bluuebunny/crossref_metadata_2025 huggingface dataset:
Incidence of Malignant Diseases in Punjab: A Retrospective Study in a Tertiary Level Government Hospital in Punjab
Authors: Singla Deeksha , Singla Anand , Kaur Manpreet , Walia Darshanjit Singh
Published: April 2021

Introduction: Cancer is a grave problem with increase in incidence of various malignancies at an alarming rate in Punjab. Crude annual incidence rate of all cancers in Punjab has increased from 58.0 in 1990 to 85.5 in 2016 while crude mortality incidence ratio of all cancers in Punjab is 0.61 in females and 0.81 in males. Not only it is increasing mortality and morbidity, but it is also increasing the economic burden on a state already facing financial crisis. The exact burden of malignancies is not well known, although many local surveys have been done. Aim: To know the accurate burden of malignant diseases in patients presenting to a tertiary level government hospital in Punjab. Materials and Methods: A retrospective observational study in which data of all cases diagnosed to have malignant disease on histopathology at Government Medical College and Rajindra Hospital, Patiala, Punjab, from January, 2006 to December, 2015. The data was retrieved on yearly basis and total of each malignant disease was done to know the exact incidence of various malignancies over the decade by the measure of relative frequency. Results: A total of 4270 patients (41.65% in age group 41 to 70 years) were diagnosed to have malignant disease on histopathology out of which 2341 (54.82%) were females and 1929 (45.18%) were males. Leading causes of malignancy were the cancers of the f emale genital organs i.e., 20.05%, followed by breast cancer i.e., 1 8.17% and cancers of lip, oral cavity and pharynx i.e., 15.36%. Conclusions: Maximum incidence was seen in Carcinoma Breast followed by carcinoma cervix and carcinoma larynx. Early screening, timely diagnosis and management along with regular scrutiny of records should be done in routine to know the actual burden of cancer in the society.
Estimation of Calcium and Iron Levels in Gingival Crevicular Fluid and Serum in Periodontal Health and Disease
Authors: Krishnan Sridevi Sivarama , Vikram Vignesh , Meenakshi Bhagavatham , Chandran Chitraa R
Published: April 2021

Introduction: Gingival Crevicular Fluid (GCF) has been referred to as a promising medium for detection of markers for periodontal disease activity. Analysis of GCF shows minute changes in biomarker levels well before the onset of clinical signs and symptoms; which helps to even predict a person’s predisposition towards periodontal disease occurrence. The elemental analysis of human blood serum is noteworthy in routine clinical practice as well as in medical research. Aim: This study was done to determine the changes in calcium and iron levels in GCF and serum in human subjects with normal periodontal health and those with disease. Materials and Methods: This was a cross-sectional study conducted from March 2019 to December 2019. Eight study subjects (4 healthy subjects and 4 periodontitis cases) were selected from the patients reporting to the Department of Periodontics at Tagore Dental College and Hospital, Chennai. The subjects were chosen based on inclusion and exclusion criteria and all patients were subjected to a clinical examination wherein the Probing Depth (PD) and Clinical Attachment Level (CAL) were recorded by a single examiner using William’s Periodontal probe. The GCF samples were collected by Capillary Tubing method. Blood was collected by venipuncture and centrifuged to provide serum samples. Dual viewing Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) was used to estimate Calcium and Iron in GCF and serum. SPSS version 21.0 was used for statistical analysis. Mann Whitney U test was used for comparing the groups. p-value less than 0.05 was considered statistically significant. Results: Serum iron levels were significantly less in periodontitis patients than healthy subjects (p-value 0.043). GCF iron level (p-value 0.386), GCF calcium level (p-value 0.149) and serum calcium level (p-value 0.564) did not show any major variation among subjects with normal periodontal health and those with disease. Conclusion: The findings of this study showed that iron and calcium are present in GCF and serum samples of healthy persons and patients with chronic periodontitis which can be detected using ICP-OES. A significant difference in serum iron levels between health and disease could indicate a patient’s predisposition towards developing periodontitis. Calcium levels in GCF and serum do not point towards periodontal disease activity.
Awareness and Practices about Skin Care among Medical Students: A cross-sectional study
Authors: Upadhyay Henil , Parikh Charmy , Nair Pragya Ashok
Published: April 2021

Introduction: Skin care is defined as practices that help in maintaining the structural and functional integrity of the skin. Routine skin care focuses on keeping it clean, balanced, protected and free from irritation. This can be achieved with a simple regimen including gentle cleansing, moisturising and protecting the skin from UV rays. Aim: To evaluate the awareness and practices regarding skin care among medical students. Materials and Methods: This was a cross-sectional study involving medical students studying at a medical college in Western India. A questionnaire consisting of close-ended questions regarding skin care awareness and practices was used as study tool. Data was analysed using the STATA14 software. Results: The study group comprised of 300 participants of which 201 (67%) were females and the rest 99 (33%) were males. The age of participants ranged from 17 to 23 years. Ninety-three (31%) felt that ideally face should be washed twice in a day, while 153 (51%) students were having the awareness regarding makeup removal before sleep. The ideal sunscreen SPF was not known by 211 (70.3%) students while 47 (15.7%) knew that it should be 30-50. Awareness regarding physical exercise, yoga and meditation improving the skin health was seen in 201 (67%) and 235 (78.3%), respectively. Awareness regarding adequate sleep and healthy diet necessary for healthy skin was reported by 261 (87%) and 250 (83.3%) students, respectively. Total 129 (43%) students used Over-The-Counter (OTC) products or face wash to wash their face, 167 (55.7%) used some or other cosmetic products, 226 (75.3%) students didn’t share their cosmetic products with others while 277 (92.3%) students didn’t use sunscreen routinely. Conclusion: Medical students need to be aware about skin care practices, so that they can educate the general public about its importance particularly in country like India where most of the general population is under the influence of advertisements in newspaper and television about routine skin care.
Determination of Combination Factor as an Aid in Orthodontic Treatment Planning in Western Region of Saudi Arabian Young Male Population- A Retrospective Cephalometric Study
Authors: Devanna Raghu , Felemban Nayef H , Althomali Yousef , Gupta Puneet
Published: April 2021

Introduction: Diagnosis and treatment planning in orthodontics determines the treatment outcome and long term stability. Cephalometric radiography is an essential diagnostic aid in orthodontics and hence numerous studies have been carried out in the past. Aim: To determine the Combination Factor (CF) through evaluation of the mean Overbite Depth Indicator (ODI) and Anteroposterior Dysplasia Indicator (APDI) values in western region of Saudi Arabian young male patients which would act as an aid in orthodontic treatment planning. Materials and Methods: A retrospective cephalometric study was conducted on 80 Saudi Arabian young male patients ranging in age from 7 to 14 years. Data was collected from records derived from the University Dental Hospital. Patients (n=80) were divided into four age groups: ages 7 (n=20), 8-9 (n=20), 10-11 (n=20), and 12-14 (n=20) years. Lateral cephalometric images were hand-traced and measured by one standardised and calibrated investigator. Statistical analysis was done with significance level set at 0.05, assuming that the length of the 95% confidence interval was two. One-way analysis of variance, followed by the Tukey test used to compare the mean ODI and APDI values of different groups. The statistical data were analysed through SPSS version 24 for Windows (IBM SPSS, Chicago, IL, USA). Results: The mean ODI value was 69.2688° and standard deviation 4.66670°, respectively. The overall APDI mean value was 81.7063° and standard deviation 4.18987°, respectively. There were no significant differences in the mean ODI and APDI values among different age groups (p>0.05). Conclusion: This retrospective cephalometric study determined the CF for western region of Saudi Arabian young male population to be 150.96°. This factor can be used as a diagnostic aid for planning orthodontic treatment. When the CF, is under the norm (150.96°), the skeletal pattern tends to improve with dental extractions. A CF higher than the norm (150.96°) will maintain a better relation with a non-extraction treatment.
The Abuse of Central Nervous System Stimulants and its Impact on the Youth of Eastern Nigeria
Authors: Nwokike M. O. , Anusiem C. A. , Arinze C. O. , Ogbonna A. O.
Published: April 2021

The class of drugs designated as central nervous system (CNS) stimulants includes the four social drugs that find use among some youth of Eastern Nigeria; caffeine, nicotine, cocaine and marijuana. CNS stimulants increase or enhance the activity of monoamines (such as dopamine and nor epinephrine) in the brain, which leads to increased heart rate, blood pressure, and respiration. They also have a high potential for addiction. Addiction is defined as a chronic, relapsing brain disease that is characterized by compulsive drug seeking and use, despite harmful consequences. It is considered a brain disease because these drugs change the brain structure and function. The aim of this review is to answer the following questions: What are the common types of CNS stimulants abused in Eastern Nigeria? What prompts people to start taking these drugs? Why do people become addicted to these drugs? How does CNS stimulant abuse gain foothold in Eastern Nigeria? What are the implications of this drug taking for the users and the development of youth? How does the abuse of these stimulants affect the Eastern Nigerian society? How can the use of CNS stimulants among youth of eastern Nigeria be prevented or discouraged? Is there any treatment available for the youth addicted to CNS stimulants in Eastern Nigeria?
Targeting Signaling Pathways of Hyaluronic Acid and Integrin Receptors by Synergistic Combination Nanocomposites Inhibits Systemic Metastases and Primary Triple Negative Breast Cancer
Authors: Zhang Tian , Fu Chaoping , Alradwan Ibrahim , Yen TinYo , Lip HoYin , Cai Ping , Rauth Andrew M. , Zhang Liming , Wu Xiao Yu
Published: April 2021

Triple negative breast cancer (TNBC) has a poor prognosis due to its aggressive nature, high incidence of distant metastasis, and lack of targets for effective therapy. Therefore, a novel multifunctional biopolymer‐anticancer drug combination nanomedicine is designed for the prevention of spontaneous metastasis while treating primary TNBC. Oligomeric hyaluronic acid (oHA) and doxorubicin (DOX) at a synergistic ratio against TNBC cells are co‐loaded in a polymer‐lipid hybrid nanoparticle (PLN) which is then functionalized with an internalizing cyclic peptide iRGD (iRGD‐DOX‐oHA‐PLN). iRGD conjugation enhances cellular uptake and cytotoxicity in vitro and nanoparticle (NP) accumulation in human TNBC tumors that overexpress integrins. NP‐delivered oHA inhibits cell migration and invasion in vitro via the intracellular release of oHA that interacts with the receptor for hyaluronan mediated motility and downregulates the phospho‐extracellular signal‐regulated kinase (p‐ERK) signaling pathway. Intravenously injected iRGD‐DOX‐oHA‐PLN significantly inhibits the growth of primary TNBC tumors in a mouse model and prevents spontaneous metastasis to the lungs and lymph nodes, superior to free solutions of DOX, oHA, or both and NP formulations loaded with DOX or oHA. These results suggest that iRGD‐DOX‐oHA‐PLN can be a promising bioactive polymer‐drug combination nanomedicine for the treatment of TNBC and prevention of its spontaneous metastasis.
Variants associated with urea cycle disorders in Japanese patients: Nationwide study and literature review
Authors: Kido Jun , Matsumoto Shirou , Sugawara Keishin , Sawada Takaaki , Nakamura Kimitoshi
Published: April 2021

Urea cycle disorders (UCDs) are inherited metabolic diseases that lead to hyperammonemia with variable clinical manifestations. Using data from a nationwide study, we investigated the onset time, gene variants, clinical manifestations, and treatment of patients with UCDs in Japan. Of the 229 patients with UCDs diagnosed and/or treated between January 2000 and March 2018, identified gene variants and clinical information were available for 102 patients, including 62 patients with ornithine transcarbamylase (OTC) deficiency, 18 patients with carbamoyl phosphate synthetase 1 (CPS1) deficiency, 16 patients with argininosuccinate synthetase (ASS) deficiency, and 6 patients with argininosuccinate lyase (ASL) deficiency. A total of 13, 10, 4, and 5 variants in the OTC, CPS1, ASS, and ASL genes were respectively identified as novel variants, which were neither registered in ClinVar databases nor previously reported. The onset time and severity in patients with UCD could be predicted based on the identified gene variants in each patient from this nationwide study and previous studies. This genetic information may help in predicting the long‐term outcome and determining specific treatment strategies such as liver transplantation in patients with UCDs.
Tailored Synthesis of Skeletally Diverse Stemona Alkaloids through Chemoselective Dyotropic Rearrangements of β‐Lactones
Authors: Guo Zhen , Bao Ruiyang , Li Yuanhe , Li Yunshan , Zhang Jingyang , Tang Yefeng
Published: April 2021

The collective synthesis of skeletally diverse Stemona alkaloids featuring tailored dyotropic rearrangements of β‐lactones as key elements is described. Specifically, three typical 5/7/5 tricyclic skeletons associated with stemoamide, tuberostemospiroline and parvistemonine were first accessed through chemoselective dyotropic rearrangements of β‐lactones involving alkyl, hydrogen, and aryl migration, respectively. By the rational manipulation of substrate structures and reaction conditions, these dyotropic rearrangements proceeded with excellent efficiency, good chemoselectivity and high stereospecificity. Furthermore, several polycyclic Stemona alkaloids, including saxorumamide, isosaxorumamide, stemonine and bisdehydroneostemoninine, were obtained from the aforementioned tricyclic skeletons through late‐stage derivatizations. A novel visible‐light photoredox‐catalyzed formal [3+2] cycloaddition was also developed, which offers a valuable tool for accessing oxaspirobutenolide and related scaffolds.
Acridino[2,1,9,8‐klmna]acridine Bisimides: An Electron‐Deficient π‐System for Robust Radical Anions and n‐Type Organic Semiconductors
Authors: Tajima Keita , Matsuo Kyohei , Yamada Hiroko , Seki Shu , Fukui Norihito , Shinokubo Hiroshi
Published: April 2021

We report the synthesis and properties of acridino[2,1,9,8‐klmna]acridine bisimide (AABI), a nitrogen‐doped anthanthrene with two imide functionalities. AABI exhibits excellent electron affinity as evident by its low‐lying LUMO level (−4.1 eV vs. vacuum). Single‐electron reduction of one AABI derivative afforded the corresponding radical anion, which was stable under ambient conditions. Photoconductivity measurements suggest that the intrinsic electron mobility of an N‐phenethyl AABI derivative obeys a band‐transport model. Accordingly, an electron mobility of 0.90 cm2 V−1 s−1 was attained with the corresponding single‐crystal organic field‐effect transistor (OFET) device. The vacuum‐deposited OFET device consisting of a polycrystalline sample exhibited high electron mobility of up to 0.27 cm2 V−1 s−1 even in air. This study demonstrates that dual incorporation of both imide substituents and imine‐type nitrogen atoms is an effective strategy to create novel electron‐deficient π‐systems.
Persistent peri‐Heptacene: Synthesis and In Situ Characterization
Authors: Ajayakumar M. R. , Ma Ji , Lucotti Andrea , Schellhammer Karl Sebastian , Serra Gianluca , Dmitrieva Evgenia , Rosenkranz Marco , Komber Hartmut , Liu Junzhi , Ortmann Frank , Tommasini Matteo , Feng Xinliang
Published: April 2021

n‐peri‐Acenes (n‐PAs) have gained interest as model systems of zigzag‐edged graphene nanoribbons for potential applications in nanoelectronics and spintronics. However, the synthesis of n‐PAs larger than peri‐tetracene remains challenging because of their intrinsic open‐shell character and high reactivity. Presented here is the synthesis of a hitherto unknown n‐PA, that is, peri‐heptacene (7‐PA), in which the reactive zigzag edges are kinetically protected with eight 4‐tBu‐C6H4 groups. The formation of 7‐PA is validated by high‐resolution mass spectrometry and in situ FT‐Raman spectroscopy. 7‐PA displays a narrow optical energy gap of 1.01 eV and exhibits persistent stability (t1/2≈25 min) under inert conditions. Moreover, electron‐spin resonance measurements and theoretical studies reveal that 7‐PA exhibits an open‐shell feature and a significant tetraradical character. This strategy could be considered a modular approach for the construction of next‐generation (3 N+1)‐PAs (where N≥3).
Can a Procedure for the Growth of Single‐layer Graphene on Copper be used in Different Chemical Vapor Deposition Reactors?
Authors: Hakami Mariam , Deokar Geetanjali , Smajic Jasmin , Batra Nitin M. , Costa Pedro M. F. J.
Published: April 2021

In the last decade, catalytic chemical vapor deposition (CVD) has been intensively explored for the growth of single‐layer graphene (SLG). Despite the scattering of guidelines and procedures, variables such as the surface texture/chemistry of catalyst metal foils, carbon feedstock, and growth process parameters have been well‐scrutinized. Still, questions remain on how best to standardize the growth procedure. The possible correlation of procedures between different CVD setups is an example. Here, two thermal CVD reactors were explored to grow graphene on Cu foil. The design of these setups was entirely distinct, one being a “showerhead” cold‐wall type, whereas the other represented the popular “tubular” hot‐wall type. Upon standardizing the Cu foil surface, it was possible to develop a procedure for cm2‐scale SLG growth that differed only by the carrier gas flow rate used in the two reactors.
Aptamers: The Powerful Molecular Tools for Virus Detection
Authors: Han Cong , Li Qian , Ji Haishuo , Xing Wenping , Zhang Limin , Zhang Liyun
Published: April 2021

Aptamers are short single‐stranded DNA or RNA oligonucleotides selected by the technique of systematic evolution of ligands by exponential enrichment (SELEX). Aptamers have been demonstrated to bind various targets from small‐molecule to cells or even tissues in the way of antibodies. Thus, they are called chemical antibodies. We summarize and evaluate recent developments in aptamer‐based sensors (for short aptasensors) for virus detection in this review. These aptasensors are mainly classified into optical and electronic aptasensors based on the type of transducer. Nowadays, the smartphone has become the most widely used mobile device with billions of users worldwide. Considering the ongoing COVID‐19 outbreak, smartphone‐based aptasensors for a portable and point‐of‐care test (POCT) of COVID‐19 detection will be of great importance in the future.
Does quality management improve the internalization of environmental practices? An empirical study in Africa
Authors: Tayo Tene Christian Valery , Boiral Olivier , Heras‐Saizarbitoria Iñaki
Published: April 2021

This article analyzes the role of quality management in the internalization of environmental practices. A qualitative study based on interviews with 35 practitioners was conducted in three African countries (Cameroon, Senegal, and Ivory Coast). The results highlight the contrasting roles played by the main reference model for quality management—International Organization for Standardization (ISO) 9001—in the internalization of the international standard for corporate environmental management—ISO 14001—with positive points related to formal and documentary aspects and perverse effects such as increased bureaucracy and a focus on quality at the expense of the environment. The results also point to four configurations of integration of environmental practices according to the level of quality management internalization and the level of institutional pressure to adopt corporate environmental management: poor integration, partial integration, substantial integration, and sustainable integration.
Wanting sex and willing to kill: Examining demographic and cognitive characteristics of violent “involuntary celibates”
Authors: Williams D. J. , Arntfield Michael , Schaal Kaleigh , Vincent Jolene
Published: April 2021

Over the past several years, an online community of self‐described “incels,” referring to involuntary celibates, has emerged and gained increased public attention. Central to the guiding incel ideology and master narrative are violent misogynistic beliefs and an attitude of entitlement, based on male gender and social positioning, with respect to obtaining desired and often illusory sexual experiences. While violence and hate speech within the incel community are both common, there exists a notable subset of incels who have been willing to act on those violent beliefs through the commission of acts of multiple murder. This study explores the demographic, cognitive, and other characteristics of seven self‐identified incels who have attempted and/or successfully completed homicide. The findings suggest that although self‐perceptions tend to reflect either grandiosity or self‐deprecation, homicidal incels share similar demographic characteristics and dense common clusters of neutralization techniques, cognitive distortions, and criminal thinking errors.
Resveratrol is an inhibitor of sodium‐dependent inorganic phosphate transport in triple‐negative MDA‐MB‐231 breast cancer cells
Authors: Lacerda‐Abreu Marco Antonio , Russo‐Abrahão Thais , Meyer‐Fernandes José Roberto
Published: April 2021

Metastasis is a major cause of death in patients with breast cancer. A growing body of evidence has demonstrated the antitumour effects of resveratrol, a non‐flavonoid polyphenol. Resveratrol inhibits metastatic processes, such as the migration and invasion of cancer cells. In several cancer types, the importance of inorganic phosphate (Pi) for tumor progression has been demonstrated. The metastatic process in breast cancer is associated with Na+‐dependent Pi transporters. In this study, we demonstrate, for the first time, that resveratrol inhibits the Na+‐dependent Pi transporter. Results from kinetic analysis shows that resveratrol inhibits Na+‐dependent Pi transport non‐competitively. Resveratrol also inhibits adhesion/migration in MDA‐MB‐231 cells, likely related to inhibition of the Na+‐dependent Pi transporter.
Wet‐Spun PEDOT/CNT Composite Hollow Fibers as Flexible Electrodes for H2O2 Production**
Authors: Cui Qing , Bell Daniel Josef , Wang Siqi , Mohseni Mojtaba , Felder Daniel , Lölsberg Jonas , Wessling Matthias
Published: April 2021

The electrochemical synthesis of hydrogen peroxide (H2O2) using the oxygen reduction reaction (ORR) requires highly catalytic active, selective, and stable electrode materials to realize a green and efficient process. The present publication shows for the first time the application of a facile one‐step bottom‐up wet‐spinning approach for the continuous fabrication of stable and flexible tubular poly(3,4‐ethylene dioxythiophene) (PEDOT : PSS) and PEDOT : PSS/carbon nanotube (CNT) hollow fibers. Additionally, electrochemical experiments reveal the catalytic activity of acid‐treated PEDOT : PSS and its composites in the ORR forming hydrogen peroxide for the first time. Under optimized conditions, the composite electrodes with 40 wt % CNT loading could achieve a high production rate of 0.01 mg/min/cm2 and a current efficiency of up to 54 %. In addition to the high production rate, the composite hollow fiber has proven its long‐term stability with 95 % current retention after 20 h of hydrogen peroxide production.
Tuning the Anodic and Cathodic Dissolution of Gold by Varying the Surface Roughness
Authors: Chinnaiah Jeyabharathi , Kasian Olga , Dekshinamoorthy Amuthan , Vijayaraghavan Saranyan , Mayrhofer Karl J. J. , Cherevko Serhiy , Scholz Fritz
Published: April 2021

This work presents the reactivity and dissolution of an as‐polished and electrochemically pre‐treated polycrystalline Au electrode, which is used as a model system. The effect of the electrochemical pre‐treatment in corrosive 0.37 M HCl solutions on the Au surface roughness and dissolution is investigated by varying the number of pre‐treatment steps at 1.16 V against the reversible hydrogen electrode. It is shown that the first 10 s pre‐treatment of the as‐polished Au results in a higher surface roughness and thus higher electrochemically active surface area (ECSA) than that of the as‐polished Au. With the subsequent pre‐treatments, however, the ECSA is gradually decreasing reaching a steady value. The dissolution rate of the pre‐treated Au electrodes upon potential cycling in 0.1 M H2SO4 is determined by in situ inductively coupled plasma mass spectrometry. A non‐linear dependence of Au dissolution amount is found with respect to the number of pre‐treatments. The overall total Au dissolution rate follows a similar trend as ECSA/roughness. However, an important difference in the dissolution behavior is identified with respect to dissolution processes during Au oxidation (anodic dissolution) and Au reduction (cathodic dissolution): the former is more sensitive to the surface roughness. Thus, the ratio between Au anodic and cathodic dissolution amounts decreases substantially with decrease in surface roughness. This finding is explained by the slow and fast dissolution kinetics for anodic and cathodic processes, respectively. Current work further advances our understanding of the complex Au dissolution mechanism.
Click Chemistry in Ultra‐high Vacuum – Tetrazine Coupling with Methyl Enol Ether Covalently Linked to Si(001)
Authors: Glaser Timo , Meinecke Jannick , Freund Lukas , Länger Christian , Luy Jan‐Niclas , Tonner Ralf , Koert Ulrich , Dürr Michael
Published: April 2021

The additive‐free tetrazine/enol ether click reaction was performed in ultra‐high vacuum (UHV) with an enol ether group covalently linked to a silicon surface: Dimethyl 1,2,4,5‐tetrazine‐3,6‐dicarboxylate molecules were coupled to the enol ether group of a functionalized cyclooctyne which was adsorbed on the silicon (001) surface via the strained triple bond of cyclooctyne. The reaction was observed at a substrate temperature of 380 K by means of X‐ray photoelectron spectroscopy (XPS). A moderate energy barrier was deduced for this click reaction in vacuum by means of density functional theory based calculations, in good agreement with the experimental results. This UHV‐compatible click reaction thus opens a new, flexible route for synthesizing covalently bound organic architectures.
Synergistic Effect of NiLDH@YZ Hybrid and Mechanochemical Agitation on Glaser Homocoupling Reaction
Authors: Mokhtar Mohamed , Alzhrani Ghalia , Aazam Elham S. , Saleh Tamer S. , Al‐Faifi Sulaiman , Panja Subir , Maiti Debabrata
Published: April 2021

Herein, we report the synthesis of nickel‐layered double hydroxide amalgamated Y‐zeolite (NiLDH@YZ) hybrids and the evaluation of the synergistic effect of various NiLDH@YZ catalysts and mechanochemical agitation on Glaser homocoupling reactions. Nitrogen adsorption‐desorption experiments were carried out to estimate the surface area and porosity of NiLDH@YZ hybrids. The basicity and acidity of these hybrids were determined by CO2‐TPD and NH3‐TPD experiments respectively and this portrayed good acid‐base bifunctional feature of the catalysts. The NiLDH@YZ‐catalyzed mechanochemical Glaser coupling reaction achieved best yield of 83 % for the 0.5NiLDH@0.5YZ hybrid after 60 min of agitation, which revealed the highest acid‐base bifunctional feature compared to all the investigated catalysts. The developed catalyst has proven itself as a robust and effective candidate that can successfully be employed up to four catalytic cycles without significant loss in catalytic activity, under optimized reaction conditions. This work demonstrated a new strategy for C−C bond formation enabled by the synergy between mechanochemistry and heterogeneous catalysis.
Aryne Multicomponent Reactions by Directed C−H Activation
Authors: Sunnam Sunil Kumar , Belani Jitendra D.
Published: April 2021

Arylation via ortho C−H activation by the aid of directing groups has been explored recently by many researchers. Herein, a palladium‐catalyzed C−H arylation using 8‐aminoquinoline as a bidentate directing group has been developed. The reaction furnishes only C−H arylation, unlike previous methods where cyclization to corresponding isoquinolones is observed. More interestingly, sequential C−H functionalization was observed when methylacrylate and acrylonitrile was added; this led to C−H olefination with the aryl group, which was installed from the aryne precursor.
Synthesis of Lignans Based on a Borate‐mediated One‐pot Sequential Suzuki‐Miyaura Coupling of Cyclic Boranes
Authors: Sato Ko , Tanaka Hiroshi
Published: April 2021

Lignans are a group of polyphenolic phytochemicals that possess a large spectrum of chemical structures and biological activities. Here the syntheses of lignans – anwulignan, burseran, dehydroxycubebin, ruburisandrin B, and sesamin – are achieved based on a borate‐mediated one‐pot sequential Suzuki‐Miyaura coupling of cis‐ and trans‐fused bicyclic boranes, which were prepared by diastereoselective cyclic hydroboration of exo‐cyclic diene with cyclopentyl‐ and thexylboranes, respectively. A one‐pot sequential Suzuki‐Miyaura coupling of each cyclic borate with various aryl bromides initiated by activation of the cyclic borane with the carbon nucleophile provided 2,3‐dibenzylbutane derivatives with different aromatic substituents. Finally, the syntheses of naturally occurring lignans were accomplished in several steps from the products of Suzuki‐Miyaura coupling.
A Stable Homoleptic Divinyl Tetrelene Series
Authors: Roy Matthew M. D. , Baird Samuel R. , Dornsiepen Eike , Paul Lucas A. , Miao Linkun , Ferguson Michael J. , Zhou Yuqiao , Siewert Inke , Rivard Eric
Published: April 2021

The synthesis of the new bulky vinyllithium reagent (MeIPr=CH)Li, (MeIPr=[(MeCNDipp)2C]; Dipp=2,6‐iPr2C6H3) is reported. This vinyllithium precursor was found to act as a general source of the anionic 2σ, 2π‐electron donor ligand [MeIPr=CH]−. Furthermore, a high‐yielding route to the degradation‐resistant SiII precursor MeIPr⋅SiBr2 is presented. The efficacy of (MeIPr=CH)Li in synthesis was demonstrated by the generation of a complete inorganic divinyltetrelene series (MeIPrCH)2E: (E=Si to Pb). (MeIPrCH)2Si: represents the first two‐coordinate acyclic silylene not bound by heteroatom donors, with dual electrophilic and nucleophilic character at the SiII center noted. Cyclic voltammetry shows this electron‐rich silylene to be a potent reducing agent, rivalling the reducing power of the 19‐electron complex cobaltocene (Cp2Co).
Jens Weitkamp's Joy of Thinking
Authors: de Mijolla‐Mellor Sophie
Published: April 2021

With the evocation of Jens Weitkamp's life and character this paper tackles from the psychoanalytic theory of Sublimation (Sublimierung) the nature of the specific pleasure taken by researchers. They realize passionately their own driving forces but thus indirectly contribute to culture and progress of humanity. Any sublimated drive to knowledge is based on the acceptance that knowledge always implies simultaneously a future knowledge to be. This specific pleasure is based not on sexual abstinence as stated by Freud but on the renunciation to a stable security, enjoying a mobile order instead of fixity. Nevertheless, the sublimatory derivation that ensures the transition from destructiveness to exploratory curiosity is conditioned by the ability of the researcher not to destroy the object but only its enigmatic character.
Dilute gas‐particle suspension in a diffuser: A two‐fluid modelling approach
Authors: Senapati Santosh Kumar , Dash Sukanta Kumar
Published: April 2021

The present study evaluates the loss coefficient of a diffuser carrying a gas–solid mixture with the volume fraction of the solid in the medium to upper limits of the dilute phase flow (solid volume fraction in the range of 0.005–0.10). In light of the computational analysis, it is observed that an increase in the concentration of the solid phase always helps in overcoming the losses despite a significant dissipation of energy due to collisions. Moreover, the loss coefficient lessens as the solid‐phase density reduces. Under the operating conditions where the collisions become significant, a critical particle size (≈200 μm) is obtained. The loss coefficient mitigates gradually with an increase in the particle size up to this value but enhances beyond it. An increase in the diffuser angle enhances the loss; however, its effect becomes less prominent as the solid volume fraction increases (typically for solid volume fraction greater than or equal to 0.02).
Systematic review of financial burden assessment in cancer: Evaluation of measures and utility among adolescents and young adults and caregivers
Authors: Salsman John M. , Danhauer Suzanne C. , Moore Justin B. , Ip Edward H. , McLouth Laurie E. , Nightingale Chandylen L. , Cheung Christabel K. , Bingen Kristin M. , Tucker‐Seeley Reginald D. , Little‐Greene Denisha , Howard Dianna S. , Reeve Bryce B.
Published: April 2021

The cost of cancer care is rising and represents a stressor that has significant and lasting effects on quality of life for many patients and caregivers. Adolescents and young adults (AYAs) with cancer are particularly vulnerable. Financial burden measures exist but have varying evidence for their validity and reliability. The goal of this systematic review is to summarize and evaluate measures of financial burden in cancer and describe their potential utility among AYAs and their caregivers. To this end, the authors searched PubMed, Embase, the Cochrane Library, CINAHL, and PsycINFO for concepts involving financial burden, cancer, and self‐reported questionnaires and limited the results to the English language. They discarded meeting abstracts, editorials, letters, and case reports. The authors used standard screening and evaluation procedures for selecting and coding studies, including consensus‐based standards for documenting measurement properties and study quality. In all, they screened 7250 abstracts and 720 full‐text articles to identify relevant articles on financial burden. Eighty‐six articles met the inclusion criteria. Data extraction revealed 64 unique measures for assessing financial burden across material, psychosocial, or behavioral domains. One measure was developed specifically for AYAs, and none were developed for their caregivers. The psychometric evidence and study qualities revealed mixed evidence of methodological rigor. In conclusion, several measures assess the financial burden of cancer. Measures were primarily designed and evaluated in adult patient populations with little focus on AYAs or caregivers despite their increased risk of financial burden. These findings highlight opportunities to adapt and test existing measures of financial burden for AYAs and their caregivers.
Defect Engineering in 2D Photocatalytic Materials for CO2 Reduction
Authors: Pan Rongrong , Liu Jia , Zhang Jiatao
Published: April 2021

Two‐dimensional (2D) photocatalysts are promising candidates for efficient conversion of inexhaustible solar energy into clean fuels and chemicals. Defect engineering is proved to be a powerful tool to promote their performance in photocatalytic CO2 reduction reaction. This review concisely summarizes the recent progress in design and controllable creation of defects in 2D photocatalysts, together with an introduction of the characterization techniques that can be adopted to unveil the atomic arrangement and electronic structure of the defects. Moreover, the impacts of the defect states on the functions of 2D photocatalysts in three basic steps of photocatalytic CO2 process are discussed. Finally, the challenges and future possibilities in developing advanced 2D photocatalysts for improving the performance of CO2 reduction via defect engineering are outlined.
Evaluation of self‐organizing and self‐managing heterogeneous high performance computing clouds through discrete‐time simulation
Authors: Giannoutakis Konstantinos M. , Filelis‐Papadopoulos Christos K. , Gravvanis George A. , Tzovaras Dimitrios
Published: April 2021

Recently, a new management and resource delivery model based on self‐organization and self‐management (SOSM) principles for heterogeneous cloud infrastructures was proposed. The novel architecture was designed and implemented for the provision of cloud resources for delivering high performance computing services. The cost of deployment of such framework on large‐scale cloud infrastructures is prohibitive, thus discrete‐time simulation techniques were adopted in order to evaluate its efficiency and scalability. In this work, extensive simulation experimentation is being reported and discussed, concerning four evaluation criteria, for comparing the traditional centralized resources allocation scheme to the alternative of SOSM. From the results obtained, it can be derived that SOSM can provide improved service delivery, computational efficiency, power consumption, scalability and management of resources for millions of cloud nodes, compared to the centralized resource allocation approach.
Long‐Term Generation of Longitudinal Spin Order Controlled by Ammonia Ligation Enables Rapid SABRE Hyperpolarized 2D NMR
Authors: Vaneeckhaute Ewoud , De Ridder Sophie , Tyburn Jean‐Max , Kempf James G. , Taulelle Francis , Martens Johan A. , Breynaert Eric
Published: April 2021

Symmetry breaking of parahydrogen using iridium catalysts converts singlet spin order into observable hyperpolarization. In this contribution, iridium catalysts are designed to exhibit asymmetry in their hydrides, regulated by in situ generation of deuterated ammonia governed by ammonium buffers. The concentrations of ammonia (N) and pyridine (P) provide a handle to generate a variety of stereo‐chemically asymmetric N‐heterocyclic carbene iridium complexes, ligating either [3xP], [2xP;N], [P;2xN] or [3xN] in an octahedral SABRE type configuration. The non‐equivalent hydride positions, in correspondence with the ammonium buffer solutions, enables to extend singlet‐triplet or
mixing at high magnetic field and experimentally induce prolonged generation of non‐equilibrium longitudinal two‐spin order. This long‐lasting magnetization can be exploited in hyperpolarized 2D‐OPSY‐COSY experiments providing direct structural information on the catalyst using a single contact with parahydrogen. Separately, field cycling revealed hyperpolarization properties in low‐field conditions. Controlling catalyst stereochemistry by introducing small and deuterated ligands, such as deuterated ammonia, simplifies the spin‐system. This is shown to unify experimental and theoretically derived field‐sweep experiments for four‐spin systems.
Single‐phase front‐end modified interleaved Luo power factor correction converter for on‐board electric vehicle charger
Authors: Jothimani Gnanavadivel , Palanichamy Yogalakshmi , Natarajan Senthil Kumar , Rameshkumar Thangasankaran
Published: April 2021

This paper proposes a modification in the interleaved negative output elementary Luo converter to act as front‐end power factor correction converter for on‐board electric vehicle (EV) charger. The proposed converter is simple in design and offers non‐inverted DC link output voltage. The proposed converter has the advantages—high efficiency, near unity power factor, low AC source current distortion resulting in power quality enhancement, better DC load voltage regulation, and reduced component count. Due to interleaved configuration, rating of circuit components gets greatly reduced. Also, minimum numbers of circuit components pave the way for simple system design of on‐board EV charger. The steady‐state performance of the designed 100‐W, 48‐V converter with closed‐loop controller is analyzed under universal input voltage variation and wide range of load power variation. The converter is designed to provide stable operation when subjected to sudden disturbance in load power/supply voltage. The simulation analysis is done using MATLAB/Simulink platform. A prototype of 48‐V, 100‐W converter is built and tested. Results obtained reveal the superior performance of proposed converter under steady‐state and transient conditions.
ROCA: Auto‐resolving overlapping and conflicts in Access Control List policies for Software Defined Networking
Authors: Asif Awais Bin , Imran Muhammad , Shah Nadir , Afzal Mehtab , Khurshid Hasnat
Published: April 2021

Software‐defined networking (SDN) is a new networking architecture that decouples both the control and management planes from the data plane of forwarding devices. Control and management planes are implemented at a logically centralized entity called the controller. Despite numerous advantages, SDN is more prone to logical errors like loops, black holes, network reachability problems, and access control list (ACL) policies violation. In the existing approaches, the network requirements are specified by different network administrators using the ACL policies. SDN allows multiple network administrators to specify the ACL policies simultaneously, which may lead to conflicts and overlaps among the ACL policies. In this research work, a novel technique, called auto‐resolving overlapping and conflicts in ACL policies (ROCA), is proposed to efficiently detect and solve both the conflicts and the overlaps among the ACL policies by using the techniques of set theory, 3D structure, and separating axis theorem. It is shown by simulation and testing on the real network traces that ROCA outperforms the existing approaches in terms of computation time avoiding conflicts and overlapping among the ACL policies.
Persistent organic pollutants at the synapse: Shared phenotypes and converging mechanisms of developmental neurotoxicity
Authors: Latchney Sarah E. , Majewska Ania K.
Published: April 2021

The developing nervous system is sensitive to environmental and physiological perturbations in part due to its protracted period of prenatal and postnatal development. Epidemiological and experimental studies link developmental exposures to persistent organic pollutants (POPs) including polychlorinated biphenyls, polychlorinated dibenzo‐p‐dioxins, polybrominated diphenyl ethers, and benzo(a)pyrene to increased risk for neurodevelopmental disorders in children. Mechanistic studies reveal that many of the complex cellular processes that occur during sensitive periods of rapid brain development are cellular targets for developmental neurotoxicants. One area of research interest has focused on synapse formation and plasticity, processes that involve the growth and retraction of dendrites and dendritic spines. For each chemical discussed in this review, we summarize the morphological and electrophysiological data that provide evidence that developmental POP exposure produces long‐lasting effects on dendritic morphology, spine formation, glutamatergic and GABAergic signaling systems, and synaptic transmission. We also discuss shared intracellular mechanisms, with a focus on calcium and thyroid hormone homeostasis, by which these chemicals act to modify synapses. We conclude our review highlighting research gaps that merit consideration when characterizing synaptic pathology elicited by chemical exposure. These gaps include low‐dose and nonmonotonic dose‐response effects, the temporal relationship between dendritic growth, spine formation, and synaptic activity, excitation‐inhibition balance, hormonal effects, and the need for more studies in females to identify sex differences. By identifying converging pathological mechanisms elicited by POP exposure at the synapse, we can define future research directions that will advance our understanding of these chemicals on synapse structure and function.
The impact of COVID‐19 on body‐dissatisfied female university students
Authors: Zhou Yuan , Wade Tracey D.
Published: April 2021

Objective

This study investigated the impact of COVID‐19 on young women's disordered eating and their responses to online interventions to reduce disordered eating.

Method

University students at risk of developing an eating disorder (N = 100) were randomly assigned to either receiving an online intervention to reduce disordered eating or not. Forty‐one participants entered the study from September 2019 to March 2020 (pre‐COVID) and 59 after physical distancing was introduced due to COVID pandemic (during COVID). Online assessments were conducted at baseline and 1‐week follow up.

Results

There was a significant increase in weight concerns, disordered eating, and negative affect among participants entering the trial during COVID compared to pre‐COVID. The increases in the first two variables remained when adjusting for baseline negative affect. No significant interactions between time, condition and COVID status were observed.

Discussion

Young women experienced increased levels of disordered eating after the onset of COVID. While no interactions with COVID were detected, changes to within‐group effect sizes for disordered eating more than doubled for both online interventions and assessment from pre‐COVID to during COVID, suggesting any attention to issues related to disordered eating in the context of reduced social contact may be beneficial.
Planar or Bent? Redox Modulation of Hydrogenase Bimetallic Models by the [Ni2(μ‐SAr)2] Core Conformation
Authors: Murueta‐Cruz Brenda A. , Berlanga‐Vázquez Armando , Martínez‐Otero Diego , Benitez Luis Norberto , Castillo Ivan , Mondragón‐Díaz Alexander
Published: April 2021

Five neutral nickel(II) bimetallic models of the active site of [NiFe]‐hydrogenase supported by tridentate sulfur‐rich RNS2 ligands, were synthesized and tested as electrocatalysts for proton (H+) reduction. Complexes were classified according to the −NR substituent (1: 1‐methylpyrene; 2: 2‐methylthiophene; 3: phenyl) and as type a for those without bulky substituents and type b for the analogues with voluminous groups. Solid state structures were determined for three dimers, revealing [Ni2(μ‐SAr)2] frameworks, in which the two coordination planes around the Ni centres define a dihedral angle (θ) that is influenced by the substituents on the ligands (2 a: θ=180.0°, Ni ⋅⋅⋅ Ni=3.356 Å; 2 b: θ=98.55°, Ni ⋅⋅⋅ Ni=2.760 Å; 3 a: θ=107.32°, Ni ⋅⋅⋅ Ni=2.825 Å). Using CF3COOH as H+ source, 1 b and 2 b exhibit catalytic activity at −1.72 V (icat/ip≈2.40) and −1.80 V (icat/ip≈2.89) vs the ferrocenium/ferrocene couple (Fc+/Fc), respectively. In contrast, type a complexes were not viable catalysts. This behaviour suggests a relationship between the dimer conformation and its activity, due to a Ni ⋅⋅⋅ Ni cooperative effect, which is favoured in angular molecules and appears to assist during electrocatalytic H+ reduction.
Glyoxylic Acid: A Carboxyl Group‐Assisted Metal‐Free Decarboxylative Reaction Toward Propargylamines
Authors: Huang Liliang , Xie Yujuan , Ge Panyuan , Huang Junhai , Feng Huangdi
Published: April 2021

Readily available propargylamines are not only fundamental building blocks in organic synthesis, but also possess many prominent biological activities. A highly efficient, concise and environmentally benign decarboxylative reaction of glyoxylic acid monohydrate with secondary amines and alkynes has been elaborated, and a variety of propargylamines are delivered in moderate to good yields under metal‐free conditions. A mechanism involving a carboxyl group that assists the reactivity of alkynes, which makes the procedure of Michael addition proceeded smoothly, has been proposed.