The Main Progress of Perovskite Solar Cells in 2020-2021

Perovskite solar cells(PSCs)emerging as a promising photovoltaic technology with high efficiency and low manufacturing cost have attracted the attention from all over the world.Both the efficiency and stability of PSCs have increased steadily in recent years,and the research on reducing lead leakage and developing eco-friendly lead-free perovskites pushes forward the commercialization of PSCs step by step.This review summarizes the main progress of PSCs in 2020 and 2021 from the aspects of efficiency,stability,perovskite-based tandem devices,and lead-free PSCs.Moreover,a brief discussion on the development of PSC modules and its challenges toward practical application is provided.

Methylenetetrahydrofolate Reductase Gene Polymorphism C677T is Associated with Increased Risk of Coronary Heart Disease in Chinese Type 2 Diabetic Patients

Objective Chronic cardiovascular diseases induced by long-term poor blood glucose control are the main cause of death in patients with type 2 diabetes mellitus(T2DM).Previous researches report that methylenetetrahydrofolate reductase gene(MTHFR)polymorphisms might influence the occurrence of coronary heart disease(CHD)in T2DM patients.The purpose of this study was to evaluate whether MTHFR C677T and A1298C mutations are associated with the risk of CHD inT2DM patients.Methods A total of 197 subjects with T2DM were studied,of which 95 patients with CHD.The genotypes of MTHFR C677T and A1298C were analyzed by using dideoxy chain-termination method,and compared between patients with CHD and those without CHD.Results We found that the frequency of the 677T allele was significantly higher in T2DM patients with CHD than those without CHD(P=0.011).However,there was no significant difference in any of the examined haplotypes between T2DM patients with and without CHD.Furthermore,the 677T allele was associated with a higher risk of CHD development in diabetic patients with lower homocysteine(Hey)levels(≤15μmol/L)(P=0.006),while no effect of MTHFR gene polymorphism on the incidence of CHD was found in patients with higher Hey levels(>15 μmol/L)(P=0.491).Conclusion The MTHFR C677T gene polymorphism is associated with the risk of CHD of diabetic patients and could be used as an effective marker for CHD in Chinese diabetic populations with normal Hey levels.

Multi-site anchoring of single-molecule for efficient and stable perovskite solar cells with lead shielding

The emergence of perovskite solar cells(PSCs) has greatly promoted the progress of photovoltaic technologies.The rapid development of PSCs has been driven by the advances in optimizing perovskite films and their adjacent interfaces.However,the polycrystalline perovskite layers in most highly efficient PSCs still contain various defects that greatly limit photovoltaic performance and stability of the devices.Herein,we introduce a multifunctional additive ethylene diamine tetra methylene phosphonic sodium(EDTMPS) with multiple anchor points into the precursor of perovskite to improve the efficiency and stability of PSCs and provide in-situ protection of lead leakage.The addition of EDTMPS acts as a crystal growth controller and passivation agent for perovskite films,thereby slowing down the crystallization rate of the film and obtaining high-quality perovskite films.Our study also provides an insight into how the modifier modulate the interfacial energy level arrangement as well as affect transfer of charge carriers and their recombination under photoinduced excitation.As a result,the power conversion efficiency(PCE) of single subcell with a working area of 0.255 cm^(2) increases significantly from 20.03% to 23.37%.Moreover,we obtained a PCE of 19.16% for the 25 cm^(2) module.Importantly,the unencapsulated EDTMP-modified PSCs exhibit better operational and thermal stability,as well as in-situ absorption of leaked lead ions.

Incorporation ofγ-aminobutyric acid and cesium cations to formamidinium lead halide perovskites for highly efficient solar cells

The stability issue has become one of the main challenges for the commercialization of perovskite solar cells(PSCs).Formamidinium(FA)-based perovskites have shown great promise owing to their improved thermal and moisture stability.However,these perovskites are suffering from phase transition and separation.Here,a method of incorporating of γ-aminobutyric acid(GABA) and cesium cations into FAPbl_(3) is developed to improve the phase stability.It is demonstrated that the crystallinity of α-FAPbl_(3) phase is greatly improved and the phase transition temperature is significantly dropped.The resultant solar cell therefore obtains a champion power conversion efficiency(PCE) of 23.71%,which is one of the highest efficiencies for methylammonium-free PSCs.Furthermore,it shows an impressively enhanced stability under illumination,exhibiting the great potential of FA-based perovskites for efficient and stable solar cells.

Next-generation Sequencing of MHC Class Ⅰ Genes Reveals Trans-species Polymorphism in Eutropis multifasciata and Other Species of Scincidae

The genes of the major histocompatibility complex(MHC) encode cell surface proteins that are essential for adaptive immunity. MHC genes show the most prominent genetic diversity in vertebrates,reflecting the adaptation of populations to their evolving environment, population survival and reproduction. In the present study, we used nextgeneration sequencing(NGS) to study the loci polymorphism of exon 3 of the MHC class Ⅰ genes in an ovoviviparous skink, the many-lined sun skink,Eutropis multifasciata and five other species of Scincidae, to quantify genetic variation. In addition,we genotyped the same MHC class Ⅰ genes of E.multifasciata using clone sequencing, to directly compare the effectiveness of both analytical techniques for MHC genotyping. NGS detected 20MHC class Ⅰ alleles in E. multifasciata, and 2 to 15 alleles in the other five Scincidae species. However,clone sequencing detected only 15 of those MHC class Ⅰ alleles in E. multifasciata. In addition, transspecies polymorphism of MHC class Ⅰ genes was studied by constructing a phylogenetic tree using the gene sequences obtained by NGS. Phylogenetic analysis revealed that MHC class I alleles were shared among different species of Scincidae with trans-species polymorphism, and did not exhibit specific genealogical inheritance. These results have important implications for understanding polymorphism interspecies diversity in the MHC genes of Scincidae, and the evolution of the MHC more broadly.

Archaea Diversity of Five Hot Springs in Lushan from Henan

There are five hot springs named separately SHANGT,ZHONGT,WENT,XIAT and SHENT in Lushan County,Pingdingshan City,Henan Province.The archaeal diversity of the five hot springs was investigated and analyzed.16 S rD NA v4-5 genes of archaea were sequenced by Illumina Hisiq2500 PE250 technology.The numbers of sample sequences and OTUs were sorted by using Uparse,Mothur,SILVA,MUSCLE and Qiime software.Finally,the archaeal abundance and diversity in the five hot springs were analyzed.87993,67326,44400,48611 and 48495 effective reads have been obtained from SHANGT,ZHONGT,WENT,XIAT and SHENT respectively,and 520,280,678,451 and 437 OTUs have been acquired.The analysis of archaeal classification showed that the archaea from the five hot springs could be classified into 11 phyla,in which Thaumarchaeota accounted for 95.25%and was the dominant archaea.In the genera level,the dominant archaea of the SHANGT,ZHONGT and WENT was Candidatus-Nitrosocaldus,and unidentified-Thaumarchaeota was the dominant archaea in XIAT and SHENT.The results showed that the five hot springs in Lushan are rich in microbial resources.The research provided basic data for further research and utilization of the archaea resources in the five hot springs of Lushan.

A Study of Multi-Node and Dual-Hop Collaborative Communication Performance Based on Harmonic Mean Method

Closed form expressions for the PDF and MGF of the harmonic mean of two independent exponential variates are cited and derived, and then applied to study the performance of cellular multi-node and dual-hop cooperative communication systems with non-regenerative relays over flat Rayleigh fading channels. We derive the probability density function (PDF) and asymptotic symbol error rate (SER) expression with MRC scheme. Then we use Matlab to simulate the performance.

Engineering biomimetic silk fibroin hydrogel scaffolds with“organic-inorganic assembly”strategy for rapid bone regeneration

Although natural polymers have been widely used in constructing bone scaffolds,it still remains challenging to fabricate natural polymer-derived bone scaffolds with biomimetic mechanical properties as well as outstanding osteogenic properties for large-size and weight-bearing bone defects regeneration.Herein,an“organic-inorganic assembly”strategy is developed to construct silk fibroin(SF)-based bone scaffolds with the aforementioned merits.After secondary structure reshuffling,the 3.3-fold increment ofβ-sheet structures in SF hydrogel resulted in a 100-fold improvement of mineral-assembly efficacy via influencing the ion adsorption process and providing templates for mineral growth.Notably,abundant minerals were deposited within the hydrogel and also on the surface,which indicated entire mineral-assembly,which ensured the biomimetic mechanical properties of the digital light processing 3D printed SF hydrogel scaffolds with haversian-mimicking structure.In vitro experiments proved that the assembly between the mineral and SF results in rapid adhesion and enhanced osteogenic differentiation of human bone marrow-derived mesenchymal stem cells.In vivo experiments further proved that the mineral-assembled SF hydrogel scaffold could significantly enhance integration and bone regeneration at the weight-bearing site within one month.This SF-based“organic-inorganic assembly”strategy sheds light on constructing cell-free,growth factor-free and natural polymer-derived bone scaffolds with biomimetic 3D structure,mechanical properties and excellent osteogenic properties.

A survey of ictal physical examination during VEEG monitoring in a tertiary epilepsy center

Background Ictal examination based on video-based electroencephalography(EEG)is crucial for locating and lat-eralizing seizures.In this study,we aimed to evaluate the quality of ictal examination in the Comprehensive Epilepsy Center of West China Hospital,Sichuan University,in order to provide information for quality improvement in daily clinical practice.Methods Video recordings of 100 patients with epilepsy were retrospectively reviewed.The performance of the ictal examination was independently reviewed by two epileptologists using an ictal examination protocol.Results In this retrospective analysis,589 seizure episodes from 100 patients with epilepsy were reviewed.The ages of the patients ranged from 3 to 77 years,with a mean age of 25.8±12.8 years.Among the 589 seizure episodes,a majority(93.7%)were focal seizures.For 226(38.4%)seizures,the medical staff arrived at the bedside.Among them,153(153/226,64.7%)seizure episodes,the medical staff arrival at the bedside within 30 s of onset,and 120(120/226,53.1%)seizures were tested by the medical staff.The compliance rates for"safety"and"visibility"reached 80%or higher while"naming","retelling",and“memory testing”only reach less than 3%.Conclusions Our survey identified the main problems in ictal assessments.It is challenging to complete a standard-ized examination for new trainees at Epilepsy Monitoring Units.Regularly strengthening training in ictal examination and understanding of semiology may improve patients’examination ability.However,further study of the implemen-tation of training is necessary.

Highly selective NIR fluorescent probe for acetylcholinesterase and its application in pesticide residues detection

A series of near-infrared(NIR)fluorescent substrates(NDRO-1∼8)derived from fluorophore NDRH with different volumes of ester bond as the recognition group were designed and synthesized for the detection of acetylcholinesterase(AChE),among which NDRO-1 with the smallest acetate group displayed the highest activity toward AChE.The detection limit of NDRO-1 for sensing AChE was 0.32μg/mL,and K_(m )was 6.40μmol/L,indicating ultra-sensitivity and good affinity of NDRO-1 toward AChE.NDRO-1 was used to detect the inhibitory of four kinds of pesticides including methamidophos,dichlorvos,and the detection limit was lower than 50μg/L,which was further used in pesticide residues detection.

Low temperature fabrication for high-performance semitransparent CsPbI_(2)Br perovskite solar cells

All-inorganic CsPbI_(2)Br perovskite with suitable bandgap and excellent thermal stability has been reported as the most promising candidate for efficient perovskite solar cells (PSCs). However, the high annealing temperature (> 250 ℃) and poor stability of α-CsPbI_(2)Br greatly limit the future application in photovoltaic field. Herein, a facile method is reported to prepare α-CsPbI_(2)Br perovskite film with high stability at low temperature (70 ℃) by incorporating a small amount of γ-aminobutyric acid (GABA) in the precursor solutions. The devices exhibit reproducible photovoltaic performance with a champion efficiency up to 15.16%, along with the excellent stability, maintaining more than 80% of its initial efficiency after stored in ambient condition for 600 h without any encapsulation. Most importantly, the method enables fabrication of semitransparent CsPbI_(2)Br PSCs with a PCE of 6.76%, as well as an average visible transparency (AVT) of 25.38%. To the best of our knowledge, this is the first attempt to apply CsPbI_(2)Br to the semitransparent solar cells.

Staphylococcus aureus bloodstream infection in a Chinese tertiary-care hospital:A single-center retrospective study

To the Editor:Despite major advances in medical care,the incidence and mortality of bloodstream infection(BSI)remain high,which is still a global public health challenge.BSI can be caused by various microorganisms,and the most common organisms are Escherichia coli,Klebsiella pneumoniae,and Staphylococcus aureus(S.aureus),according to the China Antimicrobial Surveillance Network(CHINET).[1]S.aureus is the third most common cause of BSI,which is associated with shortterm mortality rates of 15–30%,long-term excess mortality,and increased healthcare costs.At present,there are many studies on Gram-negative bacteremia but relatively few on S.aureus bloodstream infection(SA-BSI),especially in China.With the occurrence of new treatments and clinical conditions,such as aging and extensive antibiotic resistance,it is necessary to reanalyze the clinical characteristics and prognosis of SA-BSI.

Fludarabine inhibits type I interferon-induced expression of the SARS-CoV-2 receptor angiotensin-converting enzyme 2

Angiotensin-converting enzyme 2(ACE2)is the receptor for severe acute respiratory syndrome coronavirus(SARS-CoV)and SARS-CoV-2 and is upregulated after infection with these viruses,which assists the entry of these viruses into the target cells.1,2,3 In addition,ACE2 is a human interferon-stimulated gene.4 In response to viral infection,host cells produce vast amounts of type I interferon(IFN)to defend against viral infection.5 Type I IFNs,such as IFN-α,can upregulate the phosphorylation of signal transducer and activator of transcription 1(STAT1)and 2(STAT2).6,7 Thus,whether and how IFN-αcould promote and whether blockade of the IFN-α-STAT pathway could inhibit the expression of ACE2 are largely unknown.Given the importance of ACE2 for SARS-CoV-2 invasion and the clinical practice of IFN treatment to combat viral infection,herein,we addressed these issues via a series of in vitro experiments.

A long-term retaining molecular coating for corneal regeneration

Corneal injuries will cause corneal surface diseases that may lead to blindness in millions of people worldwide.There is a tremendous need for biomaterials that can promote corneal regeneration with practical feasibility.Here we demonstrate a strategy of a protein coating for corneal injury regeneration.We synthesize an o-nitrosobenzaldehyde group(NB)-modified gelatin(GelNB),which could adhere directly to the corneal surface with covalent bonding to form a thin molecular coating.The molecular coating could avoid rapid clearance and provide a favorable environment for cell migration,thereby effectively accelerating corneal repair and regeneration.The histological structure of the regenerated cornea is more similar to the native cornea.This molecular coating can be used conveniently as an eye drop solution,which makes it a promising strategy for corneal regeneration.

The effect of renin–angiotensin–aldosterone system inhibitors in patients with hypertension and COVID-19:A meta-analysis of randomized controlled trials and propensity score-matched studies

Background:High-quality evidence for whether the use of renin–angiotensin–aldosterone system(RAAS)in-hibitors worsens clinical outcomes for patients with coronavirus disease 2019(COVID-19)is lacking.The present study aimed to evaluate the effect of RAAS inhibitors on disease severity and mortality in patients with hyper-tension and COVID-19 using randomized controlled trials(RCTs)and propensity score-matched(PSM)studies.Methods:A literature search was conducted with PubMed,Embase,and Scopus databases from 31 December 2019 to 10 January 2022.We included RCTs and PSM studies comparing the risk of severe illness or mortality in patients with hypertension and COVID-19 treated or not treated with RAAS inhibitors.Individual trial data were combined to estimate the pooled odds ratio(OR)with a random-effects model.Results:A total of 17 studies(4 RCTs and 13 PSM studies)were included in the meta-analysis.The use of RAAS inhibitors was not associated with an increased risk of severe illness(OR=1.00,95%confidence interval[CI]:0.88–1.14,I^(2)=28%)or mortality(OR=0.96,95%CI:0.83–1.11,I^(2)=16%)for patients with hypertension and COVID-19.Furthermore,there was no significant difference in the severity of COVID-19 when patients continued or discontinued treatment with RAAS inhibitors(OR=1.01,95%CI:0.78–1.29,I^(2)=0%).Conclusions:This study suggests that there was no association between treatment with RAAS inhibitors and worsened COVID-19 disease outcomes.Our findings support the current guidelines that RAAS inhibitors should be continued in the setting of the COVID-19 pandemic.However,the benefit of RAAS inhibitor medications for COVID-19 patients should be further validated with more RCTs.