Multiple-polarization-sensitive photodetector based on a perovskite metasurface

Most polarization-sensitive photodetectors detect either linearly polarized (LP) or circularly polarized (CP) light. Here, we experimentally demonstrate a multiple-polarization photodetector based on a hybrid organic-inorganic perovskite (HOIP) metasurface, which is sensitive to both LP and CP light simultaneously. The perovskite metasurface is composed of a HOIP antenna array on a single-crystal HOIP film. Owing to the antenna anisotropy, the absorption of linearly polarized light at the metasurface depends on the polarization angle; also, due to the mirror asymmetry of the antenna elements, the metasurface is also sensitive to different circular polarizations. Polarization-dependent photocurrent responses to both LP and CP light are detected. Our results highlight the potential of perovskite metasurfaces for integrated photoelectric applications.

[Characteristic Analysis of nirS Denitrifying Bacterial Community in Lijiahe Reservoir During Stratification]

To explore the composition of the nirS denitrifying bacterial community during stratification in spring(March to May) in a drinking water reservoir and its relationship with water quality, the water quality and relative abundance and structure of the denitrifying bacterial community were analyzed using in-situ monitoring coupled with Illumina high-throughput sequencing technology in the Lijiahe Reservoir. The results showed that:① through high-throughput sequencing, 4 phyla and 13 genera were identified. The dominant bacterial phylum was Proteobacteria, and its relative abundance was between 52.5% and 70.6%. The overall trend of the relative abundance of Proteobacteria decreased on the time scale (P<0.05), and its relative abundance in the surface and middle layers was higher than that of the bottom layer on the spatial scale (P<0.05). There was no difference in the proportion of Proteobacteria between the surface and middle layers (P>0.05), and the abundance of its bottom layer was relatively stable; eight genera of bacteria with denitrification function were identified, among which the dominant bacterial genera (relative abundance>1%) were Dechloromonas and Pseudomonas. The relative abundance of Dechloromonas showed a trend of first decreasing and then increasing on the time scale, whereas the relative abundance of Pseudomonas showed a trend of increasing first and then decreasing on the time scale. There were no differences on the spatial scale between these two genera (P>0.05); the changes in bacterial diversity and abundance were basically similar, with a trend of first increasing and then decreasing on the time scale. The highest diversity and abundance of the bacterial community gradually increased with increasing depth on the spatial scale. ② ρ(TN) of the reservoir during stratification was 2.35-2.91 mg·L^-1, and the nitrogen pollution was more serious. In March and April, ρ(TN) on the vertical scale was basically similar and showed a decreasing trend. In May, the content of total nitrogen was higher than that in March and April, and the highest value of total nitrogen content occurred in the surface layer. ③ Redundancy analysis showed that water temperature, dissolved oxygen, nitrate, and ammonia nitrogen were the main driving factors, and ammonia nitrogen showed a significantly negative correlation with Dechlormonas. In summary, the study of nirS-type denitrification communities and related influencing factors will contribute to analyzing the characteristics of denitrifying bacterial community changes in a micro-polluted drinking water reservoir and provide a theoretical research basis for the biological remediation of nitrogen pollution in such reservoirs in the future.

Effects of air pollutant exposure on lung function in exercisers: a systematic review and meta-analysis

OBJECTIVE

The aim of this study is to systematically evaluate the effect of air pollutant exposure on lung function in exercisers.

MATERIALS AND METHODS

Computer search Web of Science, PubMed, EBSCO and Cochrane Library, MINORS scale for literature quality evaluation, and Stata 12.0 software for statistical analysis.

RESULTS

According to the literature inclusion and exclusion criteria, a total of 14 pieces of literature were screened and included in the Meta-analysis, and the literature quality was relatively high. Meta-analysis shows that air pollutant exposure has no significant effect on FVC, FEV1 and PEF of exercisers (p>0.05); but it can significantly increase the FeNO level of exercisers [Z=2.26, p = 0.024, SMD=-0.228, 95% CI= (-0.426, -0.031)]. Egger linear regression analysis shows that FVC [β=-4.64, p = 0.004, 95% CI= (-7.32,-1.95)] has the possibility of publication bias; FEV1, PEF and FeNO p>0.05 and 95% CI contains 0, there is no publication bias in the included literature. There is no sensitivity problem in the included literature, and the combined result is robust and reliable.

CONCLUSIONS

Exposure to air pollutants may cause allergic airway inflammation by increasing FeNO levels in exercised populations, and adversely affecting human health.

Catalytic O2 Activation toward Oxidative N-S Bond Formation by a Thiolato Fe(III) Complex

Compounds with the benzisothiazol-3-one (BIT) skeleton perform excellently in pharmaceutical science, while current synthetic methods remain limited in term of synthetic efficiency. Herein, we report the catalytic intramolecular N-S bond...

[Preliminary application of transoral robotic thyroidectomy: experience from an initial 30 cases]

Objective: To examine the surgical outcome of transoral robotic thyroidectomy. Methods: Clinic data of total 30 cases of transoral robotic thyroidectomy at the Department of Thyroid and Breast Surgery, the 960^th Hospital of People's Liberation Army from May 2020 to December 2020 were analyzed retrospectively. There were 3 males and 27 females, aged (31.5±11.0) years (range: 17 to 55 years), including 6 cases of benign tumor and 24 cases of malignant cancer (all papillary thyroid carcinoma). An inverted U-shaped incision 1.5 cm in length was made over the end of the frenulum of the lower lip. A wide subplatysmal space was created by bluntly passing with a vascular tunneller (8 mm diameter), and a 12 mm trocar was inserted through the lip incision for the camera port. Lateral oral mucosal incisions 8 mm in length were made near both lateral labial commissures, 8 mm robot trocars were inserted through the incisions. An 5 mm trocar was inserted through an incision made along the patient's right axillary fold into the subplatysmal working space and was connected with 5 mm ProGrasp for counter traction during the operation and for later drain insertion. Numerical scoring system (NSS) was used to assess cosmetic effect 1 month post-operation. Results: All the 30 transoral robotic thyroidectomies was successful, no case conversed to open operation. Postoperative hospital stay was (6.3±1.2) days (range: 4 to 10 days). The tumor size of thyroid cancers was (5.3±3.0) mm (range: 2 to 15 mm). Lymph node metastasis was observed in 12 cases. The retrieved central lymph node number was 10.5±4.4 (range: 4 to 20), while the central metastatic lymph node number was 2(2) (range: 1 to 11). Postoperative transient hypoparathyroidism occurred in 2 cases. Permanent hypoparathyroidism and vocal cord palsy didn't occur. Other surgical complications included hematoma, surgical site infection and perforation of chin flap, retrospectively in 1 case. Local regional lymph node recurrence wasn't developed during 1 to 7 months follow-up. All patients were satisfied with the postoperative cosmetic outcomes,NSS was 9.4±0.8 (range: 8.7 to 9.6). Conclusion: Transoral robotic thyroidectomy is safe and effective, suitable for early thyroid cancers without lateral lymph node metastasis, and has superior cosmetic results when the patients are selected carefully.

[Effects of different doses of glucocorticoids on minimally invasive procedures in pain patients with type 2 diabetes]

Objective: To investigate the effects of different doses of glucocorticoids on minimally invasive procedures in patients with type 2 diabetes mellitus (T2DM), and optimize the clinical pathways of minimally invasive procedures. Methods: The clinical data of 284 patients with T2DM who received minially invasive procedures from the Department of Pain Medicine, West China Hospital, Sichuan University from May 2017 to May 2020 were retrospectively reviewed. The patients were divided into two groups according to the main diagnostic types: spine-related group (n=148) and herpes zoster group (n=136). According to the cumulative dose of glucocorticoids (GCs) per unit body surface area during the hospitalization, patients were further divided into three subgroups: low-dose group (GCs<3.5 mg/m²), medium-dose group (3.5 mg/m² ≤GCs<7 mg/m²), and high-dose group (GCs≥7 mg/m²). The clinical characteristics of the patients in different subgroups of the two diseases groups were compared. The effects of the glucocorticoids on the pain intensity, blood glucose, length of hospital stay (LOS) and total hospitalization cost were compared among the 3 subgroups of the two diseases groups. Results: There were no significant differences in the age, gender, height, weight, visual analog scale (VAS) and fasting blood glucose before procedures between the two groups (all P>0.05). The VAS score of the low-dose group from the spine-related group was 4.5±1.6, which was higher than that of the medium-dose group (3.5±1.3) (P=0.004). VAS score was 4.3±1.3 in the medium-dose group and 4.4±1.6 in the high-dose group from the herpes zoster group, which were higher than that in the low-dose group (3.5±0.9) (P=0.006). In terms of blood glucose, the impact on the fasting blood glucose before and after the procedures in the low-dose group from the spine-related group was less than that in the medium dose group (P=0.013). In the herpes zoster group, the blood glucose of the low-dose group was (11±5) mmol/L, which had less influence on the blood glucose fluctuation during the hospitalization than that in the high-dose group [(15±5) mmol/L] (P<0.05). The LOS and hospitalization cost in the low-dose group from the spine-related group were (9±4) d and (10 583±4 851) yuan, respectively, which were less than those in the medium-dose group [(11±3) d and (15 202±7 418) yuan] and high-dose group [(13±6) d and (18 100±4 138) yuan] (all P<0.05); however, there was no significant difference among different subgroups in the herpes zoster group (all P>0.05). Conclusion: When used in the patients with T2DM undergoing minimally invasive procedures for spine-related diseases, low-dose glucocorticoids can obtain more clinical benefit than high dose, and high dose can lead to raised blood glucose, prolong the LOS, and increase the hospitalization cost.

[Outcomes of 1 000 cases of robotic thyroidectomy by bilateral axillo-breast approach: a retrospective study in a single center]

Objective: To examine the surgical outcome, completeness and safety of robotic thyroidectomy by bilateral axillo-breast approach (BABA). Methods: From February 2014 to May 2019, 1 000 cases of robotic thyroidectomy via BABA at the Department of Thyroid and Breast Surgery, the 960^th Hospital of People's Liberation Army were performed. The clinicopathologic characteristics, operation times, perioperative complications, and oncologic outcomes of patients underwent robotic thyroidectomy were collected and reviewed retrospectively. There were 216 males and 784 females, aging (42.3±11.5) years (range: 7 to 75 years). There were 270 cases with benign tumors, and 730 cases with malignant cancers (the tumor diameter was (7.9±6.7) mm (range: 0.1 to 60.0 mm)). Results: There were 999 patients received robotic thyroidectomy using BABA approach successfully, while only 1 case conversed to open operation. The postoperative hospital stay was (7.5±2.5) days (range: 2 to 30 days). Among the 730 patients with thyroid cancers, 725 cases (99.3%) were papillary thyroid carcinoma, 579(79.3%) cases were with papillary thyroid microcarcinoma. Lymph node metastasis was observed in 371(50.8%) cases. The retrieved central lymph node number was 11.2±6.1 (range: 1 to 44),and the retrieved lateral lymph node number was 14.0±8.8 (range: 1 to 52). Postoperative transient hypoparathyroidism and vocal cord palsy occurred in 247(24.70%) and 56(5.60%) cases. Both of permanent hypoparathyroidism and vocal cord palsy occurred in 2 (0.20%) cases. Other surgical complications included chyle leakage (6.1%, 28/460), trachea injury (0.40%, 4/1 000), carotid artery injury (0.10%, 1/1 000). Local regional lymph node recurrence was developed in 4 patients. All patients were satisfied with the postoperative cosmetic outcomes. Conclusions: Robotic thyroidectomy by BABA is safe and effective, suitable for large benign tumors and early thyroid cancers with central or lateral lymph node metastasis. It could obtain superior cosmetic results.

[gwasfilter: an R script to filter genome-wide association study]

Objective: To develop an R script that can efficiently and accurately filter genome-wide association studies (GWASs) from the GWAS Catalog Website. Methods: The selection principles of GWASs were established based on previous studies. The process of manual filtering in the GWAS Catalog was abstracted as standard algorithms. The R script (gwasfilter.R) was written by two programmers and tested many times. Results: It takes six steps for gwasfilter.R to filter GWASs. There are five main self-defined functions among this R script. GWASs can be filtered based on "whether the GWAS has been replicated" "sample size" "ethnicity of the study population" and other conditions. It takes no more than 1 second for this script to filter GWASs of a single trait. Conclusions: This R script (gwasfilter.R) is user-friendly and provides an efficient and standard process to filter GWASs flexibly. The source code is available at github (https://github.com/lab319/gwas_filter).

Diffuse reflection and reciprocity-protected transmission via a random-flip metasurface

Rough surfaces lead to diffused light in both reflection and transmission, thereby blurring the reflected and transmitted images. Here, we merge the traditionally incompatible diffuse reflection and undistorted transmission by introducing the concept of random-flip metasurfaces made of randomly flipped components. These metasurfaces have a globally random phase in reflection that leads to diffuse reflection, while the local space inversion and reciprocity principle ensure distortion-free transmission. Notably, the metasurface reflects like a rough surface yet transmits like a smooth one in a broad spectrum. On the basis of complementary random arrays of gold nanorods, we verified this functionality by both optical spectroscopy and imaging experiments over a broad range of frequencies from the visible to the infrared regime. This feature, which originates from breaking the phase correlation between reflection and transmission by the metasurface, could enable a range of new optical materials and display technology.

Flexible Phase Change Materials for Electrically-Tuned Active Absorbers

Phase change materials (PCMs), such as GeSbTe (GST) alloys and vanadium dioxide (VO₂ ), play an important role in dynamically tunable optical metadevices. However, the PCMs usually require high thermal annealing temperatures above 700 K, but most flexible metadevices can only work below 500 K owing to the thermal instability of polymer substrates. This contradiction limits the integration of PCMs into flexible metadevices. Here, a mica sheet is chosen as the chemosynthetic support for VO₂ and a smooth and uniformly flexible phase change material (FPCM) is realized. Such FPCMs can withstand high temperatures while remaining mechanically flexible. As an example, a metal-FPCM-metal infrared meta-absorber with mechanical flexibility and electrical tunability is demonstrated. Based on the electrically-tuned phase transition of FPCMs, the infrared absorption of the metadevice is continuously tuned from 20% to 90% as the applied current changes, and it remains quite stable at bending states. The metadevice is bent up to 1500 times, while no visible deterioration is detected. For the first time, the FPCM metastructures are significantly added to the flexible material family, and the FPCM-based metadevices show various application prospects in electrically-tunable conformal metadevices, dynamic flexible photodetectors, and active wearable devices.

[Study on the relationship between ABCB1 gene polymorphism and hemorrhage risk after thrombolysis of cerebral ischemic stroke in Shangqiu area]

Using a cross-sectional study, 246 patients with hemorrhage and transformation after cerebral ischemic stroke(CIS) thrombolysis who were admitted to Shangqiu First People's Hospital, Shangqiu Municipal Hospital, and Shangqiu Liangyuan Traditional Chinese Medicine Hospital from March 2018 to May 2020 were selected as the observation group, 246 patients with no hemorrhage transformation after CIS thrombolysis during the same period were selected as the control group with a ratio of 1∶1. Polymerase chain reaction and pyrosequencing methods were used to detect the single nucleotide polymorphisms of the two groups of ABCB1 genes. The frequency distribution of each genotype of the two groups of ABCB1 gene polymorphism sites was counted. The conditional logistic regression equation was used to analyze the CIS after thrombolysis. Related influencing factors of hemorrhage transformation, and compare the single nucleotide polymorphisms of ABCB1 gene in patients with different prognosis in the observation group. The results showed that the CC genotype frequency of rs1045642 in the observation group was 34.55% higher than that of the control group 25.02%, the CT genotype frequency was 12.20%, and the TT genotype frequency 3.25% was lower than that of the control group 14.63% and 9.35% (χ²=21.527, P<0.05); GG genotype frequency at rs2032582 locus in observation group was 17.89%, GT genotype frequency 21.54% was lower than control group 37.60%, 93.96%, TT genotype frequency 10.57% higher than control group 2.44%, the difference was statistically significant (χ²=80.427, P<0.05); TT genotype at rs1045642 is a protective factor for hemorrhage transformation, and TT genotype at rs2032582 is a risk factor for hemorrhage transformation (OR=2.903, P<0.05). The risk of bleeding after thrombolysis in CIS patients in Shangqiu area may be related to the TT genotype at the ABCB1 rs1045642 locus and the TT genotype at the rs2032582 locus.

[Roles of nurses in sleep medicine]

Sleep health becomes an important component of global public health. The incidence of sleep disorders is increasing rapidly worldwide, which seriously affects people's quality of life. In China, the lack of professional sleep physicians and technicians, the distribution of sleep centers and the unbalanced development of medical resources have seriously restricted the development of sleep medicine and the improvement of sleep health guarantee level. In Europe and America and other developed countries, sleep medicine has become a new interdisciplinary discipline. The development of nurses as sleep coordinator has become an irresistible trend. Nurses have been trained to become the main force of sleep technicians. These successful attempts in the field of sleep medicine provide reference for promoting the development of nursing care in China from the aspects of medical care, teaching and research.

[A family of renal coloboma syndrome]

The proband was a 5-year-old boy with binocular esotropia since childhood. Ocular examination showed the binocular optic cup was wide and deep excavated with radial emergence of the retinal vessels and retinal detachment was seen in the left eye. The father of the proband with worse vision of the right eye from a child and received a kidney transplant 10 years ago. Ocular examination showed large optic nerves with large optic cups of the right eye accompanied by retinal detachment in macular area. The left eye showed normal size of the optic disc and etinoschisis. Both nerves had anomalous vascular patterns. The sister of the proband showed binocular wide and deep optic cups, and the vascular course was normal. Renal color Doppler ultrasound and urine routine examination showed that the proband and his sister had bilateral renal calcification, pyelic separation and mild proteinuria. The results of gene detection showed heterozygous mutation (c.419_421delGGA) of the PAX2 gene in this family. Combined with the above examination results, the diagnosis was renal coloboma syndrome. (Chin J Ophthalmol, 2021, 57: 454-457).

Metasurface-assisted broadband optical absorption in ultrathin perovskite films

Ultrathin hybrid organic-inorganic perovskite (HOIP) films have significant potential for use in integrated high-performance photoelectric devices. However, the relatively low optical absorption capabilities of thinner films, particularly in the long-wavelength region, pose a significant challenge to the further improvement of photoelectrical conversion in ultrathin HOIP films. To address this problem, we propose a combining of ultrathin HOIP film with plasmonic metasurface to enhance the absorption of the film effectively. The metasurface excites localized surface plasmon resonances and deflects the reflected light within the HOIP film, resulting in an obvious enhancement of film absorption. Finite-difference time-domain simulation results reveal that the far-field intensities, deflection angles, and electric field distributions can be effectively varied by using metasurfaces with different arrangements. Examination of the reflection and absorption spectra reveals that embedding a specifically designed metasurface into the HOIP film produces an obvious enhancement in broadband optical absorption compared with pure HOIP films. We further demonstrate that this broadband absorption promotion mechanism can be effective at a wide range of HOIP film thicknesses. Comparison of the absorption spectra at various incidence angles of ultrathin HOIP films with and without underlying metasurfaces indicates that the addition of a metasurface can effectively promote absorption under wide-angle incident light illumination. Moreover, by extending the metasurface structure to a two-dimensional case, absorption enhancements insensitive to the incident polarization states have also been demonstrated. This proposed metasurface-assisted absorption enhancement method could be applied in designing novel high-performance thin-film solar cells and photodetectors.

Development and preliminary test of a space-resolved vacuum-ultraviolet spectroscopy in EAST

The impurity radiation from the divertor region of the EAST tokamak is dominantly in the wavelength range of vacuum ultraviolet (VUV) due to the elevated edge electron temperature. A space-resolved VUV spectroscopy is developed to measure impurity radiation in the divertor region. An eagle-type VUV spectrometer with a focal length of 1 m is adopted in this system, equipped with a spherical grating and a charged-coupled device (CCD) detector. The performance of the VUV spectrometer is preliminarily tested on a synchrotron radiation facility. The wavelength calibration is conducted near 65 nm. It is found that the wavelength range observed by the CCD detector is about 11.07 nm around the central wavelength of about 65 nm. With a linear dispersion of 0.0053 nm/pixel, it is possible to measure the ion temperature lower than 20 eV at the edge region by analyzing the Doppler broadening of a carbon line. These test results show that the performance of the VUV spectrometer is capable of measuring divertor radiation and analyzing the ion temperature of edge impurity ions.

[Effectiveness and safety of idarucizumab in the management of perioperative complications of atrial fibrillation catheter ablation in atrial fibrillation patients under dabigatran therapy]

Objective: To investigate the efficacy and safety of idarucizumab in the treatment of perioperative cardiac tamponade and thromboembolic events during catheter ablation in atrial fibrillation (AF) patients under dabigatran therapy. Methods: This study was a retrospective analysis enrolling patients under dabigatran therapy, who underwent catheter ablation for AF at Beijing Anzhen Hospital from January 2019 to December 2020 and developed perioperative cardiac tamponade or acute ischemic stroke (AIS) and received idarucizumab to reverse the anticoagulant effect of dabigatran. Patients' age, sex, renal function, coagulation test and safety events at 30 d after idarucizumab administration were collected and analyzed. The clinical presentation and prognosis were also analyzed. Results: A total of 7 patients were included, 2 (2/7) were male, mean age was (66.3±11.2) years, serum creatinine level was (66.3±13.6) μmol/L, estimated glomerular filtration rate was (89.4±11.2) ml·min-1·1.73 m-2, CHA2DS2-VASc and HAS-BLED scores were (3.2±1.9) and (1.3±1.3), respectively. Five patients (5/7) developed cardiac tamponade during the perioperative period and the time interval to the last dose of dabigatran was (6.3±2.6) h. Idarucizumab was given at (36.4±16.7) min after the definitive diagnosis of cardiac tamponade. A significant decrease of activated partial thromboplastin time was achieved after idarucizumab administration in all five cases. Pericardial puncture and drainage were applied to all patients (5/5) with cardiac tamponade, the drainage volume was (1 037.0±846.9) ml, the retention time of pericardial drainage catheter was (27.9±13.9) h, and the recovery time of anticoagulation was (28.4±13.2) h. One patient (1/5) underwent thoracotomy for hemostasis due to excessive blood loss with the aim of ensuring complete hemostasis. Bleeding occurred in 1 patient (1/5) after the first restart of anticoagulation. AIS occurred in 2 patients (2/7) after operation. One case (1/2) received intravenous thrombolysis after receiving 5.0 g idarucizumab, no hemorrhagic transformation was observed, and the recovery process was satisfactory. Another patient in this group experienced significantly prolonged onset time and 5.0 g idarucizumab was applied before intravascular thrombectomy, there was no bleeding complication in this patient after thrombectomy. At the time of discharge, the consciousness was not significantly improved, and the muscle strength of the right lower limb was recovered somehow compared with that before operation. No hypersensitivity reactions or thrombotic events occurred in these patients within 30 days of the administration of idarucizumab. Conclusion: In AF catheter ablation-associated cardiac tamponade and AIS, idarucizumab is safe and effective in rapidly reversing the anticoagulant effect of dabigatran, use of thrombectomy saves valuable time for timely hemostasis and improvement of cerebral blood circulation.

Intercomparison of Monte Carlo calculated dose enhancement ratios for gold nanoparticles irradiated by X-rays: Assessing the uncertainty and correct methodology for extended beams

Results of a Monte Carlo code intercomparison exercise for simulations of the dose enhancement from a gold nanoparticle (GNP) irradiated by X-rays have been recently reported. To highlight potential differences between codes, the dose enhancement ratios (DERs) were shown for the narrow-beam geometry used in the simulations, which leads to values significantly higher than unity over distances in the order of several tens of micrometers from the GNP surface. As it has come to our attention that the figures in our paper have given rise to misinterpretation as showing 'the' DERs of GNPs under diagnostic X-ray irradiation, this article presents estimates of the DERs that would have been obtained with realistic radiation field extensions and presence of secondary particle equilibrium (SPE). These DER values are much smaller than those for a narrow-beam irradiation shown in our paper, and significant dose enhancement is only found within a few hundred nanometers around the GNP. The approach used to obtain these estimates required the development of a methodology to identify and, where possible, correct results from simulations whose implementation deviated from the initial exercise definition. Based on this methodology, literature on Monte Carlo simulated DERs has been critically assessed.

[Influence of Storm Runoff on the Spectral Characteristics of Dissolved Organic Matter (DOM) in a Drinking Water Reservoir During the Flood Season]

To explore the influence of storm runoff on reservoir organic matter during the flood season, the Lijiahe Reservoir was selected to analyze variations in the content and components of dissolved organic matter (DOM) during four periods (before runoff, flood peak period, 1 week after runoff, and 6 weeks after runoff) using three-dimensional fluorescence spectroscopy parallel factor analysis (EEMs-PARAFAC) and ultraviolet-visible (UV-Vis) spectra. The results showed that:① the turbidity and DOC content of the reservoir increased significantly during the flood peak period (P<0.01) and gradually decreased thereafter; ② the UV-Vis spectrum characteristics showed that a(254) and a(355) were significantly increased in the flood peak period (P<0.01) while E2/E3 and E3/E4 were significantly decreased (P<0.01), indicating that the concentration, relative molecular weight, and degree of DOM humification in the reservoir were increased by storm runoff; ③ four DOM components were identified as terrestrial humus (C1 and C2), microbial humus (C3), and a tryptophan-like component (C4). The fluorescence intensity of the C1-C3 components increased significantly during the flood peak period (P<0.05), indicating that the increase in the DOM humic-like component was caused by the storm runoff. At the same time, a decrease in the fluorescence intensity of the C1-C4 components was observed after the flood peak period, indicating that DOM continuously settled and degraded after runoff; and ④ Pearson's correlation analyses showed that DOM fluorescence intensity and turbidity were significantly correlated (r>0.467, P<0.05), indicating that the observed decrease in DOM content was related to the sedimentation of suspended solids. A principal component analysis (PCA) showed that the water quality in the reservoir reflected the observed characteristics during the different runoff periods. Overall, this study reveals the effects of the storm runoff on DOM content and its components over the short and long term, providing scientific support for the management of drinking water quality.

[Analysis of pregnancy outcome of single and double blastocysts in the freeze-thaw cycle]

Objective: To compare the clinical outcomes of one and two blastocysts in the freeze-thaw transplantation cycle. Methods: Totally 3 675 cycles of frozen thawed blastocyst transplantation in Reproductive Medical Center of the Second Nanning People's Hospital from January 2012 to December 2016 were analyzed retrospectively. According to the quantity and quality of transferred blastocysts, all the patient were divided into two groups: (1) one embryo group, including the single excellent group (one high quality blastocyst) and the single non excellent group (one non high quality blastocyst); (2) two embryo groups, including the double excellent group (two high quality blastocysts), the one excellent and one non excellent group (one high quality blastocyst+one non high quality blastocyst), and the two non excellent group (two non high quality blastocysts were transplanted). Then the patients were divided into subgroups according to their ages: less than 35 years old, 35-40 years old and over 40 years old. On this basis, the implantation rate, clinical pregnancy rate, multiple birth rate and live birth rate were compared. Results: (1) The implantation rate, clinical pregnancy rate, multiple birth rate, preterm birth rate and live birth rate were all significantly increased, while the abortion rate was significantly reduced in the double blastocyst group (all P<0.05). (2) In the group of<35 years old, the rates of multiple birth and preterm birth in the double blastocyst group were significantly higher than those in the single optimal group (P<0.01). (3) In the 35-40 years old group, the clinical pregnancy rate, multiple birth rate and live birth rate of the double excellent group were significantly higher than those of the single excellent group (P<0.01); while the clinical pregnancy rate and live birth rate of the one excellent and one non excellent group and the double non excellent group were not significantly different from those of the single excellent group (P>0.05), but the multiple birth rate and preterm birth rate were significantly increased (P<0.01). The clinical pregnancy rate, live birth rate and multiple birth rate of double non optimal group were significantly higher than those of single non optimal group (P<0.01). (4) In the group>40 years old, there were no significant differences in clinical pregnancy rate and live birth rate between the two groups (P>0.05). There were no significant differences in implantation rate, clinical pregnancy rate and live birth rate between double non optimal group and single non optimal group (P>0.05). Conclusion: No matter the age of the patients, if the couple have high quality blastocysts, we should give priority to single high quality blastocyst transplantation; even if they have no high quality blastocysts, we should also consider single blastocyst transplantation, in order to reduce the risk of multiple pregnancy and improve the cumulative live birth rate, so as to improve the pregnancy outcome.

[Advances in Microbe-Derived Taste and Odor Compounds in Typical Aquatic Ecosystems]

Olfactory microorganisms mainly include actinomycetes, algae, and myxobacteria, and are widely found in typical water ecosystems such as water source reservoirs, lakes, streams, and oceans. Biologically-derived taste and odor compounds can cause severe off-flavor problems at trace concentrations, threatening the safety of water supplies. Physical and chemical methods have been implemented, but they need to be improved and optimized. Microbial methods show attractive prospects due to their environmentally friendly characteristics. This article reviews the literature regarding the types, biological sources, detection methods, control measures, influencing factors, and odor-producing mechanisms of microbial methods. Future research directions and fields of investigation are discussed in order to promote the related research of taste and odor compounds and ensure the safety of urban water supplies.

Flexible Ultrathin Single-Crystalline Perovskite Photodetector

Flexible optoelectronic devices attract considerable attention due to their prominent role in creating novel wearable apparatus for bionics, robotics, health care, and so forth. Although bulk single-crystalline perovskite-based materials are well-recognized for the high photoelectric conversion efficiency than the polycrystalline ones, their stiff and brittle nature unfortunately prohibits their application for flexible devices. Here, we introduce ultrathin single-crystalline perovskite film as the active layer and demonstrate a high-performance flexible photodetector with prevailing bending reliability. With a much-reduced thickness of 20 nm, the photodetector made of this ultrathin film can achieve a significantly increased responsivity as 5600A/W, 2 orders of magnitude higher than that of recently reported flexible perovskite photodetectors. The demonstrated 0.2 MHz 3 dB bandwidth further paves the way for high-speed photodetection. Notably, all its optoelectronic characteristics resume after being bent over thousands of times. These results manifest the great potential of single-crystalline perovskite ultrathin films for developing wearable and flexible optoelectronic devices.