Publications by authors named "Tianhua Ren"

13 Publications

  • Page 1 of 1

Strong Purcell effect in deep subwavelength coaxial cavity with GeSn active medium.

Opt Lett 2021 Aug;46(16):3889-3892

We propose a deep subwavelength plasmonic cavity based on a metal-coated coaxial structure with as the active medium. A fundamental surface plasmon polariton mode is strongly confined on the sidewall of the metal core, with the quality factor up to 5×10 at 10 K. By reducing the cavity dimension to a few nanometers, this cavity mode shows a strong plasmon binding with the mode volume down to 8×10 (/), and significant size-dependent damping caused by the non-local optical response. The Purcell factor is achieved as high as 2×10 at 10 K and 7×10 at 300 K. This cavity design provides a systematic guideline of scaling down the cavity size and enhancing the Purcell factor. Our theoretical demonstration and understanding of the subwavelength plasmonic cavity represent a significant step toward the large-scale integration of on-chip lasers with a low threshold.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1364/OL.432164DOI Listing
August 2021

Artificial Intelligence Can Effectively Predict Early Hematoma Expansion of Intracerebral Hemorrhage Analyzing Noncontrast Computed Tomography Image.

Front Aging Neurosci 2021 26;13:632138. Epub 2021 May 26.

Department of International Medical, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.

This study aims to develop and validate an artificial intelligence model based on deep learning to predict early hematoma enlargement (HE) in patients with intracerebral hemorrhage. A total of 1,899 noncontrast computed tomography (NCCT) images of cerebral hemorrhage patients were retrospectively analyzed to establish a predicting model and 1,117 to validate the model. And a total of 118 patients with intracerebral hemorrhage were selected based on inclusion and exclusion criteria so as to validate the value of the model for clinical prediction. The baseline noncontrast computed tomography images within 6 h of intracerebral hemorrhage onset and the second noncontrast computed tomography performed at 24 ± 3 h from the onset were used to evaluate the prediction of intracerebral hemorrhage growth. In validation dataset 1, the AUC was 0.778 (95% CI, 0.768-0.786), the sensitivity was 0.818 (95% CI, 0.790-0.843), and the specificity was 0.601 (95% CI, 0.565-0.632). In validation dataset 2, the AUC was 0.780 (95% CI, 0.761-0.798), the sensitivity was 0.732 (95% CI, 0.682-0.788), and the specificity was 0.709 (95% CI, 0.658-0.759). The sensitivity of intracerebral hemorrhage hematoma expansion as predicted by an artificial intelligence imaging system was 89.3%, with a specificity of 77.8%, a positive predictive value of 55.6%, a negative predictive value of 95.9%, and a Yoden index of 0.671, which were much higher than those based on the manually labeled noncontrast computed tomography signs. Compared with the existing prediction methods through computed tomographic angiography (CTA) image features and noncontrast computed tomography image features analysis, the artificial intelligence model has higher specificity and sensitivity in the prediction of early hematoma enlargement in patients with intracerebral hemorrhage.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fnagi.2021.632138DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8188896PMC
May 2021

Expert Consensus for Treating Cancer Patients During the Pandemic of SARS-CoV-2.

Front Oncol 2020 18;10:1555. Epub 2020 Aug 18.

Department of Medical Oncology, Hubei Cancer Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

The sudden pandemic of SARS-Cov-2 (also known as novel coronavirus disease 2019, COVID-19) poses a severe threat to hundreds of millions of lives in the world. The complete cure of the virus largely relies on the immune system, which becomes particularly a challenge for the cancer subjects, whose immunity is generally compromised. However, in a constant evolving situation, the clinical data on the prevalence of SARS-Cov-2 for cancer patients is still limited. On top of a wide range of medical references and interim guidelines including CDC, NCI, ASCO, ESMO, NCCN, AACR, ESMO, and the National Health Commission of China, etc., we formed into a guideline based on our experience in our specialized cancer hospital in Wuhan, the originally endemic center of the virus. Furthermore, we formulated an expert consensus which was developed by all contributors from different disciplines after fully discussion based on our understanding and analysis of limited information of COVID-19. The consensus highlighted a multidisciplinary team diagnostic model with assessment of the balance between risks and benefits prior to treatment, individualizing satisfaction of patients' medical needs, and acceptability in ethics and patients' socio-economic conditions.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fonc.2020.01555DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7462010PMC
August 2020

Sustainable Aromatic Aliphatic Polyesters and Polyurethanes Prepared from Vanillin-Derived Diols via Green Catalysis.

Polymers (Basel) 2020 Mar 5;12(3). Epub 2020 Mar 5.

Department of Polymer Materials &Engineering, College of Materials & Metallurgy, Guizhou University, West Campus, Huaxi District, Guiyang 550025, China.

The design and preparation of polymers by using biobased chemicals is regarded as an important strategy towards a sustainable polymer chemistry. Herein, two aromatic diols, 4-(hydroxymethyl)-2-methoxyphenol and 2-(4-(hydroxymethyl)-2-methoxyphenoxy)ethanol, have been prepared in good yields through the direct reduction of vanillin and hydroxyethylated vanillin (4-(2-hydroxyethoxy)-3-methoxybenzaldehyde) using NaBH, respectively. The diols were submitted to traditional polycondensation and polyaddition with acyl chlorides and diisocyanatos, and serials of new polyesters and polyurethanes were prepared in high yields with moderate molecular weight ranging from 17,000 to 40,000 g mol. Their structures were characterized by H NMR, C NMR and FTIR, and their thermal properties were studied by TGA and differential scanning calorimetry (DSC), indicating that the as-prepared polyesters and polyurethanes have T in the range of 16.2 to 81.2 °C and 11.6 to 80.4 °C, respectively.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/polym12030586DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7182816PMC
March 2020

Molecular Beam Epitaxy of Highly Crystalline Monolayer Molybdenum Disulfide on Hexagonal Boron Nitride.

J Am Chem Soc 2017 07 3;139(27):9392-9400. Epub 2017 Jul 3.

SinBeRISE CREATE, National Research Foundation , CREATE Tower, 1 Create Way, Singapore 138602, Singapore.

Atomically thin molybdenum disulfide (MoS), a direct-band-gap semiconductor, is promising for applications in electronics and optoelectronics, but the scalable synthesis of highly crystalline film remains challenging. Here we report the successful epitaxial growth of a continuous, uniform, highly crystalline monolayer MoS film on hexagonal boron nitride (h-BN) by molecular beam epitaxy. Atomic force microscopy and electron microscopy studies reveal that MoS grown on h-BN primarily consists of two types of nucleation grains (0° aligned and 60° antialigned domains). By adopting a high growth temperature and ultralow precursor flux, the formation of 60° antialigned grains is largely suppressed. The resulting perfectly aligned grains merge seamlessly into a highly crystalline film. Large-scale monolayer MoS film can be grown on a 2 in. h-BN/sapphire wafer, for which surface morphology and Raman mapping confirm good spatial uniformity. Our study represents a significant step in the scalable synthesis of highly crystalline MoS films on atomically flat surfaces and paves the way to large-scale applications.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/jacs.7b05131DOI Listing
July 2017

Chemical Vapor Deposition of High-Quality Large-Sized MoS Crystals on Silicon Dioxide Substrates.

Adv Sci (Weinh) 2016 08 31;3(8):1500033. Epub 2016 Mar 31.

Centre for Advanced 2D Materials National University of Singapore 6 Science Drive 2 Singapore 117546 Singapore; Department of Chemistry National University of Singapore 3 Science Drive 3 Singapore 117546 Singapore.

can be grown on SiO/Si substrates via a two-stage chemical vapor deposition method. The maximum size of MoS crystals can be up to about 305 μm. The growth method can be used to grow other transition metal dichalcogenide crystals and lateral heterojunctions. The electron mobility of the MoS crystals can reach ≈30 cm V s, which is comparable to those of exfoliated flakes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/advs.201600033DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5071677PMC
August 2016

Metformin Protects Cells from Mutant Huntingtin Toxicity Through Activation of AMPK and Modulation of Mitochondrial Dynamics.

Neuromolecular Med 2016 Dec 25;18(4):581-592. Epub 2016 May 25.

Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 600 North Wolfe Street, CMSC 8-121, Baltimore, MD, 21287, USA.

Huntington's disease (HD) is a devastating neurodegenerative disease caused by the pathological elongation of the CAG repeats in the huntingtin gene. Caloric restriction (CR) has been the most reproducible environmental intervention to improve health and prolong life span. We have demonstrated that CR delayed onset and slowed disease progression in a mouse model of HD. Metformin, an antidiabetic drug, mimics CR by acting on cell metabolism at multiple levels. Long-term administration of metformin improved health and life span in mice. In this study, we showed that metformin rescued cells from mutant huntingtin (HTT)-induced toxicity, as indicated by reduced lactate dehydrogenase (LDH) release from cells and preserved ATP levels in cells expressing mutant HTT. Further mechanistic study indicated that metformin activated AMP-activated protein kinase (AMPK) and that inhibition of AMPK activation reduced its protective effects on mutant HTT toxicity, suggesting that AMPK mediates the protection of metformin in HD cells. Furthermore, metformin treatment prevented mitochondrial membrane depolarization and excess fission and modulated the disturbed mitochondrial dynamics in HD cells. We confirmed that metformin crossed the blood-brain barrier after oral administration and activated AMPK in the mouse brain. Our results urge further evaluation of the clinical potential for use of metformin in HD treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s12017-016-8412-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5112128PMC
December 2016

An adenosine A3 receptor agonist inhibits DSS-induced colitis in mice through modulation of the NF-κB signaling pathway.

Sci Rep 2015 Mar 12;5:9047. Epub 2015 Mar 12.

Department of Gastroenterology, The Affiliated Hospital of Guangdong Medical College, No. 57 South Renmin Avenue, Zhanjiang 524001, China.

The role of the adenosine A3 receptor (A3AR) in experimental colitis is controversial. The A3AR agonist N(6)-(3-iodobenzyl)adenosine-5'-N-methyluronamide (IB-MECA) has been shown to have a clinical benefit, although studies in A3AR-deficient mice suggest a pro-inflammatory role. However, there are no studies on the effect of 2-Cl-IB-MECA and the molecular mechanism of action of A3AR in murine colitis models in vivo. Is it the same as that observed in vitro? The interaction between 2-CL-IB-MECA and A3AR in a murine colitis model and the signaling pathways associated with this interaction remain unclear. Here we demonstrate a role for the NF-κB signaling pathway and its effect on modifying the activity of proinflammatory factors in A3AR-mediated biological processes. Our results demonstrated that A3AR activation possessed marked effects on experimental colitis through the NF-κB signaling pathway.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/srep09047DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4357005PMC
March 2015

Activation of adenosine A3 receptor alleviates TNF-α-induced inflammation through inhibition of the NF-κB signaling pathway in human colonic epithelial cells.

Mediators Inflamm 2014 22;2014:818251. Epub 2014 Apr 22.

Department of Gastroenterology, The Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, China.

To investigate the expression of adenosine A3 receptor (A3AR) in human colonic epithelial cells and the effects of A3AR activation on tumor necrosis factor alpha (TNF-α-) induced inflammation in order to determine its mechanism of action in human colonic epithelial cells, human colonic epithelial cells (HT-29 cells) were treated with different concentrations of 2-Cl-IB-MECA prior to TNF-α stimulation, followed by analysis of NF-κB signaling pathway activation and downstream IL-8 and IL-1β production. A3AR mRNA and protein were expressed in HT-29 cells and not altered by changes in TNF-α or 2-Cl-IB-MECA. Pretreatment with 2-Cl-IB-MECA prior to stimulation with TNF-α attenuated NF-κB p65 nuclear translocation as p65 protein decreased in the nucleus of cells and increased in the cytoplasm, inhibited the degradation of IκB-α, and reduced phosphorylated-IκB-α level significantly, compared to TNF-α-only-treated groups. Furthermore, 2-Cl-IB-MECA significantly decreased TNF-α-stimulated IL-8 and IL-1β mRNA expression and secretion, compared to the TNF-α-only treated group. These results confirm that A3AR is expressed in human colonic epithelial cells and demonstrate that its activation has an anti-inflammatory effect, through the inhibition of NF-κB signaling pathway, which leads to inhibition of downstream IL-8 and IL-1β expression. Therefore, A3AR activation may be a potential treatment for gut inflammatory diseases such as inflammatory bowel disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1155/2014/818251DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4016939PMC
December 2014

Effects of delivering recombinant tissue plasminogen activator on a new infusion system during endovascular intervention in patients with lower limb ischemia.

Thorac Cardiovasc Surg 2013 Aug 23;61(5):445-52. Epub 2013 Jan 23.

Department of Vascular Surgery, Beijing Chao Yang Hospital, Affiliate of Capital Medical University, Beijing, People's Republic of China.

Background: To evaluate the feasibility and effects of recombinant tissue plasminogen activator (rt-PA) delivered by a new infusion system during endovascular intervention therapy in patients who had limb ischemia within 6 months.

Methods: From November 2006 to December 2010, 103 consecutive patients were randomly distributed in two groups. 10 mg (group A) and 5 mg (group B) bolus of rt-PA was respectively injected into the proximal occlusive lesion by a new infusion system. Subsequently, additional rt-PA of 10 mg (group A) and 5 mg (group B) was injected into the thrombotic occlusion, respectively. Significant underlying lesions were treated by endovascular intervention or surgery. Rates of major and minor complication, procedural success, and clinical success were evaluated statistically.

Results: Rates of complete lysis and partial lysis success were 12.6% (13 of 103) and 87.4% (90 of 103), respectively. To treat underlying lesions, 84.5% (84 of 103) patients received balloon angioplasty/stent implantation and 4.9% (5 of 103) patients received surgical correction. After final definitive treatment, procedural success rate was up to 99% (102 of 103) and clinical success rate was 100%. Comorbidity conditions and patient characteristics did not statistically influence the rates of success and complication. During the follow-up period of 30-day, 6-, 12- month, there was no statistical difference in the amputation-free survival rates between these two groups.

Conclusion: It is safe and effective to treat lower limb ischemia by combining adjunctive endovascular intervention with bolus of rt-PA (10 to 20 mg) given by a new infusion system. But long-term effects of thrombolysoangioplasty therapy in treating lower limb ischemia must be confirmed by large-scale population studies before routine use.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1055/s-0032-1331265DOI Listing
August 2013

Impact of disrupting adenosine A₃ receptors (A₃⁻/⁻ AR) on colonic motility or progression of colitis in the mouse.

Inflamm Bowel Dis 2011 Aug 3;17(8):1698-713. Epub 2010 Dec 3.

Department of Anesthesiology, Ohio State University, Columbus, Ohio.

Background: Pharmacological studies suggest that adenosine A₃AR influences motility and colitis. Functional A₃⁻/⁻AR knockout mice were used to prove whether A₃AR activation is involved in modulating either motility or colitis.

Methods: A₃AR was probed by polymerase chain reaction (PCR) genotyping, Western blot, and immunochemistry. Motility was assessed in vivo by artificial bead-expulsion, stool-frequency, and FITC-dextran transit. Colitis was induced with dextran sodium sulfate (DSS) in A₃⁻/⁻AR or wildtype (WT) age- and sex-matched controls. Progression of colitis was evaluated by histopathology, changes in myeloperoxidase (MPO), colon length, CD4(+) -cells, weight-loss, diarrhea, and the guaiac test.

Results: Goat anti-hu-A₃ antiserum identified a 66 kDa immunogenic band in colon. A₃AR-immunoreactivity is expressed in SYN(+) -nerve varicosities, s-100(+) -glia, and crypt cells, but not 5-HT(+) (EC), CD4(+) (T), tryptase(+) (MC), or muscle cells. A₃AR immunoreactivity in myenteric ganglia of distal colon >> proximal colon by a ratio of 2:1. Intestinal transit and bead expulsion were accelerated in A₃⁻/⁻AR mice compared to WT; stool retention was lower by 40%-60% and stool frequency by 67%. DSS downregulated A₃AR in epithelia. DSS histopathology scores indicated less mucosal damage in AA₃⁻/⁻AR mice than WT. A₃⁻/⁻AR phenotype protected against DSS-induced weight loss, neutrophil (MPO), or CD4(+) -T cell infiltration, colon shortening, change in splenic weight, diarrhea, or occult-fecal blood.

Conclusions: Functional disruption of A₃AR in A₃⁻/⁻AR mice alters intestinal motility. We postulate that ongoing release of adenosine and activation of presynaptic-inhibitory A₃AR can slow down transit and inhibit the defecation reflex. A₃AR may be involved in gliotransmission. In separate studies, A₃⁻/⁻AR protects against DSS colitis, consistent with a novel hypothesis that A₃AR activation contributes to development of colitis.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/ibd.21553DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3116114PMC
August 2011

Activation of adenosine low-affinity A3 receptors inhibits the enteric short interplexus neural circuit triggered by histamine.

Am J Physiol Gastrointest Liver Physiol 2009 Dec 1;297(6):G1147-62. Epub 2009 Oct 1.

Dept. of Anesthesiology, The Ohio State Univ., Columbus, 43210, USA.

We tested the novel hypothesis that endogenous adenosine (eADO) activates low-affinity A3 receptors in a model of neurogenic diarrhea in the guinea pig colon. Dimaprit activation of H2 receptors was used to trigger a cyclic coordinated response of contraction and Cl(-) secretion. Contraction-relaxation was monitored by sonomicrometry (via intracrystal distance) simultaneously with short-circuit current (I(sc), Cl(-) secretion). The short interplexus reflex coordinated response was attenuated or abolished by antagonists at H2 (cimetidine), 5-hydroxytryptamine 4 receptor (RS39604), neurokinin-1 receptor (GR82334), or nicotinic (mecamylamine) receptors. The A1 agonist 2-chloro-N(6)-cyclopentyladenosine (CCPA) abolished coordinated responses, and A1 antagonists could restore normal responses. A1-selective antagonists alone [8-cyclopentyltheophylline (CPT), 1,3-dipropyl-8-(2-amino-4-chlorophenyl)xanthine (PACPX), or 8-cyclopentyl-N(3)-[3-(4-(fluorosulfonyl)benzoyloxy)propyl]-xanthine (FSCPX)] caused a concentration-dependent augmentation of crypt cell secretion or contraction and acted at nanomolar concentrations. The A3 agonist N(6)-(3-iodobenzyl)-adenosine-5'-N-methyluronamide (IB-MECA) abolished coordinated responses and the A3 antagonist 3-ethyl-5-benzyl-2-methyl-4-phenylethynyl-6-phenyl-1,4-(+/-)-dihydropyridine-3,5-dicarboxylate (MRS1191) could restore and further augment responses. The IB-MECA effect was resistant to knockdown of adenosine A1 receptor with the irreversible antagonist FSCPX; the IC(50) for IB-MECA was 0.8 microM. MRS1191 alone could augment or unmask coordinated responses to dimaprit, and IB-MECA suppressed them. MRS1191 augmented distension-evoked reflex I(sc) responses. Adenosine deaminase mimicked actions of adenosine receptor antagonists. A3 receptor immunoreactivity was differentially expressed in enteric neurons of different parts of colon. After tetrodotoxin, IB-MECA caused circular muscle relaxation. The data support the novel concept that eADO acts at low-affinity A3 receptors in addition to high-affinity A1 receptors to suppress coordinated responses triggered by immune-histamine H2 receptor activation. The short interplexus circuit activated by histamine involves adenosine, acetylcholine, substance P, and serotonin. We postulate that A3 receptor modulation may occur in gut inflammatory diseases or allergic responses involving mast cell and histamine release.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1152/ajpgi.00295.2009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2850084PMC
December 2009

Effects of platelet factor 4 on expression of bone marrow heparan sulfate in syngenic bone marrow transplantation mice.

J Huazhong Univ Sci Technolog Med Sci 2002 ;22(3):190-2

Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030.

To explore the effects of platelet factor 4(PF4) on hematopoietic reconstitution and its mechanism in syngenic bone marrow transplantation (BMT). The syngenic BMT mice models were established. 20 and 26 h before irradiation, the mice were injected 20 micrograms/kg PF4 or PBS twice into abdominal cavity, then the donor bone marrow nuclear cells (BMNC) were transplanted. On the 7th day, spleen clone forming units (CFU-S) were counted. On the 7th, 14th and 21st day after BMT, the BMNC and megakaryoryocytes in bone marrow tissue were counted and the percentage of hematopoietic tissue and expression level of heparan sulfate in bone marrow tissue were assessed. In PF4-treated groups, the CFU-S counts on the 7th day were higher than those in BMT groups after BMT. The BMNC and megakaryoryocyte counts and the percentage of hematopoietic tissue and heparan sulfate expression level were higher than those in BMT group on the 7th, 14th and 21st day after BMT (P < 0.01 or P < 0.05). PF4 could accelerate hematopoietic reconstitution of syngenic bone marrow transplantation. The promotion of the heparan sulfate expression in bone marrow may be one of mechanisms of PF4.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/BF02828176DOI Listing
November 2003
-->