain, and higher condensation in the CS/NMP extract was also higher than that in the methanol extract. Despite great difference in the yield and the relative content of components, the distributions of species, molecular weight, carbon number, and double-bond equivalent were similar to those of most organic molecules for the methanol extract and methanol-soluble portions from the CS/NMP extract. These phenomena suggested that organic molecules with similar structure but different composition, nonuniformly distributed in the coal matrix, were released more in the CS/NMP extract compared to the single methanol extract.
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http://dx.doi.org/10.1021/acsomega.0c04223DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7726752PMC
December 2020

Unraveling roles of dissolved organic matter in high arsenic groundwater based on molecular and optical signatures.

J Hazard Mater 2021 03 28;406:124702. Epub 2020 Nov 28.

State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, PR China; School of Water Resources and Environment, China University of Geosciences (Beijing), Beijing 100083, PR China.

Dissolved organic matter (DOM) is a crucial controlling factor in mobilizing arsenic. However, direct delineations of DOM regarding both optical properties and molecular signatures were rarely conducted in high-arsenic groundwater. Here, both groundwater and surface water were taken from the Hetao Basin, China, to decipher DOM properties with both optical spectrophotometer and Fourier transform ion cyclotron resonance mass spectrometry. The tryptophan-like component (C4) was averagely less than 30% in groundwater DOM, being positively associated with high H/C-ratio molecules (H/C > 1.2) and mainly grouped as highly unsaturated and phenolic compounds and aliphatic compounds. Other three humic-like components (C1, C2, C3) had positive associations with low H/C-ratio molecules (H/C < 1.2), which mainly consisted of highly unsaturated and phenolic compounds, polyphenols, and polycyclic aromatics. Groundwater arsenic concentrations were positively correlated with humic-like, low H/C-ratio, and recalcitrant organic compounds, which may be the consequence of labile organic matter degradation. The degradation caused Fe(III) oxide reduction and mobilized the solid arsenic. In addition, high abundances of these recalcitrant organic compounds in high-arsenic groundwater may contribute to arsenic enrichment via electron shuttling, competition for surface sites, and complexation process. It suggested that groundwater proxies would be either the result or the cause of biogeochemical processes in aquifers.
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http://dx.doi.org/10.1016/j.jhazmat.2020.124702DOI Listing
March 2021

Spatial changes in molecular composition of dissolved organic matter in the Yangtze River Estuary: Implications for the seaward transport of estuarine DOM.

Sci Total Environ 2021 Mar 16;759:143531. Epub 2020 Nov 16.

Organic Geochemistry Unit, Key Laboratory of Geoscience Big Data and Deep Resource of Zhejiang Province, School of Earth Sciences, Zhejiang University, Hangzhou, China.

The complexity of dissolved organic matter (DOM) limits our understanding of the estuarine carbon cycle. This study adopted a combination of bulk carbon isotope, optical techniques and ultra-high resolution mass spectrometry to study the spatial heterogeneity and compositional variations of DOM across a latitudinal transect of the Yangtze River Estuary (YRE). Results show that the whole section of YRE received high abundance of protein-like C4 fluorescent component (0.66 ± 0.08 R.U.) and high relative abundance of aliphatic compounds and peptides (8.28 ± 1.46%) from phytoplankton, which would contribute to the bioavailable DOM pool of the Eastern China Sea (ECS). However, multivariate analysis indicated that polycyclic aromatics and polyphenols from the Yangtze River experienced a significant decrease of 5% within the turbidity zone, creating a significant decrease of 0.08 in aromaticity index and modulating DOM content and compositions within the YRE. 1837 molecular formulae were identified to track dynamic behaviors of terrestrial DOM in the YRE. Molecular imprints showed the removal of terrestrial molecules in the turbidity zone indicated by the decrease of 753 in molecular quantity, when water masses mixing diluted the abundance of aromatic compounds. Adsorption and flocculation could serve important mechanisms to remove terrestrial DOM, promoting the burial of terrestrial DOM within estuarine sediments. Besides, some terrestrial molecular formulae were also detected in the ECS, suggesting the potential contribution of terrestrial DOM to the carbon stock of open seas after experiencing physical and photochemical transformations. This research provides a comprehensive insight into spatial variations of estuarine DOM composition, underlining the important role of estuaries in sorting and transporting DOM.
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http://dx.doi.org/10.1016/j.scitotenv.2020.143531DOI Listing
March 2021

Understanding the Interaction between Cyclists' Traffic Violations and Enforcement Strategies: An Evolutionary Game-Theoretic Analysis.

Int J Environ Res Public Health 2020 11 15;17(22). Epub 2020 Nov 15.

School of Transportation and Civil Engineering, Nantong University, Nantong 226019, China.

An evolutionary game-theoretic analysis method is developed in this study to understand the interactions between cyclists' traffic violations and the enforcement strategies. The evolutionary equilibrium stabilities were analysed under a fixed (FPS) and a dynamic penalty strategy (DPS). The simulation-based numerical experiments show that: (i) the proposed method can be used to study the interactions between traffic violations and the enforcement strategies; (ii) FPS and DPS can reduce cyclists' probability of committing traffic violations when the perceived traffic violations' relative benefit is less than the traffic violation penalty and the enforcement cost is less than the enforcement benefit, and using DPS can yield a stable enforcement outcome for law enforcement compared to using FPS; and (iii) strategy-related (penalty amount, enforcement effectiveness, and enforcement cost) and attitudinal factors (perceived relative benefit, relative public image cost, and cyclists' attitude towards risk) can affect the enforcement strategy's impacts on reducing cyclists' traffic violations.
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http://dx.doi.org/10.3390/ijerph17228457DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7697453PMC
November 2020

Using ESI FT-ICR MS to Characterize Dissolved Organic Matter in Salt Lakes with Different Salinity.

Environ Sci Technol 2020 10 12;54(20):12929-12937. Epub 2020 Oct 12.

Key Laboratory of Water and Sediment Sciences (Ministry of Education), College of Environmental Sciences and Engineering, Peking University, Beijing 100871, People's Republic of China.

Dissolved organic matter (DOM) composition in salt lakes is critical for water quality and aquatic ecology, and the salinization of salt lakes affects the DOM composition. To the best of our knowledge, no study has explored the effects of salinity on salt lake DOM composition at the molecular level. In this work, we selected Qinghai Lake (QHL) and Daihai Lake (DHL) as typical saline lakes. The two lakes have similar geographical and climatic conditions, and the salinity of QHL is higher than that of DHL. Fourier transform ion cyclotron resonance mass spectrometry coupled with electrospray ionization was applied to compare the DOM molecular composition in the two lakes. At higher salinity, the DOM showed larger average molecular weight, higher oxidation degree, and lower aromaticity. Moreover, the proportion of DOM that is vulnerable to microbial degradation (e.g., lipids), photo-degradation (e.g., aromatic structures), or both processes (e.g., carbohydrates and unsaturated hydrocarbons) reduced at higher salinity. On the contrary, compounds that are refractory to microbial degradation (e.g., lignins/CRAM-like structures and tannins) or photo-degradation (e.g., aliphatic compounds) accumulated. Our study provides a useful and unique method to study DOM molecular composition in salt lakes with different salinity and is helpful to understand DOM transformation during the salinization of salt lakes.
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http://dx.doi.org/10.1021/acs.est.0c01681DOI Listing
October 2020

Hydrological management constraints on the chemistry of dissolved organic matter in the Three Gorges Reservoir.

Water Res 2020 Dec 19;187:116413. Epub 2020 Sep 19.

Organic Geochemistry Unit, School of Earth Sciences, Zhejiang University, Hangzhou 310027, China. Electronic address:

Reservoirs are well known as a far-reaching human modification on the functions of natural river networks. However, changes in the chemistry and reactivity of dissolved organic matter (DOM) responding to hydrological management for water retention structures, and its influence on the river carbon cycle, remain poorly understood. Here we show that hydrological management does shape the molecular composition of DOM in the world's largest Three Gorges Reservoir, as revealed by optical spectroscopy and ultrahigh-resolution mass spectrometry. Relatively higher terrestrial input, molecular complexity, isomeric complexity, and environmental stability of DOM were observed during the storage period, whereas the inverse occurred during the drainage period. The results demonstrate that the hydrodynamic processes, which are mainly controlled by water intrusion from mainstream to tributaries, are likely the underlying mechanism controlling DOM chemistry. Integrated with observations from worldwide river reservoirs, the DOM degradation experiments suggest that reservoir hydrological management would enhance DOM mineralization, thereby increase CO emission and change the river carbon cycle.
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http://dx.doi.org/10.1016/j.watres.2020.116413DOI Listing
December 2020

Coordination Investigation of the Economic, Social and Environmental Benefits of Urban Public Transport Infrastructure in 13 Cities, Jiangsu Province, China.

Int J Environ Res Public Health 2020 09 18;17(18). Epub 2020 Sep 18.

School of Transportation and Civil Engineering, Nantong University, Nantong 226000, China.

This study proposed an investigation-based multiple-criteria coordinated model to evaluate the sustainable development of urban public transport (PT) infrastructure, based on economic, social and environmental data from 2009 to 2019. The main problem with the traditional approach for assessing urban PT development is that economic and social benefits are considered individually, but also attention to environmental factors and coordination among the three issues are nearly overlooked. This leads to the likelihood of inaccuracies in the handling/assessment of sustainable development or an imbalance among the attributes in different cities. An investigation-based coordinated model was introduced in which a survey of 35 sub-criteria was conducted to derive the criteria necessary for coupling/coordination. A case study involving 13 cities in Jiangsu Province, China, illustrated the problems in coordinating PT systems and verified the efficacy of the proposed approach. With employing the entropy method, this study validated coordination of the PT infrastructure development of various cities in a balanced manner and used panel regression formulas to analyse the theoretical gap and empirical bottlenecks existing among economic, social and environmental benefits. With the findings of the study, the data-based investigation from 13 cities enabled the city planners/managers (including ones from other cities with similar urban levels) to give the individual priority between the ternary benefits, advance technology, allow big data-based informatisation and implement near-future autonomous PT vehicles.
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http://dx.doi.org/10.3390/ijerph17186809DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7557986PMC
September 2020

Exosomes from oral tissue stem cells: biological effects and applications.

Cell Biosci 2020 14;10:108. Epub 2020 Sep 14.

Institute of Stomatology, First Medical Center, Chinese PLA General Hospital, Beijing, 100853 China.

As natural nanoparticles, exosomes are a type of extracellular vesicles that are enclosed by a lipid bilayer and contain various cargos, including miRNA, mRNA, DNA and proteins. Exosomes have rapidly gained attention as a highly promising cell-free therapy. Because the cargo of exosomes changes with the changes in parent cells and status, exosomes from different types of cells may exhibit different biological effects. Considering the particularity of oral tissue stem cells, their exosomes were isolated and used to examine their related biological functions and the possibility of replacing stem cells. A variety of exosomes of oral tissue stem cells were studied, and the results revealed many special biological characteristics of these exosomes and their parent cells, especially immunomodulation, osteogenesis, odontogenesis, neuroprotection, nerve regeneration, wound healing, skin regeneration and vascularization. The oral tissue stem cell exosomes may be loaded with drugs or genes and act as tools for tumor treatment. The relevant results showed that exosomes from oral tissue stem cells were potent therapeutic tools. The present review focuses on the biological function and application of oral tissue stem cell-derived exosomes.
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http://dx.doi.org/10.1186/s13578-020-00471-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7490964PMC
September 2020

Obesity treatment effect in Danish children and adolescents carrying Melanocortin-4 Receptor mutations.

Int J Obes (Lond) 2021 01 13;45(1):66-76. Epub 2020 Sep 13.

Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.

Objectives: To determine the prevalence of Melanocortin-4 Receptor (MC4R) mutations in a cohort of children and adolescents with overweight or obesity and to determine whether treatment responses differed between carriers and noncarriers.

Methods: Using target region capture sequencing, an MC4R mutation screen was performed in 1261 Danish children and adolescents enrolled at a tertiary multidisciplinary childhood obesity treatment center. Measurements of anthropometrics, blood pressure, fasting blood biochemistry including lipid and hormone levels, and dual-energy X-ray absorptiometry were performed at baseline and throughout treatment.

Results: Of 1209 children and adolescents that met all criteria to be included in the described analyses, 30 (2.5%) carried damaging or unresolved MC4R mutations. At baseline, mutation carriers exhibited higher concentrations of plasma thyroid-stimulating hormone (p = 0.003), and lower concentrations of plasma thyroxine (p = 0.010) compared to noncarriers. After a median of 1 year of treatment (range 0.5-4.0 years), body mass index (BMI) standard deviation score (SDS) was reduced in noncarriers but not in carriers, and this difference in treatment response was statistically significant (p = 0.005). Furthermore, HDL cholesterol was reduced in carriers, a response significantly different from that of noncarriers (p = 0.017).

Conclusion: Among Danish children and adolescents with overweight or obesity entering a tertiary lifestyle intervention, 2.5% carried damaging or unresolved MC4R mutations. In contrast to noncarriers, carriers of damaging or unresolved MC4R mutations failed to reduce their BMI SDS during obesity treatment, indicating a need for personalized treatment based on the MC4R genotype.
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http://dx.doi.org/10.1038/s41366-020-00673-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7752754PMC
January 2021

Molecular transformation of dissolved organic matter in refinery wastewater.

Water Sci Technol 2020 Jul;82(1):107-119

State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Beijing 102249, China E-mail:

Dissolved organic matter (DOM) has an important impact on the water treatment and reuse of petroleum refinery wastewater. In order to improve the treatment efficiency, it is necessary to understand the chemical composition of the DOM in the treatment processes. In this paper, the molecular composition of DOM in wastewater samples from a representative refinery were characterized. The transformation of various compounds along the wastewater treatment processes was investigated. A total of 61 heteroatomic class species were detected from the DOM extracts, in which CHO (molecules composed of carbon, hydrogen, and oxygen atoms) and CHOS (CHO molecules that also contained sulfur) class species were the most abundant and account for 78.43% in relative mass peak abundance. The solid phase extraction DOM from the dichloromethane unextractable fraction exhibited a more complex molecular composition and contained more oxygen atoms than in the dichloromethane extract. During wastewater treatment processes, the chemical oxygen demand (COD) and ammonia-nitrogen were reduced by more than 90%. Volatile organic compounds (VOCs) accounted for about 30% of the total COD, in which benzene and toluene were dominant. After biochemical treatment, the VOCs were effectively removed but the molecular diversity of the DOM was increased and new compounds were generated. Sulfur-containing class species were more recalcitrant to biodegradation, so the origin and transformation of these compounds should be the subject of further research.
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http://dx.doi.org/10.2166/wst.2020.334DOI Listing
July 2020