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Layered materials exhibit different electronic and phonon properties along in-plane and out-of-plane directions; existing studies focus on their in-plane behaviors, and the influence of such anisotropies on the dynamics of photocarriers and phonons is unknown. Here, we fabricate layered PdSe2 crystals with flat edge surfaces and compare the time-resolved ultrafast spectroscopies on their basal and edge surfaces. Pronounced differences in the transient reflection spectroscopies reveal the inconsistent photocarrier and phonon dynamics behaviors on the two surfaces: the slow hot carrier relaxation process is accelerated and the thermoelasticity-induced longitudinal coherent acoustic phonon oscillation completely vanishes on the edge surface, as compared with the basal surface. Theoretical analysis reveals that the inconsistent hot carrier dynamics originate from the anisotropic properties of low-energy phonons in PdSe2, and the absence of phonon oscillation on the edge surface results from the wavevector-limited sensitivity of acoustic B1u mode. Moreover, polarization-dependent spectroscopies indicate the diverse optical anisotropies beyond the in-plane of PdSe2. This work provides a new method to explore unique physical properties and modulate the optical anisotropy of layered materials. [ABSTRACT FROM AUTHOR]

Efficient generation of spin polarization is very important for spintronics and quantum computation. In chiral materials without magnetic order nor spin-orbit coupling, we find a new spin selectivity effect—chiral phonon activated spin Seebeck (CPASS) effect. Starting with the nonequilibrium distribution of chiral phonons under a temperature gradient, the CPASS coefficients are computed based on the Boltzmann transport theory. With both the phonon-drag and band transport contributions, the spin accumulations generated by the CPASS effect exhibit quadratic dependence on the temperature gradient. The strength of the CPASS effect and the relative magnitude of both contributions are tunable by the chemical potential modulation. The CPASS effect, which gives a promising explanation on the traditional chiral-induced spin selectivity effect, provides opportunities for the exploration of advanced spintronic devices based on chiral materials even in the absence of any magnetic order and spin-orbit coupling. [ABSTRACT FROM AUTHOR]

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Elemental tellurium, conventionally recognized as a narrow bandgap semiconductor, has recently aroused research interests for exploiting Weyl physics. Chirality is a unique feature of Weyl cones and can support helicity-dependent photocurrent generation, known as circular photogalvanic effect. Here, we report circular photogalvanic effect with opposite signs at two different mid-infrared wavelengths which provides evidence of Weyl-related optical responses. These two different wavelengths correspond to two critical transitions relating to the bands of different Weyl cones and the sign of circular photogalvanic effect is determined by the chirality selection rules within certain Weyl cone and between two different Weyl cones. Further experimental evidences confirm the observed response is an intrinsic second-order process. With flexibly tunable bandgap and Fermi level, tellurium is established as an ideal semiconducting material to manipulate and explore chirality-related Weyl physics in both conduction and valence bands. These results are also directly applicable to helicity-sensitive optoelectronics devices. Materials with Weyl cones and band gaps coexisting are desired due to their combination of Weyl cones and the tunable and controllable nature of semiconductor. Here, the authors find Weyl-related band structures and semiconducting gap of tellurium. [ABSTRACT FROM AUTHOR]

The thermoelectric effects of topological semimetals have attracted tremendous research interest because many topological semimetals are excellent thermoelectric materials and thermoelectricity serves as one of their most important potential applications. In this work, we reveal the transient photothermoelectric response of Dirac semimetallic Cd3As2, namely the photo-Seebeck effect and photo-Nernst effect, by studying the terahertz (THz) emission from the transient photocurrent induced by these effects. Our excitation polarization and power dependence confirm that the observed THz emission is due to photothermoelectric effect instead of other nonlinear optical effect. Furthermore, when a weak magnetic field (~0.4 T) is applied, the response clearly indicates an order of magnitude enhancement on transient photothermoelectric current generation compared to the photo-Seebeck effect. Such enhancement supports an ambipolar transport nature of the photo-Nernst current generation in Cd3As2. These results highlight the enhancement of thermoelectric performance can be achieved in topological Dirac semimetals based on the Nernst effect, and our transient studies pave the way for thermoelectric devices applicable for high field circumstance when nonequilibrium state matters. The large THz emission due to highly efficient photothermoelectric conversion is comparable to conventional semiconductors through optical rectification and photo-Dember effect. Many topological semimetals are excellent thermoelectric materials, but previous studies were limited to steady-state properties. Here, the authors observe a transient thermoelectric response in Cd3As2 by detecting the resulting THz emission, with an enhanced response when a small magnetic field is applied. [ABSTRACT FROM AUTHOR]

Advances in femtosecond laser-material interaction facilitate the extension of maskless optical processing to the high efficiency and deep-subwavelength scale. Here, a hybrid plasmon lithography technique has been demonstrated by irradiating near-infrared femtosecond laser pulses onto the Si material coated with thin Cr films in a vacuum chamber, and superior nanograting structures are found to deeply penetrate through the thin Cr film into the underlying Si substrate. In stark contrast to the common ripple structures formed on the Si surface, the Cr-layer mediated Si nanograting structures not only exhibit the spatially super-regular arrangements with a deep-subwavelength period of 355 nm but also present the nonsinusoidal sharp-edged groove geometry with a large depth-to-width aspect ratio of 2.1. Theoretical analyses and calculations reveal that the anomalous structure characterizations are physically ascribed to the excitation of dual-interface coupled plasmons in the thin metal layer, which possess the squeezed spatial wavelength and the periodic columnar intensity distributions. Moreover, the further deepening of periodic nanostructures into the Si substrate is also elucidated by the simulation of electric field enhancements at the bottom of shallow grooves under irradiation of subsequent laser pulses. In combination with a wet etching process, the Si nanograting structures can be modified into the smooth and narrow-mouthed V-profiles, whose optical measurements show a near omnidirectional antireflection especially in the visible range of 565–750 nm, which is expected for the design of advanced photonic devices. [ABSTRACT FROM AUTHOR]

Background Self-monitoring of blood glucose (SMBG) systems are expected to be accurate and provide reliable results. The international standard ISO (International Organization for Standardization) 15197:2013 is widely accepted for the accuracy evaluation for SMBG systems. Accuracy evaluation was performed for 5 different SMBG systems in patients from multi-departments at the hospital. Method A total of 120 patients from Changzhou Second People's Hospital (Changzhou, China) were randomized and enrolled in the study. Accuracy evaluation was performed for 5 different SMBG systems: Gold AQ (Sinocare), Freestyle Optium Xceed (Abbott), Contour TS (Bayer), OneTouch Ultra (J&J) and Accu-Chek Performa (Roche). For each system, comparison measurements were performed with YSI 2300 STAT PLUS Glucose and Lactate Analyzer and Roche Cobas 8000 Modular Analyzer. Results All 5 systems showed that 100% of results fall within consensus error grid Zones A and B. Compared with YSI 2300 or Roche Cobas 8000 Modular Analyzer, Gold AQ system showed the highest accuracy. The linearity analysis also showed that Gold AQ had the highest correlation coefficient. Conclusion Compared with other SMBG systems, Gold AQ Glucose Monitoring System manufactured by Sinocare Inc. had the highest accuracy in measuring blood glucose level in patients from multi-departments at this hospital. [ABSTRACT FROM AUTHOR]

Adipose stem cells (ASCs) are an attractive cell source for treating many human diseases including osteoporosis. However, the molecular mechanisms accounting for ASC osteogenesis are poorly known. In this study, ASCs were first isolated from the fat tissues from the patients with osteoporosis. The global transcriptome profile between osteogenic differentiated ASCs and undifferentiated ASCs was compared using RNA sequencing (RNA-seq). Then, bioinformatic analysis was performed to reveal the central genes and pathways that regulated the osteogenic differentiation of ASCs. One of the interested genes C5AR1 was chosen for further investigation. A total of 1521 upregulated and 3020 downregulated genes were identified between the ASCs with osteogenic induction and controls. Functional gene ontology analysis revealed that these significantly differentially expressed genes (DEGs) were associated with cell cycle, protein binding, and nucleotide binding. Pathway analysis showed that many canonical pathways, such as the MAPK signaling pathway and the PI3K-AKT pathway, might actively be involved in regulating osteogenic differentiation of ASCs. A total of three subnetworks and 20 central nodes were identified by the protein-protein interaction analysis. In addition, the expression level of C5AR1 was significantly increased during osteogenic differentiation of ASCs. The downregulation of C5AR1 dramatically reduced the expression levels of osteogenic differentiation biomarkers and calcium nodule formation capacity. Collectively, we have provided a number of novel genes and pathways that might be indispensable for ASC osteogenic differentiation. Manipulating the levels of this candidate gene might contribute to the osteoporosis therapy. [ABSTRACT FROM AUTHOR]

Aims: To compare the efficacy and safety of saxagliptin and glimepiride in type 2 diabetes (T2D) patients who are inadequately controlled with metformin monotherapy. Materials and methods: In this 48‐week, multi‐centre, open‐label, randomized, parallel trial (NCT02280486, clinicaltrials.gov), a total of 388 T2D patients were randomized 1:1 to saxagliptin or glimepiride groups. The primary endpoint was achievement of HbA1c <7.0%, without hypoglycaemia, defined as blood glucose <3.9 mmol/L and weight gain <3.0% after 48 weeks of treatment. Results: Over 48 weeks, a greater proportion of patients achieved the primary endpoint with saxagliptin compared with glimepiride (43.3% vs 31.3%; odds ratio, 1.38, 95% CI, 1.05‐1.82; P = 0.019), especially among patients with baseline HbA1c <8.0%, duration <5 years or baseline BMI ≥25 kg/m2. Mean reduction in HbA1c was similar in the two treatment groups at Week 48 (−0.94% with saxagliptin vs −0.98% with glimepiride; P = 0.439). Bodyweight decreased with saxagliptin, but increased with glimepiride over the treatment period, and the treatment difference was −1.6 kg (P < 0.001) at Week 48. The proportion of patients experiencing hypoglycaemia was much lower with saxagliptin vs glimepiride (3.1% vs 12.8%; P < 0.001). Conclusions: This study provides evidence that, compared to glimepiride, saxagliptin more effectively achieves a composite endpoint of adequate glycaemic control without hypoglycaemia and without weight gain in T2D patients who are inadequately controlled with metformin monotherapy, especially in overweight patients with moderate hyperglycaemia and a relatively short duration of diabetes. [ABSTRACT FROM AUTHOR]

Graphene with massless Dirac fermions can have exceptionally strong third-order optical nonlinearities. Yet reported values of nonlinear optical susceptibilities for third-harmonic generation (THG), four-wave mixing (FWM) and self-phase modulation vary over six orders of magnitude. Such variation likely arises from frequency-dependent resonance effects of different processes in graphene under different doping. Here, we report an experimental study of THG and FWM in graphene using gate tuning to adjust the doping level and vary the resonant condition. We find that THG and sum-frequency FWM are strongly enhanced in heavily doped graphene, while the difference-frequency FWM appears just the opposite. Difference-frequency FWM exhibited a novel divergence towards the degenerate case in undoped graphene, leading to a giant enhancement of the nonlinearity. The results are well supported by theory. Our full understanding of the diverse nonlinearity of graphene paves the way towards future design of graphene-based nonlinear optoelectronic devices. Third-harmonic generation and four-wave mixing of light can be enhanced in graphene with gate tuning to adjust the doping level. The findings may lead to new graphene-based nonlinear optoelectronic devices. [ABSTRACT FROM AUTHOR]

Diabetic patients have an increased risk of osteoporosis-associated fractures. However, the results of most studies of the effects of diabetes on bone mass in patients with type 2 diabetes (T2DM) have been contradictory. To clarify these conflicting findings, we investigated the effects of diabetic serum on the proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs). We used human sera from subjects with different levels of glycemic control to culture the MSCs and induce osteogenic differentiation. The rate of MSC proliferation differed when MSCs were cultured with sera from diabetic subjects with different levels of hyperglycemia. Hyperglycemic sera promoted MSC proliferation to some extent, but all the diabetic sera inhibited the differentiation of MSCs to osteoblasts. The effects of type 2 diabetic sera on the proliferation and osteogenic differentiation of MSCs are closely related to glycemic control. Our data demonstrate the importance of stratifying the study population according to glycemic control in clinical research into diabetic osteoporosis. [ABSTRACT FROM AUTHOR]

We numerically examine the opportunities for wideband wavelength conversion through four-wave mixing (FWM) in a foundry-compatible 220\text-\textnm-thick silicon-on-insulator (SOI) waveguide covered with the highly nonlinear two-dimensional material of graphene. As a case study, we consider a foundry-compatible SOI waveguide shaped as a double spiral and covered with two separate graphene sheets, which are covered in turn by two solid polymer electrolyte gates. When combining subwatt-level pump powers with a short waveguide length of only a few hundreds of micrometers, “perfectly phase-matched” conversion with significant efficiencies close to -20\;\textdB can be obtained over a more than 40\text-\textTHz-wide signal band adjacent to the pump frequency. Because of the tunability of the graphene properties using the electrolyte top gates, it is also possible to obtain “quasi-phase matched” FWM conversion through a periodic sign reversal of the graphene third-order nonlinearity along the waveguide. Conversion efficiencies exceeding -30\;\textdB can be achieved over a 3.4\text-\textTHz-wide signal band that is situated as much as 58\;\textTHz away from the pump frequency. Finally, the tunability of the graphene also allows for switching the converter from the perfectly phase-matched to the quasi-phase-matched operation mode. [ABSTRACT FROM PUBLISHER]

MicroRNAs (miRNAs) negatively regulate target gene expression by binding to 3′-untranslated region of target mRNA. Single-nucleotide polymorphisms (SNPs) that reside in the miRNA target sites can affect the bindings of miRNAs to mRNAs. Compelling evidence has shown that miRNAs contribute to the etiology of type 2 diabetes (T2DM). We hypothesized that SNPs in diabetes-related miRNA target-binding sites could be associated with the risk of T2DM. We selected 10 SNPs on miRNA-binding sites by using bioinformatics software. Genotypes of T2DM patients (n=1017) and normal controls (n=1059) were analyzed by TaqMan assay. The variant genotypes rs1366600CC and TC/CC in the insulin receptor (INSR) gene, rs2292899GA in the acyl-CoA synthetase 1 (ACSL1) gene and rs11724758AA in the fatty-acid-binding protein 2 (FABP2) gene were associated with T2DM (adjusted odds ratios (ORs) (95% confidence intervals)=2.03 (1.02-4.01), 1.28 (1.04-1.57), 1.22 (1.004-1.49) and 0.76 (0.58-0.997), respectively). The analysis stratified by age, gender, waist circumstance and living habits also revealed these genotypes' effect. Furthermore, crossover analysis indicated those who exposed to both environmental factor and putative risk genotypes did have the highest risk of T2DM. A cumulative effect of SNPs rs1366600, rs2292899 and rs11724758 was observed with individuals carrying 2, 3 and 4-6 risk alleles having a gradually increased risk of T2DM (OR=1.52, 1.81 and 2.28, P for trend <0.001). Our result suggested that INSR rs1366600, ACSL1 rs2292899 and FABP2 rs11724758 could influence the susceptibility to T2DM in Chinese Han population, most likely through their effects on the specific miRNA-binding sites and functional characterizations of three genes are needed. [ABSTRACT FROM AUTHOR]

Summary Our aim was to investigate whether the ADIPOQ gene polymorphisms are associated with the metabolic syndrome (MetS). Genotypes of MetS patients ( n= 1049) and normal controls ( n= 1092) were analysed by TaqMan® assay, and serum adiponectin concentration was measured by ELISA. The variant genotypes rs266729CG; rs1063539GC, GC/CC; rs16861205AA and rs7649121AT, AT/TT (Adjusted P= 0.037, 0.044, 0.025, 0.011, 0.019, 0.020, respectively) of the ADIPOQ gene were associated with MetS. Patients with rs266729CG, CG/GG genotypes ( P= 0.034, 0.035) and rs7649121AT, AT/TT genotypes ( P= 0.013, 0.022) had higher levels of serum adiponectin than those with the CC and AA genotypes respectively. Furthermore, the prevalence of haplotypes GGAAAATC and GGGTAACC was lower in cases (10.7% and 4.5%) than in controls (12.1% and 5.9%) [Adjusted ORs (95% CIs) = 0.70 (0.54-0.91), 0.65 (0.46-0.92)]. The ADIPOQ gene variants associated with the risk of MetS in this study must be validated by further functional studies to reveal any potential effects on metabolism. [ABSTRACT FROM AUTHOR]

This study was to evaluate the association between ADIPOQ gene variants and type 2 diabetes mellitus (T2DM). TaqMan assay was performed to test the genotypes in T2DM patients ( n = 1,105) and normal control subjects ( n = 1,107). Serum adiponectin concentration was measured by ELISA kit. The variant genotypes rs7649121AT and rs7649121AT/TT, compared with the AA genotype, were associated with a significantly decreased risk of T2DM [Adjusted OR (95% CI) = 0.79(0.66-0.95), 0.80(0.67-0.96), respectively]. In stratified analysis, rs2241767AG genotype increased the risk of T2DM in obesity group [Adjusted OR (95% CI) = 1.32(1.03-1.69)]. Patients with genotype AG/GG of rs2241767 had lower levels of serum adiponectin than those with the genotype AA ( P = 0.044). Haplotype analyses were not significant. Crossover analysis of rs7649121 and environmental risk factor (obesity) indicated that the protect effect of rs7649121AT/TT maybe offset by the environmental risk. Those who exposed to environmental risk factor (obesity) had a chance to attack T2DM compared with those who did not expose to the two factors [Adjusted OR (95% CI) = 1.64(1.30-2.06)]. This study suggested that the ADIPOQ gene polymorphisms were associated with the risk of T2DM in a Chinese Han population. [ABSTRACT FROM AUTHOR]

Abstract: Peroxisome proliferator-activated receptor (PPAR-γ), which is mainly involved in adipocyte differentiation, has been suggested to play an important role in the pathogenesis of insulin resistance and atherosclerosis. We investigated the frequencies of two common tagging polymorphisms of the PPAR-γ gene and two of PPAR-α with minor allele frequency (MAF) ≥0.05 in the Chinese Han population and analyzed the correlation between the different genotypes and the risk of type 2 diabetes mellitus (T2DM). TaqMan® assay was performed to test the genotypes in T2DM patients (n = 1,105) and normal controls (n = 1,107). Serum adiponectin concentration was measured by ELISA kit. The variant genotypes rs17817276GG, rs3856806CT and rs3856806CT/TT of PPAR-γ were associated with T2DM, P = 0.023,0.037 and 0.018, respectively. Furthermore, the prevalence of haplotype GT in PPAR-γ was less frequent in the case subjects (0.3%) than in the controls (1.9%) [P < 0.001,OR(95%CI)=0.13 (0.06-0.31)]. Patients with genotype TT of rs3856806 had a higher serum level of adiponectin than those with the genotype CC and CT (P = 0.031 and 0.038, respectively). There was no statistically significant difference between patients and controls in genotype distribution of rs6537944 and rs1045570 of the RXR-α gene. The present study suggests that the variant genotypes in the PPAR-γ gene could decrease the risk for the development of T2DM in the Chinese Han population. [Copyright &y& Elsevier]

Background Previous investigations of the protein kinase C zeta ( PRKCZ) gene, a susceptibility factor for type 2 diabetes mellitus (T2DM), have focussed on its single nucleotide polymorphisms (SNPs). In a departure from these earlier studies, we tested six tagging markers of PRKCZ based on the Hapmap database to evaluate their association with T2DM. Methods PCR-RFLP was performed to test the genotypes in type 2 diabetes patients ( n = 343) and normal controls ( n = 429). Insulin-related indexes were calculated from levels of fasting plasma insulin (FPI) and fasting plasma glucose (FPG). Results The variant genotypes, rs3753242TT, rs2503706CT, rs2503706CT/ TT and rs262654TT were associated with T2DM. And the significance remained for rs3753242 TT ( p < 0.001) after the false discovery rate (FDR) correction. There was a doubling in the prevalence of the TTGCCC haplotype in the case subjects (14.2%) compared with the control subjects (6.9%) [OR (95% CI) = 2.19(1.49-3.22)]. In the control group, none of the haplotypes studied was associated with insulin-related indexes. Conclusions The PRKCZ gene variants associated with the development of T2DM in this study must be investigated in a larger population to reveal any potential effects on metabolism. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Single crystal perovskites are used in solar cells, photodetectors, and other devices due to their excellent light absorption and carrier transport characteristics. However, for light‐emitting applications, photoluminescence (PL) is usually weak for MAPbBr3 (MA = CH3NH3+) single crystals (MBSCs) compared with their polycrystalline counterpart. Therefore, developing novel techniques to process MBSCs with different morphologies for PL‐related applications is greatly needed. The current strategies for making perovskite crystals are mostly based on bottom‐up method (chemical synthesis and assembling). Here, an easy method to achieve top‐down fabrication of MBSCs, i.e., femtosecond laser processing MBSC surface by controlling the laser parameters is demonstrated. The femtosecond laser processing technology can achieve two orders of magnitude enhancement under ambient conditions in PL. In addition, the processed regions also show three times enhancement in PL under nitrogen environment. It is assumed that this is mainly due to the texture based on photon recycling and light out‐coupling mechanism, and the passivation of surface recombination centers on MBSC. This study not only provides a convenient top‐down strategy to achieve a range of morphological micro‐/nanostructures with enhanced PL on MBSC surface, but also paves the way for applications of MBSCs in light emitting or PL imaging devices. Developing novel techniques to process MAPbBr3 single crystals (MBSCs) with various morphologies for photoluminescence‐related applications is highly necessary. Multi‐morphological micro‐/nanostructures induced by a top‐down fabricating technology, i.e., femtosecond laser processing, are achieved on MBSC surfaces. Dramatically‐enhanced photoluminescence of two orders of magnitude in ambient conditions and three times in nitrogen atmosphere is demonstrated, which is promising for photoluminescence‐related applications. [ABSTRACT FROM AUTHOR]

The authors of this Article have become aware of the following recent paper that reports the electrically tunable degenerate four-wave mixing in graphene-covered SiN waveguides: “Alexander, K., Savostianova, N. A., Mikhailov, S. A., Kuyken, B. & Van Thourhout, D. Electrically tunable optical nonlinearities in graphene-covered SiN waveguides characterized by four-wave mixing. ACS Photon. 4, 3039-3044 (2017).” This reference has been added as ref. 33 in the new sentence “Very recently, degenerate four-wave mixing in graphene-covered SiN waveguides with ion-gel gating was experimentally studied33.” Accordingly, the previous sentence has been amended to read as “Few such experiments have been reported, although they have been suggested in theoretical work28-32” and all subsequent references have been renumbered. These changes have been made in the online versions. [ABSTRACT FROM AUTHOR]