Three-dimensional Porous Networks of Ultra-long Electrospun SnO_2 Nanotubes with High Photocatalytic Performance

Recent progress in nanoscience and nanotechnology creates new opportunities in the design of novel SnO2 nanomaterials for photocatalysis and photoelectrochemical. Herein, we firstly highlight a facile method to prepare threedimensional porous networks of ultra-long SnO2 nanotubes through the single capillary electrospinning technique.Compared with the traditional SnO2 nanofibers, the as-obtained three-dimensional porous networks show enhancement of photocurrent and photocatalytic activity, which could be ascribed to its improved light-harvesting efficiency and high separation efficiency of photogenerated electron–hole pairs. Besides, the synthesis route delivered three-dimensional sheets on the basis of interwoven nanofibrous networks, which can be readily recycled for the desirable circular application of a potent photocatalyst system.

Modulating MAPbI3 perovskite solar cells by amide molecules:Crystallographic regulation and surface passivation

A controllable crystallization is of practical importance to produce high-quality perovskite thin films with reduced structural defects.Lewis bases as electron-pair donor chemicals can strongly coordinate to lead ions and have been extensively employed to manipulate the growth of perovskite crystals.In this work,we demonstrate a series of Lewis-base amides,for morphological regulation of methylammonium lead triiodide(MAPbI3)thin films.The screened acetamide was demonstrated to decently improve the grain size,along with a spatial distribution at grain boundaries(GBs).The mesostructured solar cells of acetamide-modified absorbers yielded an optimized power conversion efficiency(PCE)of 20.04%with a mitigated open-circuit voltage(V_(OC))deficit of 0.39 V.This work provides a facile and cost-effective strategy toward controllable fabrication of high-performance MAPbI3 solar cells.

Continuous-wave operation of 1550 nm low-threshold triple-lattice photonic-crystal surface-emitting lasers

Benefitting from narrow beam divergence,photonic crystal surface-emitting lasers are expected to play an essential role in the ever-growing fields of optical communication and light detection and ranging.Lasers operating with 1.55μm wavelengths have attracted particular attention due to their minimum fiber loss and high eye-safe threshold.However,high interband absorption significantly decreases their performance at this 1.55μm wavelength.Therefore,stronger optical feedback is needed to reduce their threshold and thus improve the output power.Toward this goal,photonic-crystal resonators with deep holes and high dielectric contrast are often used.Nevertheless,the relevant techniques for high-contrast photonic crystals inevitably complicate fabrication and reduce the final yield.In this paper,we demonstrate the first continuous-wave operation of 1.55μm photonic-crystal surface-emitting lasers by using a‘triple-lattice photonic-crystal resonator’,which superimposes three lattice point groups to increase the strength of in-plane optical feedback.Using this geometry,the in-plane 180°coupling can be enhanced threefold compared to the normal single-lattice structure.Detailed theoretical and experimental investigations demonstrate the much lower threshold current density of this structure compared to‘single-lattice’and‘double-lattice’photonic-crystal resonators,verifying our design principles.Our findings provide a new strategy for photonic crystal laser miniaturization,which is crucial for realizing their use in future high-speed applications.

Wavelength-tunable multi-point pump semiconductor disk laser based on an intra-cavity transmission grating

We report a wavelength-tunable multi-point pump scheme of the semiconductor disk lasers(SDLs).By designing an external cavity of SDL with an intra-cavity transmission grating,multiple pump gain regions share the same resonator.The effect of the intra-cavity grating on the output laser power,wavelength,and beam quality was investigated.The emission wavelength could be tuned over a bandwidth of~18 nm.With multi-point pumping,we achieve the laser output power with almost no loss,and further improvement is limited by the thermal effect.The changes in the beam are due to the mode selectivity by the intra-cavity grating.

Different dosages of methylprednisolone therapy for acute necrotizing encephalopathy of childhood:a 6-year multicenter retrospective study

To the Editor:Acute necrotizing encephalopathy(ANE)is a rare but often devastating neurologic disorder in children.[1]Hereditary susceptibility and cytokine storm play important roles in ANE pathogenesis,[2,3]but the specific molecular biological mechanism is unclear.

Giant two-photon absorption of anatase TiO_(2) in Au/TiO_(2) core-shell nanoparticles

We report on deep-to-near-UV transient absorption spectra of core-shell Au∕SiO_(2) and Au∕TiO_(2) nanoparticles(NPs) excited at the surface plasmon resonance of the Au core, and of UV-excited bare anatase TiO_(2) NPs. The bleaching of the first excitonic transition of anatase TiO_(2) at ~3.8 e V is a signature of the presence of electrons/holes in the conduction band(CB)/valence band(VB) of the material. We find that while in bare anatase TiO_(2) NPs, two-photon excitation does not occur up to the highest used fluences(1.34 mJ∕cm^(2)), it takes place in the TiO_(2) shell at moderate fluences(0.18 mJ∕cm^(2)) in Au∕TiO_(2) core-shell NPs, as a result of an enhancement due to the plasmon resonance. We estimate the enhancement factor to be of the order of ~10~8–10~9. Remarkably, we observe that the bleach of the 3.8 eV band of TiO_(2) lives significantly longer than in bare TiO_(2), suggesting that the excess electrons/holes in the conduction/valence band are stored longer in this material.

Preoperative diagnosis of malignant pulmonary nodules in lung cancer screening with a radiomics nomogram

Background:Lung cancer is the most commonly diagnosed cancer worldwide.Its survival rate can be significantly improved by early screening.Biomarkers based on radiomics features have been found to provide important physiological information on tumors and considered as having the potential to be used in the early screening of lung cancer.In this study,we aim to establish a radiomics model and develop a tool to improve the discrimination between benign and malignant pulmonary nodules.Methods:A retrospective study was conducted on 875 patients with benign or malignant pulmonary nodules who underwent computed tomography(CT)examinations between June 2013 and June 2018.We assigned 612 patients to a training cohort and 263 patients to a validation cohort.Radiomics features were extracted from the CT images of each patient.Least absolute shrinkage and selection operator(LASSO)was used for radiomics feature selection and radiomics score calculation.Multivariate logistic regression analysis was used to develop a classification model and radiomics nomogram.Radiomics score and clinical variables were used to distinguish benign and malignant pulmonary nodules in logistic model.The performance of the radiomics nomogram was evaluated by the area under the curve(AUC),calibration curve and Hosmer-Lemeshow test in both the training and validation cohorts.Results:A radiomics score was built and consisted of 20 features selected by LASSO from 1288 radiomics features in the training cohort.The multivariate logistic model and radiomics nomogram were constructed using the radiomics score and patients’age.Good discrimination of benign and malignant pulmonary nodules was obtained from the training cohort(AUC,0.836;95%confidence interval[CI]:0.793-0.879)and validation cohort(AUC,0.809;95%CI:0.745-0.872).The Hosmer-Lemeshow test also showed good performance for the logistic regression model in the training cohort(P=0.765)and validation cohort(P=0.064).Good alignment with the calibration curve indicated the good performance of the nomogram.Conclusions:The established radiomics nomogram is a noninvasive preoperative prediction tool for malignant pulmonary nodule diagnosis.Validation revealed that this nomogram exhibited excellent discrimination and calibration capacities,suggesting its clinical utility in the early screening of lung cancer.

High beam quality broad-area diode lasers by spectral beam combining with double filters

A modified spectral beam combining(SBC) approach based on double asymmetrical filters was proposed. By using this scheme, the high-order lateral modes at the edge of the far-field pattern can be suppressed in the external cavity, and the beam quality in the slow-axis direction was improved from 16.1 to 13.4 compared to the conventional SBC. In the meanwhile, the electrical-to-optical efficiency from the modified SBC was more than 40% with an output power of 34.1 W, which is similar to that of the conventional SBC.

Tuning porosity of coal-derived activated carbons for CO_(2) adsorption

A simple method was developed to tune the porosity of coal-derived activated carbons,which provided a model adsorbent system to investigate the volumetric CO_(2)adsorption performance.Specifically,the method involved the variation of the activation temperature in a K2CO3 induced chemical activation process which could yield activated carbons with defined microporous(<2 nm,including ultra-microporous<1 nm)and meso-microporous structures.CO_(2)adsorption isotherms revealed that the microporous activated carbon has the highest measured CO_(2)adsorption capacity(6.0 mmol∙g^(–1)at 0℃and 4.1 mmol∙g^(-1)at 25℃),whilst ultra-microporous activated carbon with a high packing density exhibited the highest normalized capacity with respect to packing volume(1.8 mmol∙cm−3 at 0℃and 1.3 mmol∙cm^(–3)at 25℃),which is significant.Both experimental correlation analysis and molecular dynamics simulation demonstrated that(i)volumetric CO_(2)adsorption capacity is directly proportional to the ultra-micropore volume,and(ii)an increase in micropore sizes is beneficial to improve the volumetric capacity,but may lead a low CO_(2)adsorption density and thus low pore space utilization efficiency.The adsorption experiments on the activated carbons established the criterion for designing CO_(2)adsorbents with high volumetric adsorption capacity.

Highly efficient and precise base editing in discarded human tripronuclear embryos

CRISPR/Cas9 is a powerful tool for genome editing （Komor et al., 2017）. Recently, it has been employed in several attempts to edit the human embryos （Liang et al., 2015; Kang et al., 2016; Tang et al., 2017）.

Ultrathin Hematite Photoanode with Gradient Ti Doping

The poor photoelectrochemical(PEC)performance derived from insufficient charge separation in hematite photoanode crucially limits its application.Gradient doping with band bending in a large region is then considered as a promising strategy,facilitating the charge transfer ability due to the built-in electric field.Herein,we developed a synthetic strategy to prepare gradient Ti-doped ultrathin hematite photoelectrode and systematically investigated its PEC performance.The as-synthesized electrode(1.5-6.0%doping level from the surface to the substrate)delivered a photocurrent of about 1.30mAcm^(-2) at 1.23V versus the reversible hydrogen electrode(RHE),which is nearly 100%higher than that of homogeneously doped hematite electrode.The enhanced charge transfer property,induced by the energy band bending due to the built-in electric field,has been further confirmed by electrochemical measurements.This strategy of gradient doping should be adaptable and can be applied for other functional materials in various fields.

Plasma exchange therapy for acute necrotizing encephalopathy of childhood

Importance Acute necrotizing encephalopathy(ANE)is a rare disease with high mortality.Plasma exchange(PLEX)has recently been reported to treat ANE of childhood(ANEC),but its efficacy is uncertain.Objective This study aimed to investigate the effectiveness of PLEX on ANEC.Methods A retrospective study was conducted in four pediatric intensive care units from December 2014 to December 2020.All patients who were diagnosed with ANEC were included;however,these patients were excluded if their length of stay was less than 24 h.Participants were classified into PLEX and non-PLEX groups.Results Twenty-nine patients with ANEC were identified,10 in the PLEX group and 19 in the non-PLEX group.In the PLEX group,C-reactive protein,procalcitonin,alanine aminotransferase,and aspartate aminotransaminase levels were significantly lower after 3 days of treatment than before treatment(13.1 vs.8.0,P=0.043;9.8 vs.1.5,P=0.028;133.4 vs.31.9,P=0.028;282.4 vs.50.5,P=0.046,respectively).Nine patients(31.0%,9/29)died at discharge,and a significantly difference was found between the PLEX group and non-PLEX group[0 vs.47.4%(9/19),P=0.011].The median follow-up period was 27 months,and three patients were lost to follow-up.Thirteen patients(50.0%,13/26)died at the last follow-up,comprising three(33.3%,3/9)in the PLEX group and ten(58.8%,10/17)in the non-PLEX group,but there was no significant difference between the two groups(P=0.411).Three patients(10.3%,3/29)fully recovered.Interpretation PLEX may reduce serum C-reactive protein and procalcitonin levels and improve liver function in the short term.PLEX may improve the prognosis of ANEC,and further studies are needed.

Highly Prevalent SARS-CoV-2 Antigenemia in COVID-19 Patients

Background:Many issues,such as severity assessment and antibody responses,remain to be answered eagerly for evaluation and understanding of COVID-19.Immune lesion is one of key pathogenesis of the disease.It would be helpful to understand the disease if an investigation on antigenemia and association was conducted in the patients with SARS-CoV-2 infection.Methods:A total of 156 patients admitted to the First People’s Hospital of Hefei or Anhui Provincial Hospital on January to February 2020 were involved in this study.SARS-CoV-2 nucleocapsid(NP)antigen,specific IgM/IgG antibodies,and RNA were detected in sequential sera from three COVID-19 patients,and additional 153 COVID-19 patients by means of NP-antigen capture enzyme-linked immunosorbent assay,colloidal gold quick diagnosis,and real-time RT-PCR,respectively.The clinical types of COVID-19 patients were classified into asymptomatic,mild,moderate,severe,and critical,following on the Chinese guideline of COVID-19 diagnosis and treatment.The demographic and clinical data of patients were obtained for comparable analysis.Results:NP antigen was detected in 5 of 20 sequential sera collected from three COVID-19 patients with typically clinical symptoms,and 60.13%(92/153)expanded samples collected within 17days after illness onset.No SARS-CoV-2 RNA segment was detected in these sera.The NP positive proportion reached a peak(84.85%,28/33)on 6 to 8days after illness onset.Both NP concentration and positive proportion were increased with the increase of clinical severity of COVID-19.Compared to NP negativepatients,NP positive patients had older age[years,medians(interquartileranges(IQR)),49(6)vs.31(11)],lowerpositive proportion of NP specific IgM[27.17%(25/92)vs.59.02%(36/61)],and IgG[21.74%(20/92)vs.59.02%(36/61)]antibodies,and longer duration[days,medians(IQR),24(10)vs.21(13)]from illness to recovery.Conclusions:SARS-CoV-2 NP antigenemia occurred in COVID-19,and presented highly prevalent at early stage of the disease.The antigenemia was related to clinical severity of the disease,and may beresponsible for the delay of detectable SARS-Cov-2IgM.