bluuebunny/crossref_metadata_2025 huggingface dataset:
Spinal Dysraphism- A Histopathological Study of 45 Cases
Authors: Sandhya Bangaru , Sabitharani SS , Niharikareddy Yandapally
Published: July 2021

Introduction: Dysraphic conditions of spine resulting from non closure of the neural groove, consists of different types of malformations and they are called spina bifida, which have been classified into several types. Myelomeningocele (MMC) and Meningocele (MC) come under spina bifida cystica. Aim: To review the clinical and pathological findings of congenital spinal dysraphism and discuss the pathological diagnosis Materials and Methods: A descriptive cross-sectional type of study was conducted in 45 cases of spinal dysraphism during the period from October 2012 to February 2016, in the Department of Pathology of a tertiary care hospital, Hyderabad, India. Cases which were diagnosed as spinal dysraphism by clinical and radiological examination, tissue specimens were sent to the department of pathology along with clinical and radiological findings. Haematoxylin and Eosin (H&E) staining was done in all cases, followed by detailed microscopic study of slides. Histopathological findings such as epithelial, mesodermal, neuroectodermal changes were elucidated in detail and findings were compared with literature. Results: In a total of 45 cases there were 30 cases of MMC, nine cases of MC and six cases of encephalocele. Loss of epidermal appendages were seen in 91% of cases and neuropil like matrix was present in 76% cases. Conclusion: The embryogenesis of spina bifida involves ectoderm, neuroectoderm and mesoderm. A detailed definition of histopathological aspects will help in understanding these anomalies and should be a part of a detailed histopathology report.
A Study on Impact of Farmer Producer Organisation on Farmers’ Income in Andhra Prdesh
Authors: Vedasri R. , Mishra R. K.
Published: July 2021

The present paper gives the information about the impact of Farmer Producer Organisation on farmers income. The data was collected from both the members of FPO and non- members regarding the socio-economic factors and farming details of farmers. Logistic regression which was a binary regression model was used for determining the factors influencing the farmers to join as group members and then ordinary least square regression was estimated to study the impact of FPOs on farmers income by including inverse mills ratio which was calculated in logistic regression model, to remove the selection bias. The results showed that education, distance to market and age are the factors determining the farmers to join as members of FPO. The impact study results showed that group membership, hired labour, crop production area, share of crop sold and market size are the factors that are positively significant and increasing the farmers income.
Factors Affecting the Level of Rural Households Livelihood Diversification in Gamo Zone, Southern Ethiopia
Authors: Wallole Wanno , Gecho Yishak , Tefera Tewodros
Published: July 2021

Livelihood diversification is enchanting a significant effect in generating household’s income. The livelihood diversification includes:on-farm, non-farm and off-farm strategies which are undertaken to get extra income and moderate hazard and insecurity. The purpose of this study was to examine the factors affecting the level of rural household livelihood diversification in Gamo Zone, Southern Ethiopia. The study was conducted by using a cross-sectional research design. It is a quantitative dominant concurrent mixed research methodology where the qualitative research is complemented with interpretations and triangulation. By applying multi-stage random sampling technique, a sample size of 400 household heads from 6 sample villages was selected and data were collected using interview schedule and via key informant interviews and focus group discussions. Descriptive statistics were analyzed and presented by using tables, graphs and figures while chi-square-test and F-test were employed to make statistical inferences. Tobit model was employed to identify the intensity of factors affecting of rural household’s livelihood diversification. Out of the 14 hypothesized explanatory variables, 6 variables namely age, education, access to extension, media access, distance to urban centers and training were found to have significant effect in rural household livelihood diversification decision. Therefore, the findings of this imply that rural households’ development policies should consider these factors in designing rural household livelihood diversification strategy.
Per-se Performance of Buckwheat (Fagopyrum esculentum L.) Genotypes for Plant Growth, Yield and Seed Quality Parameters in Prayagraj Agro-climatic Conditions
Authors: Thammineni Krishna Sai , Chaurasia Arun Kumar , Shukla Pradeep Kumar , Babu Anche Hareesh , Dileep Retineni
Published: July 2021

Buckwheat is one of the most important alternative food crops it being a rich sources of protein and high nutritious value. The field experiment was conducted during rabi season in the year 2019-2020 at Department of Genetics and Plant Breeding Research farm, Naini Agriculture Institute, Prayagraj. With an objective to evaluate and identify suitable genotypes in Praygraj Agro-climatic conditions based on different quantitative and seed quality parameters. The field experiment conducted using randomized block design in field with 3 replications and complete randomized design in laboratory experiment with 4 replications. The results showed that among the 13 genotypes, EC-2018742 found to be promising genotype with 23.55 seeds infloresence-1 481.71 seed plant-1 and 725.55 g seed yield plot-1 maximum yield recorded of 17.64 q/ha, genotype EC-2018742 found to be vigorous among the 13 genotypes with high seed vigour indices were found suitable for cultivation in Prayagraj region.
Burden of HIV, Tuberculosis Infection and Risk Factors amongst Inmates of Correctional Institutions in Port Harcourt Nigeria
Authors: Jeremiah Theresa Awortu , Jacob Ransom Baribefii , Jeremiah Zaccheaus Awortu , Mgbere Osaro , Anyamene Chris , Enweani-Nwokelo Ifeoma Bessie
Published: July 2021

Aims: Burden of infectious diseases in correctional institutions constitutes a public health concern due to the confined nature and congestion of the prisons. This study aimed at surveying Burden of HIV, Tuberculosis Infection and Risk factors amongst inmates of Correctional Institutions in Port Harcourt Nigeria

Study Design: The study was descriptive, comprising both males and females. A total of 178 inmates constituted the study population

Place and Duration of Study: Port Harcourt Maximum Prisons, Creek Road and the Juvenile Remand Home, Borokiri, Port Harcourt, Nigeria, between the months of May to December 2019.

Methodology: Two millilitres of blood was collected from each participant after receiving their informed consent. The blood was dispensed into EDTA anti-coagulant bottles and used for serological investigations of HIV 1&2, and TB.  Samples positive for TB was confirmed using the GeneXpert Molecular technique while HIV 1&2 were confirmed using Real-Time PCR and their Viral Loads determined.

Results: The overall prevalence of HIV and MTB in the study population were: HIV 1 & 2 (3.9%) and Tuberculosis (0.6%) The Mean Viral Loads of positive samples were HIV 1&2 (479.3 copies/ml); and High MTB was detected. The most significant risk factors identified are as follows:, inmates with tattoos on their bodies (c2=83.6, p<0.0001), took part in blood initiation ceremonies (c2=110.1, p<0.0001), have exchanged needles/sharp objects (c2=2.2, p>0.0001), have tribal marks (c2=58.4, p<0.0001), received blood (c2=151.1, p<0.0001). Majority of the inmates have had sex before, 159(89.3%) [89(56.0%) had multiple sex partners up to 3 and above, 32(20.1%) had 2 partners while 38(23.9%) said they were single sex partners (c2=37.1, p<0.0001)]. On condom use, 90(50.6%) of the inmates do not use condom while 88(49.4%) admitted they use condoms. 7(3.9%) of the inmates have indulged in anal sex (c2=151.1, p<0.0001). 6(3.4%) had history of family drug use while 23(12.9%) have used drugs prior to imprisonment

Conclusion: The prevalence of HIV among inmates in this study is quite high and remains a public health problem while that of Mycobacterium tuberculosis (MTB) though appearing relatively low still remains a public health risk. The risk factors amongst inmates of Correctional Institutions in Port Harcourt Nigeria have been identified in this study. The high HIV 1 & 2 prevalence with MTB prevalence with high viral load results indicates poor health conditions which if not contained can spread to other inmates. This requires prompt interventions and treatment among the correctional inmates.
The Relevance between Fecal Tumor M2 Pyruvate Kinase and Colonoscopy for the Detection of Cancer Colon
Authors: Genedy Muhammed Essam , Ezzat Sherif El-Sayed , Hazzaa Sahar Mohey Eldin , Elbedewy Mohamed Mohamed
Published: July 2021

Background: Colorectal cancer (CRC) determination is focused on clinical, serological and endoscopic observations These methods are considered as non-invasive, cost-effective and convenient clinical examination methods. A direct association between M2 Pyruvate Kinase (M2-PK) and separate oncoprotein is the product of dissociation of tetrameric form from dimeric structure in tumor cells. The aim of this analysis is to assess the sensitivity in high risk or symptomatic populations of fecal tumor M2-PK.

Methods: This study is a cross sectional study carried out on 50 patients who were categorized into two groups: 25 patients with colorectal neoplasms (group 1). 25 patients symptomatizing of: diarrhea, persistent abdominal discomfort or bleeding per rectum, without colorectal neoplasms (group 2).

Results: The median value of stool M2-PK showed statistically significance. At cut-off ≥ 70 of stool M2-PK to predict activity, sensitivity was 88%, specificity was 84%, PPV was 84.6% and NPV was 87.5%. AUC was 0.907 and P value was <0.001.

Conclusions: Fecal M2-PK can be used as a pre colonoscopy screening test for CRC patients and is superior to other tumor markers (CEA and CA19.9) as it is more sensitive and specific. As a result of its low cost and ease of use, it is a viable tool for pre-selecting individuals who undergo colonoscopy.
Diagnostic Strategies of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection: Operational Recommendations for Health Professionals
Authors: Zrieq Rafat , Khemakhem Asma M. , Haouas Najoua , Zeariya Mohammed G. M. , Alshammari Fares , Algahtani Fahad D.
Published: July 2021

Due to the massive impact of the coronavirus disease 2019 (COVID-19) pandemic worldwide, the accurate and early diagnosis and isolation of infected individuals remains the main way of rapidly curtailing the extension of the disease. The increasing incidence of mutations in the virus RNA sequence represents the principal challenge for the use of molecular approaches for COVID-19 diagnosis. Additionally, because severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spreads differently to that of its Coronaviridae counterparts, unconventional strategies and diagnostic algorithms must be utilized and comprehensively expanded. Therefore, in this study, we sought to conduct a detailed in-depth investigation using many scientific interfaces to i) determine the fastest, most cost-effective, and most comprehensive diagnostic techniques, and ii) identify the proper specimens used for SARS-CoV-2 detection. To accomplish that, we reviewed previous studies investigated for the diagnosis of COVID-19. These strategies are organized to help health professionals and policymakers to quickly choose and apply the appropriate diagnostic approaches.
Assessment of Indications, Risk Factors, & Materno-foetal Outcomes of LSCS (Emergency & Planned) in a Tertiary Care Rural Hospital of Wardha District, India
Authors: Gupta Anupama , Muntode Pramita A. , Gaidhane Abhay
Published: July 2021

Background: Occurrence of elective Caesarean Section (CS) is prevalent in the advanced age group, i.e. 26-30 years while higher incidence of emergency CS is seen in 20-25 years, the younger age group. Emergency caesarean delivery analogous with substantially greater maternal and foetal delivery complications in contrast to elective caesarean sections regardless of its growing acceptance as a preferable alternative to vaginal delivery. The study attempts to determine risk factors for emergency and scheduled caesarean surgeries, along with indications of LSCS and maternal-foetal outcomes.

Method: Prospective observational study will be carried out on post-natal care women who have undergone LSCS in the past 1 week in the rural tertiary care hospital, Wardha. Study participants will be approached in the OBGY Post Natal Care Ward 1or 2 days post-delivery after assuring their comfort. A predesigned & pre-structured questionnaire containing socio-demographic profile, maternal details, and reasons for planned/emergency C-section, neonatal details etc.

Results: From the baseline study, the average number of caesarean-sections was 55-60 %. Proportion of elective and emergency caesarean was 41.40 % and 58.60% respectively. Emergency group is expected to show all of the complications significantly higher in terms of both maternal and fetal outcome.

Conclusion: Previous c-section, foetal distress and misrepresentation of the foetus (Breech and Transverse Lie) were recorded as a most important indicator of caesarean section along with obstructed labour. Higher incidence of emergency CS was 20-25 years, while the incidence of elective C-Section was prevalent. in the age group of 26-30 years; Modifiable risk factors for the Caesarean Section, such as early marriage with its associated inadequate pelvic growth and unnecessary avoidance of hospital delivery due to fear of CS, should be discouraged.
Management and Outcomes of Pregnancy with Gestational Hypertension and Hyperthyroidism: A Case Report
Authors: Dagadkar Arundhatee
Published: July 2021

Introduction: Hyperthyroidism associated increases in thyroid hormone concentrations have to be differentiated from physiological adjustments in thyroid hormone economic system that rise up all through being pregnant, especially in the first trimester. For one thousand births, one or two instances of gestational hyperthyroidism exist. It's critical to stumble on hyperthyroidism in a pregnant female due to the fact it is able to have harmful outcomes for each the mom and the infant.

Presenting Complaint and Investigations: Patient’s chief complaints were vomiting, discomfort since 2 days. After physical examination and investigations, doctor diagnosed this as case of G2A1 with 35 weeks gestational age. This was a known case of gestational hypertension with hyperthyroidism. Investigations included Blood test, urine test, thyroid Profile, USG.

Obstetric History: Patient had bad obstetric history. 2.5 months spontaneous abortion was reported.

The Main Diagnoses, Therapeutic Interventions, and Outcomes: Gestational Hypertension with Known case of Hyperthyroidism. The patient had undergone various investigations like blood tests, USG, Physical examination. After physical examination and investigation doctor took a decision of emergency Lower segmental Caesarean section. Under spinal anaesthesia Lower segmental Caesarean section was done and outcome is good.

Nursing Perspectives: Administered fluid replacement i.e. DNS and RL, Fetal monitoring, monitored all vital signs and observed the outcomes of treatment.

Conclusion: Treatment and control of hypertension and hyperthyroidism in pregnancy at the right time increases the pregnancy's outcome.
Exploring the Pathogenic Role of Stress in Inflammatory Bowel Disease and its Management
Authors: Suraj Shaini , Prakash Anand , Dawande Pratibha , Noman Obaid
Published: July 2021

Every organism is constantly adapting to changes happening in the environment.  This adaptation helps in maintaining homeostasis.  All organisms must adapt at molecular, cellular, physiological, and behavioral levels.  Amongst many factors which act as a threat to homeostasis, one of them is stress.  The organism has to bring about both physiological and behavioral changes.  The various researches in recent years have shown that adverse life events, along with chronic stress, and depression leads to increased likelihood of relapse in patients with quiescent IBD. Many studies of experimental stress in animal models of colitis support this. Till date, the therapeutic successes of stress reduction therapies have not been explored largely.  This is also due to methodological difficulties in going ahead with such studies.  This paper tries to explore the recent researches in enhancing our understanding of the pathogenic role played by psychological stress in inflammatory bowel disease and focuses our attention on the need for controlled studies on the curative prospective of stress reduction therapies for IBD.
Overview of the Presentation and Updated Management of Sinusitis
Authors: Alasmari Khaled Abdullah S. , Alzahrani Lena Defallah G. , Al-ruwaili Sultan Suliman Q. , Alenezi Rahaf Naif A. , Bukhari Sarah Fahad M. , Altmimi Sarah Muqbil B. , Alanazi Shaden Akram A. , Aljohani Lama Muaysh M. , Alanazi Alshaymaa Akram A. , Almutairi Afnan Mohammed H.
Published: July 2021

Acute and chronic sinusitis are common primary care presentations. They are caused by mucosal inflammation, which inhibits mucociliary function of the nose and paranasal sinuses. Because it affects the mucous membranes that line both the nose and the sinuses, the complete medical word for sinusitis is "rhinosinusitis". Sinusitis is usually caused by a viral upper respiratory tract infection, with bacterial sinusitis occurring in about 2% of cases, yet in most cases overall antibiotics are being used and prescribed which is in most part are not needed, and cases often resolves without antibiotics need, most general practitioners rely on clinical findings to make the diagnosis. Watchful waiting and symptom treatment with nasal oxymetazoline, pseudoephedrine, and saline nasal irrigation are recommended. In this paper, we overview the presentation and management of sinusitis.
Alzheimer's Disease: History, Stages, Diagnosis and Its Future
Authors: Jiwtode Urvi , Chakole Swarupa , Bhatt Neha
Published: July 2021

Background: Alzheimer’s is a brain disease in which brain cells responsible for memory loss and other intellectual functions starts to die. It can also be said that there is a loss of connections in nerve cells of brain. Although scientists have not yet found out the main underlying cause of this disease, there are several other factors that have been studied which leads to alzheimer’s. Some of them include tangling of TAU protein, plaques formed by amyloid, shrinkage in brain tissue etc. It is the 6th leading cause of death in US and 3rd in older people. It was discovered by a psychiatrist Alzheimer’s, who researched on a patient Auguste D. He noticed dementia, aggressiveness and some other mental illness in her and then studied her brain after her death. Alzheimer’s is asymptomatic in early stages, that is why we cannot start the treatment in early stage. The disease can be identified once a person start getting symptoms. But until then the damage has already begun and progressed. We do not have a cure for this disease yet. It can only be delayed by treating the symptoms and by therapy. But the scientists are carrying out different clinical trials such as detangling of TAU protein etc to make this disease fully curable.
Comparative Study of Malaria Diagnosis: Rapid Diagnostic Test (RDTs) Against Microscopy among Pregnant Women Attending Antenatal Clinic in Specialist Hospital, Sokoto
Authors: Mohammed K. , Iduh M. U. , Saheed S. M. , Ashcroft O. F. , Garba M. K. , Nataala S. U.
Published: July 2021

Background: Malaria is an infectious disease caused by a protozoan parasite of the genus Plasmodium. It was estimated that 219 million cases of malaria occur in 87 countries, with an estimated death of 435,000 in 2017 among pregnant women. Other species include P. ovale, P. vivax, and P. malariae is a blood parasite of human and is one of the major public health burdens in developing countries, particularly in Sub-Saharan Africa. It is estimated that about 3.5 billion people globally and 450 million people are thought to be ill as a result of such infections, the majority being children.

Aims: This study was aimed at comparing RDTs against microscopy in the detection of malaria parasite among pregnant women. Samples were collected and analyzed following cross-sectional comparative study design. It was conducted between Septembers to November 2019.

Study Design: This was a cross-sectional, comparative study

Place and Duration of Study: This study was conducted among patients attending Specialist Hospital Sokoto, Sokoto State, between March and November, 2019.

Methodology: A total of 106 participants were enrolled for the study. Standard parasitological examination was carried out on blood samples using microscopy followed by Rapid Diagnostic test (RDTs).

Results: Finding revealed, in this study, CareStart kit had sensitivity of 77.7%, specificity of 100s%. It is expected that any RDT used for malaria diagnosis should have a high sensitivity of 95% and specificity 97% (WHO, 2003); this is in contrast with the RDTs results in this study.

The false negative (FN) Carestart and SD-Bioline kits in this study were 10% and 21%, respectively using microscopy as the gold standard due to lack of sensitivity of RDTs at low parsitaemia compared to microscopy.

The false positive rate in this study for the Carestart and SD-Bioline kits are 0% and 0% respectively. Out of 106 patients screened, 35% and 24% tested positive for Plasmodiumfalciparum using Carestart and SD-Bioline RDTs respectively, while 45% were positive to malaria by microscopic examination. There was high prevalence of malaria parasite among age group 18-23 which is 42.2%.

Conclusion: It can be concluded that using microscopy is more time consuming compared to RDTs due to the fact that the time taken to read the results for RDTs is within five minutes and that of microscopy is higher compared to RDTs. Over all prevalence of malaria by microscopy was 42.5% while the prevalence of malaria by Carestart and SD-bioline was 33% and 22.6% respectively. Conventional microscopy remains the gold standard compared to RDTs according to this study with the level of its sensitivity and specificity which is higher than RDTs.
Hybrid Speciation
Authors: Abbott Richard J , Rieseberg Loren H
Published: July 2021

Hybridisation between genetically divergent populations may lead to the formation of new evolutionary lineages. This may occur via duplication of a hybrid's chromosome complement (allopolyploid speciation) or by stabilisation of a fertile hybrid segregant (homoploid hybrid speciation). Although more common in plants, both modes of hybrid speciation also occur in fungi and in animals, including fish, amphibians and insects. The successful origin and establishment of hybrid species is highly dependent on an ability to occupy novel and/or spatially isolated habitats, in order to escape the effects of competition and gene flow from parental species. This ability is favoured by the generation of genetic novelty resulting from the dramatic effects that hybridisation (and genome duplication in allopolyploids) have on modifying genome structure and gene expression. Examples of recently originated allopolyploid and homoploid hybrid species are important models for investigating processes involved in hybrid speciation and establishment.

Key Concepts

Hybridisation between genetically divergent populations is promoted by habitat disturbance and may lead to the formation of new evolutionary lineages.

Hybrid speciation may occur via the duplication of a hybrid's chromosome complement (allopolyploid speciation) or by the stabilisation of a reproductively isolated, fertile hybrid segregant (homoploid hybrid speciation).

Allopolyploidy leads to instantaneous reproductive isolation between the allopolyploid neospecies and its parents and is therefore an example of very rapid speciation.

Allopolyploidy is very common in higher plants but less common in animals, although examples are known in insects, crustaceans, molluscs, fish, amphibians, reptiles and mammals.

Homoploid hybrid speciation is thought to be relatively rare, although an increasing number of homoploid hybrid species of animals, plants and fungi are being recognised using molecular markers.

Homoploid hybrid speciation can be completed within a few generations, although several hundred generations may be required before the genome of the hybrid neospecies is fully stabilised.

Considerable genetic novelty is generated in the early stages of allopolyploidy and homoploid hybrid speciation due to the marked effects that hybridisation (and genome duplication in the case of allopolyploidy) have on modifying genome structure and gene expression.

Such genetic novelty aids the establishment of hybrid neospecies in ecologically divergent habitats, thus reducing the likelihood of competition and crossing with parents.

Several examples are known of new allopolyploid and homoploid hybrid species originating within the past 250 years, and these have become important models for investigating processes involved in hybrid speciation and establishment.
Coalescence: The Sharing of Ancestry of Alleles
Authors: Brookfield John FY
Published: July 2021

Coalescence is the process whereby alleles sampled from a population are traced back to a single ancestor. When the variation that exists between the alleles is neutral in its effects on Darwinian fitness, the analysis of expected patterns in coalescent processes is simple. The structure of genealogies can reveal whether the population has been constant in size and whether it has been geographically subdivided. It can also suggest whether selection has operated. Software tools based on coalescence ideas are becoming increasingly useful, as the availability of DNA sequence data showing variation within‐and between‐species increases. These are having an impact on the way in which samples of individuals from different geographic locations are interpreted in terms of the history of populations. Through the study of ancient DNA, and in studies of rapidly evolving viruses, the coalescent approach can be applied to trace the history of samples differing in time.

Key Concepts

Variation exists at the molecular level between alleles in a population, which is mainly the result of neutral or nearly neutral mutations.

Alleles share ancestry and the DNA sequence variation between the alleles is dependent on the shape of the tree linking alleles to a common ancestor.

The tree of alleles, examined backwards in time, is characterised by coalescence events where the number of ancestral lineages is reduced by one.

The rate at which such coalescences occur depends inversely on the (effective) population size.

The pattern of variation thus gives information about the way in which the (effective) population size has changed over time.

Simple models of coalescence assume no recombination and thus a single tree connecting the alleles, but recombination can be included in models using a sequential Markovian coalescent.

Estimation of population size from the rate of coalescence assumes the population is panmictic but subdivided populations can be modelled using a structured coalescent.

Deviations from expected coalescence processes seen for individual genetic loci may indicate adaptive or balancing selection at those loci.
Microstructure Evolution, Mechanical, and Corrosion Behavior of Cryogenic Friction Stir‐Processed AA2014 Alloy
Authors: Satyanarayana Marukurthi V. N. V. , Kumar Adepu
Published: July 2021

Herein, a large‐area stir zone (SZ) is fabricated in AA2014 alloy via overlapping friction stir processing (FSP). The microstructure and texture evolution of AA2014 alloy during FSP is examined using electron backscattered diffraction (EBSD). EBSD maps reveal recrystallized fine grains with high‐angle grain boundaries in SZ due to dynamic recovery (DRV) and continuous dynamic recrystallization (C‐DRX). Severe plastic straining induced by the tool leads to the formation of the A‐(110) <111> component. The texture component is further investigated with X‐ray analysis, and the results are reported. Mechanical testing reveals that ductility significantly increases after FSP, whereas the hardness and strength remain lower than that of base metal (BM) due to thermal softening. Corrosion studies show that the corrosion attack is significantly controlled after FSP due to the development of a homogeneous fine‐grained structure and uniformly distributed fine precipitates.
Influencing the Hydrogen Porosity in Aluminum Casting by (Re)active Filter Materials
Authors: Fankhänel Beate , Hubálková Jana , Aneziris Christos G. , Stelter Michael , Charitos Alexandros
Published: July 2021

Nonmetallic inclusions and pores are the most common sources of aluminum casting defects. For this reason, great importance is attached to cleaning the aluminum melts, especially in secondary metallurgy. Herein, the results of several experiments in which innovative filter materials are tested with regard to their influence on hydrogen porosity in castings made of an AlCu4Ti alloy are presented. Reactive filter materials based on spodumene (LiAl(Si2O6)) are applied and compared with conventional ceramic foam filters made of alumina and new active carbon‐bonded alumina filters. It is found that spodumene has two different functions. On the one hand, the use of a spodumene‐containing filter material promotes the formation of gaseous hydrogen and, on the other hand, it can be assumed that some of the hydrogen is bound within the filter. Above phenomena are dependent on the reactivity of the filter coating. Therefore, spodumene in appropriate amounts can contribute to a reduction of porosity in the casting.
Enhanced Mechanical and Thermal Resistances of Nanoimprinted Antireflective Moth‐Eye Surfaces Based on Poly Vinylidene Fluoride/TiO2 Surface Nanocomposites
Authors: Jacobo-Martín Alejandra , Hernández Jaime J. , Pedraz Patricia , Navarro-Baena Iván , Monclús Miguel A. , Molina-Aldareguia Jon M. , Rodríguez Isabel
Published: July 2021

Herein, the fabrication of bioinspired moth‐eye antireflective (AR) films based on surface nanocomposites of poly vinylidene fluoride (PVDF) and TiO2 nanoparticles produced in a single thermal nanoimprint lithography step is described. The incorporation of nanoparticles enhances the mechanical and thermal stability of the AR topography as demonstrated by nanoindentation tests and in situ temperature‐dependent grazing incidence X‐ray scattering measurements using synchrotron radiation. The effect of thermal annealing and UV radiation on the degradation in the optical performance and durability of the AR films is also evaluated in weathering tests. Improving the thermal and mechanical behavior as well as the long‐term durability of nanoimprinted polymer AR films will significantly expand their potential for implementation in solar devices.
Design and Directional Growth of (Mg1−xZnx)(Al1−yCry)2O4 Single‐Crystal Fibers for High‐Sensitivity and High‐Temperature Sensing Based on Lattice Doping Engineering and Acoustic Anisotropy
Authors: Wang Tao , Wang Haoyuan , Zhang Jian , Lin Na , Wang Gao , Jia Zhitai , Zhao Xian , Tao Xutang
Published: July 2021

High‐performance temperature sensors for the harsh environment are vital components for meeting the increasing demands for the development of existing and emerging technologies. In this study, specifically oriented (Mg1−xZnx)(Al1−yCry)2O4 single‐crystal fibers (SCF) are grown by the laser‐heated pedestal growth technique and used as acoustic waveguides for ultrasonic temperature sensors (UTS) for the first time. The anisotropic sensor performance of the MgAl2O4 SCF‐UTS are investigated under a longitudinal wave and transverse wave conditions, and the [110]‐oriented MgAl2O4 SCF‐UTS is found to have the highest sensitivity and resolution among all the MgAl2O4 SCF‐UTS. On this basis, a unit sensitivity of 40.38–67.50 ns °C−1 m−1 and a resolution of 1.24–0.74 °C are achieved for the [110]‐oriented (Mg0.9Zn0.1)(Al0.995Cr0.005)2O4 SCF‐UTS in the range of 20–1200 °C, both of which represent the best sensor performance achieved by a SCF‐UTS to date. The positive temperature‐dependent sensor performance, accompanied by a high working temperature (≈2000 °C) and outstanding anti‐oxidation, indicates that the [110]‐oriented (Mg0.9Zn0.1)(Al0.995Cr0.005)2O4 SCF‐UTS is a promising candidate for ultra‐high temperature sensors. This study demonstrates a feasible strategy for the rational design of high‐performance temperature sensors through a combination of crystal design, acoustic anisotropy, and lattice doping engineering.
Shape‐Memory Photonic Thermoplastics from Cellulose Nanocrystals
Authors: Boott Charlotte E. , Soto Miguel A. , Hamad Wadood Y. , MacLachlan Mark J.
Published: July 2021

Responsive materials prepared using shape‐memory photonic crystals have potential applications in rewritable photonic devices, security features, and optical coatings. By embedding chiral nematic cellulose nanocrystals (CNCs) in a polyacrylate matrix, a shape‐memory photonic crystal thermoplastic (CNC‐SMP) allows reversible capture of different colored states is reported. In this system, the temperature is used to program the shape‐memory response, while pressure is used to compress the helical pitch of the CNC chiral nematic organization. By increasing the force applied (≈140–230 N), the structural color can be tuned from red to blue. Then, on‐demand, the CNC‐SMP can recover to its original state by heating it above the glass transition temperature. This cycle can be performed over 15 times without any loss of the shape‐memory behavior or mechanical degradation of the sample. In addition, multicolor readouts can be programmed into the chiral nematic CNC‐SMP by using a patterned substrate to press the sample, while the glass transition temperature of the CNC‐SMP can be tuned over a 90 °C range by altering the monomer composition used to prepare the polyacrylate matrix.
Organic Semiconductor Nanotubes for Electrochemical Devices
Authors: Eslamian Mohammadjavad , Mirab Fereshtehsadat , Raghunathan Vijay Krishna , Majd Sheereen , Abidian Mohammad Reza
Published: July 2021

Electrochemical devices that transform electrical energy to mechanical energy through an electrochemical process have numerous applications ranging from robotics and micropumps to microlenses and bioelectronics. To date, achievement of large deformation strains and fast responses remains challenging for electrochemical actuators wherein drag forces restrict the device motion and electrode materials/structures limit the ion transportation. Results for electrochemical actuators, electrochemical mass transfers, and electrochemical dynamics made from organic semiconductors (OSNTs) are reported. The OSNTs device exhibits high‐performance with fast ion transport and accumulation in liquid and gel‐polymer electrolytes. This device demonstrates an impressive performance, including low power consumption/strain, a large deformation, fast response, and excellent actuation stability. This outstanding performance stems from the enormous effective surface area of nanotubes that facilitates ion transport and accumulation resulting in high electroactivity and durability. Experimental studies of motion and mass transport are utilized along with the theoretical analysis for a variable–mass system to establish the dynamics of the device and to introduce a modified form of Euler‐Bernoulli's equation for the OSNTs. Ultimately, a state‐of‐the‐art miniaturized device composed of multiple microactuators for potential biomedical applications is demonstrated. This work provides new opportunities for next‐generation actuators that can be utilized in artificial muscles and biomedical devices.
Elucidating the Mechanism of Fast Na Storage Kinetics in Ether Electrolytes for Hard Carbon Anodes
Authors: Dong Ruiqi , Zheng Lumin , Bai Ying , Ni Qiao , Li Yu , Wu Feng , Ren Haixia , Wu Chuan
Published: July 2021

The sodium storage performance of a hard carbon (HC) anode in ether electrolytes exhibits a higher initial Coulombic efficiency (ICE) and better rate performance compared to conventional ester electrolytes. However, the mechanism behind faster Na storage kinetics for HC in ether electrolytes remains unclear. Herein, a unique solvated Na+ and Na+ co‐intercalation mechanism in ether electrolytes is reported using designed monodispersed HC nanospheres. In addition, a thin solid electrolyte interphase film with a high inorganic proportion formed in an ether electrolyte is visualized by cryo transmission electron microscopy and depth‐profiling X‐ray photoelectron spectroscopy, which facilitates Na+ transportation, and results in a high ICE. Furthermore, the fast solvated Na+ diffusion kinetics in ether electrolytes are also revealed via molecular dynamics simulation. Owing to the contribution of the ether electrolytes, an excellent rate performance (214 mAh g−1 at 10 A g−1 with an ultrahigh plateau capacity of 120 mAh g−1) and a high ICE (84.93% at 1 A g−1) are observed in a half cell; in a full cell, an attractive specific capacity of 110.3 mAh g−1 is achieved after 1000 cycles at 1 A g−1.
Ultrasensitive NO2 Gas Sensors Based on Layered α‐MoO3 Nanoribbons
Authors: Li Wei , Xing Kaijian , Liu Porun , Chuang Chenghao , Lu Ying‐Rui , Chan Ting‐Shan , Tesfamichael Tuquabo , Motta Nunzio , Qi Dong‐Chen
Published: July 2021

The detection and monitoring of nitrogen dioxide (NO2) plays a vital role in the environmental, healthcare, farming, and industrial sectors. However, the development of NO2 gas sensors with simultaneously high sensitivity, reversibility, low detection limit, and excellent selectivity remains challenging. In this work, an ultrasensitive NO2 gas sensor with superb selectivity and reversibility is demonstrated based on α‐phase molybdenum trioxide (α‐MoO3). Nanoribbons of α‐MoO3 are synthesized via vapor phase transport (VPT) and systematically characterized using a combination of advanced characterization probes. At an optimal operating temperature of 125 °C, the α‐MoO3‐based sensor shows a very high sensitivity toward NO2 with a detection limit as low as 24 ppb, while also exhibiting excellent selectivity and reversibility. Such impressive performance originates from the layered nature of the α‐MoO3 nanoribbons as well as the hierarchical assembly of the nanoribbons as the sensing layer. The study demonstrates a facile sensing platform based on α‐MoO3 for ultrasensitive and selective NO2 gas sensing.
Reconstruction Compression Correlation Demodulation for Raman Optical Time Domain Reflection
Authors: Li Jian , Zhou XinXin , Yin Zitong , Wang Chenyi , Xu Yang , Zhang Jianzhong , Zhang Mingjiang
Published: July 2021

A novel optical mechanism and scheme of Raman optical time domain reflection (ROTDR) for improving achievable spatial resolution is proposed. Herein, the Raman backscattering characteristic of the optical fiber based on the amplified spontaneous emission (ASE) detection is first theoretically analyzed. Then, the propagation model of the ASE Raman anti‐Stokes trace is established. Based on the propagation model, the time domain difference reconstruction is applied to the whole collected Raman anti‐Stokes trace. The reconstructed Raman anti‐Stokes signal and ASE signal, which are first proposed here, show a distinct correlation characteristic. For this characteristic, a higher signal‐to‐noise ratio (SNR) demodulation scheme, named compression correlation demodulation, is used to detect the temperature change along the optical fiber. The positive correlation peak generated by the proposed mechanism produces a multiplied amplification effect through compressing the whole intensity points of Raman anti‐Stokes in the fiber under test (FUT) region. Furthermore, the proposed scheme reduces the crosstalk of the non‐FUT in the demodulation process. Benefiting from this new optical sensing mechanism and scheme, a simulation experiment with 7.5 mm spatial resolution and 0.1 °C temperature sensitivity is demonstrated, and the spatial resolution is independent of sensing distance. These advances greatly facilitate the practicability of ROTDR.
Enantioselective Vinylogous Mannich Reaction of Acyclic Vinylketene Silyl Acetals with Acyclic Ketimines
Authors: Ogura Kazuki , Takehara Tsunayoshi , Suzuki Takeyuki , Nakamura Shuichi
Published: July 2021

The first enantioselective vinylogous Mannich reaction of acyclic vinylketene silyl acetals with acyclic ketimines derived from alkynyl ketoesters was developed. Excellent yields and enantioselectivities were obtained from the reaction using bis(imidazoline)‐Zn(II) catalyst. Based on experiments and MO calculation, a plausible transition state was proposed to explain the stereoselectivity of the reaction. The obtained products were converted into various amines and a lactam. This process provides an efficient route for the synthesis of acyclic δ‐amino‐α,β‐unsaturated carbonyl compounds and their derivatives.

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A Novel Stimuli‐Responsive Injectable Antibacterial Hydrogel to Achieve Synergetic Photothermal/Gene‐Targeted Therapy towards Uveal Melanoma
Authors: Wang Shaoyun , Chen Baohui , Ouyang Liping , Wang Donghui , Tan Ji , Qiao Yuqin , Ge Shengfang , Ruan Jing , Zhuang Ai , Liu Xuanyong , Jia Renbing
Published: July 2021

Uveal melanoma (UM) is the most prevalent primary intraocular malignant tumor with a high lethal rate. Patients who undergo conventional enucleation treatments consistently suffer permanent blindness, facial defects, and mental disorders, therefore, novel therapeutic modalities are urgently required. Herein, an injectable and stimuli‐responsive drug delivery antibacterial hydrogel (CP@Au@DC_AC50) is constructed via a facile grinding method that is inspired by the preparation process of traditional Chinese medicine. The incorporation of gold nanorods can enhance the mechanical strength of the hydrogel and realize photothermal therapy (PTT) and thermosensitive gel‐sol transformation to release the gene‐targeted drug DC_AC50 on demand in response to low‐density near‐infrared (NIR) light. The orthotopic model of UM is built successfully and indicates the excellent efficiency of CP@Au@DC_AC50 in killing tumors without damage to normal tissue because of its synergistic mild temperature PTT and gene‐targeted therapy. Moreover, the eyeball infection model reveals the remarkable antibacterial properties of the hydrogel which can prevent endophthalmitis in the eyeball. There is negligible difference between the CP@Au@DC_AC50+NIR group and normal group. This NIR light‐triggered gene‐targeted therapy/PTT/antibacterial treatment pattern provides a promising strategy for building multifunctional therapeutic platform against intraocular tumors and exhibits great potential for the clinical treatment of UM.
Single‐Molecule Doping: Conductance Changed By Transition Metal Centers in Salen Molecules
Authors: Kilibarda Filip , Strobel Alexander , Sendler Torsten , Wieser Matthias , Mortensen Michael , Trads Julie Brender , Helm Manfred , Kerbusch Jochen , Scheer Elke , Gemming Sibylle , Gothelf Kurt V. , Erbe Artur
Published: July 2021

The creation of molecular components for use as electronic devices has made enormous progress. In order to advance the field further toward realistic electronic concepts, methods for the controlled modification of the conducting properties of the molecules contacted by metallic electrodes need to be further developed. Here a comprehensive study of charge transport in a class of molecules that allows modifications by introducing metal centers into organic structures is presented. Single molecules are electrically contacted and characterized in order to understand the role of the metal centers in the conductance mechanism through the molecular junctions. It is shown that the presence of single metal ions modifies the energy levels and the coupling of the molecules to the electrical contacts, and that these modifications lead to systematic variations in the statistical behavior of transport properties of the molecular junctions. A rigorous statistical analysis of thousands of junctions is performed to reveal this correlation. The understanding of the role of the metal ion in the resulting conductance properties is an essential step toward the development of molecular electronic circuits.
Magnetic Properties and Growth‐Induced Anisotropy in Yttrium Thulium Iron Garnet Thin Films
Authors: Rosenberg Ethan R. , Litzius Kai , Shaw Justin M. , Riley Grant A. , Beach Geoffrey S. D. , Nembach Hans T. , Ross Caroline A.
Published: July 2021

Rare‐earth iron garnets (REIG) have recently become the materials platform of choice for spintronic studies on ferrimagnetic insulators. However, thus far the materials studied have mainly been REIG with a single rare earth species such as thulium, yttrium, or terbium iron garnets. In this study, magnetometry, ferromagnetic resonance, and magneto‐optical Kerr effect imaging is used to explore the continuous variation of magnetic properties as a function of composition for YxTm3−x iron garnet (YxTm3−xIG) thin films grown by pulsed laser deposition on gadolinium gallium garnet substrates. It is reported that the tunability of the magnetic anisotropy energy, with full control achieved over the type of anisotropy (from perpendicular, to isotropic, to an in‐plane easy axis) on the same substrate. In addition, a nonmonotonic composition‐dependent anisotropy term is reported, which is ascribed to growth‐induced anisotropy similar to what is reported in garnet thin films grown by liquid‐phase epitaxy. Ferromagnetic resonance shows linear variation of the damping and the g‐factor across the composition range, consistent with prior theoretical work. Domain imaging reveals differences in reversal modes, remanant states, and domain sizes in YxTm3−x iron‐garnet thin films as a function of anisotropy.
Developing functional relationships between sesame growth, development, and nitrogen nutrition during early season
Authors: Sehgal Akanksha , Smith Callie Ann , Walne Charles Hunt , Chastain Daryl , Shankle Mark , Reddy Kambham Raja
Published: July 2021

Plants, being sessile, are subjected to multiple environmental stresses of varying intensity throughout their life cycle. Among the stresses, low fertility, drought, salinity, and nonoptimal temperatures limit crop productivity worldwide. Functional relationships between leaf N and crop growth are prerequisites to developing management tools that optimize productivity in the field. An outdoor pot‐culture experiment was conducted to determine the relationship between leaf N and sesame (Sesamum indicum L.) growth and development. Plants were grown in pots filled with fine sand and irrigated with full‐strength Hoagland's nutrient solution until 10 d after sowing (DAS). Five N treatments were then imposed: one treatment of full‐strength Hoagland's nutrient solution (control, 100% N), and four reformulations of Hoagland's nutrient solution containing reduced N at 60, 20, 10, and 0% of the control. Treatments were maintained until plants were harvested at 31 DAS. Growth, including several root traits, photosynthesis, and leaf N were measured at the end of the experiment. Maximum values were achieved at 5.3% leaf N in the leaves except for transpiration rate, stomatal conductance, and root/shoot ratio. Even though all growth rates declined with lower leaf N, the leaf area expansion among shoot and root volume among the root growth traits were most sensitive to leaf N. Among the root developmental traits, number of root tips was more sensitive to leaf N than other parameters. Among the plant dry components, leaf dry weight had the most considerable decrease. The root/shoot ratio increased under N deficiency. These N stress response indices and critical leaf N levels for various growth processes will help model and manage sesame crops in the field.