bluuebunny/crossref_metadata_2025 huggingface dataset:
Stereoselective synthesis and characterization of monocyclic cis‐β‐lactams containing 5‐methyl‐1,3,4‐thiadiazole‐2‐thiol moiety
Authors: Singh Vedeshwar N. , Sharma Sitaram
Published: July 2021

This article describes the stereoselective synthesis of monocyclic cis‐β‐lactams. The 2‐(4‐chlorophenoxy)‐acetic acid or 2‐phenoxy‐acetic acid with a carboxylic acid activator 2‐ethoxy carbonyl DCPN generate ketene in situ, which reacts with imines derived from substituted tetralone carbaldehyde yielded monocyclic cis‐β‐lactams having 5‐methyl‐1,3,4‐thiadiazole‐2‐thiol moiety through [2+2] cyclo‐addition reaction (Staudinger reaction). All structures of cis‐β‐lactams were elucidated by a spectral technique like FT‐IR, 1H and 13C NMR spectra, HRMS, and single X‐ray crystallography. The cis configuration of the β‐lactams was determined based on coupling constant (J) value using 1H NMR for hydrogens H‐3 and H‐4 of the β‐lactams ring. This work presents the synthesis of β‐lactams more simply with high yields. The products were simply purified by crystallization technique.
Computed tomography validated right ventricular mid‐septal lead implantation using right ventricular angiography
Authors: Shenthar Jayaprakash , Rai Maneesh K. , Chakali Siva S. , Pillai Vivek , Delhaas Tammo
Published: July 2021

Background

Right ventricular (RV) mid‐septal pacing has been proposed as an alternative to RV apical pacing. Fluoroscopic and electrocardiogram criteria are unreliable for predicting the RV mid‐septal lead position. This study aimed to define the optimal RV mid‐septal pacing site using RV angiography.

Methods

We randomized patients undergoing pacemaker implantation (PPM) to the RV angiography‐guided group (Group A) or conventional fluoroscopy‐guided group (Group F). In Group A, we performed an angiogram in right anterior oblique (RAO 30°), left anterior oblique (LAO 40°), and left lateral (LL) views. We made a 5‐segment grid in RAO 30° and LL views and a 3‐segment grid in LAO 40° on the angiographic silhouette to define the lead position. Computed tomography (CT) was used to validate the lead tip position in both groups.

Results

We enrolled 53 patients (Group A: 26, Group F: 27) with a mean age of 55.9 ± 12.2 years. CT images validated the lead position in the mid‐septum (Group A, 23 [88.5%]; Group F, 11 [40.7%], P = .0003) and anteroseptal (Group A, 3 [11.5%]; Group F, 5 [18.5%], P = .24). In Group F, the lead was in the anterior wall in 9 patients (33.3%) and the right ventricular outflow tract in 2 (7.4%) patients and none in these two positions in Group A. The lead tip in segment one on the angiographic 5‐segment grid in RAO 30° and LL views indicated a mid‐septal lead position on CT.

Conclusions

RV angiography is safe and may be used to confirm the mid‐septal lead position during PPM.
Catheter inversion during cavotricuspid isthmus catheter ablation: The new shaft visualization catheter reduces fluoroscopy use
Authors: Santoro Amato , Baiocchi Claudia , Sisti Nicolò , Zacà Valerio , Pondrelli Carlo Renato , Falciani Francesca , Lamberti Filippo
Published: July 2021

Aims

Catheter ablation (CA) is the choice therapy of cavotricuspid isthmus (CTI) atrial flutter. The aim of this study was to describe our approach to improve the CTI ablation using a zero‐fluoroscopy (ZF). The procedural difficulties could be related to anatomical characteristics of the CTI.

Methods

One hundred eighty‐eight patients that performed CA of CTI were retrospectively and consecutively evaluated between 2017 and 2019. The studied population was divided into two groups. Eighty‐eight patients who were undergone CA using ablation catheter without shaft visualization catheter (NSV) were Group 1. One hundred patients were undergone CA using ablation catheter with a shaft visualization (SV); they were Group 2. The catheter was looped at the Eustachian ridge after 200 seconds of radiofrequencies (RF) without elimination of local electrogram.

Results

A conduction line block of CTI was obtained in all patients of Group 2 using a ZF approach. In 16 patients of Group 1, the catheter inversion was obtained using fluoroscopy to avoid damages during its loop. In Group 2, a complete CTI block was obtained with a catheter inversion approach in ten patients without fluoroscopy, visualizing the shaft and the tip of the ablation catheter on the electroanatomic (EAM) map. In the overall population studied the use of SV had a linear correlation with the ZF approach (r = .629; P < .001). The duration of RF was lower in Group 2 than in Group 1 (Group 1: 27.8 ± 6.3 vs Group 2: 15.6 ± 7.2 minutes; P < .01). The procedure time between two groups was lower in Group 2 than in Group 1 (Group 1: 58.4 ± 22.4 vs Group 2: 42.2 ± 15.7 minutes; P < .01). No differences between two groups were documented regarding success and complications.

Conclusions

The visualization of the shaft's catheter on the EAM permitted the catheter inversion safely in order to overcome some complex CTI anatomy and obtain bidirectional block. The SV reduced procedure time, RF applications and fluoroscopy exposition during CTI ablation.
An evaluation of CMIP5 and CMIP6 climate models in simulating summer rainfall in the Southeast Asian monsoon domain
Authors: Khadka Dibesh , Babel Mukand S. , Abatan Abayomi A. , Collins Matthew
Published: July 2021

In this study, 28 climate models from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) and 32 models from the sixth phase (CMIP6) have been evaluated for their ability to simulate large‐scale atmospheric circulations (using rainfall, wind fields, geopotential height, temperature, and moisture flux convergence) for the summer monsoon in Southeast Asia. Using a multi‐criteria decision making technique, models have been ranked based on 25 metrics which compare their performances with observation data. Results indicate a better representation of annual rainfall cycles as well as spatial pattern by CMIP6 models compared to CMIP5. Though majority of the models from both CMIPs show late onset and early retreat of the rainy season, CMIP6 GCMs simulate the onset, retreat, and the length of the rainy season closer to the observation. Large‐scale circulation patterns evaluated using spatial correlation and root mean square error (RMSE) show improvements in CMIP6 across all metrics, especially for the moisture flux convergence. Performances for large‐scale circulation are generally reflected in rainfall simulation; however, few models showed that better simulations of rainfall do not exclusively depend on their performance for large‐scale variables. Overall, CMIP6 models are found to be superior to CMIP5 models in simulating rainfall and large‐scale circulation, which is likely attributable to CMIP6 model's higher spatial resolutions, increased number of vertical levels, improved atmospheric and land surface parameterization, etc. Finally, subsets of optimal models from CMIP5 and CMIP6 that proved to be better at representing the summer monsoons in the study area are identified. These models are recommended to develop robust future projections that can be used for climate change impact and adaptation studies.
Future projections of precipitation, surface temperatures and drought events over the monsoon transitional zone in China from bias‐corrected CMIP6 models
Authors: Piao Jinling , Chen Wen , Wang Lin , Chen Shangfeng
Published: July 2021

Bias‐corrected monthly precipitation and surface temperature datasets are constructed for the monsoon transitional zone (MTZ) in China during 1965–2100 based on 21 coupled climate models from phase 6 of the Coupled Model Intercomparison Project (CMIP6) using the equi‐ratio and equidistant cumulative distribution function quantile‐based mapping methods (equi‐ratio cumulative distribution function [ERCDF] and equidistant cumulative distribution function [EDCDF]), respectively. The efficiencies of the two methods are verified via cross‐validation by the jack‐knife method, and the biases are remarkably reduced compared to those of the raw model outputs. Then, the bias‐corrected model outputs are applied to future projections of precipitation, surface temperatures and drought events under the medium (SSP2‐4.5) and high (SSP5‐8.5) shared socioeconomic pathway scenarios. The obtained results present pronounced increases in both the projected annual mean precipitation and temperature fields for the model ensemble mean. In accompany, the MTZ is predicted to become drier in the three future periods; this result was attributed to the dramatic increases in semiarid events and to the decreases in humid events. The drought tension showed more rapid development under SSP585 than under the other scenario, with comparable occurrence frequencies of relatively wet and dry events in the long‐term period, posing a serious threat to regional sustainable development.
A novel intramedullary nail to control interfragmentary motion in diaphyseal tibial fractures
Authors: Ziran Navid , McCarty Colin P. , Ho Nathan C. , Gilmartin Neda F. , Ebramzadeh Edward , Park Sang‐Hyun , Sangiorgio Sophia N.
Published: July 2021

Numerous animal and human studies have demonstrated the benefit of controlled interfragmentary motion on fracture healing. In this study, we quantified interfragmentary motion and load transfer in tibial fractures fixed using a novel intramedullary nail (IMN) that allows controlled axial motion. Fifty composite tibias with various fracture patterns were utilized. For all test conditions, two interlocking screws were used to fix the nail in the proximal metaphysis, and two interlocking screws through the distal metaphysis. The nail allowed either no motion (static mode) or 1 mm (dynamic mode) of cyclic axial motion between the two fracture fragments for every fracture pattern tested. As expected, strain shielding was more prominent under static nail conditions. In contrast, specimens tested under dynamic nail conditions transferred axial load between the fracture fragments such that strains near the fracture site were generally similar to those measured on an intact tibia. Maximum shear strains proximal to the fracture were significantly lower in specimens with oblique or butterfly fracture patterns (p < 0.01) compared to intact specimens. This decrease in shear strain indicates that strain shielding effects were likely present due to the implant. However, strain shielding appeared to be reduced in tensile and compressive principal strains. In summary, the novel IMN allowed controlled axial motion between the fragments in a variety of common diaphyseal tibial fracture patterns. Clinical Significance: The present in vitro biomechanical study investigated a novel intramedullary nail capable of controlled axial interfragmentary motion which may potentially enhance fracture healing.
Prognostic factors for survival in advanced thymomas: The role of the number of involved structures
Authors: Chiappetta Marco , Aprile Vittorio , Lococo Filippo , Zanfrini Edoardo , Nachira Dania , Meacci Elisa , Korasidis Stylianos , Ambrogi Marcello , Lucchi Marco , Margaritora Stefano
Published: July 2021

Background and Objectives

The Masoka‐Koga and tumor node metastases staging systems for thymoma are based on structures involved, but the prognostic role of the number of infiltrated/involved structures is still debated. We analyzed the prognostic role of involved structures and their combinations in locally advanced thymomas patients.

Methods

Data on 174 surgically treated locally advanced thymoma patients from 1/01/1990 to 31/12/2015 were reviewed. Clinical and pathological characteristic, involved structures, number of involved structures and different combinations were correlated to cancer specific survival (CSS) using Kaplan–Meier product‐limit method.

Results

Five and 10‐year CSS was 92% and 87%. Masaoka Stage 3 (p < 0.001), absence of pericardial involvement (p = 0.001), number of involved structures (p = 0.018), R0 (p < 0.001) and adjuvant radiotherapy (p = 0.008) were favorable prognostic CSS factors. A significant better prognosis was present in ≤2 involved structures vs >2 involved structures (5‐ and 10‐year CSS: 95% and 93% vs. 80% and 51%). Multivariable analysis confirmed as independent prognostic factor R0 (p = 0.033, hazard ratio [HR]: 0.093, 95% confidence interval [CI] 0.010–0.827) and number of involved structures (p = 0.046, HR: 0.187, 95% CI: 0.036–0.968). In Masaoka Stage 3, patients with ≤2 involved structures had a significant better CSS than patients with >2 (10‐year CSS: 98% vs. 73%, p = 0.008).

Conclusions

The number of involved structures and the concomitant involvement of the pericardium seems to be associated with a poor prognosis in surgically treated advanced thymoma patients.
Electrochemical behavior of AISI 302 austenitic stainless steel in coal chemical high‐salt wastewater
Authors: Yang Guangming , Wang Weibing , Ren Yongsheng , Ma Yulong
Published: July 2021

In this study, the effect of grain size and grain boundary characteristic distribution on the corrosion resistance of AISI 302 austenitic stainless steel in simulated coal chemical high‐salt wastewater was evaluated by electrochemical impedance spectroscopy and potentiodynamic polarization measurements. The grain size of the heat‐treated sample is significantly increased and contains a greater fraction of high‐angle grain boundaries (HAGBs) and twin content. As the heat treatment temperature and time increase, the passivation current density increases, which makes the passive film more susceptible to attack. The coarse‐grained microstructure has exhibited worse pitting resistance due to its higher fraction of the HAGBs.
Corrosion behavior of carbon steel coated with a zinc‐rich paint containing metallic compounds under wet and dry cyclic conditions
Authors: Takahashi Masamitsu , Deguchi Hiroshi , Hayashi Yasunori , Kimura Akihiko , Hanaki Koushu , Tsuchiya Hiroaki , Yamashita Masato , Fujimoto Shinji
Published: July 2021

The corrosion behavior of carbon steel coated with a zinc‐rich paint containing two metallic compounds, Al2(SO4)3 and CaO, as anticorrosive additives was examined under wet and dry cyclic corrosion test conditions. The zinc‐rich paint coating without the two metallic compounds formed a white corrosion product and red iron rust on the surface after the corrosion test, whereas the coating with the metallic compounds showed reduced surface corrosion products. The corrosion current density of the painted steel substrate decreased drastically due to the incorporation of metallic compounds in the paint. The zinc‐rich paint coating modified with the metallic compounds contained dispersed simonkolleite (Zn5(OH)8Cl2·H2O) phase and possibly very fine CaSO4 particles, which remarkably improved the protectiveness of the zinc‐rich paint coating.
Correlation between microstructure and corrosion behavior in an AISI 316L steel pipeline exposed for 100,700 h at 640°C in a petrochemical plant
Authors: Calderón‐Hernández José W. , Alves  Sandro F. , de Moraes Flavio P. , de Melo Hercílio G. , Padilha Angelo F.
Published: July 2021

The microstructure and electrochemical properties of 316L stainless steel were investigated after two conditions: aged at 640°C for 100,700 h and solution annealed at 1050°C for 2 h. While the aged samples were obtained from a pipe of a petrochemical reactor plant that was in service, the solution annealing was carried out in a conventional laboratory furnace. After aging, the precipitates present in decreasing order of quantity were sigma, Laves phase, and M23C6. After solution annealing, the microstructure was full austenitic. These results were in agreement with equilibria phase simulation with Thermo‐Calc software. Intergranular corrosion susceptibility, evaluated by means of the single loop electrochemical potentiokinetic reactivation technique and Practice A of ASTM 262, indicated a preponderant role for the sigma precipitate. The pitting potential (Epit) was evaluated through potentiodynamic polarization curves in 0.6 M NaCl and electrochemical impedance spectroscopy was performed at the corrosion potential to complement the information about the corrosion resistance.
Movement Disorders Associated with Hypogonadism
Authors: Gonzalez‐Latapi Paulina , Sousa Mario , Lang Anthony E.
Published: July 2021

A variety of movement disorders can be associated with hypogonadism. Identification of this association may aid in guiding workup and reaching an accurate diagnosis. We conducted a comprehensive and structured search to identify the most common movement disorders associated with hypogonadism. Only Case Reports and Case Series articles were included. Ataxia was the most common movement disorder associated with hypogonadism, including entities such as Gordon‐Holmes syndrome, Boucher‐Neuhäuser, Marinesco‐Sjögren and Perrault syndrome. Tremor was also commonly described, particularly with aneuploidies such as Klinefelter syndrome and Jacob's syndrome. Other rare conditions including mitochondrial disorders and Woodhouse‐Sakati syndrome are associated with dystonia and parkinsonism and either hypo or hypergonadotropic hypogonadism. We also highlight those entities where a combination of movement disorders is present. Hypogonadism may be more commonly associated with movement disorders than previously appreciated. It is important for the clinician to be aware of this association, as well as accompanying symptoms in order to reach a precise diagnosis.
Multi‐source observations and high‐resolution numerical model applied on the analysis of a severe convective weather affecting the airport
Authors: Wan Ziwei , Liu Xinhua , Xu Chenlu
Published: July 2021

In order to explore the application of multi‐source data from different observational systems (including meteorological stations, radar, and airport observational reports) and high‐resolution numerical model results in the analysis of severe convective weather affecting airports, a local severe convective weather event that affected Beijing Capital International Airport (ZBAA) on 26 June 2018 was studied in this work. Although there was no significant triggering of synoptic systems, the process produced a violent thunderstorm with strong wind gusts, poor prevailing visibility, and hail in just a 30‐min period, resulting in severe impacts on the airport operations. In addition to the routine analysis of weather using observations from meteorological stations and radar, high spatial and temporal resolution data from instruments at the airport were used to reveal the fine‐scale characteristics of the development and evolution of various associated meteorological parameters, which demonstrably served as a useful auxiliary dataset for the analysis of this event. Furthermore, the reliability of the high‐resolution numerical (Weather Research and Forecasting) model simulation was evaluated by using these 1‐min‐scale airport observations. Based on what was judged to be a reliable simulation of the meteorological variables by the model, the trigger and strengthening mechanisms of the storm formed in this region of complex topography, as well as the interaction with another cell, were explored. The model results suggested that convections were initially triggered by the interaction of southerly flow from the plain and northwesterly flow from the mountains, in conjunction with the effect of orographic uplift. The outflow of the cold pool from the former cell prevented the later cell (affecting ZBAA) from moving east. Due to the strong vertical wind shear in the lower levels, the echo tilted to a certain extent and formed an inner secondary circulation, contributing to the maintenance and strengthening for the storm.
ODE‐based double‐preconditioning for solving linear systems Aαx=b and f(A)x=b
Authors: Antoine Xavier , Lorin Emmanuel
Published: July 2021

This article is devoted to the computation of the solution to fractional linear algebraic systems using a differential‐based strategy to evaluate matrix–vector products , with . More specifically, we propose ODE‐based preconditioners for efficiently solving fractional linear systems in combination with traditional sparse linear system preconditioners. Different types of preconditioners are derived (Jacobi, incomplete LU, Padé) and numerically compared. The extension to systems is finally considered.
Synthesis and Characterization of Ligand‐Linked Pt Nanoparticles: Tunable, Three‐Dimensional, Porous Networks for Catalytic Hydrogen Sensing
Authors: Loof Daniel , Thüringer Oliver , Schowalter Marco , Mahr Christoph , Pranti Anmona Shabnam , Lang Walter , Rosenauer Andreas , Zielasek Volkmar , Kunz Sebastian , Bäumer Marcus
Published: July 2021

Porous networks of Pt nanoparticles interlinked by bifunctional organic ligands have shown high potential as catalysts in micro‐machined hydrogen gas sensors. By varying the ligand among p‐phenylenediamine, benzidine, 4,4‘‘‐diamino‐p‐terphenyl, 1,5‐diaminonaphthalene, and trans‐1,4‐diaminocyclohexane, new variants of such networks were synthesized. Inter‐particle distances within the networks, determined via transmission electron microscopy tomography, varied from 0.8 to 1.4 nm in accordance with the nominal length of the respective ligand. While stable structures with intact and coordinatively bonded diamines were formed with all ligands, aromatic diamines showed superior thermal stability. The networks exhibited mesoporous structures depending on ligand and synthesis strategy and performed well as catalysts in hydrogen gas microsensors. They demonstrate the possibility of deliberately tuning micro‐ and mesoporosity and thereby transport properties and steric demands by choice of the right ligand also for other applications in heterogeneous catalysis.
Fabrication of the amphiphilic hyperbranched poly(ether amine)@graphene (hPEA‐AN@G) hybrid assemblies by ball milling
Authors: Li Jin , Ma Xiaodong , Su Zhilong , Yin Jie , Jiang Xuesong
Published: July 2021

Organic–inorganic hybrid assembly is a very attractive means for constructing complex functional materials. Here, a simple method for the preparation of amphiphilic hybrid graphene nanosheets (hPEA‐AN@G) is developed via the in situ hybrid assembly of anthracene‐ended hyperbranched poly(ether amine) (hPEA‐AN) and graphene by ball milling graphite in aqueous solution with hPEA‐AN. The amphiphilic hPEA‐AN, consisting of hydrophilic hPEA chains and electron‐rich π‐conjugated aromatic AN capped on the periphery, not only interacts strongly with graphene nanosheets and water molecules but also endows the hybrid hPEA‐AN@G assemblies with hydrophilic surfaces and functional groups. The concentration of the resulting few‐layered hPEA‐AN@G is as high as 3.5 mg mL–1. Moreover, the total interaction energy (VT) of hPEA‐AN@G is VT,max = 4.2 meV nm–2 calculated according to the classical Derjaguin–Landau–Verwey–Overbeek theory, as high as 16 800 eV for a 2 μm × 2 μm graphene flake, suggesting a high stability of the hPEA‐AN@G assemblies. The as‐prepared hPEA‐AN@G can be redispersed well in several organic solvents including N,N‐dimethylformamide, 1,4‐dioxane, acetone and ethanol for more than 3 months. The superior performance and convenient fabrication make this method very promising for the production of graphene nanosheets on a large scale in both aqueous and organic solution. © 2021 Society of Industrial Chemistry.
Water‐assisted mechanical testing of polymeric thin‐films
Authors: Zhang Song , Galuska Luke A. , Gu Xiaodan
Published: July 2021

Thin films with a nanometer‐scale thickness are of great interest to both scientific and industrial communities due to their numerous applications and unique behaviors different from the bulk. However, the understanding of thin‐film mechanics is still greatly hampered due to their intrinsic fragility and the lack of commercially available experimental instruments. In this review, we first discuss the progression of thin‐film mechanical testing methods based on the supporting substrate: film‐on‐solid substrate method, film‐on‐water tensile tests, and water‐assisted free‐standing tensile tests. By comparing past studies on a model polymer, polystyrene, the effect of different substrates and confinement effect on the thin‐film mechanics is evaluated. These techniques have generated fruitful scientific knowledge in the field of organic semiconductors for the understanding of structure–mechanical property relationships. We end this review by providing our perspective for their bright prospects in much broader applications and materials of interest.
Self‐assembled free‐floating nanomaterials from sequence‐defined polymers
Authors: Babi Jon , Zhu Linglan , Lin Angela , Uva Azalea , El‐Haddad Hana , Peloewetse Atang , Tran Helen
Published: July 2021

Sequence‐defined polymers can be programmed to self‐assemble into precise nanostructures for applications in biosensing, drug delivery, optics, and molecular computation. Inspired by the natural self‐assembly processes present in biological protein and DNA systems, sets of molecular design rules have emerged across materials classes as instructions to build a variety of tunable structures. This review highlights recent advances in self‐assembled sequence‐defined and sequence‐specific polymers across peptides, peptoids, DNA, and non‐biological synthetic materials, with a focus on synthesis, assembly processes and overall structure. Specifically, these self‐assembled structures are free‐floating, as such constructs can potentially serve as a platform for the aforementioned applications. Emphasis is placed on the molecular design of polymers that self‐assemble into zero‐dimensional, one‐dimensional, two‐dimensional, or three‐dimensional nanostructures. With the development of automated syntheses and increasing control over self‐assembly, future work may focus on emerging classes of compatible hybrid materials with exciting directions toward new architectures and applications.
The IRIS Imager: A freeware program for quantification of paint removal on IRIS films
Authors: Limmer Matt A. , Evans Abby E. , Seyfferth Angelia L.
Published: July 2021

Soils with seasonal or continuous water saturation are characterized by unique redox‐related processes including Fe and Mn oxide reduction. Indicators of reduction in soils (IRIS) devices were created as low‐cost, direct sensors of such reduced chemistry. Such IRIS devices are painted with oxides of Fe or Mn, inserted into the soil, and then removed after a period of time; once removed, the paint lost due to reductive dissolution of these oxides is used to indicate the presence, location, and/or intensity of reducing conditions. However, quantifying the paint removal using existing methods can be subjective and time consuming. Here, we describe the use of the IRIS Imager, an image analysis program that calculates removal of paint from IRIS films in L*a*b* color space (where L* is lightness, a* is red–green value, and b* is blue–yellow value) by comparing the change in lightness between initial and final IRIS film images. Paint removal from films deployed in flooded rice (Oryza sativa L.) paddy soils were quantified using the IRIS Imager, the grid method, and chemical extractions of IRIS films. All three methods were suitable for quantification of paint removal, but the IRIS Imager provided additional statistics to assess heterogeneity in paint removal on individual films and a less subjective approach to quantifying Mn oxide paint removal when Fe oxidation on Mn films was present. This free software can be used with IRIS devices to reproducibly measure paint removal from Fe oxide and Mn oxide IRIS and Fe oxide precipitation on Mn oxide IRIS.
A Sensitive Microextraction Method Using Effervescence Tablets to Disperse Fe3O4 Nanoparticles for Cadmium Determination in Lake Water Samples
Authors: Borahan Tülay , Karlıdağ Nazime Ebrar , Zaman Buse Tuğba , Bakırdere Sezgin
Published: July 2021

In this study, an effective and sensitive method was developed for the preconcentration of cadmium in flame atomic absorption spectrometer system combined with a 5‐holes cut slotted quartz tube (SQT‐FAAS). For this aim, a dispersive solid‐phase microextraction method based on a magnetic effervescent tablet consisting of Fe3O4 nanoparticles (EA‐MNP‐dSPME) was proposed. In the developed microextraction method, the dispersion of the nanoparticles used as adsorbents was assisted by the effervescent tablets generated from a mixture of sodium carbonate and sodium dihydrogen phosphate dihydrate. In order to obtain the highest extraction and instrumental output, all variables that affect the efficiency was investigated comprehensively and optimum conditions were determined with univariate optimization steps. The detection power of the conventional FAAS system was enhanced about 135 folds with respect to the LOD value of the developed method (0.34 ng mL−1) obtained under the optimum conditions. The EA‐MNP‐dSPME method presented high reproducibility with a low %RSD value calculated as 8.1 %. In order to validate the accuracy and applicability of the method, matrix matching method based recovery studies were carried out using the lake water samples taken from Horseshoe Island. The percent recovery results reported between 99.9–104.3 % with percent relative standard deviation below 7.9 % indicated the developed method‘s applicability for the accurate and precise determination of cadmium.
Fabrication of Flexible Graphene Paper/MnO2 Composite Supercapacitor Electrode through Electrodeposition of MnO2 Nanoparticles on Graphene Paper
Authors: Liu Gu , Liu Jian , Xu Kejun , Wang Liuying , Xiong Shanxin
Published: July 2021

The flexible electrodes are the crucial components for fabricating wearable supercapacitors. In this study, we present a quick and convenient method to prepare graphene paper (GP) as a flexible current collector on a large scale by an easy one‐step method. The composite electrode integrated with GP and MnO2 as a flexible supercapacitor was obtained by an electrochemical deposition method without using binder or conductive agent. The substrate (GP) of electrode not only provides mechanical strength, but also contributes energy storage capacity. The MnO2 nanoparticles deposited on the surface of GP further improved the electrochemical performance of composite. The neat GP can give a specific capacitance of 184 F/g at a current density of 1 A/g. At a current density of 1 A/g, the specific capacitance of the GP/MnO2 composite with a deposition time of 30 s is as high as 410 F/g. The method presented here shows great potential for the development of flexible electrode materials in practical energy storage devices.
Preparation of Sulfonated Polyarylene Ether Nitrile Hollow Fiber Membrane Adsorbent and Its Potential in Separation Lithium Ion from Brine
Authors: Wang Zhihui , Li Xiulei , Tao Baifu , Guo Ruili
Published: July 2021

In this paper, a series of sulfonated polyarylene ether nitriles copolymers (SPEN) with adjustable sulfonic acid groups are synthesized through nucleophilic substitution reaction. Then, the SPEN hollow fiber membrane (SPENH) adsorbents are successfully prepared by dry‐wet phase conversion. Due to the increase of hydrophilic groups sulfonic acid (−SO3H) and increases surface roughness, the water contact angle of SPENH‐60 is as low as 46.97°, and the wettability of SPENH adsorbent is improved. In addition, SPENH‐60 adsorbent has a high porosity of 97.87 % and −SO3H groups (1.53 mmol g−1), which shows an excellent Li+ adsorption uptake of up to 20.54 mg⋅g−1. The adsorption kinetics of Li+ follows the pseudo‐second‐order adsorption kinetic and the adsorption isotherm data conforms to the Langmuir model. The selectivity factors of Li+ to Na+, K+, Ca2+ and Mg2+ are 5.019, 4.038, 2.726 and 48.348, respectively. After 10 times of adsorption‐desorption cycles, the adsorption uptake decrease by only 4.3 %. Therefore, SPENH adsorbent has the potential to selectively separate and recycle Li+ from brine.
The United States should recognize and support caregiving youth
Authors: Armstrong‐Carter Emma , Johnson Catherine , Belkowitz Julia , Siskowski Connie , Olson Elizabeth
Published: July 2021

In the United States, more than 5.4 million children and adolescents under age 18 provide care for family members who are aging or have chronic illness, disability, or other health conditions that require assistance. In this policy report, we describe youth’s care for the family, and highlight the increasing prevalence, global challenges, and uneven successes of measurement and categorization. We briefly summarize research on how caregiving affects youth’s academic, social, and emotional well‐being. Next, we present novel, emerging evidence from the public school‐based 2019 Youth Risk Behavior Survey for the State of Florida, which suggests that as many as 24% of middle school students and 16% of high school students provide at least some care to the family on a regular basis. Drawing on this evidence, we discuss targeted social programs which have been shown to promote the well‐being of caregiving youth outside of the United States, as well as a 13‐year‐old school‐based intervention in The School District of Palm Beach County, Florida. We conclude with specific recommendations for a path toward recognizing and supporting caregiving youth via policy and practice in the United States. Our aim is to increase the awareness and feasibility of identifying and supporting caregiving youth and their families via government‐organized data collection and targeted social policies.
Review disclosure conditions for health and safety emergencies
Authors: Rainsberger Richard
Published: July 2021

Last month, a COVID‐19 question came from a vice president of student services about a student who had violated the university's COVID testing program. The student's records were sent to a hearing panel. The student was subsequently dismissed until this fall.
Enrollment decline steepest in a decade; community colleges hit the hardest
Authors: Hope Joan
Published: July 2021

Enrollment for spring 2021 in the United States experienced a one‐year decline of 3.5% — or 603,000 students, according to a recent report from the National Student Clearinghouse Research Center. Overall spring enrollment dropped to 16.9 million students, compared with 17.5 million in spring 2020. That's the steepest decline and largest student headcount drop since the Clearinghouse began publishing enrollment data a decade ago.
State of the art in development of molecularly imprinted biosensors
Authors: Wu Licheng , Li Xiaolei , Miao Haohan , Xu Jingjing , Pan Guoqing
Published: July 2021

Biosensors are a class of smart devices fabricated for target analyte detection. A biosensor is commonly made of three basic components: a specific bioreceptor, a physicochemical transducer, and a signal processing device. The bioreceptor part features one of the more crucial technologies of a biosensor to perform specific detection of analytes. They commonly make use of various molecular recognition elements, such as enzymes, natural receptors, antibodies, nucleic acid aptamers, and even synthetic receptors. Then, the molecular recognition events of these bioreceptors can be translated into readable signals in various forms like electrochemical, optical, piezo/pyro electric, etc. Finally, these signals are mathematically processed for quantitative analysis. Nowadays, the great advances in biomimetic materials, in particular the synthetic receptors based on molecularly imprinted polymers (MIPs), promote tremendous development of biosensors. Integration of this field with artificial intelligence enables emerging design of advanced biosensors, which has moved from concept to implementation, meanwhile facing new opportunities and challenges. With no doubt, bioreceptor innovation based on molecular imprinting is an emerging driving force for biosensors development. In this review paper, we provide an overview of MIP‐based biosensors, and also their challenges and opportunities moving forward toward wearable devices are discussed.
Explainable artificial intelligence: an analytical review
Authors: Angelov Plamen P. , Soares Eduardo A. , Jiang Richard , Arnold Nicholas I. , Atkinson Peter M.
Published: July 2021

This paper provides a brief analytical review of the current state‐of‐the‐art in relation to the explainability of artificial intelligence in the context of recent advances in machine learning and deep learning. The paper starts with a brief historical introduction and a taxonomy, and formulates the main challenges in terms of explainability building on the recently formulated National Institute of Standards four principles of explainability. Recently published methods related to the topic are then critically reviewed and analyzed. Finally, future directions for research are suggested.

This article is categorized under:

Technologies > Artificial Intelligence

Fundamental Concepts of Data and Knowledge > Explainable AI
Quantitative element analysis with an energy dispersive X‐ray fluorescence instrument equipped with a highly oriented pyrolytic graphite filter
Authors: Sokoltsova Tetiana , Esbelin Eric , Lépy Marie‐Christine
Published: July 2021

This paper presents an energy‐dispersive X‐ray fluorescence (XRF) instrumentation mainly intended for the quantitative analysis of actinides based on their intense L X‐ray lines. The experimental setup is equipped with a highly oriented pyrolytic graphite (HOPG) optic as a bandpass filter placed between a sample and a detection system. In such an arrangement, it modifies the spectral distribution of the fluorescence radiation and helps recording a spectrum in the energy range from 10 to 18 keV, while suppressing parts considered to be useless. In order to perform accurate quantitative analyses of the recorded spectra, the classical quantification algorithm based on the fundamental parameters (FP) must be adapted to take into account the effect of the HOPG optic on the measured intensities. This requires to determine the transmission function of the HOPG filter and implement it in the algorithm. The validity of this approach is checked in different application examples.
Improved access through ball milling: Octahedral Ta6 cluster alkoxides with weakly coordinating cations and a rare example of an electron‐poor Ta6 cluster
Authors: Schröder Florian , Köckerling Martin
Published: July 2021

From the reaction of activated (ball‐milled) [Ta6I14] with Mg‐methanolate or ethanolate the first examples of compounds with hexanuclear Ta6 units which have the octahedral edges bridged by alcoholato ligands are obtained. Either methanolato or iodido ligands are further attached to the exo sites of the Ta6 octahedra. The [Ta6(OCH3)i12(OCH3)a6]2− and [Ta6(OCH3)i12Ia6]2−/1− units were crystallized with large cations. Single crystal X‐ray diffraction studies have revealed the structures of four of these compounds. They show that the Ta−Ta atom distances are shorter than those found in comparable Ta6 halides, because of the much less pronounced matrix effect of the smaller O atoms compared to i. e. Cl. The cluster unit in (PPN)[Ta6(OC2H5)i12Ia6] comprises a rare example of an electron‐poor ensemble with 13 cluster based electrons (located in highest in energy, metal based orbitals). Differences of bond lengths between the clusters with 13 CBEs and 14 CBEs are in line with published theoretical descriptions of the bonding situation.
|Isolation and characterization of novel bacteriophages as a potential therapeutic option for Escherichia coli urinary tract infections
Authors: González-Villalobos Edgar , Ribas-Aparicio Rosa María , Montealegre Gerardo Erbey Rodea , Belmont-Monroy Laura , Ortega-García Yerisaidy , Aparicio-Ozores Gerardo , Balcázar José Luis , Eslava-Campos Carlos Alberto , Hernández-Chiñas Ulises , Molina-López José
Published: July 2021

Urinary tract infections (UTIs) are mainly caused by uropathogenic Escherichia coli (UPEC), whose impact can be exacerbated by multidrug-resistant (MDR) strains. Effective control strategies are, therefore, urgently needed. Among them, phage therapy represents a suitable alternative. Here, we describe the isolation and characterization of novel phages from wastewater samples, as well as their lytic activity against biofilm and adherence of UPEC to HEp-2 cells. The results demonstrated that phage vB_EcoM-phiEc1 (ϕEc1) belongs to Myoviridae family, whereas vB_EcoS-phiEc3 (ϕEc3) and vB_EcoS-phiEc4 (ϕEc4) belong to Siphoviridae family. Phages showed lytic activity against UPEC and gut commensal strains. Phage ϕEc1 lysed UPEC serogroups, whereas phages ϕEc3 and ϕEc4 lysed only UTI strains with higher prevalence toward the O25 serogroup. Moreover, phages ϕEc1 and ϕEc3 decreased both biofilm formation and adherence, whereas ϕEc4 was able to decrease adherence but not biofilm formation. In conclusion, these novel phages showed the ability to decrease biofilm and bacterial adherence, making them promising candidates for effective adjuvant treatment against UTIs caused by MDR UPEC strains.

Key points

Phage with lytic activity against MDR UPEC strains were isolated and characterized under in vitro conditions.

A novel method was proposed to evaluate phage activity against bacterial adherence in HEp-2 cell..

Phages represent a suitable strategy to control infections caused by MDR bacteria.
Clinical Performance Status and Technical Factors Affecting Outcomes from Percutaneous Transhepatic Biliary Interventions; A Multicentre, Prospective, Observational Cohort Study
Authors: Makris Gregory C. , Macdonald Andrew C. , Allouni Kader , Corrigall Hannah , Tapping Charles R. , Hughes Jane Philips , Anthony Suzie , Boardman Phil , Patel Rafiudin , Wigham Andrew , Husainy Mohammad Ali , See Teik Choon , Cast James , Olliff Simon , Travis Simon , Laasch Hans-Ulrich , Nice Colin , Uberoi Raman
Published: July 2021

Purpose

The purpose of this study was to evaluate the predictive value of a ‘Modified Karnofsky Scoring System’ on outcomes and provide real-world data regarding the UK practice of biliary interventions.

Materials and Methods

A prospective multi-centred cohort study was performed. The pre-procedure modified Karnofsky score, the incidence of sepsis, complications, biochemical improvement and mortality were recorded out to 30 days post procedure.

Results

A total of 292 patients (248 with malignant lesions) were suitable for inclusion in the study. The overall 7 and 30 day mortality was 3.1% and 16.1%, respectively. The 30 day sepsis rate was 10.3%. In the modified Karnofsky ‘high risk’ group the 7 day mortality was 9.7% versus 0% for the ‘low risk’ group (p = 0.002), whereas the 30 day mortality was 28.8% versus 13.3% (p = 0.003). The incidence of sepsis at 30 days was 19% in the high risk group versus 3.3% at the low risk group (p = 0.001)

Conclusion

Percutaneous biliary interventions in the UK are safe and effective. Scoring systems such as the Karnofsky or the modified Karnofsky score hold promise in allowing us to identify high risk groups that will need more careful consideration and enhanced patient informed consent but further research with larger studies is warranted in order to identify their true impact on patient selection and outcomes post biliary interventions.
Correction to: Impact of interventionalist’s experience and gender on radiation dose and procedural time in CT-guided interventions—a retrospective analysis of 4380 cases over 10 years
Authors: Theilig Dorothea , Mayerhofer Anna , Petschelt David , Elkilany Aboelyazid , Hamm Bernd , Gebauer Bernhard , Geisel Dominik
Published: July 2021

A Correction to this paper has been published: 10.1007/s00330-021-08138-8
(H)IF applicable: promotion of neurogenesis by induced HIF-2 signalling after ischaemia
Authors: Leu Tristan , Fandrey Joachim , Schreiber Timm
Published: July 2021

HIF-2 represents a tissue-specific isoform of the hypoxia-inducible factors (HIFs) which regulate oxygen homeostasis in the cell. In acute oxygen deficiency, HIF transcription factors ensure the timely restoration of adequate oxygen supply. Particularly in medical conditions such as stroke, which have a high mortality risk due to ischaemic brain damage, rapid recovery of oxygen supply is of extraordinary importance. Nevertheless, the endogenous mechanisms are often not sufficient to respond to severe hypoxic stress with restoring oxygenation and fail to protect the tissue. Herein, we analysed murine neurospheres without functioning HIF-2α and found that special importance in the differentiation of neurons can be attributed to HIF-2 in the brain. Other processes, such as cell migration and signal transduction of different signalling pathways, appear to be mediated to some extent via HIF-2 and illustrate the function of HIF-2 in brain remodelling. Without hypoxic stress, HIF-2 in the brain presumably focuses on the fine-tuning of the neural network. However, a therapeutically increase of HIF-2 has the potential to regenerate or replace destroyed brain tissue and help minimize the consequences of an ischaemic stroke.
Salivary IL-8 as a putative predictive biomarker of radiotherapy response in head and neck cancer patients
Authors: Principe Sara , Zapater-Latorre Enrique , Arribas Leo , Garcia-Miragall Enrique , Bagan Jose
Published: July 2021

Objectives

Ionizing radiation increases the expression of a number of salivary proteins involved in immunoregulatory networks related to infection, injury, inflammation, and cancer. Our main objective was to analyze whether there are significant differences in salivary cytokines before and after radiotherapy and whether any of them are associated to better outcomes after radiotherapy serving as a potential predictive biomarker of response to the treatment.

Materials and methods

We analyzed a panel of eight salivary markers (IL-4, IL-6, IL-8, and IL-10; MCP-1; TNF-α; VEGF; and EGF) in a group of HNC patients (N = 30), before and after irradiation treatment pre- and post-RT. We also compared these results with a group of healthy controls (N = 37). In both groups, we used stimulated saliva and we performed immunoassays based on multi-analyte profiling technology (Luminex xMAP).

Results

In our group of 30 HNC patients, 24 of them showed a good clinical response after radiotherapy treatment while 6 cases did not respond to radiotherapy. The data revealed a post-treatment increase in multiple cytokines in the stimulated saliva of HNC patients; the increases in IL-8 and MCP-1 were statistically significant (p ≤ 0.001 and p ≤ 0.0001, respectively). Analysis of receiver operating characteristic curves indicated the strong potential of IL-8 as a predictive biomarker of RT good outcomes (area under the curve = 0.84; p = 0.018).

Conclusions

After analyzing the panel of salivary cytokines, IL-8 showed the best association to the response to radiotherapy; in this sense, low IL-8 levels in the saliva of HNC patients before receiving irradiation therapy are associated with positive RT outcomes.

Clinical relevance

Salivary IL-8 expression in HNC patients undergoing RT may serve as a potential predictive biomarker of response to the treatment.
Wigner ensemble Monte Carlo simulation without splitting error of a GaAs resonant tunneling diode
Authors: Muscato Orazio
Published: July 2021

A Monte Carlo technique for the solution of the Wigner transport equation has been developed, based on the generation and annihilation of signed particles (Nedjalkov et al. in Phys Rev B 70:115319, 2004). A stochastic algorithm without time discretization error has been recently introduced (Muscato and Wagner in Kinet Relat Models 12(1):59–77, 2019). Its derivation is based on the theory of piecewise deterministic Markov processes. Numerical experiments are performed in the case of a GaAs resonant tunneling diode. Convergence of the time-splitting scheme to the no-splitting algorithm is demonstrated. The no-splitting algorithm is shown to be more efficient in terms of computational effort.