Pax6-Induced Proliferation and Differentiation of Bone Marrow Mesenchymal Stem Cells Into Limbal Epithelial Stem Cells.

Corneal integrity, transparency, and visual acuity are maintained by corneal epithelial cells (CECs), which are continuously renewed by limbal epithelial stem cells (LESCs). The limbal stem cell deficiency is associated with ocular diseases. This study aimed to develop a novel method to differentiate bone marrow mesenchymal stem cells (BM-MSCs) into LESC-like cells using a culture medium and paired box 6 (Pax6) transfection. The LESC-like cells were confirmed using the LESC markers CK14 and p63 and CEC marker CK12. Pax6 induces BM-MSCs to differentiate into LESC-like cells in vitro. Mouse models of chemical corneal burn were obtained and treated with the LESC-like cells. The transplantation experiment indicated that Pax6-reprogrammed BM-MSCs attached to and replenished the damaged cornea through the formation of stratified corneal epithelium. The proliferation and colony formation abilities of Pax6-overexpressing BM-MSCs were significantly enhanced. These findings provide evidence that BM-MSCs might serve as an excellent candidate for generating bioengineered corneal epithelium and provide a new strategy for the treatment of clinical corneal damage.

Signatures of hot carriers and hot phonons in the re-entrant metallic and semiconducting states of Moiré-gapped graphene.

Stacking of graphene with hexagonal boron nitride (h-BN) can dramatically modify its bands from their usual linear form, opening a series of narrow minigaps that are separated by wider minibands. While the resulting spectrum offers strong potential for use in functional (opto)electronic devices, a proper understanding of the dynamics of hot carriers in these bands is a prerequisite for such applications. In this work, we therefore apply a strategy of rapid electrical pulsing to drive carriers in graphene/h-BN heterostructures deep into the dissipative limit of strong electron-phonon coupling. By using electrical gating to move the chemical potential through the "Moiré bands", we demonstrate a cyclical evolution between metallic and semiconducting states. This behavior is captured in a self-consistent model of non-equilibrium transport that considers the competition of electrically driven inter-band tunneling and hot-carrier scattering by strongly non-equilibrium phonons. Overall, our results demonstrate how a treatment of the dynamics of both hot carriers and hot phonons is essential to understanding the properties of functional graphene superlattices.

The Impact of Self-Consistency Congruence on Non-Suicidal Self-Injury in College Students: The Mediating Role of Negative Emotion and the Moderating Role of Gender.

Non-suicidal self-injury (NSSI) can be defined as the deliberate destruction of body tissues to generate harm. College students have a higher incidence of NSSI. With the deepening of research on college students' NSSI, the connection between their self-consistency congruence and NSSI has drawn the attention of many scholars. The current study examined the association between self-concordance and NSSI, the mediating function of negative emotions, and the moderating role of gender. We surveyed 1020 college students from three universities in Jiangxi Province using a self-concordant scale, a NSSI questionnaire, and a negative emotion questionnaire. The results showed that self-concordance was negatively correlated with NSSI. There is an obvious negative connection between self-consistency congruence and negative emotions. There was a significant positive correlation between negative emotions and the NSSI scores. Negative emotions could mediate the association between self-consistency congruence and NSSI. Compared to males, females' self-concordant effects on negative emotions are easier to moderate.

Asymmetrically Engineered Nanoscale Transistors for On-Demand Sourcing of Terahertz Plasmons.

Terahertz (THz) plasma oscillations represent a potential path to implement ultrafast electronic devices and circuits. Here, we present an approach to generate on-chip THz signals that relies on plasma-wave stabilization in nanoscale transistors with specific structural asymmetry. A hydrodynamic treatment shows how the transistor asymmetry supports plasma-wave amplification, giving rise to pronounced negative differential conductance (NDC). A demonstration of these behaviors is provided in InGaAs high-mobility transistors, which exhibit NDC in accordance with their designed asymmetry. The NDC onsets once the drift velocity in the channel reaches a threshold value, triggering the initial plasma instability. We also show how this feature can be made to persist beyond room temperature (to at least 75 °C), when the gating is configured to facilitate a transition between the hydrodynamic and ballistic regimes (of electron-electron transport). Our findings represent a significant step forward for efforts to develop active components for THz electronics.

Graphene on Chromia: A System for Beyond-Room-Temperature Spintronics.

Evidence of robust spin-dependent transport in monolayer graphene, deposited on the (0001) surface of the antiferromagnetic (AFM)/magneto-electric oxide chromia (Cr2 O3 ), is provided. Measurements performed in the non-local spin-Hall geometry reveal a robust signal that is present at zero external magnetic field and which is significantly larger than any possible ohmic contribution. The spin-related signal persists well beyond the Néel temperature (≈307 K) that defines the transition between the AFM and paramagnetic states, remaining visible at the highest studied temperature of close to 450 K. This robust character is consistent with prior theoretical studies of the graphene/Cr2 O3 system, predicting that the lifting of sub-lattice symmetry in the graphene shall induce an effective spin-orbit term of ≈40 meV. Overall, the results indicate that graphene-on-chromia heterostructures are a highly promising framework for the implementation of spintronic devices, capable of operation well beyond room temperature.

Interaction of magnolia bark extracts with Staphylococcus aureus DNA and evaluation of the stability of their antibacterial activities.

Magnolia bark is an edible traditional Chinese medicine that has antibacterial activity against Staphylococcus aureus. In the present study, interactions between S. aureus DNA and raw magnolia bark (RMB) and ginger mix-fried magnolia bark (GMB) aqueous extracts were determined via spectroscopic methods. Fluorescence spectroscopy and Stern-Volmer constants showed that S. aureus DNA quenched the fluorescence of the extracts by static quenching. UV-Vis spectroscopy and iodide quenching experiments indicated that the interactions between S. aureus DNA and the fluorescent substances might involve groove binding or electrostatic interactions. In 4', 6-diamidino-2-phenylindole competitive assays, the fluorescence intensity at decreased as the extract amount was increased. This indicates that groove binding is responsible for the fluorescence quenching. The antibacterial activity of GMB aqueous extract treated under light, cold, heat and cycling hot-cold conditions decreased by 13.99, 9.31, 10.89 and 14.40%, respectively, whereas that of RMB aqueous extract treated under the same conditions decreased by 8.91, 14.99, 14.99 and 13.70%, respectively. The results indicate that S. aureus DNA quenches the fluorescence of GMB and RMB aqueous extracts by grooving interactions. Additionally, the antibacterial activities of GMB and RMB extracts are sensitive to light and temperature, respectively.

Mechanism and antibacterial activity of vine tea extract and dihydromyricetin against Staphylococcus aureus.

Vine tea (Ampelopsis grossedentata) has been approved as a new food ingredient in 2013. Both vine tea extract (VTE) and its active ingredient, 2R, 3R-Dihydromyricetin (DMY), showed good antibacterial activity. The mechanism of VTE and DMY against Staphylococcus aureus were evaluated by morphology observation, cell membrane and wall assay, protein assay, and DNA assay in this study. The results of SEM and TEM revealed that the VTE and DMY changed the morphology of S. aureus. The leakage of AKPase and ß-galactosidase in treated groups demonstrated that the membrane integrity of S. aureus was disrupted. Meanwhile, the results of protein assay showed that VTE and DMY inhibited the expression of total proteins, and decreased activities of a few energy metabolism enzymes, total ATPase. Moreover, spectral and competitive analysis revealed that VTE and DMY interacted with DNA by groove and intercalation binding. Finally, the suspension experiments of Chinese cabbage and barley showed that inhibitors had strong inhibitory effect on bacteria growth. Overall, the results suggested that VTE and DMY may be potential food preservatives for inhibiting pathogen.

Cheek Microbial Communities Vary in Young Children with Atopic Dermatitis in China.

BACKGROUND: Atopic dermatitis (AD) is a chronic, recurrent skin condition with recently increased incidence in younger children. AD development has been correlated with the skin microbiome, and Staphylococcus aureus enrichment causes significant increases in skin lesions. OBJECTIVE: Our objectives were to compare the microbial diversity of the cheek skin of children with or without AD aged 0-1 years in China, and to determine whether 4 types of skin-isolated bacteria could inhibit S. aureus in vitro. METHODS: The skin microbial samples of cheek skin of children were sequenced by 16S rRNA V1-V2 region. Four skin isolated bacterial fermentation supernatants were tested for effects on S. aureus growth, membrane formation, and induction of cytokine secretion from HaCaT cells. RESULTS: Bacterial diversity decreased significantly in skin with severe AD compared to healthy skin (p < 0.01). Seven phyla had content >1%, 4 of which differed in AD (p < 0.05). 38 genera had content >1%, 15 differed (p < 0.05). Differences in 8 species were observed (p < 0.05). In vitro antibacterial and cellular experiments showed that S. aureus growth, biofilm formation, and induction of interleukin (IL)-1α and IL-6 secretion from HaCaT cells were significantly inhibited by Klebsiella oxytoca, Kocuria rhizophila, and Staphylococcus epidermidis culture supernatants (p < 0.05). CONCLUSION: Skin microbiome changes in children varied with age and with AD. There were complex interactions between skin isolated bacteria and S. aureus which could inhibit S. aureus growth and biofilm formation in vitro, suggesting that these microorganisms could be used in AD treatment.

Gate-Controlled Metal-Insulator Transition in TiS3 Nanowire Field-Effect Transistors.

We explore the electrical characteristics of TiS3 nanowire field-effect transistor (FETs), over the wide temperature range from 3 to 350 K. These nanomaterials have a quasi-one-dimensional (1D) crystal structure and exhibit a gate-controlled metal-insulator transition (MIT) in their transfer curves. Their room-temperature mobility is ∼20-30 cm2/(V s), 2 orders of magnitude smaller than predicted previously, a result that we explain quantitatively in terms of the influence of polar-optical phonon scattering in these materials. In the insulating state (<∼220 K), the transfer curves exhibit unusual mesoscopic fluctuations and a current suppression near zero bias that is common to charge-density wave (CDW) systems. The fluctuations have a nonmonotonic temperature dependence and wash out at a temperature close to that of the bulk MIT, suggesting they may be a feature of quantum interference in the CDW state. Overall, our results demonstrate that quasi-1D TiS3 nanostructures represent a viable candidate for FET realization and that their functionality is influenced by complex phenomena.

Effect of cosmetic chemical preservatives on resident flora isolated from healthy facial skin.

BACKGROUND/AIMS: Healthy skin harbors numerous microbes known to maintain its health and prevent attacks from external pathogens. The influence of chemical preservatives commonly used in cosmetic products on facial resident flora remains poorly characterized. In this study, we aimed to investigate the antibacterial activity of five such preservatives on in vitro cultivated skin-resident bacteria. METHODS: Both Gram-positive and Gram-negative bacteria were isolated on blood agar, tryptic soy agar, and nutrient agar; Gram-negative bacteria were then selected on Hank's balanced salt solution containing antibiotics and Reasoner's 2A. The minimum inhibitory concentrations (MICs) of methylisothiazolinone (MTI), iodopropynyl butylcarbamate (IPBC), ethylhexylglycerin (EHG), methylparaben (MP), and phenoxyethanol (PE) were estimated for nine facial resident bacteria, Escherichia coli, and Staphylococcus aureus using serial broth dilution in vitro. RESULTS: The maximum test concentrations coincided with the upper limits set by the "Cosmetic Safety and Technical Specification" (2015 edition, China). Nine facial resident bacteria were isolated from 14 healthy adults: Staphylococcus epidermidis, Staphylococcus capitis, Kocuria, Micrococcus luteus, Bacillus, Acinetobacter, Pseudomonas parafulva, Pseudomonas oleovorans, and Roseomonas cervicalis. MTI and IPBC displayed the strongest effect on all tested strains (MICs ≤0.01%), followed by EHG and MP (MICs ≤0.3%), and finally PE with the weakest effect (MIC ≤1%). CONCLUSION: The five chemical preservatives assayed inhibited survival of the nine facial resident bacteria isolates, when tested at the maximum allowed limit. The corresponding MICs will provide a reference for the effective utilization of these compounds in product formulations.

CO2-Mediated Formation of Chiral Carbamates from meso-Epoxides via Polycarbonate Intermediates.

Carbon dioxide has attracted broad interest as a renewable C1 feedstock for efficient transformation into value-added organic chemicals; nevertheless, far less attention was paid to its stereochemically controlled catalytic fixation/conversion processes. Here, we report a new strategy for the selective synthesis of chiral carbamates from carbon dioxide via polycarbonate intermediates, which are formed by the desymmetric copolymerization of meso-epoxides using enantiopure dinuclear Co(III) catalyst systems with 99% enantioselectivity. Subsequent degradation reaction of the resultant polycarbonates with various primary or secondary amine nucleophiles can afford optically active carbamates, with the complete configuration retention of the two chiral carbon centers. Our accomplishment reported here opens up a new route to prepare a wide range of CO2-based carbamate scaffolds with excellent yields and 99% enantiomeric excess.

Tuning Fano resonances with a nano-chamber of air.

By designing a polymer-film-coated asymmetric metallic slit structure that only contains one nanocavity side-coupled with a subwavelength plasmonic waveguide, the Fano resonance is realized in the experiment. The Fano resonance originates from the interference between the narrow resonant spectra of the radiative light from the nanocavity and the broad nonresonant spectra of the directly transmitted light from the slit. The lateral dimension of the asymmetric slit is only 825 nm. Due to the presence of the soft polymer film, a nano-chamber of air is constructed. Based on the opto-thermal effect, the air volume in the nano-chamber is expanded by a laser beam, which blueshifts the Fano resonance. This tunable Fano resonance in such a submicron slit structure with a nano-chamber is of importance in the highly integrated plasmonic circuits.

Crystalline-gradient polycarbonates prepared from enantioselective terpolymerization of meso-epoxides with CO2.

The development of efficient processes for CO2 transformation into useful products is a long-standing goal for chemists, since CO2 is an abundant, inexpensive and non-toxic renewable C1 resource. Here we describe the enantioselective copolymerization of 3,4-epoxytetrahydrofuran with CO2 mediated by biphenol-linked dinuclear cobalt complex, affording the corresponding polycarbonate with >99% carbonate linkages and excellent enantioselectivity (up to 99% enantiomeric excess). Notably, the resultant isotactic polycarbonate is a typical semicrystalline polymer, possessing a melting point of 271 °C. Furthermore, the enantioselective terpolymerization of 3,4-epoxytetrahydrofuran, cyclopentene oxide and CO2 mediated by this dinuclear cobalt complex gives novel gradient polycarbonates, in which the decrement of one component and the increment of the other component occur sequentially from one chain end to the other end. The resultant terpolymers show perfectly isotactic structure and have unique crystalline-gradient nature, in which the crystallinity continuously varies along the main chain.

Portal vein thrombosis after partial splenic embolization in liver cirrhosis: efficacy of anticoagulation and long-term follow-up.

PURPOSE: To investigate the treatment and long-term outcome of portal vein thrombosis (PVT) after partial splenic embolization (PSE). MATERIALS AND METHODS: From January 2006 to December 2011, 145 patients with hypersplenism caused by cirrhotic portal hypertension underwent PSE. In 11 cases, PVT was detected 13-42 days after PSE. Among the 11 patients, 5 underwent anticoagulant therapy because of clinical symptoms, and 6 did not receive anticoagulation because they were symptom-free (4 patients) or experienced variceal bleeding (2 patients). The long-term follow-up data from these 11 patients were analyzed retrospectively. RESULTS: The 11 patients with PVT had a mean splenic infarction ratio of 71.5%. The mean duration of follow-up was 37.6 months. During the follow-up period, none of the 5 patients who underwent anticoagulation developed variceal hemorrhage despite presenting with large esophagogastric varices. Four of the five patients achieved complete resolution of thrombosis, and one did not develop thrombus progression. However, among the 6 patients who did not undergo anticoagulation, 2 developed esophagogastric variceal hemorrhage secondary to thrombus progression, 3 developed cavernous transformation of the portal vein and variceal progression, and 1 had partial calcification of the thrombus. Two patients who had variceal bleeding or rebleeding underwent a transjugular intrahepatic portosystemic shunt. Complete recanalization of the portal vein was achieved after the procedures. CONCLUSIONS: PVT is a severe, potentially fatal complication of PSE. Early detection of PVT and prompt anticoagulation are effective to avoid serious consequences of PVT.

Effect of transplantation with autologous bone marrow stem cells on acute myocardial infarction.

BACKGROUND: This study was designed to investigate the effects of treatment with autologous mesenchymal stem cells (MSCs) by intracoronary transplantation on myocardial infarction (MI) in swine. METHODS: MSCs were transfected with a lentiviral vector carrying the gene encoding green fluorescent protein (GFP) and labeled in vitro with superparamagnetic iron oxide (SPIO). An acute MI (AMI) model was established by percutaneous balloon occlusion. Dual-labeled MSC suspensions were injected through the infarct-related coronary artery using an over-the-wire (OTW) balloon device in the experimental group (n=5), while normal saline was injected into the control (n=5). Stem cell migration and improvements of cardiac function were evaluated by magnetic resonance imaging (MRI), single-photon emission computed tomography (SPECT), and ultrasonic cardiogram (UCG) both before MSC transplantation and after 8 weeks. At 8weeks after transplantation, myocardial tissue was analyzed by histopathologic analyses. RESULTS: Blue SPIO particles were in the cytoplasm of the MSCs. The labeling efficiency reached 100%. MRI revealed hypointensities of SPIO-labeled MSCs that were clustered in the myocardial infarct area after MSC transplantation. As time progressed, the signal gradually weakened and the area shrank. SPECT revealed that the myocardial filling defect was reduced and the amount of surviving myocardium was significantly increased at 8weeks. UCG revealed significant improvement when compared with the control at 8 weeks after transplantation. Prussian blue-positive cells were observed in the MI border zone. Fluorescence-positive cells were also observed, but the number of such cells was fewer than before. CONCLUSIONS: In vivo serial tracking of SPIO-labeled MSCs can be achieved by MRI. Intracoronary transplantation of SPIO-labeled MSCs can increase cardiac function and promote myocardial viability.

Magnetic resonance evaluation of transplanted mesenchymal stem cells after myocardial infarction in swine.

INTRODUCTION: Our objective was to trace and evaluate intracoronary transplanted mesenchymal stem cells (MSCs) labelled with superparamagnetic iron oxide (SPIO) by using magnetic resonance imaging (MRI) in a swine model of myocardial infarction (MI). METHODS: MSCs were transfected with a lentiviral vector carrying the gene encoding green fluorescent protein (GFP) and labelled in vitro with SPIO. At 2 weeks after MI, swine were randomized to intracoronary transplantation of dual-labelled MSCs (n=10), MSC-GFP (n=10), and saline (n=5). MRI examination was performed with a 1.5-T clinical scanner at 24 hours, 3 weeks, and 8 weeks after cell transplantation. Signal intensity changes, cardiac function, and MI size were measured by means of MRI. The correlation between MRI findings and histomorphologic findings was also investigated. RESULTS: MSCs could be efficiently and safely labelled with SPIO and GFP, and multipotentiality was not affected, especially for cardiomyocyte-like cell differentiation. Signal intensity on T2*-weighted imaging decreased substantially in the interventricular septum 24 hours after injection of MSCs. The intensity of hypointense signals appeared to increase throughout the later time points. Both dual-labelled MSCs and MSC-GFP could dramatically reduce the size of MI and improve cardiac function. Histologic data revealed that cells positive for Prussian blue stain were found mainly in the border zone, which also showed green fluorescence. CONCLUSIONS: In vivo 8-week tracing of dual-labelled MSCs can be achieved by MRI. Intracoronary transplantation of dual-labelled MSCs can increase cardiac function and reduce the size of MI in a swine model.

[Transportal variceal sclerotherapy with n-butyl-2-cyanoacrylate for gastric fundal varices].

OBJECTIVE: To evaluate the technique, safety and clinical efficacy of transportal variceal sclerotherapy with n-butyl-2-cyanoacrylate (NBCA) for gastric fundal varices. METHODS: Twenty-one patients with gastric fundal varices confirmed by endoscopy were enrolled in this study. The causes of the gastric varices were cirrhosis caused by hepatitis virus B or C (n = 16) and hepatocellular carcinoma with portal venous obstruction (n = 5). Percutaneous transhepatic or transplenic portography were performed on all 21 patients. The gastric varices were treated with NBCA-lipiodol mixture injected via a microcatheter introduced into the varices. For 8 patients who had large gastrorenal shunts (GRS), a balloon-occluded catheter was introduced into the GRS via the right femoral and left renal veins before injecting the NBCA-lipiodol. During the NBCA-lipiodol injection, the balloon was inflated to block the flow of GRS. Follow-up evaluations included findings of the laboratory liver function tests, upper intestinal endoscopies, and the occurrences of rebleeding. RESULTS: In 20 patients (95.2%), the gastric varices were successfully obliterated with 2-8 ml of NBCA-lipiodol. In one patient with a large GRS, sclerotherapy was not successfully performed because a balloon-occluded catheter was not available during the procedure. In five patients, small amounts of NBCA-lipiodol entered into the distal pulmonary artery branches. Two of them suffered from transient irritable coughs; no patient developed severe pulmonary embolism. Embolization of portal venous branches occurred in two patients, which were not treated specifically. In comparison with the findings before the treatments, the serum alanine aminotransferase levels decreased at both 3 and 6 months after treatments (P less than 0.05); serum albumin levels increased at 6 months (P less than 0.05); the prothrombin times decreased at 6 months (P less than 0.05); but no significant changes were seen in the serum bilirubin levels. Fifteen patients were followed-up endoscopically for 3 months after the treatment. Gastric varices were completely resolved in 10 patients (66.7%) and were markedly smaller in 4 patients (26.6%). Worsening of the esophageal varices occurred in 3 patients (20%). All the patients were followed-up from 1 to 30 months [(16.7+/-8.8) months]. Rebleeding was observed in 4 patients, and the cumulative rebleeding rate at 1 year was 9.52%. CONCLUSION: Transportal variceal sclerotherapy with NBCA is a safe and effective method for treating gastric varices. Microcatheter technique and occlusion of the large gastrorenal shunt with a balloon-occluded catheter are necessary to ensure obliteration of gastric varices and prevent pulmonary embolism.

[The role of multi-detector row CT in the diagnosis and hemodynamic studies of gastric varices in portal hypertension].

OBJECTIVE: To evaluate the value of multi-detector row CT (MDCT) in the diagnosis and hemodynamic studies of gastric varices (GV) in portal hypertension by comparison with endoscopy and DSA direct portography. METHODS: Thirty-six consecutive cirrhotic patients with GV confirmed by endoscopy underwent tri-phase contrast-enhanced CT scans and CT portography (CTP) within 2 weeks after endoscopy examination. Three independent experienced radiologists, who were blinded to the patients' clinical data, analyzed the CT images, including the size and location of GV as well as afferent and efferent veins of GV, separately. Interobserver agreement among the 3 radiologists with regard to the diagnosis of submucosal and perigastric GV was determined by Kappa (k) values. The findings of endoscopy were used as standards. RESULTS: Sub mucosal GV was diagnosed in 34 of the 36 patients (94.4%) and perigastric GV in all 36 patients (100%) by the observation of the 3 radiologists. MDCT showed an excellent interobserver reliability with regard to the diagnosis of submucosal GV (kappa = 0.85) and perigastric GV (kappa = 1.0). Agreement between MDCT and endoscopy with regard to the opacification of variceal size and location were 86.1% and 88.9% respectively. The sensitivity, specificity, accuracy, and positive predictive value of CTP in the opacification of afferent and efferent veins of GV were all more than 80%. The frequencies of participation of posterior gastric vein and short gastric vein in blood supply to gastric fundal varices in the isolated gastric varices and gastroesophageal varices type 2 (GEV2) were 94.1% and 70.6% respectively, both significantly higher than those in the gastroesophageal varices type 1 (GEV1, 52.6% and 31.6%, respectively, both P < 0.05). The main blood drainage route of GEV1 was via azygous system into the super vena cava (100%), whereas in the gastric fundal varices the main blood drainage route was via the gastrorenal shunts into the inferior vena cava (82.4%). CONCLUSION: MDCT can be used as an important tool for detecting submucosal and perigastric GV, and can clearly reveal the size, location, and hemodynamics of GV.