bluuebunny/crossref_metadata_2025 huggingface dataset:
Cobalt‐Catalyzed One‐Pot Asymmetric Difunctionalization of Alkynes to Access Chiral gem‐(Borylsilyl)alkanes
Authors: You Yang'en , Ge Shaozhong
Published: July 2021

Enantioselective cobalt‐catalyzed one‐pot hydrosilylation and hydroboration of terminal alkynes has been developed employing a cobalt catalyst generated from Co(acac)2 and (R,R)‐Me‐Ferrocelane. A variety of terminal alkynes undergo this asymmetric transformation, affording the corresponding gem‐(borylsilyl)alkane products with high enantioselectivity (up to 98 % ee). This one‐pot reaction combines (E)‐selective hydrosilylation of alkynes and consecutive enantioselective hydroboration of (E)‐vinylsilanes with one chiral cobalt catalyst. This protocol represents the most straightforward approach to access versatile chiral gem‐(borylsilyl)alkanes from readily available alkynes with commercially available cobalt salt and chiral ligand.
Synthesis of novel functionalized methacrylate copolymers and their copolymerization kinetics, thermal stability, and biocidal properties
Authors: Erol Ibrahim , Güldiken Ahmet
Published: July 2021

In the first step of this study, 2‐[(methoxy‐1,3‐benzothiazole‐2‐yl)amino]‐2‐oxoethyl methacrylate (MBAOM) monomer was synthesized and characterized. Then, a series copolymers were obtained by free‐radical copolymerization method of MBAOM and glycidyl methacrylate, which is a commercial monomer at 65°C in 1,4‐dioxane solvent. Structural characterizations of synthesized monomer and copolymers were carried out using Fourier transform infrared spectrophotometer and nuclear magnetic resonance spectroscopy (1H and 13C‐NMR) instruments. The composition of the copolymers was estimated by elemental analysis. The thermal behaviors of all the polymers have been investigated using the differential scanning calorimetry and the thermogravimetric analysis. A kinetic study of the thermal decomposition of copolymers was investigated using thermogravimetric analyzer with non‐isothermal methods selected for analyzing solid‐state kinetics data. The activation energy (Ea) values were calculated via Kissinger and Ozawa models in a period of α = 0.10–0.80. Photostability of the copolymers was investigated. Also, the biological activity of the copolymers against different bacterial and fungal species has been investigated.
Development of pullulan‐based carriers for controlled release of hydrophobic ingredients
Authors: Carvalho Layde T. , Moraes Rodolfo M. , Teixeira Ana Julia R. M. , Tada Dayane B. , Alves Gizelda M. , Lacerda Talita M. , Santos Julio C. , Santos Amilton M. , Medeiros Simone F.
Published: July 2021

Polymeric nanoparticles have great potential for targeted and controlled delivery of drugs for several health treatments. In this work, pullulan‐graft‐poly(ε‐caprolactone) (Pull‐g‐PCL) nanoparticles were prepared and used to encapsulate indomethacin via dialysis. The nanoparticles were characterized with respect to size, size distribution, and morphology, using dynamic light scattering and transmission electron microscopy. The average diameter of nanoparticles was 220.0 and 273.7 nm, with and without indomethacin, respectively. Encapsulation of indomethacin and its release from the nanoparticles were studied, and the calculated value of indomethacin efficiency encapsulation was 35.05 wt%. The ensuing release kinetics were evaluated in vitro at 37°C and pH 7.4 and evidenced the efficiency of polymer nanoparticles in reducing the release rate of the ingredient. Pull‐g‐PCL nanoparticles represent, therefore, promising materials with potential for application in controlled release systems of hydrophobic substances.
N‐Heterocyclic Carbene‐Catalyzed Asymmetric C−O Bond Construction Between Benzoic Acid and o‐Phthalaldehyde: Mechanism and Origin of Stereoselectivity
Authors: Deng Qianqian , Mu Fangjing , Qiao Yan , Wei Donghui
Published: July 2021

A computational study was contributed to explore the origin of stereoselectivity of NHC‐mediated cyclization reaction between benzoic acid and o‐phthalaldehyde for asymmetric construction of phthalidyl ester. The most energetically favorable pathway mainly includes the following steps: (1) nucleophilic attack on carbonyl carbon of o‐phthalaldehyde by catalyst NHC, (2) formation of Breslow intermediate, (3) oxidation by DQ, (4) asymmetric formation of dual C−O bonds, and (5) dissociation of catalyst with the product. The C−O bond formation was testified as the stereoselectivity‐determining step, the R‐configurational pathway is more energetically favorable than the S‐configurational one. The non‐covalent interaction (NCI) and atom‐in‐molecule (AIM) analyses were performed to reveal that the O−H ⋅⋅⋅ O and C−H ⋅⋅⋅ O hydrogen‐bond interactions are the key factors for controlling the stereoselectivity. The detailed mechanism and origin of stereoselectivity give useful insights for understanding organocatalytic reactions for asymmetric construction of C−O bond.
Attention training in children with autism spectrum disorder improves academic performance: A double‐blind pilot application of the computerized progressive attentional training program
Authors: Spaniol Mayra Muller , Mevorach Carmel , Shalev Lilach , Teixeira Maria Cristina T. V. , Lowenthal Rosane , de Paula Cristiane Silvestre
Published: July 2021

Atypical attention has been reported in individuals with autism spectrum disorder (ASD) with studies pointing to an increase in attention deficit and hyperactivity disorder‐like symptomatology. Individuals with ASD may also present academic difficulties and it is possible that they face a double‐barrier for academic attainment from both core ASD symptomatology and from attention atypicalities, which are directly linked to academic performance. This raises the possibility that academic difficulties in ASD may benefit from cognitive training targeting attention. To test this possibility, we used the computerized progressive attentional training (CPAT) intervention in a double‐blind, active control with follow‐up intervention study in Brazil. The CPAT is a computerized attention training program that was recently piloted with schoolchildren with ASD in the UK. Twenty‐six participants (8–14 years) with ASD in the São Paulo's ASD Reference Unit were assigned to either the CPAT (n = 14) or active control group (n = 12), which were matched at baseline. Two 45‐min intervention sessions per week were conducted over a 2‐month period. School performance, attention, fluid intelligence, and behavior were assessed before, immediately after and 3 months following the intervention. Significant group by time interactions show improvements in math, reading, writing and attention that were maintained at follow‐up for the CPAT (but not the active control) group, while parents of children from both groups tended to report behavioral improvements. We conclude that attention training has the potential to reduce obstacles for academic attainment in ASD. Combined with the previous pilot study, the current results point to the generality of the approach, which leads to similar outcomes in different cultural and social contexts.

Lay Abstract

Attention difficulties tend to occur in ASD and are linked to academic performance. In this study, we demonstrate that school performance in math, reading and writing in children with ASD can improve following an intervention that trains basic attention skills (the CPAT intervention). The improvements we report are stable and were maintained 3‐months following the intervention. This study, which was conducted in a public‐health setting in Brazil, extends previous research in schools in the UK pointing to the cross‐cultural and cross‐settings efficacy of the intervention.
Generalization of response interruption and redirection procedure with vocal stereotypy
Authors: Barszcz Holly , Griffith Annette K. , Weigand Patricia , Garcia Yors
Published: July 2021

This study used a combined design to evaluate the effects of nonvocal demands on vocal stereotypy in novel locations by implementing a concurrent multiple baseline design across settings, replicated across all participants. Results indicated that both the traditional and modified response interruption and redirection (RIRD) intervention were effective at reducing occurrences of vocal stereotypic behaviors for all four participants. The traditional RIRD intervention initially resulted in a larger decrease of these behaviors than the modified RIRD intervention; however, by the end of the study, the effects of both interventions on occurrences of vocal stereotypic behaviors were similar. Additionally, the effects of the RIRD intervention on occurrences of vocal stereotypic behavior met mastery criteria and generalized across settings for all four participants. The RIRD intervention generalized to the additional setting in less time than it took for the RIRD intervention to be effective in the first setting for all four participants.
Accelerated stability study of the ester prodrug remdesivir: Recently FDA‐approved Covid‐19 antiviral using reversed‐phase‐HPLC with fluorimetric and diode array detection
Authors: Hamdy Mohamed M. A. , Abdel Moneim Mona M. , Kamal Miranda F.
Published: July 2021

Remdesivir (RDV) is the first antiviral drug, approved by the Food and Drug Administration, to treat severe acute respiratory syndrome coronavirus 2. RDV is a relatively new chemical entity, ‘ester prodrug’, with no reported stability profile. Due to the urgency of its use and thus fast production, it is important to develop a stability‐indicating method for its assay. Chromatographic separation was carried out on a C18 column (250 × 4.6 mm, 5 µm) with dual detection: diode array at 240 nm and fluorescence at λex/em 245/390 nm. Isocratic elution of acetonitrile and distilled water (acidified with phosphoric acid, pH 4) in the ratio of 55:45 (v/v), respectively, was used. The linearity range using HPLC‐diode array detection was 0.1–15 μg/mL, whereas that using fluorimetric detection was 0.05–15 μg/mL. As per the International Conference on Harmonization guidelines, RDV has been degraded by accelerated alkaline, acidic, neutral hydrolysis, oxidative, heat, and photolytic stress conditions. Possible degradation hypothesis of the parent molecule has been suggested and illustrated. The proposed methods have achieved selective determination of the intact drug with no peaks overlapping in all assumptions. Extensive degradation confirms threatened drug stability at thermal and basic hydrolytic stressing. The developed methods were fully validated and proved suitable for quality control routine analysis of RDV in raw material and pharmaceutical dosage forms.
Alterations of the intrinsic amygdala‐hippocampal network in juvenile myoclonic epilepsy
Authors: Lee Dong Ah , Ko Junghae , Lee Ho‐Joon , Kim Hyung Chan , Park Bong Soo , Park Sihyung , Kim Il Hwan , Park Jin Han , Lee Yoo Jin , Park Kang Min
Published: July 2021

Introduction

Several lines of evidence suggest that the amygdala–hippocampus is involved in the epileptogenic network of juvenile myoclonic epilepsy (JME). The aim of this study was to investigate the alterations in the individual nuclei of the amygdala and hippocampal subfields, and the intrinsic amygdala‐hippocampal network of patients with JME compared to healthy controls.

Methods

This retrospective study conducted at a single tertiary hospital involved 35 patients with newly diagnosed JME, and 34 healthy subjects. We calculated the individual structural volumes of 18 nuclei in the amygdala, and 38 hippocampal subfields using three‐dimensional volumetric T1‐weighted imaging and FreeSurfer program. We also performed an analysis of the intrinsic amygdala‐hippocampal global and local network based on these volumes using a graph theory and Brain Analysis using Graph Theory (BRAPH) program. We investigated the differences in these volumes and network measures between patients with JME and healthy controls.

Results

There were no significant volume differences in the nuclei of the amygdala and hippocampal subfields between patients with JME and healthy controls. However, we found significant differences in the global network between patients with JME and healthy controls. The mean clustering coefficient was significantly decreased in patients with JME compared to healthy controls (0.473 vs. 0.653, p = .047). In addition, specific regions in the hippocampal subfields showed significant differences in the local network between the two groups. The betweenness centrality of the right CA1‐head, right hippocampus–amygdala‐transition area, left hippocampal fissure, left fimbria, and left CA3‐head, was increased in patients with JME compared to healthy controls.

Conclusion

The intrinsic amygdala‐hippocampal global and local networks differed in patients with JME compared to healthy controls, which may be related to the pathogenesis of JME, and memory dysfunction in patients with JME.
Ugandan and British individuals' views of refugees in their countries: An exploratory mixed‐methods comparison
Authors: Hellmann Jens H. , Übergünne‐Otte Lena , Heimlich Steven , Kalyegira Juma , Echterhoff Gerald , Memon Amina , Knausenberger Judith , Schlechter Pascal
Published: July 2021

Using an exploratory mixed‐methods approach, we examined thoughts concerning refugees reported by participants from a non‐Western country, Uganda, and the United Kingdom (total N = 113). We explored whether, due to various sociocultural, political and geographic differences, critical features of refugee migration (e.g., migration forcedness and migration‐related perils) would be viewed differently by Ugandan and UK participants. An inductive qualitative content analysis of responses in an online survey yielded 11 categories with 40 subcategories revealing several similarities between Ugandan and UK participants. For instance, similar proportions of participants from both countries acknowledged refugees' suffering before their migration and the forced nature of refugees' migration. However, we also found that more British than Ugandan participants referred to perils refugees suffer during their journeys, possibly resulting from differences in refugees' migration routes (e.g., crossing other countries, travelling by dilapidated boats, migration duration). Furthermore, Ugandan but not British participants took pride in international praise their country received for its forthcoming treatment of refugees. There were no differences regarding the extent to which Ugandan and British individuals exhibited prejudice towards refugees or experienced threats from refugees. We discuss the theoretical and practical implications of our findings for refugee integration.
Phytochemical, Antiplasmodial, Cytotoxic and Antimicrobial Evaluation of a Southeast Brazilian Brown Propolis Produced by Apis mellifera Bees
Authors: Ribeiro Victor Pena , Arruda Caroline , Aldana‐Mejia Jennyfer Andrea , Bastos Jairo Kenupp , Tripathi Siddharth K. , Khan Shabana I. , Khan Ikhlas A. , Ali Zulfiqar
Published: July 2021

Seven phenolic compounds (ferulic acid, caffeic acid, 4‐methoxycinnamic acid, 3,4‐dimethoxycinnamic acid, 3‐hydroxy‐4‐methoxybenzaldehyde, 3‐methoxy‐4‐hydroxypropiophenone and 1‐O,2‐O‐digalloyl‐6‐O‐trans‐p‐coumaroyl‐β‐D‐glucopyranoside), a flavanonol (7‐O‐methylaromadendrin), two lignans (pinoresinol and matairesinol) and six diterpenic acids/alcohol (19‐acetoxy‐13‐hydroxyabda‐8(17),14‐diene, totarol, 7‐oxodehydroabietic acid, dehydroabietic acid, communic acid and isopimaric acid) were isolated from the hydroalcoholic extract of a Brazilian Brown Propolis and characterized by NMR spectral data analysis. The volatile fraction of brown propolis was characterized by CG‐MS, composed mainly of monoterpenes and sesquiterpenes, being the major α‐pinene (18.4 %) and β‐pinene (10.3 %). This propolis chemical profile indicates that Pinus spp., Eucalyptus spp. and Araucaria angustifolia might be its primary plants source. The brown propolis displayed significant activity against Plasmodium falciparum D6 and W2 strains with IC50 of 5.3 and 9.7 μg/mL, respectively. The volatile fraction was also active with IC50 of 22.5 and 41.8 μg/mL, respectively. Among the compounds, 1‐O,2‐O‐digalloyl‐6‐O‐trans‐p‐coumaroyl‐β‐D‐glucopyranoside showed IC50 of 3.1 and 1.0 μg/mL against D6 and W2 strains, respectively, while communic acid showed an IC50 of 4.0 μg/mL against W2 strain. Cytotoxicity was determined on four tumor cell lines (SK‐MEL, KB, BT‐549, and SK‐OV‐3) and two normal renal cell lines (LLC‐PK1 and VERO). Matairesinol, 7‐O‐methylaromadendrin, and isopimaric acid showed an IC50 range of 1.8–0.78 μg/mL, 7.3–100 μg/mL, and 17–18 μg/mL, respectively, against the tumor cell lines but they were not cytotoxic against normal cell lines. The crude extract of brown propolis displayed antimicrobial activity against C. neoformans, methicillin‐resistant Staphylococcus aureus, and P. aeruginosa at 29.9 μg/mL, 178.9 μg/mL, and 160.7 μg/mL, respectively. The volatile fraction inhibited the growth of C. neoformans at 53.0 μg/mL. The compounds 3‐hydroxy‐4‐methoxybenzaldehyde, 3‐methoxy‐4‐hydroxypropiophenone and 7‐oxodehydroabietic acid were active against C. neoformans, and caffeic and communic acids were active against methicillin‐resistant Staphylococcus aureus.
Long non‐coding RNAs and microorganism‐associated cancers
Authors: Ranjbar Reza , Behjatfar Mojtaba , Teimouri Ali , Aghaie Fard Arad , Maniati Mahmood , Taheri‐Anganeh Mortaza
Published: July 2021

Cancerous cells are abnormal cells characterized by aberrant growth and proliferation, which can involve various types of cells and tissues. Through numerous signalling pathways, many mechanisms are involved in cells that keep them normal. These signalling pathways are tightly set by different proteins whose expression is regulated by a large number of factors. In other words, when a regulating factor does not act properly or undergoes a change in its function or expression, the result will be that the subordinate gene and subsequently the related protein will show deranged expression and activity. This leads to disordered signalling pathways which bring about uncontrolled proliferation in cells. One of the most significant factors in adjusting the expression of genes is noncoding RNAs. It should be noted that all underlying causes initiating malignancy try to alter the main regulatory factors in cellular processes and gene expression and direct the cell to an unregulated state. Microorganisms have been identified as one of the important elements to direct normal cells to abnormality. That is, they probably agitate the malignant traits through manipulating significant factors such as ncRNAs in given cells using their own or host‐related factors. The present study is aimed at examining how the long noncoding RNAs are involved in microorganism‐mediated cancers.
The death knell of bare metal stents: The Cobra stent's encouraging results with short‐term antiplatelet therapy
Authors: Patel Nachiket J. , Heuser Richard R.
Published: July 2021

Key Points

The Cobra PzF is a non‐drug eluting, non‐bare metal stent coated with a polyzene‐F polymer that is thrombo‐resistant and reduces inflammation and neointimal proliferation.

The current study demonstrates the Cobra PzF is safe and efficacious.

Further studies are needed to determine if there is a DAPT duration advantage of the Cobra PzF over current DES platforms.
Gettin' Ziggy with it
Authors: Liskov Steven , Gray William A.
Published: July 2021

Key Points

Interventional therapies directed at closure of sinus venosus atrial septal defect (SVASD) rely on comprehensive pre‐operative cardiac imaging to identify appropriate candidates.

Operator familiarity with the covered 10 zig Cheatham platinum (CP) stent system is critical for adequate stent anchoring, defect closure, and avoidance of pulmonary vein occlusion.

The long‐term durability of 10 zig CP sent systems in SVASD closure remains unknown.
Merkel cell carcinoma on the right calf in association with chronic lymphocytic leukemia: A case report
Authors: Mohammadzadeh Hamideh , Babaniamansour Sepideh , Majidi Mohammadreza , Zare Abolfazl , Dehghani Firouzabadi Mohammad , Karkon‐Shayan Sepideh
Published: July 2021

This study showed a rare case of Merkel cell carcinoma (MCC) with atypical manifestations accompanied by chronic lymphocytic leukemia of B‐cell type that underwent chemotherapy and had poor prognosis. The findings suggest that the physicians should consider MCC when performing diagnosis and assess all possible associated risk factors like neoplasms to achieve good prognosis.
A Novel Gemini Sulfonic Ionic Liquid Immobilized MCM‐41 as Efficient Catalyst for Doebner‐Von Miller Reaction to Quinoline
Authors: Li An , Wang Xinyang , Li Yuhang , Luo Caiwu , Zhang Jiance , Liu Kun , Zhang Cen , Zhou Congshan
Published: July 2021

A novel 2,2′‐bipyridine‐based gemini sulfonic ionic liquid was first synthesized and then immobilized on MCM‐41 support (named IL1/MCM‐41), which was further characterized using XRD, FT‐IR, SEM, TEM, N2‐physisorption, XPS and TG techniques. These characterization results revealed that the IL1/MCM‐41 presented a whole ordered mesoporous structure, excellent thermal stability as well as the interaction between ionic liquid with MCM‐41. Catalytic activity of the obtained IL1/MCM‐41 was systematically evaluated for the Doebner‐Von Miller reaction to generate quinoline. Compared to conventional imidazole‐type single sulfonic ionic liquid supported on MCM‐41 (named IL2/MCM‐41), IL1/MCM‐41 exhibited higher catalytic activity and better reusability, which was probably due to the synergistic catalytic effect of the dual sulfonic acid group on IL2 and the stronger interaction between dipyridine ring of ionic liquid with MCM‐41 support, respectively. Meanwhile, a plausible reaction routes for the synergistic catalytic action of dual sulfonic acid to quinoline over the IL1/MCM‐41 catalyst was also proposed in this paper.
Synthesis of 4‐Trifluoromethylated 1,3‐Butadienes via Palladium Catalyzed Heck Reaction
Authors: Li Yang , Hao Meng , Chang Yu‐Chen , Liu Yuan , Wang Wen‐Fei , Sun Ning , Zhu Wen‐Qing , Gao Ziwei
Published: July 2021

Main observation and conclusion

1,3‐Butadiene plays a key role in modern synthetic chemistry and biochemistry because it is a key intermediate in the synthesis of many drugs. A new and effective method for the synthesis of 4‐trifluoromethylated 1,3‐butadiene through the fluorinated Heck reaction catalyzed by Pd(0) is described. Without additives, 1‐chloro‐3,3,3‐trifluoropropene (an inexpensive CF3 structural unit that is harmless to ozone) reacts with enamide to synthesize 4‐trifluoromethylated 1,3‐butadienes with good yield, high regioselectivity and chemical selectivity, and strong tolerance of substrate functional groups such as alkynes, aldehyde, and ester groups.
Maleimide Chemistry: Enabling the Precision Polymer Synthesis
Authors: Mejia Glauber , Wang Yongquan , Huang Zhihao , Shi Qiunan , Zhang Zhengbiao
Published: July 2021

Herein is presented a compilation of the main characteristics of maleimide chemistry in developing the precisely controlled polymers, including the design of sequence‐controlled polymers, topological polymers, and polymeric single‐chain nanoparticles. The synthetic methods, relied on the versatilities of the maleimide moieties as a latent monomer which leads to an efficient alternative in various innovative applications, especially in self‐healing material, self‐reporting materials for real‐time monitoring, and also in data storage and anticounterfeiting technologies. The core of the content in this review is focused on the up‐to‐data advances and publications on the major of maleimide chemistry in our research group.

What is the most favorite and original chemistry developed in your research group?

Maleimide chemistry in precision polymer synthesis.

How do you get into this specific field? Could you please share some experiences with our readers?

When I was a junior high school student, the chemistry attracted me very much. Chemistry is an extraordinary magic, which virtually generates molecules, basic units and everything on earth. I selected the polymer chemistry area when I pursuit my MSc and PhD in Soochow University. The polymer chemistry is the basic and originality of polymer science, which has created tremendous useful materials and greatly benefited humanity in the past century. Engaging in chemistry research is tedious and hard most of the time, but I like the joy and accomplishment at the moment when the experiment succeeds. It's like tea tasting, the

kind of fleeting back sweetness makes me yearn and intoxicated.

How do you supervise your students?

I always encourage students to believe themselves, however don't always believe what others have said. The students should have their own judgments based on broad literature survey, comprehensive learning and deep thinking. The students should not take the publications but the improvements of research capability as the only target when pursuing the academic degree.

What is the most important personality for scientific research?

Be joyful, enthusiastic, persistent and careful.

How do you keep balance between research and family?

I like cooking for my family. Cooking is similar with chemical experiments. I think that cooking is a good balance between research and family.
Impact of the new pulmonary hypertension definition on long‐term mortality in patients with severe aortic stenosis undergoing valve replacement
Authors: Maeder Micha T. , Weber Lukas , Weilenmann Daniel , Chronis Joannis , Joerg Lucas , Pohle Susanne , Haager Philipp K. , Brutsche Martin , Neumann Thomas , Schoch Otto D. , Rickli Hans
Published: July 2021

Background

The new 2018 pulmonary hypertension (PH) definition includes a lower mean pulmonary artery pressure (mPAP) cut‐off (>20 mmHg rather than ≥25 mmHg) and the compulsory requirement of a pulmonary vascular resistance (PVR) ≥3 Wood units (WU) to define precapillary PH. We assessed the clinical impact of the 2018 compared to the 2015 PH definition in aortic stenosis (AS) patients undergoing aortic valve replacement (AVR).

Methods

Severe AS patients (n = 487) undergoing pre‐AVR right heart catheterization were classified according to the 2015 and 2018 definitions. Post‐AVR mortality (median follow‐up 44 months) was assessed.

Results

Based on the 2015 definition, 66 (13%) patients exhibited combined pre and postcapillary PH (CpcPH), 116 (24%) isolated post‐capillary PH (IpcPH), 28 (6%) precapillary PH, and 277 (57%) no PH at all. Overall, 52 (11%) patients were reclassified: 23 no PH into IpcPH; 8 no PH into precapillary PH; 20 precapillary PH into no PH; 1 CpcPH into IpcPH. By the 2015 definition, only CpcPH patients displayed increased mortality, whereas by the 2018 definition, precapillary PH patients also experienced higher mortality than those without PH. Among the PH definition components, PVR ≥3 WU was the strongest predictor of death (hazard ratio > 4).

Conclusions

In severe AS, a higher number of IpcPH patients are diagnosed by the 2018 definition, even though they have the same prognosis as those without PH. Patients with true precapillary PH are more accurately identified by the 2018 definition that includes a pulmonary vascular disease criterion, that is, PVR ≥3 WU, a strong mortality predictor.
Early‐onset pancreatic cancer research: Making sense of confounding and bias
Authors: Miksad Rebecca A. , Calip Gregory S.
Published: July 2021

A historically understudied group with increasing incidence, patients with early‐onset pancreatic cancer (EOPC) appear to have different treatment patterns than patients with average‐age‐onset pancreatic cancer (AOPC). Differences in the causal pathways of confounders and sources of bias common to all retrospective research suggest that future research is needed to confirm findings and that interventions to increase the receipt of appropriate treatment and to improve outcomes may differ between patients with EOPC and patients with AOPC.
Performance of the IBIS/Tyrer‐Cuzick model of breast cancer risk by race and ethnicity in the Women's Health Initiative
Authors: Kurian Allison W. , Hughes Elisha , Simmons Timothy , Bernhisel Ryan , Probst Braden , Meek Stephanie , Caswell‐Jin Jennifer L. , John Esther M. , Lanchbury Jerry S. , Slavin Thomas P. , Wagner Susanne , Gutin Alexander , Rohan Thomas E. , Shadyab Aladdin H. , Manson JoAnn E. , Lane Dorothy , Chlebowski Rowan T. , Stefanick Marcia L.
Published: July 2021

BACKGROUND

The IBIS/Tyrer‐Cuzick model is used clinically to guide breast cancer screening and prevention, but was developed primarily in non‐Hispanic White women. Little is known about its long‐term performance in a racially/ethnically diverse population.

METHODS

The Women's Health Initiative study enrolled postmenopausal women from 1993‐1998. Women were included who were aged <80 years at enrollment with no prior breast cancer or mastectomy and with data required for IBIS/Tyrer‐Cuzick calculation (weight; height; ages at menarche, first birth, and menopause; menopausal hormone therapy use; and family history of breast or ovarian cancer). Calibration was assessed by the ratio of observed breast cancer cases to the number expected by the IBIS/Tyrer‐Cuzick model (O/E; calculated as the sum of cumulative hazards). Differential discrimination was tested for by self‐reported race/ethnicity (non‐Hispanic White, non‐Hispanic Black, Hispanic, Asian or Pacific Islander, and American Indian or Alaskan Native) using Cox regression. Exploratory analyses, including simulation of a protective single‐nucleotide polymorphism (SNP), rs140068132 at 6q25, were performed.

RESULTS

During follow‐up (median 18.9 years, maximum 23.4 years), 6783 breast cancer cases occurred among 90,967 women. IBIS/Tyrer‐Cuzick was well calibrated overall (O/E ratio = 0.95; 95% CI, 0.93‐0.97) and in most racial/ethnic groups, but overestimated risk for Hispanic women (O/E ratio = 0.75; 95% CI, 0.62‐0.90). Discrimination did not differ by race/ethnicity. Exploratory simulation of the protective SNP suggested improved IBIS/Tyrer‐Cuzick calibration for Hispanic women (O/E ratio = 0.80; 95% CI, 0.66‐0.96).

CONCLUSIONS

The IBIS/Tyrer‐Cuzick model is well calibrated for several racial/ethnic groups over 2 decades of follow‐up. Studies that incorporate genetic and other risk factors, particularly among Hispanic women, are essential to improve breast cancer–risk prediction.
Morphological properties of the axon initial segment‐like process ofAIIamacrine cells in the rat retina
Authors: Liu Jian Hao , Singh Jeet Bahadur , Veruki Margaret Lin , Hartveit Espen
Published: July 2021

Signal processing within the retina is generally mediated by graded potentials, whereas output is conveyed by action potentials transmitted along optic nerve axons. Among retinal neurons, amacrine cells seem to be an exception to this general rule, as several types generate voltage‐gated Na+(Nav) channel‐dependent action potentials. The AII, a narrow‐field, bistratified axon‐less amacrine cell found in mammalian retinas, displays a unique process that resembles an axon initial segment (AIS), with expression of Navchannels colocalized with the cytoskeletal protein ankyrin‐G, and generates action potentials. As the role of spiking in AIIs is uncertain, we hypothesized that the morphological properties of the AIS‐like process could provide information relevant for its functional importance, including potential pre‐ and/or postsynaptic connectivity. For morphological analysis, we injected AII amacrine cells in slices with fluorescent dye and immunolabeled the slices for ankyrin‐G. Subsequently, this enabled us to reliably identify AII‐type processes among ankyrin‐G‐labeled processes in wholemount retina. We systematically analyzed the laminar localization, spatial orientation, and distribution of the AIS‐like processes as a function of retinal eccentricity. In the horizontal plane, the processes displayed no preferred orientation and terminal endings were randomly distributed. In the vertical plane, the processes displayed a horizontal preference, but also ascended and descended into the inner nuclear layer and proximal inner plexiform layer, respectively. These results suggest that the AII amacrine AIS‐like process is unlikely to take part in conventional synaptic connections, but may instead be adapted to respond to volume neurotransmission by means of extrasynaptic receptors.
Phase noise suppression in LC oscillators: Tutorial
Authors: Bagheri Mohammad , Li Xun
Published: July 2021

This paper presents a comprehensive study of phase noise (PN) suppression in LC‐tank oscillators. The goal of this study is to provide designers with the latest techniques for reducing PN in cross‐coupled oscillators. To this end, we begin with a discussion of two prevalent PN models in oscillators: Hajimiri and Demir. We prefer the Hajimiri model because it does not involve very complicated math, and it offers engineers better insight into designing low‐PN oscillators in the two‐PN close‐in regions in an oscillator spectrum (1/f2 and 1/f3). In 1/f2 region, we show that a need for a large output‐voltage swing leads to Class D and B oscillators, and a large output‐current swing results in Class C oscillators. Also, reduction of the impulse sensitivity functions (ISFs) of an oscillator core can happen in Class F oscillators. A few solutions are presented for mitigating flicker noise up‐conversion, such as adding resistances, controlling the oscillation amplitude, decreasing the conduction angle, guiding the high‐frequency harmonics of current, and shifting the phase of VGS against VDS. We also provide a comparison of recent state‐of‐the‐art literature to show what constitutes a good PN in both 1/f2 and 1/f3 regions in cross‐coupled oscillators. We conclude that a cross‐coupled oscillator can reach the best performances in 1/f3 and 1/f2 PN regions if the oscillator is designed in Class C with the K block and uses the techniques of narrowing the conduction angle, the tail inductor, and the modified tank simultaneously.
Changes of esophageal varices in hepatitis C patients after achievement of a sustained viral response by direct‐acting antivirals
Authors: Takakusagi Satoshi , Saito Naoto , Ueno Takashi , Hatanaka Takeshi , Namikawa Masashi , Tojima Hiroki , Takizawa Daichi , Naganuma Atsushi , Kosone Takashi , Arai Hirotaka , Sato Ken , Kakizaki Satoru , Takagi Hitoshi , Uraoka Toshio
Published: July 2021

Objectives

The changes in portal hypertension after achieving a sustained viral response (SVR) by direct‐acting antivirals (DAAs) have not been fully elucidated. Consequently, noninvasive and inexpensive predictors need to be investigated. We therefore explored factors associated with the progression of EVs after the achievement of an SVR with DAAs in patients with chronic hepatitis C.

Methods

Eighty‐nine patients, who had achieved an SVR with DAAs and could have their esophagogastroduodenoscopy (EGD) findings compared between before DAAs administration and after achieving an SVR achievement were enrolled in this study. We compared the patients with and without EVs progression. Furthermore, the cumulative progression rates of EVs were also analyzed.

Results

The fibrosis‐4 index (FIB‐4) before DAAs administration was the only significant factor for the progression of EVs after an SVR (odds ratios: 1.2, 95% confidence intervals: 1.05–1.38, p = 0.01). In a receiver operating characteristics analysis, the cut‐off of FIB‐4 for the progression of EVs was 8.41 (sensitivity: 0.63, specificity: 0.86, positive predictive value: 0.31, negative predictive value: 0.96), namely EVs of those with more than 8.41 of FIB‐4 progressed and those with less than 8.41 of FIB‐4 did not.

Conclusions

As patients with FIB‐4 ≥ 8.41 may have progressions of EVs, periodic surveillance by EGD should be continued in such cases, even after an SVR is achieved.
Trophic niche overlap between sympatric harbour seals (Phoca vitulina) and grey seals (Halichoerus grypus) at the southern limit of their European range (Eastern English Channel)
Authors: Planque Yann , Spitz Jérôme , Authier Matthieu , Guillou Gaël , Vincent Cécile , Caurant Florence
Published: July 2021

Sympatric harbour (Phoca vitulina) and grey seals (Halichoerus grypus) are increasingly considered potential competitors, especially since recent local declines in harbour seal numbers while grey seal numbers remained stable or increased at their European core distributions. A better understanding of the interactions between these species is critical for conservation efforts. This study aimed to identify the trophic niche overlap between harbour and grey seals at the southern limit of their European range, in the Baie de Somme (BDS, Eastern English Channel, France), where numbers of resident harbour seals and visiting grey seals are increasing exponentially. Dietary overlap was identified from scat contents using hierarchical clustering. Isotopic niche overlap was quantified using δ13C and δ15N isotopic values from whiskers of 18 individuals, by estimating isotopic standard ellipses with a novel hierarchical model developed in a Bayesian framework to consider both intraindividual variability and interindividual variability. Foraging areas of these individuals were identified from telemetry data. The three independent approaches provided converging results, revealing a high trophic niche overlap due to consumption of benthic flatfish. Two diet clusters were dominated by either small or large benthic flatfish; these comprised 85.5% [CI95%: 80.3%–90.2%] of harbour seal scats and 46.8% [35.1%–58.4%] of grey seal scats. The narrower isotopic niche of harbour seals was nested within that of grey seals (58.2% [22.7%–100%] overlap). Grey seals with isotopic values similar to harbour seals foraged in coastal waters close to the BDS alike harbour seals did, suggesting the niche overlap may be due to individual grey seal strategies. Our findings therefore provide the basis for potential competition between both species (foraging on benthic flatfish close to the BDS). We suggest that a continued increase in seal numbers and/or a decrease in flatfish supply in this area could cause/amplify competitive interactions and have deleterious effects on harbour seal colonies.
Long‐term trends in marine turtle size at maturity at an important Atlantic rookery
Authors: Phillips Katrina F. , Stahelin Gustavo D. , Chabot Ryan M. , Mansfield Katherine L.
Published: July 2021

For species reaching maturity at a range of ages or sizes, factors that influence juvenile growth and size at maturity may have lasting impacts on overall fitness. Assessing when animals reach maturity is especially challenging for species which are difficult to follow through time as a result of highly migratory behavior, long life spans, or both. We examined nesting female size in a reproductive assemblage of green turtles (Chelonia mydas) and loggerheads (Caretta caretta) on the east coast of Florida, USA. We used a long‐term dataset from 1982 to 2019 to estimate a minimum size at maturity interval on the basis of two standard deviations below mean female size for each species. The minimum size intervals for green turtles (81.4–89.3 cm) and loggerheads (68.1–79.1 cm) were lower than most previous estimates in the literature, many of which were simply the smallest individual ever observed. There was a significant decrease in the upper bound of the minimum size interval over the study period for both green turtles (1.6 cm) and loggerheads (4.1 cm). These shifts in size at maturity may be the result of changes in population demographics, habitat quality, and behavioral reactions to these changes. The development and periodic reassessment of robust estimators of maturity are an important part of programs centered around the monitoring and conservation of vulnerable wildlife populations.
Monitoring of circulating amino acids in patients with pancreatic cancer and cancer cachexia using capillary electrophoresis and contactless conductivity detection
Authors: Tůma Petr , Hložek Tomáš , Kamišová Jana , Gojda Jan
Published: July 2021

Branched chain amino acids (BCAAs), alanine and glutamine are determined in human plasma by capillary electrophoresis with contactless conductivity detection (CE/C4D). The baseline separation of five amino acids from other plasma components is achieved on the short capillary effective length of 18 cm in 3.2 mol/L acetic acid with addition of 13% v/v methanol as background electrolyte. Migration times range from 2.01 min for valine to 2.84 min for glutamine, and LODs for untreated plasma are in the interval 0.7–0.9 μmol/L. Sample treatment is based on the addition of acetonitrile to only 15 μL of plasma and supernatant is directly subjected to CE/C4D. Circulating amino acids are measured in patients with pancreatic cancer and cancer cachexia during oral glucose tolerance test. It is shown that patients with pancreatic cancer and cancer cachexia syndrome exhibit low basal circulating BCAAs and glutamine levels and loss of their insulin‐dependent suppression.
Performance evaluation of graphene oxide–MnO2 nanocomposite for alkaline membrane fuel cell
Authors: Ahmed Mushtaq , Ahmad Shahbaz , Nawaz Tahir , Durrani M. Ali , Ali Asghar , Saher Saim , Khan Muhammad Alam Zaib , Egilmez Mehmet , Samreen Ayesha , Mustafa Faisal
Published: July 2021

The manganese dioxide/graphene oxide (MnO2/GO) nanocomposites were prepared from hydrothermally synthesized MnO2 nanorods and graphene oxide. Electrocatalytic performance for the oxygen reduction reactions (ORR) of the fabricated MnO2/GO nanocomposites was evaluated using the rotating disk electrode (RDE) method. It is found that MnO2/GO nanocomposites deliver significantly enhanced performance compared to standalone MnO2 and GO with current density and onset potential values of 5.1 mA/cm2 and 0.93 V versus RHE, respectively. The alkaline membrane fuel cell (AMFC) characteristics were also studied. In particular, the single‐cell alkaline fuel cell stack with MnO2/GO nanocomposite as cathode loading produced a peak power density value of 82 mW/cm2. Our findings revealed great potential for MnO2/GO nanocomposites for their electrocatalytic performance and utilization in AMFC as the cathode. Namely, MnO2/GO achieved fuel cell functionalities that were comparable to the widely used commercial Pt/C. The enhanced electrochemical performance of MnO2/GO is attributed to the synergistic interaction between highly conductive GO sheets and active sites of MnO2 nanorods. The commendable performance of MnO2/GO suggests that it can be used as electrocatalysts in alkaline fuel cell applications.
Layered metal halide perovskite solar cells: A review from structure‐properties perspective towards maximization of their performance and stability
Authors: de Holanda Matheus S. , Moral Raphael F. , Marchezi Paulo E. , Marques Francisco C. , Nogueira Ana Flávia
Published: July 2021

Perovskite solar cells (PSCs) technology is now reaching its full potential in terms of power conversion efficiency, but still presenting problems related to long‐term stability under operating conditions. One of the most promising alternatives to PSCs is the layered PSCs (2D‐PSCs). Layered perovskites present a huge compositional variety, which can be used to directly tune photophysical characteristics that influence the operational mechanisms of the devices. This review addresses the structural organization of both the organic and inorganic sublattices, focusing on how the structure influences the quantum and dielectric confinement, phonons and charge carriers' dynamics, charge mobility, and structural defects. We discuss the relation between the structure‐properties of layered perovskites with the performance of solar cells. We, then, offer insights into how these characteristics have been controlled in the assembly of 2D‐PSCs to improve their efficiency and stability. We conclude by giving a perspective of future developments and open areas of exploration that might impact the progress of this rapidly growing technology.

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Morphodynamics of an erodible channel under varying discharge
Authors: Adams David L.
Published: July 2021

Alluvial channels arise through the interaction between morphology, hydraulics, and sediment transport, known as the ‘fluvial trinity’. Over relatively short timescales where climate and geology are fixed but discharge and sediment supply may vary, this process facilitates adjustments towards steady state, where the system oscillates around a mean condition. The relationship between changes in conditions and geomorphic response may be highly complex and nonlinear, especially in systems with multiple modes of adjustment. This study examines the adjustment of an erodible channel with fixed banks and a widely graded sediment mixture to successive increases in discharge. With each increase in discharge, components of the fluvial trinity adjusted towards a steady state. Particularly at relatively low discharges, adjustments were controlled by intrinsic thresholds and highlighted important morphodynamic processes. Notably, there was a strong interplay between channel morphology and sediment transport, and an effect whereby larger‐than‐average grains controlled channel deformation. These two processes occurred at the bar scale and were highly spatialised, which has two important implications: (1) reach‐averaged representations of process provide only partial insight into morphodynamics; and (2) models of rivers that suppress these process feedbacks and size‐dependent transport may not replicate morphodynamics that typically occur in field conditions. The experiments provide quantitative evidence for conceptual models describing exponential approaches towards steady state and the potential for transiency if disturbance frequency exceeds the recovery time. They also highlight how in natural rivers, particularly those with greater degrees of freedom for adjustment (notably, lateral adjustment and meandering), continuous changes in discharge may lead to nonlinear rather than steady‐state behaviour. In these settings, more holistic analytical frameworks that embrace different aspects of the system are critical in understanding the direction, magnitude and timing of channel adjustments.
Linking the explicit probability of entrainment of instrumented particles to flow hydrodynamics
Authors: AlObaidi Khaldoon , Valyrakis Manousos
Published: July 2021

Obtaining a better understanding of the underlying dynamics of the interaction of turbulent flows and the bed surface that contains them, leading to the transport of coarse particles in fluvial, coastal, and aeolian environments, is considered as one of the fundamental objectives and the most complex problems in Earth surface dynamics and engineering. Recent technological advancements have made it possible to directly assess sediment entrainment rather than monitoring surrogate flow metrics, which could be related indirectly to sediment entrainment. In this work, a novel and low‐cost instrumented particle, 7 cm in diameter, is used to directly assess the incipient entrainment of a coarse particle resting on a bed surface. The particle has inertial measurement units (IMUs) embedded within its waterproof shell, enabling it to track the particle's motions and quantify its inertial dynamics. The sensors of the instrumented particle are calibrated using simple and easy‐to‐validate theoretically physical motions to estimate the uncertainties in their readings, which are reduced using an inertial sensor fusion process. A series of well‐designed laboratory flume incipient motion experiments are performed to assess the entrainment of the instrumented particle for a range of flowrates near the threshold of motion. The readings of the instrumented particle are used to derive metrics that are related to the probability of its incipient entrainment. The flow velocity measurements are obtained for the experiment runs, and the derived metrics are explicitly linked to the flow hydrodynamics responsible for the entrainment. The framework presented in this work can be used for a range of similar applications of low‐cost instrumented particles, spanning the interface of sensing and instrumentation in engineering (i.e., infrastructure and environmental monitoring) and geosciences (e.g., habitat assessment).