All-dielectric absorber based on nano-graphite sheets/ionogels with configurable absorbing band.

With the increasing complexity of the electromagnetic environment, there is a growing demand for the manipulation of electromagnetic waves, leading to the rapid development in configurable microwave absorbers. All-dielectric absorbers offer broadband and high-intensity absorption effects in microwave absorption and shielding. However, they face a significant challenge: their performance is not adjustable once the design is completed. In this study, we propose a solution to this problem by creating all-dielectric absorbers with flexibly configurable absorbing properties. We achieve this by designing a composite material of ionogels/nano-graphite sheets into compressible deformable absorbing units that can be molded into different shapes using 3D printing modes. The plasticity allows us to change the performance of the all-dielectric absorber, including the microwave absorption intensity, absorption peak, frequency bandwidths, and wide-angle absorption performance. With this approach, we can flexibly manipulate electromagnetic waves using all-dielectric absorbers through different plasticity models.

Origami-based microwave absorber with a reconfigurable bandwidth.

Reconfigurability is critical for the research fields in electromagnetics, mechanics, and acoustics, due to the controllability of functionalities. This Letter numerically and experimentally demonstrates an origami-based absorber with a reconfigurable bandwidth. The proposed structure provides four transformable models: flat sheet, single-arch-folded, double-arch-folded, and U-shaped strips filled, corresponding to the performance of nearly no absorption, one-peak absorption, two-peak absorption, and ultra-broadband absorption (3.4-18 GHz), which clearly demonstrates the bandwidth-enhancement effect. In contrast with the traditional structural absorbers, the transformable flat sheet and U-shaped strips are obtained by three-dimensional printing, which exhibits an obvious superiority in prototype fabrication. These results provide a feasible strategy for energy dissipation and origami transformation.

Non-high-density lipoprotein cholesterol may predict the cardio-cerebrovascular risk in patients on maintenance hemodialysis.

BACKGROUND: Non-high-density lipoprotein cholesterol (non-HDL-C) may be an independent risk factor for cardio-cerebrovascular disease (CVD); however, the cutoff level in patients on maintenance hemodialysis (MHD) is unknown. METHODS: This was a retrospective multicenter study of MHD patients treated at 10 dialysis centers in Guangdong Province from July 1, 2016, to April 1, 2017. Laboratory test data were collected and CVD complications and outcomes recorded. RESULTS: In total, 1288 eligible patients were included in this study; the non-HDL-C interquartile range was 2.76 (2.24-3.45) mmol/L. Over a median follow-up time of 24 months, 141 patients developed CVD. The non-HDL-C level was a principal risk factor for such events (P < 0.05; 95% confidence interval 0.800-0.842). The maximum Youden index was 0.549 and the best cutoff > 3.39 mmol/L. CONCLUSION: Higher baseline non-HDL-C levels may increase the CVD risk in MHD patients. Thus, non-HDL-C effectively predicts CVD.

Bowel symptoms and self-care strategies of survivors in the process of restoration after low anterior resection of rectal cancer.

BACKGROUND: The purpose of this research is to identify the bowel symptoms and self-care strategies for rectal cancer survivors during the recovery process following low anterior resection surgery. METHODS: A total of 100 participants were investigated under the structured interview guide based on the dimensions of "symptom management theory". RESULTS: 92% of participants reported changes in bowel habits, the most common being the frequent bowel movements and narrower stools, which we named it finger-shaped consistency stools. The 6 most frequently reported bowel symptoms were excessive flatus (93%), clustering (86%), urgency (77%), straining (62%), bowel frequency (57%) and anal pendant expansion (53%). Periodic bowel movements occurred in 19% participants. For a group of 79 participants at 6 to 24 months post-operation, 86.1% reported a significant improvement of bowel symptoms. Among 68 participants of this subgroup with significant improvements, 70.5% participants reported the length of time it took was at least 6 months. Self-care strategies adopted by participants included diet, bowel medications, practice management and exercise. CONCLUSIONS: It is necessary to educate patients on the symptoms experienced following low anterior resection surgery. Through the process of trial and error, participants have acquired self-care strategies. Healthcare professionals should learn knowledge of such strategies and help them build effective interventions.

Physical mechanisms for tuning the nonlinear effects in photonic crystals.

By simultaneously taking field localization and slow light effects into account, in this paper we make use of a field averaging method to calculate the effective nonlinear refractive index coefficient (n2) of Kerr photonic crystals (PhCs) in the first band. Although the nonlinear PhC is beyond the traditional long-wavelength limit, interestingly, the theoretically calculated effective n2 agrees well with one numerically measured via the self-phase-modulation induced spectral broadening. Moreover, due to the cooperative influence of field localization and slow light effects, the effective n2 of the PhC decreases slowly at first and then goes up quickly with increasing frequency. This kind of dispersive nonlinearity is purely induced by the periodic nanostructures because the optical parameters of both components of the PhC we took are frequency-independent. Our results may pave the way for enhancing or limiting nonlinear effects and provide a method for producing the dispersive nonlinearity.

Use of cataract surgery in urban Beijing: a post screening follow-up of the elderly with visual impairment due to age-related cataract.

OBJECTIVE: To understand the perception for the use of cataract surgical services in a population of acceptors and non-acceptors of cataract surgery in urban Beijing. METHODS: From a community-based screening program a total of 158 patients with presenting visual acuity of less than 6/18 on either eye due to age-related cataract were informed about the possibility of surgical treatment. These patients were interviewed and re-examined 36 to 46 months after initial screening. The main reasons for not accepting surgery were obtained using a questionnaire. Vision function and vision-related quality of life scores were assessed in those who received and did not receive surgery. RESULTS: At the follow-up examination 116 of the 158 patients were available and 36 (31.0%) had undergone cataract surgery. Cases who chose surgery had higher education level than those who did not seek surgery (OR=2.64, 95% CI: 1.08-6.63, P=0.02). There were no significant differences in vision function (P=0.11) or quality of life scores (P=0.16) between the surgery group and the non-surgery group. Main reasons for not having surgery included no perceived need (50.0%), feeling of being "too old" (19.2%), and worry about the quality of surgery (9.6%). Cost was cited by 1 (1.9%) subject as the main reason for not seeking surgery. CONCLUSIONS: The data suggest that in China's capital urban center for patients with moderate visual impairment there is a relative low acceptance rate of cataract surgery, mainly due to people's perception of marginal benefits of surgery. Cost is not a determining factor as barrier to undergo surgery and patients with poorer education are less likely to undertake surgery.

Gonioscopy and ultrasound biomicroscopy in the detection of angle closure in patients with shallow anterior chamber.

OBJECTIVE: To assess the agreement between gonioscopy and ultrasound biomicroscopy (UBM) in detecting angle closure in Chinese patients with shallow anterior chamber. METHODS: An observational comparative study of the two different examination methods was conducted. Patients with normal intraocular pressure and temporal peripheral anterior chamber depth less than a quarter of corneal thickness based on slit lamp examination were included in this study from December 2007 to May 2009 in the outpatient clinic of First Hospital of Tsinghua University. Gonioscopy was performed with a Goldman goniolens in dark room first and followed by full beam light and indentation. If the filtering trabecular meshwork was invisible or any peripheral anterior synechia was found, that quadrant of the angle was considered closed. UBM was first undertaken in a darkened room then repeated with normal room lighting. If iridotrabecular apposition was showed, that quadrant of the angle was considered closed. The status of angle closure of each quadrant with different methods was recorded. RESULTS: 85 eyes of 46 patients were included in this study. The agreement between gonioscopy and UBM was poor (Κ<0.4) with Kappa analysis in both dark and light conditions in each quadrant. The accordance of agreement between gonioscopy and UBM was hardly affected by age or sex, while in dark condition, eyes with deeper anterior chamber (P=0.005) or plateau iris configuration tended to produce different results (P=0.075) in the 2 methods. CONCLUSION: Gonioscopy and UBM are both indispensable methods for detecting angle closure, neither can completely replace the other.

Third order nonlinear optical property of Bi2Se3.

The third order nonlinear optical property of Bi2Se3, a kind of topological insulator (TI), has been investigated under femto-second laser excitation. The open and closed aperture Z-scan measurements were used to unambiguously distinguish the real and imaginary part of the third order optical nonlinearity of the TI. When excited at 800 nm, the TI exhibits saturable absorption with a saturation intensity of 10.12 GW/cm² and a modulation depth of 61.2%, and a giant nonlinear refractive index of 10⁻¹4 m²/W, almost six orders of magnitude larger than that of bulk dielectrics. This finding suggests that the TI:Bi2Se3 is indeed a promising nonlinear optical material and thus can find potential applications from passive laser mode locker to optical Kerr effect based photonic devices.

Impact of Vitamin D on the Occurrence and Development of Intestinal Diseases: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

AIM: To determine the impact of vitamin D on the occurrence and progression of intestinal disorders, the authors of this study have conducted a systematic review and meta-analysis. BACKGROUND: Vitamin D regulates inflammation and immunity in association with reducing the disease symptoms of several gastrointestinal diseases, including inflammatory bowel diseases (IBD), Crohn's disease (CD), ulcerative colitis (UC), and colorectal cancer (CRC). However, the exact role of vitamin D in the occurrence and development of intestinal diseases is unclear so far. METHODOLOGY: The relevant studies were searched in PubMed and screened based on inclusion and exclusion criteria. The quality of full-text studies was assessed using National Heart, Lung, and Blood Institute (NIH) scale. The study was conducted as per the PRISMA guidelines. The overall estimate was calculated in terms of risk ratio with a 95% confidence interval. The publication bias was assessed qualitatively using a funnel plot, and heterogeneity among studies was calculated using I2 statistics. All analyses were done using RevMan 5.0. RESULTS: The overall risk ratio using random effect model was found to be 0.89 (0.70, 1.12), which indicates the non-significant role of vitamin D in the occurrence and development of intestinal diseases as compared to the non-vitamin D group. However, after exclusion of studies with low and high sample sizes, a significant reduction in intestinal diseases was observed in the vitamin D group as compared to the non-vitamin D group. Further, no heterogeneity among the studies was observed. CONCLUSION: Based on available evidence, vitamin D might play a significant role in the reduction of intestinal diseases; however, more studies with high sample sizes are required to draw a valid conclusion.

Efficient Calibration of Groundwater Contaminant Transport Models Using Bayesian Optimization.

Numerical modeling is a significant tool to understand the dynamic characteristics of contaminants transport in groundwater. The automatic calibration of highly parametrized and computationally intensive numerical models for the simulation of contaminant transport in the groundwater flow system is a challenging task. While existing methods use general optimization techniques to achieve automatic calibration, the large numbers of numerical model evaluations required in the calibration process lead to high computing overhead and limit the efficiency of model calibration. This paper presents a Bayesian optimization (BO) method for efficient calibration of numerical models of groundwater contaminant transport. A Bayes model is built to fully represent calibration criteria and derive the objective function for model calibration. The efficiency of model calibration is made possible by the probabilistic surrogate model and the expected improvement acquisition function in BO. The probabilistic surrogate model approximates the computationally expensive objective function with a closed-form expression that can be computed efficiently, while the expected improvement acquisition function proposes the most promising model parameters to improve the fitness to the calibration criteria and reduce the uncertainty of the surrogate model. These schemes allow us to find the optimized model parameters effectively by using a small number of numerical model evaluations. Two case studies for the calibration of the Cr(VI) transport model demonstrate that the BO method is effective and efficient in the inversion of hypothetical model parameters, the minimization of the objective function, and the adaptation of different model calibration criteria. Specifically, this promising performance is achieved within 200 numerical model evaluations, which substantially reduces the computing budget for model calibration.

Semiconductor photocatalysts: A critical review highlighting the various strategies to boost the photocatalytic performances for diverse applications.

The photocatalytic technology illustrates an eco-friendly and sustainable route to overcome environmental and energy issues. The successful construction of a photocatalyst depends on four key elements: light absorption ability, the density of active sites, redox capacity, and photoinduced electron-hole recombination rate. Sincemost of intrinsic semiconductor photocatalysts cannot meet all these requirements, they are often modified to boost their photocatalytic properties. Many strategies have been adopted to design novel and efficient photocatalysts for diverse applications. Herein, we review the most efficient of these strategies and methods focused on effectively overcoming the efficiency limitations of photocatalysts to promote their large-scale application. Subsequently, a particular aim is put on the most current studies for photocatalytic applications, including CO2 reduction, N2 fixation, H2 evolution, and pollutants degradation. Finally, key challenges and future perspectives in designing and implementing semiconductor photocatalysts for large-scale applications are discussed. Therefore, it is foreseen that this review will work as a guide for future research and provides a variety of strategies to develop novel and high-performance photocatalysts for various applications.

Interaction between graphene and metamaterials: split rings vs. wire pairs.

We have recently shown that graphene is unsuitable to replace metals in the current-carrying elements of metamaterials. At the other hand, experiments have demonstrated that a layer of graphene can modify the optical response of a metal-based metamaterial. Here we study this electromagnetic interaction between metamaterials and graphene. We show that the weak optical response of graphene can be modified dramatically by coupling to the strong resonant fields in metallic structures. A crucial element determining the interaction strength is the orientation of the resonant fields. If the resonant electric field is predominantly parallel to the graphene sheet (e.g., in a complementary split-ring metamaterial), the metamaterial's resonance can be strongly damped. If the resonant field is predominantly perpendicular to the graphene sheet (e.g., in a wire-pair metamaterial), no significant interaction exists.

Wavelength-tunable picosecond soliton fiber laser with Topological Insulator: Bi2Se3 as a mode locker.

Based on the open-aperture Z-scan measurement, we firstly uncovered the saturable absorption property of the topological insulator (TI): Bi2Se3. A high absolute modulation depth up to 98% and a saturation intensity of 0.49 GWcm(-2) were identified. By incorporating this novel saturable absorber material into an erbium-doped fiber laser, wavelength tunable soliton operation was experimentally demonstrated. Our result indicates that like the atomic layer graphene, the topological insulator Bi2Se3 could also operate as an effective saturable absorber for the passive mode locking of lasers at the telecommunication band.

Sustained transdermal delivery of human growth hormone from niosomal gel: in vitro and in vivo studies.

Human growth hormone (hGH) is widely used to treat several diseases for decades. However, the current treatment regime requires frequent injections via subcutaneous route due to short in vivo half-life, which leads to pain and poor patient compliance. In this study, a novel transdermal (non-invasive) hGH loaded niosomes gel was prepared to reduce the frequency of subcutaneous injections and to improve the patient compliance. Niosomes were prepared by film hydration technique at three levels of cholesterol. The particle size and entrapment efficiency increases with an increase in the level of cholesterol. Transmission electron microscopy images confirmed the spherical shape of niosomes without aggregation. Texture profiles analysis indicates that the niosomal gel has the required mechanical properties for transdermal application. The ex vivo permeation profile showed sustain hGH release for 4 days from the niosomal gel compared to 24 h from the control gel without niosomes. A rabbit skin irritation study showed no sign of irritation after application of niosomal gel. The pharmacokinetic parameters in the rat model showed 7.22-fold higher bioavailability with niosomal gel compared to control gel. In conclusion, the study demonstrated the potential of niosomal gel as an effective long-term sustained release strategy for hGH delivery to replace traditional subcutaneous injections.

Tin-based metal organic framework catalysts for high-efficiency electrocatalytic CO2 conversion into formate.

Electrochemical reduction of carbon dioxide (ERCO2) allows for the conversion of CO2 to value-added low-carbon chemicals. Catalysts are indispensable for an efficient ERCO2 process. In this work, a Sn-based metal-organic framework (Sn-MOF) was synthesized as an electrocatalyst for the conversion of CO2 to formate (HCOO-). Such a Sn-MOF electrocatalyst exhibits an outstanding performance with a formate selectivity up to 92% and a current density of 23.2 mA cm-2 at -1.2 VRHE. Density functional theory calculations were used to probe and analyze the catalytic ERCO2 mechanism. This work shows the possibility to achieve a high efficiency of a pure Sn-MOF in catalyzing ERCO2 directly. In addition, this work provides insights into the design and synthesis of highly efficient ERCO2 electrocatalysts for practical applications.

Polymorphisms in the vascular endothelial growth factor gene and the risk of diabetic retinopathy in Chinese patients with type 2 diabetes.

PURPOSE: To investigate whether single nucleotide polymorphisms (SNPs) in the vascular endothelial growth factor (VEGF) gene are associated with diabetic retinopathy (DR) in a cohort of Chinese patients with type 2 diabetes mellitus (T2DM). METHODS: A total of 268 patients with T2DM (129 with DR and 139 without DR) were recruited and enrolled in the study. Patients with T2DM were assigned to a DR group or a diabetic-without-retinopathy group, based on the duration of diabetes and grading of fundus images. Genotypes of eight SNPs in the VEGF gene (rs699947, rs833061, rs13207351, rs2010963, rs833069, rs2146323, rs3025021, and rs3025039) were analyzed using a mass-array genotyping system, and an association study was performed. RESULTS: After adjusting for covariates, a significant association of DR was observed with the homozygous genotype of the minor allele for promoter SNPs rs699947 (odds ratio (OR)=3.54, 95% confidence interval (CI): 1.12-11.19), rs833061 (OR=3.72, 95% CI: 1.17-11.85) and rs13207351 (OR=3.76, 95% CI: 1.21-11.71). A significant association of DR was also observed with haplotype ACA, as defined by minor alleles of promoter SNPs rs699947, rs833061, and rs13207351 (OR=1.52, 95% CI: 1.03-2.24), and haplotype GAA, as defined by SNPs rs2010963, rs833069, and rs2146323 (OR=1.62, 95% CI: 1.08-2.41). CONCLUSIONS: Our data suggest that polymorphisms in the promoter region of the VEGF gene increase the risk of DR in Chinese patients with T2DM.

Fast separation ultra-performance liquid chromatography for determination of pre-column derivative abamectin and ivermectin residues in vegetable.

A new residue method for quantification of abamectin and ivermectin in vegetable is described in the article. The derivative process is devised that acylating chemical is firstly performed by N-methylimidazole (MI) and trifluoroacetic anhydride (TFAA), then which reacted with hydroxyl function of abamerctin to make fluorescence. The influence of triethylamin (TEA) is examined. Separation is resolute by a short column of 1.7 µm size and operated at high pressure values (10.000 psi). The optimal chromatographic condition and the highest sensitivity are achieved by acetonitrile: water (95: 5), 0.4 mL/min, 0.2 µL injector. The detection limits of abamectin and ivermectin are 1 µg/kg respectively.

Microwave-assisted hydrolysis of lutein and zeaxanthin esters in marigold (Tagetes erecta L.).

Saponification of lutein and zeaxanthin was performed by microwave-assisted hydrolysis (MAH) and analysed by ultra performance liquid chromatography. The optimal condition of MAH was studied, and the degradation or isomerization of lutein and zeaxanthin were estimated under MAH. The concentrations of lutein and zeaxanthin in 20 marigold samples were assessed by saponification using traditional heater and MAH, the regression coefficient of lutein obtained by two methods was 0.9688 and that of zeaxanthin was 0.9527. The limit of detection for lutein and zeaxanthin was 0.05 and 0.1 µg/ml, respectively, and the limit of quantification for lutein and zeaxanthin was 0.05 mg/100 g and 0.1 mg/100 g, respectively.

SNHG15 knockdown inhibits diabetic nephropathy progression in pediatric patients by regulating the miR-141/ICAM-1 axis in vitro.

Long non-coding RNAs (lncRNAs) are confirmed to be involved in modulating diabetic nephropathy (DN). The present study is aimed to explore the regulatory mechanism of lncRNA small nucleolar RNA host gene 15 (SNHG15) on pediatric DN. Human glomerular mesangial cells (HGMCs) were exposed to high glucose (HG) to produce an in vitro model. The results showed that SNHG15 was remarkably up-regulated in pediatric DN tissues and HG-induced HGMCs. Functional experiments indicated that both silencing of SNHG15 and overexpression of miR-141 elevated the cell viability, and suppressed the inflammation in HG-induced HGMCs. SNHG15 was identified to be a lncRNA that could bind to miR-141, and ICAM-1 was a downstream target gene of miR-141. Both the low expression of miR-141 and high expression of ICAM-1 reversed the inhibiting effect of SNHG15 knockdown on inflammatory response, and the promoting effect on cell viability. To conclude, our study revealed that silencing of SNHG15 ameliorated the malignant behaviors of pediatric DN via modulating the miR-141/ICAM-1 axis in vitro.

Self-assembly of TiO2/ZIF-8 nanocomposites for varied photocatalytic CO2 reduction with H2O vapor induced by different synthetic methods.

Photoreduction of carbon dioxide (CO2) provides an effective perspective for solving the energy crisis and environmental problems. Herein, two types of composite photocatalysts (TiO2/ZIF-8) based on ZIF-8 and TiO2 have been designed and synthesized with the help of the grinding method and the solid-synthesis method. Both composite photocatalysts are employed for the photocatalytic reduction of CO2. In composite photocatalysts prepared by the grinding method, ZIF-8 particles are distributed on the surface of TiO2, and provide extra available spaces for storing CO2, which is beneficial for improving their photoreduction performances. As a result, an enhanced CO formation rate of 21.74 µmol g-1 h-1 with a high selectivity of 99% is obtained for this family of composite photocatalysts via the solid-gas mode without photosensitizers and sacrificial agents. For comparison, the other family of composite photocatalysts synthesized via the solid-synthesis method possesses structures similar to ZIF-8, where TiO2 is encapsulated inside the framework of ZIF-8. This structural feature obstructs the contact between the active sites of TiO2 and CO2, and leads to lower activities. The best CO formation rate of this family is only 10.67 µmol g-1 h-1 with 90% selectivity. Both the structural features of the two families of photocatalysts are described to explain their differences in photoreduction performances. The experimental finding reveals that different synthetic approaches indeed result in diversified structures and varied photocatalytic performances. This work affords a new scalable and efficient approach for the rational design of efficient photocatalysts in the area of artificial photosynthesis.