Search

Purpose: To compare the effectiveness of two isolation systems for stemness, proliferation and mesenchymal contamination of ex vivo cultured limbal epithelial cells (LECs). Methods: Whole explant and dispase digestion methods were used to isolate LECs. For whole explant isolation, one limbal explant was cultivated up to four consecutive times (through LEC1 to LEC4). The performance of LECs isolated with both systems was evaluated according to the following parameters: immunofluorescent staining for adenosine 5′-triphosphate-binding cassette member 2 (ABCG2), p63, cytokeratin 3 (K3), Ki67, and vimentin, and flow cytometry analysis for ABCG2, Ki67 and vimentin. Results: Twelve LEC cultures were established using whole explant isolation, and nine LEC cultures were established using dispase digestion isolation. In immunofluorescent staining analysis, the ABCG2, p63 and Ki67 expressions were higher in LECs isolated with dispase compared to any LECs isolated with explant. Only the differences in ABCG2 and Ki67 were statistically significant. Further, LEC4 isolated with explant had the highest percentage of cells positive for vimentin, and LEC1 had the highest percentage of cells positive for K3. However, no significant differences were detected. In flow cytometry analysis, the expressions of ABCG2 and Ki67 were statistically higher for LECs isolated with dispase compared to any LECs isolated with explant. Conclusion: Dispase digestion isolation technique was significantly superior to explant isolation techniques in terms of progenitor and proliferative cell contents. [ABSTRACT FROM AUTHOR]

Abstract: A simple method for in situ determination of the coefficient of thermal expansion (CTE) of polysilicon thin films by using micro-rotating structures is presented. The structures are heated electrically and deflect due to the thermal expansion. An analytical expression is derived to relate the CTE of the polysilicon thin film with the lateral displacement, geometrical parameters and the average temperature of the test structure. The lateral displacement is designed to be a constant value (2μm), while the average temperature of the test structure can be obtained from the measurement of resistance of the test structure. Instead of an optical or visual readout, electrical input and electrical readout are utilized. In the experiments, a current–voltage measurement system only is required and all measurements can be carried out in atmosphere. Finite element analysis and experimental results with surface micromachined polysilicon thin films are used to demonstrate the effectiveness of the proposed method. The average value of the obtained CTE is (2.76±0.09)×10−6 K−1 with temperature ranging from 450K to 500K. [Copyright &y& Elsevier]

PURPOSE: To compare safety and functional outcomes of vitrectomy with or without preoperative intravitreal bevacizumab (IVB) for proliferative diabetic retinopathy (PDR). DESIGN: A meta-analysis of randomized controlled trials. METHODS: PubMed, Medline, EMBASE, and Cochrane Controlled Trials Register were searched to identify potentially relevant randomized controlled trials. A total of 394 participants with 414 eyes in 8 trials were analyzed using RevMan 5.1 software. The primary measures included intraoperative bleeding, total surgical time, and early and late recurrent hemorrhage. RESULTS: Vitrectomy with IVB pretreatment achieved shorter overall surgical time (mean difference = -26.89 minutes, 95% confidence interval =CI] -31.38 toL22.39, P<.00001) and smaller number of endodiathermy applications (mean difference = -3.46, 95% CI -6.43 to -0.49, P = .02) compared to vitrectomy alone. The IVB group was also associated with less intraoperative bleeding (odds ratio =OR] = 0.10; 95% CI 0.02 to 0.46; P = .003) and recurrent vitreous hemorrhage within first month (OR = 0.35; 95% CI 0.21 to 0.58; P < .0001), but the proportion of recurrent vitreous hemorrhage after the first month was comparable between both groups. There were no significant differences in other complication rates between the 2 groups, with the exception of iatrogenic retinal break, which was more likely with the vitrectomy-alone group (OR = 0.27, 95% CI 0.12 to 0.63,P=.003).Resultswere robust to sensitivity analyses. CONCLUSIONS: Adjuvant intravitreal injection of bevacizumab prior to vitrectomy in PDR patients significantly eased the procedure, diminished intraoperative complications, and reduced early postoperative hemorrhage without increasing the risk of visionthreatening complications. Further trials should determine the optimal interval and dosage for IVB injection. [ABSTRACT FROM AUTHOR]

Background: Transconjunctival sutureless vitrectomy is appealing to vitreoretinal surgeons around the world. However, its use versus 20-gauge vitreoretinal surgery is still controversial. The aim of this meta-analysis was to compare the safety and functional outcomes of transconjunctival sutureless vitrectomy versus 20-gauge vitrectomy for vitreoretinal surgery. Methods: Data sources, including PubMed, Medline, EMBASE, and Cochrane Controlled Trials Register, were searched to identify potentially relevant randomized controlled trials. A meta-analysis was performed using RevMan 5.0 software. The primary factors included patients' discomfort, operating time and early postoperative complications. Visual acuity and surgically induced astigmatism were chosen as secondary outcomes. Results: A total of 471 participants with 479 eyes in eight trials between 2005 and 2011 were analyzed. Transconjunctival sutureless vitrectomy was associated with significantly fewer patients suffering from postoperative discomfort at 1 day (odds ratio [OR] 0.07; 95 % confidence interval [CI] 0.01 to 0.49; p = 0.007) and 7 days (OR 0.14; 95 % CI 0.03 to 0.73; p = 0.02) follow-up, and was more effective in reducing surgically induced astigmatism (mean difference −0.23D; 95 % CI −0.31 to −0.15; p < 0.00001) compared to 20-gauge vitrectomy. The sutureless group achieved shorter wound opening (mean difference −1.97 minutes; 95 % CI −2.69 to −1.25; p < 0.00001) as well as wound closure time (mean difference −4.55 minutes; 95 % CI −5.43 to −3.66; p < 0.00001), but the overall surgery time was comparable (mean difference −0.14 minutes; 95 % CI −3.52 to 3.24; p = 0.93). There were no significant differences in the complication rates between the two groups with the exception of postoperative hypotony, which was more likely with the sutureless group (OR 3.73; 95 % CI 1.43 to 9.76; p = 0.007). Conclusions: According to the present data, transconjunctival sutureless vitrectomy offered significantly less postoperative discomfort and decreased surgically induced astigmatism without increasing the risk of vision-threatening complications. Further trials with contemporary equipment and larger sample size are suggested to confirm this conclusion. [ABSTRACT FROM AUTHOR]

We use time-resolved optical reflectivity with femtosecond resolution to study the ultrafast dynamics of photoexcited carriers in bulk GaAs. We observe an emergence of short-lived excitons at room temperature right after photoexcitation, in terms of a sharp dip and sub-ps lifetime in the transient reflectivity changes, as long as the pump fluence increases above a critical value F c. Our findings help understand ultrafast physics in this material. [ABSTRACT FROM AUTHOR]

A hydrophobic-hydrophilic gradient rod with a length of 40 mm and a diameter of 3 mm was prepared by heating a polymethylsilsesquioxane rod in a cylindrical stove with temperature gradient. The rod was thus pyrolyzed under a temperature gradient condition. The organic end of the gradient rod appears hydrophobic with a contact angle of 109.9° while the other end is hydrophilic with a contact angle of 62.4°. The gradient chemical structure and the gradient microstructure along the rod were characterized by FTIR and SEM, respectively. [ABSTRACT FROM AUTHOR]

Background: Infection with hepatitis B virus (HBV) in pregnant women may be a threat for both mothers and fetuses. This study was performed to explore the impact of maternal HBV carrier status on pregnancy outcomes.Methods: We conducted a prospective cohort study at the Obstetrics & Gynecology Hospital of Nantong University between January 1, 2012 and September 30, 2015. A consecutive sample of 21,004 pregnant women, 513 asymptomatic HBV carriers and 20,491 non-HBV controls, was included in this study. The main outcomes of interest were selected pregnancy outcomes including miscarriage, stillbirth, preterm birth (PTB), gestational diabetes (GDM), intrahepatic cholestasis of pregnancy (ICP), preterm premature rupture of the membrane (PPROM), low birth weight (LBW), small for gestational age (SGA) and Apgar scores. The incidence of adverse pregnancy outcomes between asymptomatic HBV carriers and non-HBV controls were compared using the chi-square test and logistic regression. P values were two sided, and P <0.05 was considered to indicate statistical significance.Results: The incidences of stillbirth, PTB, GDM, ICP, PPROM, LBW, and SGA were similar between the HBV carrier and non-HBV groups. The proportion of miscarriage was significantly higher among the HBV carriers than the controls (9.36% vs 5.70%; P <0.001). After using multivariate modelling to adjust for possible socio-demographical variables and obstetric complications, women with HBV carrier status were still more likely to have miscarriage (adjusted OR 1.71, 95% CI 1.23-2.38). In addition, the incidences of other maternal and neonatal outcomes were similar between the two groups.Conclusion: Maternal HBV carrier status may be an independent risk factor for miscarriage and careful surveillance is warranted. [ABSTRACT FROM AUTHOR]

High-quality large single crystals of Ni- and Zn-doped Bi2Sr2Ca(Cu2-xMx)O8+δ (M=Ni or Zn) have been successfully grown by the traveling solvent floating zone technique. The single crystals are characterized by compositional and structural analyses and their physical properties are investigated by magnetic susceptibility and resistivity measurements. A record high critical temperature with a Tc = 97.5K has been achieved in the annealed pristine Bi2212 single crystal. Substitution of Cu by Ni or Zn reduces the superconducting transition temperature when compared with pristine Bi2Sr2CaCu2O8+δ (Bi2212) grown under similar conditions. The successful growth of such pristine Ni- and Zn-doped Bi2212 single crystals will facilitate studies of the relationship between the magnetism and superconductivity in high-temperature cuprate superconductors [ABSTRACT FROM AUTHOR]

Abstract: Cigarette smoke has been widely investigated in terms of epidemiology and pathological endpoints in relation to human lung diseases and animal study. In this study we exposed Wistar rats to cigarette smoke at concentrations of 20% and 60% to explore potential molecular mechanisms at the protein level. Exposures were conducted twice a day, 5 days a week for 43 weeks. As a major metabolite of nicotine in cigarette, cotinine level in rat urine was determined by HPLC–MS. A dose-dependent analysis indicated that cotinine may be used as an exposure marker of cigarette smoke. Expression of receptor for advanced glycation endproducts (RAGE), an immunoglobulin super family that triggers the intracellular signal cascade reaction leading to inflammation and its ligand S100A6 (calgranulin) in bronchial epithelial cells and lung tissues of rats, were found to be positive correlated with cotinine levels, indicating that RAGE and S100A6 may be attributable to inflammation and oxidative damage caused by cigarette smoke. [Copyright &y& Elsevier]

• We find evidence of two pseudogap (PG) quasiparticles (QPs) using time-resolved reflectivity, characterized by relaxation timescales of τ fast ≈ 0.2 ps and τ slow ≈ 2 ps with abrupt changes in both amplitudes A fast and A fast at T *. • The fast PG QP presents no obvious change at T c and coexists with the superconducting (SC) QP below T c. • The slow PG QP is completely suppressed at T c and replaced by the SC QP with reversed sign in Δ R / R , suggesting a competition between them. • Analysis by using the Rothwarf-Taylor model indicate that the fast PG QP is well fitted by a T -independent gap, while the slow PG QP and the SC QP are well fitted by a BCS-like T -dependent gap. The relation between pseudogap (PG) and superconducting (SC) gap, whether PG is a precursor of SC or they coexist or compete, is a long-standing controversy in cuprate high-temperature supercondutors. Here, we report ultrafast time-resolved optical reflectivity investigation of the dynamic densities and relaxations of PG and SC quasiparticles (QPs) in the underdoped Bi 2 Sr 2 CaCu 2 O 8 + δ (T c = 82 K) single crystals. We find evidence of two distinct PG components in the positive reflectivity changes in the PG state, characterized by relaxation timescales of τ fast ≈ 0.2 ps and τ slow ≈ 2 ps with abrupt changes in both amplitudes A fast and A slow at the PG-opening temperature T *. The former presents no obvious change at T c and coexists with the SC QP. The latter's amplitude starts decreasing at the SC phase fluctuation T p and vanishes at T c followed by a negative amplitude signifying the emergence of the SC QP, therefore suggesting a competition with superconductivity. [ABSTRACT FROM AUTHOR]