Publications by authors named "Lulu Ma"

77 Publications

Sulfur-Containing Compounds: Natural Potential Catalyst for the Isomerization of Phytofluene, Phytoene and Lycopene in Tomato Pulp.

Foods 2021 Jun 22;10(7). Epub 2021 Jun 22.

School of Food Science and Technology, Jiangnan University, Wuxi 214122, China.

The effects of some sulfur-containing compounds on the isomerization and degradation of lycopene, phytofluene, and phytoene under different thermal treatment conditions were studied in detail. Isothiocyanates such as allyl isothiocyanate (AITC) and polysulfides like dimethyl trisulfide (DMTS) had the effect on the configuration of PTF (phytofluene), PT (phytoene), and lycopene. The proportion of their naturally occurring -isomers (1,2-PTF and 15--PT) decreased and transformed into other isomers including all-trans configuration, while -lycopene increased significantly after thermal treatment, especially for 5--lycopene. The results showed that increase in heating temperature, time, and the concentration of DMTS and AITC could promote the isomerization reaction effectively to some extent. In addition, 15--PT and the newly formed 4-PTF were the predominant isomers in tomato at the equilibrium. Unlike the lycopene, which degraded significantly during heat treatment, the isomers of PTF and PT were stable enough to resist decomposition. Moreover, the isomerization of three carotenoids was enhanced, and the bioaccessibility of lycopene increased significantly with the addition of shii-take mushroom containing sulfur compounds, while there was no positive effect observed in that of PTF and PT.
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http://dx.doi.org/10.3390/foods10071444DOI Listing
June 2021

Lack of Spinal Neuropeptide Y Is Involved in Mechanical Itch in Aged Mice.

Front Aging Neurosci 2021 28;13:654761. Epub 2021 May 28.

Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China.

Neuropeptide Y (NPY) signaling plays an essential role in gating the pruritic afferent information in the spinal cord. Recent studies revealed that the aging process down-regulated the expression of NPY in the central nervous system. We propose that the lack of spinal NPY may be involved in certain types of pruritus in the elderly population. This study was designed to investigate the role of NPY in aging-induced itch using the senile mouse model. The expression of NPY in the spinal dorsal horn was compared between young (2 months old) and aged (24 months old) mice. Western blotting and immunohistochemistry showed that the expression of NPY was significantly reduced in the spinal dorsal horn in aged mice. In addition, a neuronal maker of apoptosis, TUNEL, was detected in the NPY positive neurons only in the aged spinal cord. Behavioral assay indicated that light mechanical stimulus evoked significantly more scratching in the aged than in the young mice, whereas chemical-evoked itch and pain-related behaviors were not altered. Intrathecal injection of either NPY or LP-NPY, a NPY receptor 1 (NPY1R) agonist, significantly alleviated the mechanically evoked itch in aged mice without altering the responses to chemical pruritogens. Our study suggested that downregulation of spinal NPY in the aged mice might play a role in the higher incidence of the mechanically evoked itch than that in the young mice. Therapies targeting the NPY system might serve as a potential strategy for alleviating the pruritic symptoms among the elderly population.
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http://dx.doi.org/10.3389/fnagi.2021.654761DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8192807PMC
May 2021

The Function of the PRRSV-Host Interactions and Their Effects on Viral Replication and Propagation in Antiviral Strategies.

Vaccines (Basel) 2021 Apr 9;9(4). Epub 2021 Apr 9.

State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, Beijing 100193, China.

Porcine reproductive and respiratory syndrome virus (PRRSV) affects the global swine industry and causes disastrous economic losses each year. The genome of PRRSV is an enveloped single-stranded positive-sense RNA of approximately 15 kb. The PRRSV replicates primarily in alveolar macrophages of pig lungs and lymphatic organs and causes reproductive problems in sows and respiratory symptoms in piglets. To date, studies on how PRRSV survives in the host, the host immune response against viral infections, and pathogenesis, have been reported. PRRSV vaccines have been developed, including inactive virus, modified live virus, attenuated live vaccine, DNA vaccine, and immune adjuvant vaccines. However, there are certain problems with the durability and effectiveness of the licensed vaccines. Moreover, the high variability and fast-evolving populations of this RNA virus challenge the design of PRRSV vaccines, and thus effective vaccines against PRRSV have not been developed successfully. As is well known, viruses interact with the host to escape the host's immune response and then replicate and propagate in the host, which is the key to virus survival. Here, we review the complex network and the mechanism of PRRSV-host interactions in the processes of virus infection. It is critical to develop novel antiviral strategies against PRRSV by studying these host-virus interactions and structures to better understand the molecular mechanisms of PRRSV immune escape.
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http://dx.doi.org/10.3390/vaccines9040364DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8070056PMC
April 2021

Carotenoid composition and antioxidant activities of Chinese orange-colored tomato cultivars and the effects of thermal processing on the bioactive components.

J Food Sci 2021 May 15;86(5):1751-1765. Epub 2021 Apr 15.

State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, Jiangsu, China.

To facilitate the production of tomato products with high bioactivity and improve the utilization of orange-colored tomatoes, the carotenoids of 11 tomato cultivars were analyzed using high-performance liquid chromatography with photodiode array detection. Moreover, antioxidant activities were evaluated by four chemical-based assays, and the influences of thermal treatment on the carotenoids in orange-colored tomatoes rich in tetra-cis (7Z, 9Z, 7'Z, and 9'Z)-lycopene, phytofluene, and phytoene were studied. The nine orange-colored tomatoes (OT) were divided into two categories: OT-B, containing five cultivars rich in β-carotene, and OT-L, containing the other four cultivars that were abundant in tetra-cis-lycopene, phytofluene, and phytoene. The antioxidant activities of OT-L were higher than those of OT-B and the SD-2 cultivar in OT-L showed similar antioxidant activity to the red tomatoes. During thermal processing, tetra-cis-lycopene in SD-2 decreased about 38% after being exposed to heat for 2 hr at 80 °C, while its content was still higher than other lycopene isomers. Other-Z-lycopenes and all-trans (E)-lycopene increased from 2.36 ± 0.19 to 14.73 ± 1.16 µg/g fresh weight (FW) and 0.75 ± 0.10 to 5.91 ± 1.02 µg/g FW, respectively. Thus, thermal treatments at lower temperature, such as cold break and pasteurization, were more suitable for processing OT-L. The results demonstrated that OT-L could be an excellent raw material to produce tomato products with high bioavailability and bioactivity. The results of this research could provide helpful information for the research and development of tomato products using orange tomatoes and benefit planters and consumers. PRACTICAL APPLICATION: Some orange tomato cultivars are promising raw materials for tomato products because of their high contents of bioactive tetra-cis-lycopene, phytofluene, and phytoene. This study demonstrated the carotenoid components and antioxidant activities of the widely planted orange-colored tomatoes in China. The obtained knowledge, including the thermal processing effects on the isomerization and degradation of carotenoids in the cultivars, will offer useful information to food processors and benefit the consumers.
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http://dx.doi.org/10.1111/1750-3841.15682DOI Listing
May 2021

Crystal structures of REF6 and its complex with DNA reveal diverse recognition mechanisms.

Cell Discov 2020 Mar 31;6(1):17. Epub 2020 Mar 31.

State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193, Beijing, China.

Relative of Early Flowing 6 (REF6) is a DNA-sequence-specific H3K27me3/2 demethylase that contains four zinc finger (ZnF) domains and targets several thousand genes in Arabidopsis thaliana. The ZnF domains are essential for binding target genes, but the structural basis remains unclear. Here, we determined crystal structures of the ZnF domains and REF6-DNA complex, revealing a unique REF6-family-specific half-cross-braced ZnF (RCZ) domain and two C2H2-type ZnFs. DNA-binding induces a profound conformational change in the hinge region of REF6. Each REF6 recognizes six bases and DNA methylation reduces the binding affinity. Both the acidic region and basic region are important for the self-association of REF6. The REF6 DNA-binding affinity is determined by the sequence-dependent conformations of DNA and also the cooperativity in different target motifs. The conformational plasticity enables REF6 to function as a global transcriptional regulator that directly binds to many diverse genes, revealing the structural basis for the epigenetic modification recognition.
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http://dx.doi.org/10.1038/s41421-020-0150-6DOI Listing
March 2020

Suppression of TLR4-MyD88 signaling pathway attenuated chronic mechanical pain in a rat model of endometriosis.

J Neuroinflammation 2021 Mar 5;18(1):65. Epub 2021 Mar 5.

Department of Human Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing, China.

Background: As a classic innate immunity pathway, Toll-like receptor 4 (TLR4) signaling has been intensively investigated for its function of pathogen recognition. The receptor is located not only on immune cells but also on sensory neurons and spinal glia. Recent studies revealed the involvement of neuronal TLR4 in different types of pain. However, the specific role of TLR4 signaling in the pain symptom of endometriosis (EM) remains obscure.

Methods: The rat endometriosis model was established by transplanting uterine horn tissue into gastrocnemius. Western blotting and/or immunofluorescent staining were applied to detect high mobility group box 1 (HMGB1), TLR4, myeloid differentiation factor-88 adaptor protein (MyD88), and nuclear factor kappa-B-p65 (NF-κB-p65) expression, as well as the activation of astrocyte and microglia. The antagonist of TLR4 (LPS-RS-Ultra, LRU) and MyD88 homodimerization inhibitory peptide (MIP) were intrathecally administrated to assess the behavioral effects of blocking TLR4 signaling on endometriosis-related pain.

Results: Mechanical hyperalgesia was observed at the graft site, while HMGB1 was upregulated in the implanted uterine tissue, dorsal root ganglion (DRG), and spinal dorsal horn (SDH). Compared with sham group, upregulated TLR4, MyD88, and phosphorylated NF-κB-p65 were detected in the DRG and SDH in EM rats. The activation of astrocytes and microglia in the SDH was also confirmed in EM rats. Intrathecal application of LRU and MIP alleviated mechanical pain on the graft site of EM rats, with decreased phosphorylation of NF-κB-p65 in the DRG and reduced activation of glia in the SDH.

Conclusions: HMGB1-TLR4-MyD88 signaling pathway in the DRG and SDH may involve in endometriosis-related hyperpathia. Blockade of TLR4 and MyD88 might serve as a potential treatment for pain in endometriosis.
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http://dx.doi.org/10.1186/s12974-020-02066-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7934423PMC
March 2021

Novel insights into the function of an N-terminal region of DENV2 NS4B for the optimal helicase activity of NS3.

Virus Res 2021 Apr 22;295:198318. Epub 2021 Jan 22.

State Key Laboratory of Agrobiotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China. Electronic address:

Dengue virus NS3 is a prototypical DEx(H/D) helicase that binds and hydrolyzes NTP to translocate along and unwind double-stranded nucleic acids. NS3 and NS4B are essential components of the flavivirus replication complex. Evidences showed that NS4B interacted with NS3 and modulated the helicase activity of NS3. Despite important insights into structural, mechanistic, and cellular aspects of the NS3 function, there is still a gap in understanding how it coordinates the helicase activities within the replicase complex for efficient replication. Here, using the DENV2 as a model, we redefined the critical region of NS4B required for NS3 function by pull-down and MST assays. The FRET-based unwinding assay showed that NS3 would accelerate unwinding duplex nucleic acids in the presence of NS4B (51-83). The simulated NS3-NS4B complex models based on the rigid-body docking delineated the potential interaction sites located in the conserved motif within the core domain of NS3. Mutations in motif I (I190A) and motif III (P319L) of NS3 interfered with the unwinding activity stimulated by NS4B. Upon binding to the NS3 helicase, NS4B assisted NS3 to dissociate from single-stranded nucleic acid and enabled NS3 helicase to keep high activity at high ATP concentrations. These results suggest that NS4B probably serves as an essential cofactor for NS3 to coordinate the ATP cycles and nucleic acid binding during viral genome replication.
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http://dx.doi.org/10.1016/j.virusres.2021.198318DOI Listing
April 2021

Ferulic acid protects cardiomyocytes from TNF-α/cycloheximide-induced apoptosis by regulating autophagy.

Arch Pharm Res 2020 Aug 27;43(8):863-874. Epub 2020 Jul 27.

Tianji State Key Laboratory of Modern Chinese Medicine, Tianjin, 301617, China.

Acute myocardial infarction (AMI) results in irreversible cardiac cell damage or death because of decreased blood flow to the heart. Apoptosis plays an important role in the process of tissue damage after myocardial infarction (MI), which has pathological and therapeutic implications. Ferulic acid (FA) is a phenolic acid endowed with strong antioxidative and cytoprotective activities. The present study aimed to investigate whether FA protects cardiomyocytes from apoptosis by regulating autophagy, which is a cellular self-digestion process, and one of the first lines of defense against oxidative stress. Apoptosis was induced by TNF-α (10 ng/mL) and cycloheximide (CHX, 5 μg/mL) in rat H9c2 cardiomyocytes. FA-inhibited TNF-α/CHX-induced apoptosis was determined by the quantification of TUNEL-positive cells, and the effect was associated with decreased ROS production and inhibited caspase3 activation. FA treatment enhanced autophagy and increased autophagy-associated protein expression, leading to an inhibition of mTOR signaling. When co-treated with 3-methyladenine (3-MA), an autophagy inhibitor, the anti-apoptotic effect of FA was attenuated. In an in vivo mouse MI model, FA treatment decreased the apoptotic cell number, reduced infarct size, and improved cardiac performance, as determined by histological and echocardiographic assessments. Taken collectively, these results suggest that FA could protect cardiomyocytes from apoptosis by enhancing autophagy.
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http://dx.doi.org/10.1007/s12272-020-01252-zDOI Listing
August 2020

The protective effects of different compatibility proportions of the couplet medicines for Astragali Radix and Radix on myocardial infarction injury.

Pharm Biol 2020 Dec;58(1):165-175

Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin, China.

Astragali Radix (AR) and Radix (ASR) combinations are used to treat cardiovascular disorders. This study investigates the protective effects of different compatibility proportions of AR and ASR on cardiac dysfunction in a C57BL/6 mouse model of myocardial infarction (MI). MI mice were induced by ligation of the left coronary artery and divided into six groups: sham, vehicle, 10 mg/kg/d simvastatin and combinations of AR and ASR at different ratios, including 1:1 (AR 2.5 g/kg + ASR 2.5 g/kg), 3:1 (AR 3.75 g/kg + ASR 1.25 g/kg) and 5:1 (AR 4.17 g/kg + ASR 0.83 g/kg). Both AR-ASR combinations and simvastatin were dissolved in saline solution and given daily by gavage. The left ventricle function, infarct size, heart tissue injury, apoptosis of cardiomyocytes, leukocyte infiltrates, capillary density and expression of cleaved caspase-3, cleaved caspase-9, Bcl-2, Bax, Bad, IL-1β, IL-6, VEGF, p-Akt and p-eNOS were analysed. Different combinations of AR and ASR improve cardiac function and reduce infarct size (61.15% vs. 39.3%, 42.65% and 45.5%) and tissue injury through different mechanisms. When AR was combined with ASR at ratio of 1:1, the inflammation and cardiomyocyte apoptosis were suppressed ( < 0.05,  < 0.01). The combination ratio of 3:1 exerted effect in promoting angiogensis ( < 0.05). In the combination of AR and ASR at 5:1 ratio, angiogenesis was significantly improved ( < 0.01) and the apoptosis was inhibited ( < 0.05). Our results reflect the regulation of multiple targets and links in herb pairs and provide an important basis for the use of AR and ASR combinations in the treatment of MI.
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http://dx.doi.org/10.1080/13880209.2020.1725581DOI Listing
December 2020

Enalapril overcomes chemoresistance and potentiates antitumor efficacy of 5-FU in colorectal cancer by suppressing proliferation, angiogenesis, and NF-κB/STAT3-regulated proteins.

Cell Death Dis 2020 06 24;11(6):477. Epub 2020 Jun 24.

Department of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, 361000, China.

5-Fluorouracil (5-FU) is one of the most effective drugs for the treatment of colorectal cancer (CRC). However, there is an urgent need in reducing its systemic side effects and chemoresistance to make 5-FU-based chemotherapy more effective and less toxic in the treatment of CRC. Here, enalapril, a clinically widely used antihypertensive and anti-heart failure drug, has been verified as a chemosensitizer that extremely improves the sensitivity of CRC cells to 5-FU. Enalapril greatly augmented the cytotoxicity of 5-FU on the cell growth in both established and primary CRC cells. The combination of enalapril and 5-FU synergistically suppressed the cell migration and invasion in both 5-FU-sensitive and -resistant CRC cells in vitro, and inhibited angiogenesis, tumor growth, and metastasis of 5-FU-resistant CRC cells in vivo without increased systemic toxicity at concentrations that were ineffective as individual agents. Furthermore, combined treatment cooperatively inhibited NF-κB/STAT3 signaling pathway and subsequently reduced the expression levels of NF-κB/STAT3-regulated proteins (c-Myc, Cyclin D1, MMP-9, MMP-2, VEGF, Bcl-2, and XIAP) in vitro and in vivo. This study provides the first evidence that enalapril greatly sensitized CRC cells to 5-FU at clinically achievable concentrations without additional toxicity and the synergistic effect may be mainly by cooperatively suppressing proliferation, angiogenesis, and NF-κB/STAT3-regulated proteins.
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http://dx.doi.org/10.1038/s41419-020-2675-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7314775PMC
June 2020

Predictors of hemodynamic instability in patients with pheochromocytoma and paraganglioma.

J Surg Oncol 2020 Jun 20. Epub 2020 Jun 20.

Department of Anesthesiology, Peking Union Medical College Hospital, Beijing, China.

Background And Objectives: Intraoperative hemodynamic instability is common in patients with pheochromocytoma and paraganglioma. The aim of this study was to identify the predictive risk factors of intraoperative hemodynamic instability.

Methods: A total of 428 patients having elective resection of pheochromocytoma and/or paraganglioma at Peking Union Medical College Hospital between January 2014 and July 2019 were included. The association between preoperative parameters and the incidence of intraoperative hemodynamic instability were evaluated. Binary logistic regression was used to assess the predictive risk factors of hemodynamic instability.

Results: Patients with intraoperative hemodynamic instability were more prone to have elevated levels of norepinephrine and epinephrine. Binary Logistic regression showed the risk factors of hemodynamic instability were tumor size >5.0 cm (odds ratio [OR], 1.889; 95% confidence interval [CI], 1.243-2.870; P = .003) and five-fold increases of urine epinephrine (OR, 2.195; 95% CI, 1.242-3.880; P = .007).

Conclusions: Intraoperative hemodynamic instability is common despite adequate preoperative medical treatment. Tumor size and high level of urinary epinephrine are tumor-related factors for intraoperative hemodynamic instability. Identifying these factors can help clinicians to manage patients more effectively and improve patients' outcomes.
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http://dx.doi.org/10.1002/jso.26079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7496938PMC
June 2020

Infective endocarditis at a tertiary-care hospital in China.

J Cardiothorac Surg 2020 Jun 10;15(1):135. Epub 2020 Jun 10.

Department of Cardiac Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100730, China.

Background: The aim of this study was to describe the clinical features and outcome of infective endocarditis at a general hospital in China and to identify the risk factors associated with in-hospital mortality.

Methods: A retrospective study was conducted and all patients diagnosed with definite or possible infective endocarditis between January 2013 and June 2018 according to the modified Duke criteria were included.

Results: A total of 381 patients were included. The mean age was 46 years old and 66.9% patients were male patients. Community acquired IE was the most common type of infective endocarditis and Viridans Group Streptococci (37.5%) was still the most common causative pathogen. The microbial etiology of infective endocarditis varied with location of acquisition. 97 (25.5%) patients had culture-negative infective endocarditis. Vegetations were detected in 85% patients and mitral valve was the most common involved valve. Operations were performed in 72.7% patients and in-hospital mortality rate was 8.4%. The risk factors of in-hospital mortality were age old than 70 years old, heart failure, stroke and medical therapy.

Conclusions: Older age, heart failure, stroke and medical therapy were risk factors of in-hospital mortality. Infective endocarditis, were mainly caused by Viridans Group Streptococci, characterized by younger patients and lower mortality rate in China.
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http://dx.doi.org/10.1186/s13019-020-01183-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7285574PMC
June 2020

Coronavirus Disease-2019 (COVID-19) and Cardiovascular Complications.

J Cardiothorac Vasc Anesth 2021 06 30;35(6):1860-1865. Epub 2020 Apr 30.

Department of Anesthesiology, Peking Union Medical College Hospital, Beijing, China. Electronic address:

The coronavirus disease-2019 (COVID-19) has become a global pandemic. It has spread to more than 100 countries, and more than 1 million cases have been confirmed. Although coronavirus causes severe respiratory infections in humans, accumulating data have demonstrated cardiac complications and poor outcome in patients with COVID-19. A large percent of patients have underlying cardiovascular disease, and they are at a high risk of developing cardiac complications. The basics of the virus, the clinical manifestations, and the possible mechanisms of cardiac complications in patients with COVID-19 are reviewed. Before an effective vaccine or medicine is available, supportive therapy and identifying patients who are at high risk of cardiac complications are important.
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http://dx.doi.org/10.1053/j.jvca.2020.04.041DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7192093PMC
June 2021

CXCL12/CXCR4 signaling induced itch and pain sensation in a murine model of allergic contact dermatitis.

Mol Pain 2020 Jan-Dec;16:1744806920926426

Department of Anesthesiology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.

Allergic contact dermatitis is a skin inflammatory disease manifested with itch and pain symptom around the inflamed area. Chemokines such as CXCL12 are involved in the pathophysiology of allergic contact dermatitis, but little has been known about the effect of CXCL12/CXCR4 signaling for nociceptive sensation accompanying allergic contact dermatitis. Our study showed that CXCL12 and CXCR4 were upregulated in trigeminal ganglion with the progression of allergic contact dermatitis through western blotting and immunofluorescence. CXCL12 and CXCR4 were mainly upregulated in small-diameter neurons, which were co-localized with nociceptive markers in trigeminal ganglion. CXCR4 and CXCL12 were also expressed in trigeminal ganglion neurons retrograded from the skin lesion. Intradermal injection of CXCL12 enhanced the itch- and pain-like behavior which could be relieved by AMD3100, a CXCR4 antagonist, without changes of mast cells. Our findings suggested that blockade of CXCL12/CXCR4 signaling pathway might be beneficial to relieve itch and pain sensation accompanying allergic contact dermatitis.
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http://dx.doi.org/10.1177/1744806920926426DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7543150PMC
June 2021

Nitrogen and sulfur codoped micro-mesoporous carbon sheets derived from natural biomass for synergistic removal of chromium(VI): adsorption behavior and computing mechanism.

Sci Total Environ 2020 Aug 30;730:138930. Epub 2020 Apr 30.

School of Metallurgy and Environment, Central South University, Lushan South Street 932, Yuelu District, Changsha 410083, China; Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon 999077, Hong Kong, China. Electronic address:

We reported the effective removal of chromium(VI) (Cr(VI)) from wastewater with nitrogen and sulfur codoped micro-mesoporous carbon sheets (N,S-MMCSs), which were fabricated by pyrolysis of natural biomass (luffa sponge) followed by chemical activation and hydrothermal treatment. N,S-MMCSs possessed a hierarchical micro-mesoporous sheet-like framework, large specific surface area (1525.45 m g), high pore volume (1.21 cm g), and appropriate N (1.81 wt%) and S (1.01 wt%) co-doping. Batch adsorption experiments suggested that Cr(VI) adsorption by the N,S-MMCSs increased with increase the solution acidity, adsorbent dosage, Cr(VI) concentration, temperature, and time. The Cr(VI) adsorption was mainly controlled by the chemisorptions and could be well interpreted by the Langmuir isotherm and pseudo-second-order kinetic models. The maximum adsorption capacities of Cr(VI) were 217.39, 277.78, and 312.50 mg g at 298, 308, and 318 K, respectively. The Cr(VI) adsorption procedure was spontaneous, endothermic, and randomness. The Cr(VI) adsorption mechanism followed the physical adsorption, electrostatic attraction, in situ reduction, and surface chelation. Besides, the density functional theory (DFT) calculation demonstrated that the N and S co-doping could decrease the adsorption energy and enhance the attractive interaction between N,S-MMCSs and Cr(VI) through the synergistic effect, and thus significantly improve the Cr(VI) adsorption property.
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http://dx.doi.org/10.1016/j.scitotenv.2020.138930DOI Listing
August 2020

Crystal structures of REF6 and its complex with DNA reveal diverse recognition mechanisms.

Cell Discov 2020 31;6:17. Epub 2020 Mar 31.

1State Key Laboratory of Agrobiotechnology and Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Biological Sciences, China Agricultural University, 100193 Beijing, China.

Relative of Early Flowing 6 (REF6) is a DNA-sequence-specific H3K27me3/2 demethylase that contains four zinc finger (ZnF) domains and targets several thousand genes in . The ZnF domains are essential for binding target genes, but the structural basis remains unclear. Here, we determined crystal structures of the ZnF domains and REF6-DNA complex, revealing a unique REF6-family-specific half-cross-braced ZnF (RCZ) domain and two C2H2-type ZnFs. DNA-binding induces a profound conformational change in the hinge region of REF6. Each REF6 recognizes six bases and DNA methylation reduces the binding affinity. Both the acidic region and basic region are important for the self-association of REF6. The REF6 DNA-binding affinity is determined by the sequence-dependent conformations of DNA and also the cooperativity in different target motifs. The conformational plasticity enables REF6 to function as a global transcriptional regulator that directly binds to many diverse genes, revealing the structural basis for the epigenetic modification recognition.
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http://dx.doi.org/10.1038/s41421-020-0150-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7105484PMC
March 2020

3D Hydrogen Titanate Nanotubes on Ti Foil: A Carrier for Enzymatic Glucose Biosensor.

Sensors (Basel) 2020 Feb 14;20(4). Epub 2020 Feb 14.

The Key Laboratory of Advanced Energy Materials Chemistry (MOE), and TKL of Metal and Molecule-based Material Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China.

Glucose oxidase (GOx) based biosensors are commercialized and marketed for the high selectivity of GOx. Incorporation nanomaterials with GOx can increase the sensitivity performance. In this work, an enzyme glucose biosensor based on nanotubes was fabricated. By using Ti foil as a carrier, hydrogen titanate nanotubes (HTNTs), which present fine 3D structure with vast pores, were fabricated in-situ by the hydrothermal treatment. The multilayer nanotubes are open-ended with a diameter of 10 nm. Then glucose oxidase (GOx) was loaded on the nanotubes by cross-linking to form an electrode of the amperometric glucose biosensor (GOx/HTNTs/Ti electrode). The fabricated GOx/HTNTs/Ti electrode had a linear response to 1-10 mM glucose, and the response time was 1.5 s. The sensitivity of the biosensor was 1.541 A·mM·cm, and the detection limit (S/N = 3) was 59 M. Obtained results indicate that the in-situ fabrication and unique 3D structure of GOx/HTNTs/Ti electrode are beneficial for its sensitivity.
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http://dx.doi.org/10.3390/s20041024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7070752PMC
February 2020

Pt-Substituted polyoxometalate modification on the surface of low-cost TiO with highly efficient H evolution performance.

Dalton Trans 2020 Feb 30;49(7):2176-2183. Epub 2020 Jan 30.

School of Materials Science and Engineering, University of Jinan, 250022, Jinan, China.

In this study, Pt-substituted polyoxometalate was first modified on the surface of commercially available TiO, forming an efficient photocatalyst with high reactivity for hydrogen evolution. During the photocatalytic process, Pt-polyoxometalates not only increase the mobility rate of electrons but also improve the separation efficiency of photoinduced electrons and holes. After photoreduction, the in situ generated Pt species are anchored on the surface of polyoxometalate anion, which prevents further agglomeration. Then, the in situ formed Pt species and polyoxometalates synergistically promote the efficiency of photoinduced electron transfer from TiO to the protons adsorbed on the Pt surface. Although the content of Pt in the nanocomposite is only 0.6%, the photocatalytic hydrogen production rate reaches 5.6 mmol g h and remains stable at 4.5 mmol g h after the continuous catalytic process. Due to the modification of TiO by Pt-substituted polyoxometalate, this nanocomposite represents a practical model that possesses highly efficient photoelectric conversion performance. The presented work not only extends the family of new TiO-polyoxometalate-based materials but also takes a further step toward the practical application of commercial TiO in photocatalytic hydrogen production.
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http://dx.doi.org/10.1039/c9dt04446aDOI Listing
February 2020

Aspirin suppresses chemoresistance and enhances antitumor activity of 5-Fu in 5-Fu-resistant colorectal cancer by abolishing 5-Fu-induced NF-κB activation.

Sci Rep 2019 11 15;9(1):16937. Epub 2019 Nov 15.

Departments of Gastrointestinal Surgery, Zhongshan Hospital of Xiamen University, Xiamen, 361000, China.

Chemoresistance to 5-fluorouracil (5-Fu)-based chemotherapy is a leading obstacle in achieving effective treatment for colorectal cancer (CRC). Typically, NF-κB activation induced by the chemotherapeutics themselves is an important cause resulting in chemoresistance. Specifically, NF-κB activation can inhibit tumor cell apoptosis and induce chemoresistance. Drugs that can prevent NF-κB activation induced by chemotherapeutics are urgently needed to overcome chemoresistance. Obviously, aspirin is one of these agents, which has been demonstrated to possess antitumor activities and as an inhibitor of NF-κB. The current study aimed to investigate whether aspirin was able to overcome the chemoresistance to 5-Fu in CRC, together with the potential synergistic mechanisms. Our results suggested that aspirin remarkably potentiated the inhibitory effect of 5-Fu on the growth and invasion of resistant cells in vitro. In vivo, aspirin markedly enhanced the antitumor activity of 5-Fu in suppressing tumor growth and metastasis, and down-regulating the expression of NF-κB-regulated genes in the 5-Fu-resistant cells. Obviously, aspirin completely eradicated the 5-Fu-induced NF-κB activation, without inducing pronounced adverse effects. Taken together, findings in this study suggest that aspirin can reverse chemoresistance and potentiate the antitumor effect of 5-Fu, which is achieved through abolishing the 5-Fu-induced NF-κB activation, suggesting that aspirin may be a promising adjuvant therapeutic agent for CRC.
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http://dx.doi.org/10.1038/s41598-019-53276-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6858464PMC
November 2019

Structural determination of Enzyme-Graphene Nanocomposite Sensor Material.

Sci Rep 2019 10 29;9(1):15519. Epub 2019 Oct 29.

Center for Life Sciences, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, 02115, USA.

State-of-the-art ultra-sensitive blood glucose-monitoring biosensors, based on glucose oxidase (GOx) covalently linked to a single layer graphene (SLG), will be a valuable next generation diagnostic tool for personal glycemic level management. We report here our observations of sensor matrix structure obtained using a multi-physics approach towards analysis of small-angle neutron scattering (SANS) on graphene-based biosensor functionalized with GOx under different pH conditions for various hierarchical GOx assemblies within SLG. We developed a methodology to separately extract the average shape of GOx molecules within the hierarchical assemblies. The modeling is able to resolve differences in the average GOx dimer structure and shows that treatment under different pH conditions lead to differences within the GOx at the dimer contact region with SLG. The coupling of different analysis methods and modeling approaches we developed in this study provides a universal approach to obtain detailed structural quantifications, for establishing robust structure-property relationships. This is an essential step to obtain an insight into the structure and function of the GOx-SLG interface for optimizing sensor performance.
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http://dx.doi.org/10.1038/s41598-019-51882-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6820869PMC
October 2019

Polarized Raman spectroscopy-stress relationship considering shear stress effect.

Opt Lett 2019 Oct;44(19):4682-4685

This Letter uses polarized Raman spectroscopy as a "strain rosette" to quantitatively determine all the in-plane components of the stress tensor for (110) silicon. Through polarized Raman spectroscopy, Raman wavenumber shifts can be obtained at the same point with different polarization directions of the incident and/or scattered light. With at least three measured Raman shifts in different polarized directions, the three stress components of a surface that contains two non-equal normal stresses and one shear stress can be calculated accordingly. We develop an analytical and linear Raman wavenumber shift-stress relationship when shear stress is considered. The experimental results verify the theoretical predictions. It shows that the simple stress condition assumption may lead to erroneous results.
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http://dx.doi.org/10.1364/OL.44.004682DOI Listing
October 2019

A disulfur ligand stabilization approach to construct a silver(i)-cluster-based porous framework as a sensitive SERS substrate.

Nanoscale 2019 Sep 29;11(35):16293-16298. Epub 2019 Aug 29.

School of Materials Science and Engineering, University of Jinan, Jinan, 250022, China. and College of Pharmacy, Jiamusi University, Jiamusi 154007, China.

An atomically-precise silver(i)-cluster-based three-dimensional (3D) framework (UJN-1) stabilized by a ditiocarb (diethyldithiocarbamate) ligand has been unveiled for the first time by self-assembly. UJN-1 is composed of both Ag clusters and Ag subunits, of which the Ag clusters are bonded with Ag subunits by sharing the ditiocarb ligand to form a microporous 3,4-connected topological framework. The chemically reduced nano-sized derivative of UJN-1 exhibits highly sensitive surface enhanced Raman scattering (SERS) towards 4-mercaptobenzoic acid (4-MBA) signal molecules, which is ascribed to the porosity as well as the distribution of abundant crystalline Ag active sites. This work sheds light on a new bottom-up approach to construct SERS-active silver(i)-cluster-based 3D materials by disulfur ligand stabilization.
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http://dx.doi.org/10.1039/c9nr05301hDOI Listing
September 2019

Predictors for blood loss in pediatric patients younger than 10 years old undergoing primary posterior hemivertebra resection: a retrospective study.

BMC Musculoskelet Disord 2019 Jun 22;20(1):297. Epub 2019 Jun 22.

Department of Anesthesiology, Peking Union Medical College Hospital, Beijing, 100730, China.

Background: Blood loss during hemivertebra resection may be substantial. Few studies have examined the risk factors of blood loss undergoing hemivertebra resection, especially those in patients under 10 years old.

Methods: Patients under 10 years old diagnosed with congenital scoliosis and hemivertebra were retrospectively included from January 2014 to October 2017. They all had primary posterior hemivertebra resection at Peking Union Medical College Hospital. Perioperative information was collected and multivariable linear logistic regression was performed to determine the independent risk factors of blood loss.

Results: One hundred three patients were included. The mean total blood loss was 346 + 178 ml. The percentage of total blood loss to the EBV was 27.0 + 13.3%. Multivariable linear logistic regression indicated that preoperative total Cobb angle (P = 0.046) and the number of fused levels (P < 0.001) were independent risk factors of total blood loss. Preoperative platelet count and preoperative coagulation function were not associated with blood loss in patients undergoing hemivertebra resection.

Conclusions: Preoperative total Cobb angle and the number of fused levels determined the blood loss for patients undergoing hemivertebra resection.
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http://dx.doi.org/10.1186/s12891-019-2675-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6589173PMC
June 2019

Synergistic antibacterial mechanism of BiTe nanoparticles combined with the ineffective β-lactam antibiotic cefotaxime against methicillin-resistant Staphylococcus aureus.

J Inorg Biochem 2019 07 12;196:110687. Epub 2019 Apr 12.

Research Center for Environmental Ecology and Engineering, School of Environmental Ecology and Biological Engineering, Wuhan Institute of Technology, No. 206, Guanggu First Road, Wuhan 430073, PR China. Electronic address:

Methicillin-resistant Staphylococcus aureus (MRSA) infections have become a serious threat to public health because traditional antibiotics are less efficient. Here, we developed a simple and efficient combination of BiTe nanoparticles (NPs) with β-lactam antibiotics cefotaxime (CTX), which presented significant synergistic antibacterial activity against MRSA. The minimal inhibitory concentration of CTX decreased from 256 to 32 μg/mL in the presence of 8 μg/mL BiTe NPs. The results of cell membrane potential and cellular K content measurements demonstrated that the destruction of membrane functions is a factor in the synergistic mechanism. Furthermore, the induction of cellular reactive oxygen species generation, inhibition of β-lactamases induced by CTX and direct damage to the cell structure constituted other factors of the synergistic mechanism. These observations suggest that reviving the efficacy of ineffective β-lactam antibiotic CTX by BiTe NPs may be a potentially effective therapeutic strategy to overcome refractory MRSA infections.
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http://dx.doi.org/10.1016/j.jinorgbio.2019.04.001DOI Listing
July 2019

Low-temperature plasma treatment-assisted layer-by-layer self-assembly for the modification of nanofibrous mats.

J Colloid Interface Sci 2019 Mar 16;540:535-543. Epub 2019 Jan 16.

Hubei International Scientific and Technological Cooperation Base of Sustainable Resource and Energy, Hubei Key Laboratory of Biomass Resource Chemistry and Environmental Biotechnology, School of Resource and Environmental Science, Wuhan University, Wuhan 430079, China. Electronic address:

To expand the template options of immersive electrostatic layer-by-layer self-assembly (LBL), which requires hydrophilic and protonation substrates, an environmentally friendly and simple plasma pretreatment that enhances the surface charge and wettability of superhydrophobic mats is employed to effectively assist LBL. With positively and negatively charged layers, chitosan (CS) and bovine serum albumin (BSA) were alternately deposited on the surface of polystyrene (PS) mats and oxygen (O) plasma-treated mats via electrostatic LBL. After the exposure of plasma gas at different time intervals, the ζ-potential values of the mats were distinct, and the value of the mats was -30.1 mV after treatment via O plasma for 70 s, which was approximately 5 times higher than that of the pristine PS mats. In addition, the average surface roughness (Ra) of the O plasma treated mats was 116.1 ± 12.6 nm, which was higher than that of the PS mats (87.6 ± 14.3 nm), due to the plasma etching. The water contact angle of the PS mats was 144.5 ± 1.4°, which decreased to 0° within 0.33 s after O plasma treatment, proving that the modified PS mats were superhydrophilic. Compared with the mats without plasma treatment, the uniform deposition of CS and BSA on O plasma-treated mats was confirmed by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. Moreover, the mats with an enhanced surface charge and wettability after plasma treatment and LBL processing also exhibited low cell cytotoxicity and facilitated cell growth well.
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http://dx.doi.org/10.1016/j.jcis.2019.01.054DOI Listing
March 2019

Wheat Straw-Derived N-, O-, and S-Tri-doped Porous Carbon with Ultrahigh Specific Surface Area for Lithium-Sulfur Batteries.

Materials (Basel) 2018 Jun 11;11(6). Epub 2018 Jun 11.

School of Metallurgy and Environment, Central South University, Lushan South Street 932, Yuelu District, Changsha 410083, China.

Recently, lithium-sulfur (Li-S) batteries have been greeted by a huge ovation owing to their very high theoretical specific capacity (1675 mAh·g) and theoretical energy density (2600 Wh·kg). However, the full commercialization of Li-S batteries is still hindered by dramatic capacity fading resulting from the notorious “shuttle effect” of polysulfides. Herein, we first describe the development of a facile, inexpensive, and high-producing strategy for the fabrication of N-, O-, and S-tri-doped porous carbon (NOSPC) via pyrolysis of natural wheat straw, followed by KOH activation. The as-obtained NOSPC shows characteristic features of a highly porous carbon frame, ultrahigh specific surface area (3101.8 m²·g), large pore volume (1.92 cm³·g), good electrical conductivity, and in situ nitrogen (1.36 at %), oxygen (7.43 at %), and sulfur (0.7 at %) tri-doping. The NOSPC is afterwards selected to fabricate the NOSPC-sulfur (NOSPC/S) composite for the Li-S batteries cathode material. The as-prepared NOSPC/S cathode delivers a large initial discharge capacity (1049.2 mAh·g at 0.2 C), good cycling stability (retains a reversible capacity of 454.7 mAh·g over 500 cycles at 1 C with a low capacity decay of 0.088% per cycle), and superior rate performance (619.2 mAh·g at 2 C). The excellent electrochemical performance is mainly attributed to the synergistic effects of structural restriction and multidimensional chemical adsorptions for cooperatively repressing the polysulfides shuttle.
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http://dx.doi.org/10.3390/ma11060989DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6025088PMC
June 2018

The suppressive effect of soluble Klotho on fibroblastic growth factor 23 synthesis in UMR-106 osteoblast-like cells.

Cell Biol Int 2018 Sep 15;42(9):1270-1274. Epub 2018 Jun 15.

Department of Nephrology, Jiangsu Province Hospital, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China.

Fibroblastic growth factor 23 (FGF23) is a hormone secreted primarily by bone. FGF23 is elevated in the serum of chronic kidney disease (CKD) patients, but the exact mechanism is not well known. Klotho is identified as an aging suppressor, which is mainly expressed in the kidney, and the level of soluble Klotho is negatively associated with FGF23 in CKD. The aim of this study was to investigate the effect and possible mechanism of Klotho on FGF23 synthesis in osteoblast-like UMR-106 cells. UMR-106 cells were divided into five groups: (i) control group; (ii) β-glycerophosphate (β-GP) group; (iii) β-GP + Klotho group; (iv) β-GP+ lithium chloride (LiCl, a Wnt/β-catenin pathway agonist) group; and (v) β-GP + Klotho + LiCl group. Subsequently, UMR-106 cells were cultured for 72 h, and the expression of FGF23, P-glycogen synthase kinase-3β (P-GSK-3β), and glycogen synthase kinase-3β(GSK-3β) were measured with Western blot analysis. The mRNA levels of FGF23 and the Wnt/β-catenin pathway target gene c-myc were determined with RT-qPCR. The results showed that β-GP induced increased expression of FGF23 mRNA and protein. Compared with the β-GP group, expression of FGF23 mRNA and protein expression were downregulated in the β-GP + Klotho group. In addition, β-GP induced increased expression of P-GSK-3β/GSK-3β and c-myc, which were all downregulated in the β-GP + Klotho group. Moreover, the expression of FGF23, P-GSK-3β/GSK-3β, and c-myc mRNA were upregulated when treated with LiCl. These results demonstrate that soluble Klotho suppresses FGF23 synthesis in osteoblast-like UMR-106 cells. The mechanism of this suppression may be partially through the inhibition of the Wnt/β-catenin pathway.
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http://dx.doi.org/10.1002/cbin.10997DOI Listing
September 2018

Sandwich-Type Nitrogen and Sulfur Codoped Graphene-Backboned Porous Carbon Coated Separator for High Performance Lithium-Sulfur Batteries.

Nanomaterials (Basel) 2018 Mar 26;8(4). Epub 2018 Mar 26.

School of Metallurgy and Environment, Central South University, Lushan South Street 932, Yuelu District, Changsha 410083, China.

Lithium-sulfur (Li-S) batteries have been identified as the greatest potential next- generation energy-storage systems because of the large theoretical energy density of 2600 Wh kg. However, its practical application on a massive scale is impeded by severe capacity loss resulted from the notorious polysulfides shuttle. Here, we first present a novel technique to synthesize sandwich-type nitrogen and sulfur codoped graphene-backboned porous carbon (NSGPC) to modify the commercial polypropylene separator in Li-S batteries. The as-synthesized NSGPC exhibits a unique micro/mesoporous carbon framework, large specific surface area (2439.0 m² g), high pore volume (1.78 cm³ g), good conductivity, and in situ nitrogen (1.86 at %) and sulfur (5.26 at %) co-doping. Benefiting from the particular physical properties and chemical components of NSGPC, the resultant NSGPC-coated separator not only can facilitate rapid Li⁺ ions and electrons transfer, but also can restrict the dissolution of polysulfides to alleviate the shuttle effect by combining the physical absorption and strong chemical adsorption. As a result, Li-S batteries with NSGPC-coated separator exhibit high initial reversible capacity (1208.6 mAh g at 0.2 C), excellent rate capability (596.6 mAh g at 5 C), and superior cycling stability (over 500 cycles at 2 C with 0.074% capacity decay each cycle). Propelling our easy-designed pure sulfur cathode to a extremely increased mass loading of 3.4 mg cm (70 wt. % sulfur), the Li-S batteries with this functional composite separator exhibit a superior high initial capacity of 1171.7 mAh g, which is quite beneficial to commercialized applications.
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http://dx.doi.org/10.3390/nano8040191DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5923521PMC
March 2018

Long-Lived and Thermoresponsive Emulsion Foams Stabilized by Self-Assembled Saponin Nanofibrils and Fibrillar Network.

Langmuir 2018 04 23;34(13):3971-3980. Epub 2018 Mar 23.

Nanofibrils from the self-assembly of the naturally occurring saponin glycyrrhizic acid (GA) can be used to produce an oil-in-water emulsion foam with a long-term stability. Through homogenization and aeration followed by rapid cooling, stable emulsion foams can be produced from the mixtures of sunflower oil and saponin nanofibrils. At high temperatures, the GA fibrils form a multilayer assembly at the interface, creating an interfacial fibrillar network to stabilize the oil droplets and air bubbles generated during homogenization. A subsequent rapid cooling can trigger the self-assembly of free GA fibrils in the continuous phase, forming a fibrillar hydrogel and thus trapping the oil droplets and air bubbles. The viscoelastic bulk hydrogel showed a high yield stress and storage modulus, which lead to a complete arrest of the liquid drainage and a strong slowdown of the bubble coarsening in emulsion foams. The jamming of the emulsion droplets in the liquid channels as well as around the bubbles was also found to be able to enhance the foam stability. We show that such stable foam systems can be destroyed rapidly and on demand by heating because of the melting of the bulk hydrogel. The reversible gel-sol phase transition of the GA hydrogel leads to thermoresponsive emulsion foams, for which the foam stability can be switched from stable to unstable states by simply raising the temperature. The emulsion foams can be further developed to be photoresponsive by incorporating internal heat sources such as carbon black particles, which can absorb UV irradiation and convert the absorbed light energy into heat. This new class of smart responsive emulsion foams stabilized by the natural, sustainable saponin nanofibrils has potential applications in the food, pharmaceutical, and personal care industries.
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http://dx.doi.org/10.1021/acs.langmuir.8b00128DOI Listing
April 2018

Reversible regulating of crystal structures based on isomerization of phenylhydrazones.

Chem Commun (Camb) 2017 Nov;53(94):12630-12633

School of Material Science and Engineering, University of Jinan, No. 336, West Road of Nan Xinzhuang, Jinan, Shandong 250022, P. R. China.

Reversible crystal transformation for phenylhydrazones 1 between the orthorhombic microporous 1-E crystal and monoclinic herringbone 1-Z crystal induced by light and heating has been demonstrated. Other than the inherent single-molecular photoreactivity, the weak intermolecular interactions and loose stacking of porous 1-E crystal favor the efficient solid-state photoisomerization.
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http://dx.doi.org/10.1039/c7cc06374aDOI Listing
November 2017