bluuebunny/crossref_metadata_2025 huggingface dataset:
Supplementation and Performance for Wheelchair Athletes: A Systematic Review
Authors: Bauermann Andreia , de Sá Karina S.G. , Santos Zilda A. , Costa e Silva Anselmo A.
Published: November 2021

This systematic review aimed to identify nutritional interventions and supplements that improve the performance for wheelchair athletes. Intervention trials involving high-performance wheelchair athletes were analyzed, including those that comprised a nutritional intervention, defined as any intervention related to food, beverages, and supplementation aiming at evaluating the performance of wheelchair athletes. Of the included studies, four evaluated caffeine supplementation, of which one also evaluated sodium citrate supplementation; two studies evaluated vitamin D supplementation; one study assessed creatine monohydrate supplementation; and one assessed carbohydrate supplementation. Most studies were conducted on athletes with spinal cord injury. Athletes who consumed caffeine exhibited an improvement in performance, but this finding is not strong enough to become a recommendation.
Quantitatively analyzing the failure processes of rechargeable Li metal batteries
Authors: Xiang Yuxuan , Tao Mingming , Zhong Guiming , Liang Ziteng , Zheng Guorui , Huang Xiao , Liu Xiangsi , Jin Yanting , Xu Ningbo , Armand Michel , Zhang Ji-Guang , Xu Kang , Fu Riqiang , Yang Yong
Published: November 2021

Advanced spectroscopy methods quantitatively elucidate the failure process of lithium metal batteries.
Neuroimaging enters the pain biomarker arena
Authors: Tracey Irene
Published: November 2021

Neuroimaging methods can be used to identify biomarkers of acute and chronic pain.
Multicenter Clinical Evaluation of ETEST Plazomicin (PLZ) for Susceptibility Testing of Enterobacterales
Authors: Blanchard Laurine S. , Van Belkum Alex , Dechaume Dominique , Armstrong Thomas P. , Emery Christopher L. , Ying Yun X. , Kresken Michael , Pompilio Marion , Halimi Diane , Zambardi Gilles
Published: November 2021

Plazomicin (PLZ), brand name ZEMDRI (Cipla Therapeutics), is a novel aminoglycoside antibiotic approved by the U.S. Food and Drug Administration (FDA) for treatment of complicated urinary tract infections including pyelonephritis.
Human mobility models reveal the underlying mechanism of seasonal movements across China
Authors: Song Bing , Yan Xiao-Yong , Tan Suoyi , Sai Bin , Lai Shengjie , Yu Hongjie , Ou Chaomin , Lu Xin
Published: November 2021

Understanding the spatial interactions of human mobility is crucial for urban planning, traffic engineering, as well as for the prevention and control of infectious diseases. Although many models have been developed to model human mobility, it is not clear whether such models could also capture the traveling mechanisms across different time periods (e.g. workdays, weekends or holidays). With one-year long nationwide location-based service (LBS) data in China, we investigate the spatiotemporal characteristics of population movements during different time periods, and make thorough comparisons for the applicability of five state-of-the-art human mobility models. We find that population flows show significant periodicity and strong inequality across temporal and spatial distribution. A strong “backflow” effect is found for cross-city movements before and after holidays. Parameter fitting of gravity models reveals that travels in different type of days consider the attractiveness of destinations and cost of distance differently. Surprisingly, the comparison indicates that the parameter-free opportunity priority selection (OPS) model outperforms other models and is the best to characterize human mobility in China across all six different types of days. However, there is still an urgent need for development of more dedicated models for human mobility on weekends and different types of holidays.
ANALYSIS OF HEAT AND MASS TRANSFER ON THE PERISTALTIC MOVEMENT OF CARREAU NANOFLUIDS
Authors: MAGESH A. , KOTHANDAPANI M.
Published: November 2021

In this investigation, we have analyzed the peristaltic movement of MHD Carreau nanofluids in a curved channel by taking the thermophoresis and Brownian motion effects into account. The governing equations of the fluid flow like the equations of continuity, momentum, temperature and concentration are modulated and abridged by using the theory of lubrication approximations. A regular perturbation is used to solve the simplified coupled nonlinear differential equations. The changes of various fluid parameters on axial velocity, temperature and concentrations are carefully calculated, and the graphical results are analyzed. According to the result of this study, it is determined that the resulting velocity of nanofluid decreases significantly when the applied radial magnetic field is strengthened. In addition, the curvature parameter has a significant impact on the concentration function, and when the curvature of the channel is increased, the absolute value of the nanoparticle concentration distribution diminishes.
Cytomegalovirus Cholangiopathy in an Immunocompetent Patient: A Case Report and Literature Review
Authors: Alibegovic Ervin , Kurtcehajic Admir , Ilic Boris , Hujdurovic Ahmed , Smajic Edinka , Habibovic Amar , Perkunic Darja
Published: November 2021

A 37-year-old man presented with jaundice, upper right quadrant pain, and intermittent fever with chills. Laboratory assessment showed biliary stasis, with total bilirubin of 203 µmol/L (2–20), conjugated bilirubin of 105 µmol/L, and alkaline phosphatase of 556 U/L (30–120). Markers for hepatitis A–E viruses were negative. Serology assessment for rubeola, herpes simplex virus, Epstein-Barr virus, and Toxoplasma gondii showed negative IgM antibodies. HIV serology status was negative. For cytomegalovirus, both types of antibodies (IgM and IgG) were positive, with an IgM level >300 U/mL. pp65 antigen was also detected as well as CMV DNA. Diagnostic imaging of the abdomen except the dilated common bile duct showed a normal appearance of the gallbladder, liver, pancreas, spleen, and both kidneys. To our knowledge, cytomegalovirus cholangiopathy in the absence of any other underlying disease has not been reported. Therefore, the presence of cholangiopathy in our patient is interesting from an imaging, laboratory, and clinical point of view.
Experimental Investigation on Mechanical Properties of Carbon Nanotube-Reinforced Epoxy Composites for Automobile Application
Authors: Merneedi Anjibabu , Natrayan L. , Kaliappan S. , Veeman Dhinakaran , Angalaeswari S. , Srinivas Chidurala , Paramasivam Prabhu
Published: November 2021

Carbon nanotubes are established as a superior form of carbon. These have superior characteristics in terms of mechanical and chemical properties when compared to the other fibres available. High-strength fibres can be employed in a composite in a short form and mass-produced to fulfil high demands in composite applications. These composites can meet the strength requirements of nonstructural and structural components in a wide range of industries. Because of their light weight and excellent strength-to-weight ratio, these composites can be used in a wide range of applications. With Young’s modulus as high as 1 TPa and tensile strength up to 63 GPa, they are among the stiffest and strongest fibres. There is currently a lot of interest in using carbon nanotubes in a matrix to take advantage of these features. There have been a variety of polymer matrices used, and nanotube/ceramic and nanotube/metal composites are gaining popularity. The study of these materials is an ongoing process, as researchers and design engineers have yet to realize their full potential. Carbon nanotubes (CNTs) are used in this study to create the composite with the resin. The percentage of CNT used as a filler material in the composite is varied from 1 to 4 percent, with the best percentage chosen for optimal mechanical properties.
Sustentabilidad como respuesta a una urgencia
Authors: Crespo Fernando
Published: November 2021

Existe una serie de informes que alertan sobre las consecuencias que tendrán tanto el cambio climático como el resultado del patrón vigente en la operación económica global, los que revelarían un conjunto de externalidades negativas a partir del año 2030. Considerando ese horizonte, en este documento, se propone la sustentabilidad como una estrategia más amplia, que permita anteponerse a escenarios que escapan a la normativa medioambiental y nos permitan generar una respuesta resiliente a los impactos futuros, considerando que ya es posible advertir esta dimensión en casos incipientes a nivel global.
Overexpression of miR-138-5p Sensitizes Taxol-Resistant Epithelial Ovarian Cancer Cells through Targeting Cyclin-Dependent Kinase 6
Authors: Liang Man , Li Qin , Shi Shuai , Tian Ya-ning , Feng Yanhong , Yang Yongkang , Dong Miao , Zhang Jing , He Jihong
Published: November 2021

Background: Ovarian cancer, one of the most malignant diseases in female, is associated with poor diagnosis and low 5-year survival rate. Taxol is a widely used chemotherapeutic drug for the treatment of ovarian cancer by targeting the microtubules of the mitotic spindle to induce cancer cell death. However, with the widespread clinical applications of Taxol, a large fraction of ovarian cancer patients developed drug resistance. Results: Here, we report miR-138-5p is significantly downregulated in epithelial ovarian cancer tissues compared with their matched normal ovarian tissues. Overexpression of miR-138-5p effectively sensitized ovarian cancer cells to Taxol. By establishing Taxol-resistant cell line from the epithelial ovarian cancer cell line, HO-8910, we found miR-138-5p was significantly downregulated in Taxol-resistant cells. Furthermore, overexpression of miR-138-5p dramatically overcame the chemoresistance of Taxol-resistant cells. Intriguingly, bioinformatic analysis indicated miR-138-5p had putative binding sites for cyclin-dependent kinase 6 (CDK6). This negative regulation was further verified from epithelial ovarian cancer tissues. Luciferase assay demonstrated miR-138-5p could directly bind to 3′UTR of CDK6. Importantly, silencing CDK6 expression by siRNA successfully increased the sensitivity of both parental and Taxol-resistant ovarian cancer cells. Finally, rescue experiments clearly elucidated restoration of CDK6 in miR-138-5p-overexpressing ovarian cancer cells successfully recovered the Taxol resistance. Conclusion: In summary, these findings suggest important molecular mechanisms for the miR-138-5p-mediated Taxol sensitivity of ovarian cancer via directly targeting CDK6, suggesting miR-138-5p is an effective therapeutic target for the noncoding RNA-based anti-chemoresistance treatment.
Molecular Characterization of Peritoneal Involvement in Primary Colon and Ovary Neoplasm: The Possible Clinical Meaning of the P2X7 Receptor-Inflammasome Complex
Authors: Solini Anna , Cobuccio Luigi , Rossi Chiara , Parolini Federico , Biancalana Edoardo , Cosio Stefania , Chiarugi Massimo , Gadducci Angiolo
Published: November 2021

Introduction: Colon cancer (CC) and epithelial ovarian cancer (EOC) are common and severe neoplasms frequently sharing a massive inflammatory involvement of peritoneum. A detailed molecular characterization of such carcinomatosis has not been performed, so far. Methods: Omental adipocytes were isolated from thirty-three adult women who underwent primary surgery for CC or EOC. Expression of several pro-inflammatory genes was determined by real-time PCR and immunofluorescence. Data were related to the clinical phenotype of the patients. Results: CD68, FGFR1, and IL-6 were significantly more expressed in adipocytes from CC patients and VEGF in adipocytes from EOC. TNFα, TGFβ, or MCP-1, as well as the pro-inflammatory platform P2X7R-NLRP3, did not differ between the 2 cancers. White blood cell count, mirroring systemic inflammation, was related to adipocyte P2X7R (R = 0.508, p = 0.003), NLRP3 (R = 0.405; p = 0.02), and MCP-1 (R = 0.448; p = 0.009). P2X7R and NLRP3 were the only inflammatory factors significantly more expressed in patients carrying both omental and peritoneal carcinosis, who were also characterized by a higher leukocytosis. None of the tested inflammatory markers was associated with tumor grading for both neoplasms; however, the presence of metastases was associated with a higher adipocyte expression of FGFR1 and TGFβ. Conclusion: We show here that rarely measured molecules seem to specifically characterize omental carcinomatosis of CC or EOC, while more common inflammatory agents like TNFα, TGFβ, or MCP-1 do not; the P2X7R-NLRP3 complex marks omental and peritoneal carcinosis and is related to circulating white blood cells and MCP-1, involved in monocyte-macrophage tissue infiltration; increased TGFβ and FGFR1 characterize the tumoral dissemination.
Treatment with Multiple Therapeutic Classes of Medication Is Associated with Survival after Stroke
Authors: Kilkenny Monique F. , Olaiya Muideen T. , Dalli Lachlan L. , Kim Joosup , Andrew Nadine E. , Sanfilippo Frank M. , Thrift Amanda G. , Nelson Mark , Pearce Christopher , Sanders Lauren , Dewey Helen , Clissold Benjamin , Grimley Rohan , Cadilhac Dominique A.
Published: November 2021

Introduction: Treatment with several therapeutic classes of medication is recommended for secondary prevention of stroke. We analyzed the associations between the number of classes of prevention medications supplied within 90 days after discharge for ischemic stroke (IS)/transient ischemic attack (TIA) and survival. Methods: This is a retrospective cohort study of adults with first-ever IS/TIA (2010–2014) from the Australian Stroke Clinical Registry individually linked with data from national pharmaceutical and Medicare claims. Exposure was the number of classes of recommended medications, i.e., blood pressure-lowering, antithrombotic, or lipid-lowering agents, supplied to patients within 90 days after discharge for IS/TIA. The longitudinal association between the number of classes of medications and survival was evaluated with Cox proportional hazards regression models using the landmark approach. A landmark date of 90 days after hospital discharge was used to separate exposure and outcome periods, and only patients who survived until this date were included. Results: Of 8,429 patients (43% female, median age 74 years, 80% IS), 607 (7%) died in the year following 90 days after discharge. Overall, 56% of patients were supplied all 3 classes of medications, 28% 2 classes of medications, 11% 1 class of medications, and 5% no class of medications. Compared to patients supplied all 3 medication classes, adjusted hazard ratios for all-cause mortality ranged from 1.43 (95% confidence interval [CI]: 1.18–1.72) in those supplied 2 medication classes to 2.04 (95% CI: 1.44–2.88) in those supplied with no medication class. Discussion/Conclusion: Treatment with all 3 classes of guideline-recommended medications within 90 days after discharge was associated with better survival. Ongoing efforts are required to ensure optimal pharmacological intervention for secondary prevention of stroke.
Cerebral Amyloid Angiopathy Is Associated With Emotional Dysregulation, Impulse Dyscontrol, and Apathy
Authors: Smith Eric E. , Crites Stephanie , Wang Meng , Charlton Anna , Zwiers Angela , Sekhon Ramnik , Sajobi Tolulope , Camicioli Richard , McCreary Cheryl R. , Frayne Richard , Ismail Zahinoor
Published: November 2021

Background

Cerebral amyloid angiopathy (CAA) causes cognitive decline, but it is not known whether it is associated with neuropsychiatric symptoms (NPS).

Methods and Results

Participants with CAA, mild cognitive impairment, mild dementia due to Alzheimer's disease, and normal cognition were recruited from stroke and dementia clinics and community advertising. NPS were captured using the Neuropsychiatric Inventory Questionnaire short form. The number and total severity (number multiplied by severity of each symptom [mild, moderate, or severe]) of NPS were analyzed using generalized linear regression with a negative binomial link and multiple linear regression, adjusting for age, sex, and education. A total of 109 participants (43 with CAA, 15 with Alzheimer's disease, 28 with mild cognitive impairment, and 23 with normal cognition) (mean age 71.1 [SD=7.6]; 53.2% male) were included. The most frequent NPS in CAA were depression/dysphoria (48.8%), irritability/lability (37.2%), agitation/aggression (37.2%), apathy/indifference (34.9%), and anxiety (32.6%). In adjusted models, patients with CAA had 3.2 times (95% CI, 1.7–6.0) more NPS symptoms and 3.1 units (95% CI, 1.0–5.1) higher expected severity score. The number of NPS was similar to patients with mild cognitive impairment (3.2 times higher than controls) but less than in patients with Alzheimer's disease dementia (4.1 times higher than controls). Within patients with CAA, there were 1.20 times (95% CI, 1.01–1.32) more NPS per 1% increase in white matter hyperintensity as a percentage of intracranial volume.

Conclusions

NPS are common in CAA, with a similar prevalence as in mild cognitive impairment. The association of the total number of NPS with higher white matter hyperintensity volume suggests that white matter damage may underlie some of these symptoms.
Predictors and occurrence of antenatal depressive symptoms in Galle, Sri Lanka: a mixed-methods cross-sectional study
Authors: Wyatt Sage , Ostbye Truls , De Silva Vijitha , Lakmali Prabodha , Long Qian
Published: November 2021

Background

There is a high prevalence of antenatal depression in low-or-middle-income countries, but information about risk factors in these settings is still lacking. The purpose of this study is to measure the prevalence of and explore risk factors associated with antenatal depressive symptoms in Galle, Sri Lanka.

Methods

This study used a mixed-method approach. The quantitative portion included 505 pregnant women from Galle, Sri Lanka, with health record data, responses to psychometric questionnaires (MSPSS and PRAQ-R2), and antenatal depression screening (EPDS). The qualitative portion included interviews with public health midwives about their experiences and routine clinical practices with women with antenatal depressive symptoms.

Results

Prevalence of antenatal depressive symptoms was 7.5%, highest in women over the age of 30 (13.0%, OR = 3.88, 95%CI = 1.71 – 9.97), with diabetes (21.9%, OR = 3.99, 95%CI = 1.50 – 9.56), or pre-eclampsia in a previous pregnancy (19.4%, OR = 3.32, 95%CI = 1.17 – 8.21). Lower prevalence was observed in the primiparous (3.3%, OR = 0.29, 95%CI = 0.12 – 0.64) employed outside the home (3.6%, OR = 0.33, 95%CI = 0.13 – 0.72), or upper-middle class (2.3%, OR = 0.17, 95%CI = 0.04 – 0.56). Anxiety levels were elevated in depressed women (OR = 1.13, 95%CI = 1.07 – 1.20), while perceived social support was lower (OR = 0.91, 95%CI = 0.89 – 0.93). After multivariable adjustment, only parity (OR = 0.20, 95%CI 0.05 – 0.74) and social support from a “special person” (OR = 0.94, 95%CI = 0.77 – 0.95) remained significantly associated with depressive symptoms. Qualitative findings also identified antenatal health problems and poor social support as risk factors for depressive symptoms. They also identified different contributing factors to poor mental health based on ethnicity, higher stress levels among women working outside the home, and misinformation about health conditions as a cause of poor mental health.

Conclusions

Prevalence of antenatal depressive symptoms in Galle is lower than the recorded prevalence in other regions of Sri Lanka. Risk factors for antenatal depressive symptoms were identified on biological, psychological, and social axes. These variables should be considered when developing future guidelines for mental health and obstetric treatment in this context.
Prognostic value of immune factors in the tumor microenvironment of patients with pancreatic ductal adenocarcinoma
Authors: Kiryu Sachie , Ito Zensho , Suka Machi , Bito Tsuuse , Kan Shin , Uchiyama Kan , Saruta Masayuki , Hata Taigo , Takano Yuki , Fujioka Shuichi , Misawa Takeyuki , Yamauchi Takashi , Yanagisawa Hiroyuki , Sato Nobuhiro , Ohkusa Toshifumi , Sugiyama Haruo , Koido Shigeo
Published: November 2021

Background

Both activated tumor-infiltrating lymphocytes (TILs) and immune-suppressive cells, such as regulatory T cells (Tregs), in the tumor microenvironment (TME) play an important role in the prognosis of patients with pancreatic ductal adenocarcinoma (PDAC).

Methods

The densities of TILs, programmed death receptor 1 (PD-1) + T cells, and forkhead box P3 (Foxp3) + T cells were analyzed by immunohistochemical staining. The associations of the immunological status of the PDAC microenvironment with overall survival (OS) time and disease-free survival (DFS) time were evaluated.

Results

PDAC patients with a high density of TILs in the TME or PD-1-positive T cells in tertiary lymphoid aggregates (TLAs) demonstrated a significantly better prognosis than those with a low density of TILs or PD-1-negativity, respectively. Moreover, PDAC patients with high levels of Foxp3-expressing T cells showed a worse prognosis than those with low levels of Foxp3-expressing T cells. Importantly, even with a high density of the TILs in TME or PD-1-positive T cells in TLAs, PDAC patients with high levels of Foxp3-expressing T cells showed a worse prognosis than patients with low levels of Foxp3-expressing T cells. A PDAC TME with a high density of TILs/high PD-1 positivity/low Foxp3 expression was an independent predictive marker associated with superior prognosis.

Conclusion

Combined assessment of TILs, PD-1+ cells, and Foxp3+ T cells in the TME may predict the prognosis of PDAC patients following surgical resection.
Spanish Civil War Horror and Regional Trauma
Authors: Aldana Reyes Xavier
Published: November 2021

This article unpacks the cultural work that Juan Carlos Medina’s Insensibles, released in English as Painless, carries out in relation to Spain’s modern history and argues that the film’s painless children are an allegory of the country’s postdictatorship generations. The rendering of fascism as monstrous is less interesting than the connection of insensitivity to the Pacto del Olvido (Pact of Forgetting) and its suppression of painful memory. The fact that the children speak Catalan is a significant overlooked aspect, because Catalonia was the last region to succumb to Nationalist military forces during the Spanish Civil War (1936–39) and is known for its independentist fervor. A regionalist reading of the film does not simply connect the present and the past; it proposes that the children of the war mediate Spain’s current troubled relationship with historical trauma and act as an artistic response to centralist ideas of a unified and stable nation-state. Such a rethinking demonstrates that the horror genre continues to offer a language of anxiety capable of negotiating and contributing to debates around the importance of national accountability, war reparations, and the condemnation of genocide.​
Selective Hydrothermal Synthesis of Water-Soluble CdTe and CdTe/CdS Colloidal Quantum Dots by Controlling the Te/Cd Molar Ratio of the Precursor Solution
Authors: Shimura Kunio , Lee TaeGi , Ito Tatsuya , Kim DaeGwi
Published: November 2021

During the synthesis of CdTe quantum dots (QDs) by the hydrothermal method, a CdS shell layer is naturally formed by the thermal decomposition of thiol ligands, and CdTe/CdS core/shell QDs are produced. Herein, we investigate the selective synthesis of CdTe and CdTe/CdS QDs to control the thermal decomposition of thiol ligands by changing the Te/Cd molar ratio of the precursor solutions. From the experimental results of X-ray photoelectron spectroscopy and optical properties of absorption and photoluminescence (PL) spectra and PL decay profiles of the synthesized colloidal QDs, it was found that the formation of the CdS shell can be controlled by varying the Te/Cd ratio of the precursor solution. Thus, the selective synthesis of CdTe and CdTe/CdS QDs with the same PL energy but different PL decay times is possible.
Specifics of interlanguage of greek learners of english as a foreign language
Authors: Καούνη Πηνελόπη
Published: November 2021

Οι Έλληνες μαθητές αγγλικών αντιμετωπίζουν πολλά είδη μαθησιακών προβλημάτων σχετικά με την κατάκτηση του αγγλικού ηχητικού συστήματος, της γραμματικής και του λεξιλογίου. Ο κύριος σκοπός της εργασίας είναι να διερευνήσει τα λάθη που κάνουν οι Έλληνες που μαθαίνουν αγγλικά σε μια προσπάθεια να εντοπιστούν τα μορφοσυντακτικά χαρακτηριστικά της Διαγλώσσας των Ελληνικών Μαθητών (GEIL). Η έρευνα βασίζεται σε λανθασμένη παραγωγή γραπτού λόγου στα αγγλικά προσπαθώντας να βρει απαντήσεις στα ακόλουθα ερευνητικά ερωτήματα: 1) Ποια συγκεκριμένα σφάλματα με υψηλή συχνότητα αποτελούν μέρος του GEIL; 2) Ποια είναι η διαφορά μεταξύ συγκεκριμένων ελληνικών λαθών και γενικών λαθών που διαπράττουν άλλοι ξένοι μαθητές αγγλικών; 3) Χρειάζεται κάθε ένα από αυτά τα είδη σφαλμάτων διαφορετική αντιμετώπιση στη διαδικασία εκμάθησης της αγγλικής γλώσσας; Η ολοκλήρωση του βασικού στόχου περιλαμβάνει τα ακόλουθα βήματα: α) Προσδιορισμός των πιο συχνών σφαλμάτων. β) Ταξινόμηση των σφαλμάτων. γ) Προσδιορισμός των πιθανών αιτιών τους. δ) Εκτίμηση της υπαγωγής τους στο ΓΕΗΛ. Η Ανάλυση σφαλμάτων είναι το κύριο θεωρητικό εργαλείο που χρησιμοποιείται για την ανάλυση των εμπειρικών δεδομένων. Τα κύρια συμπεράσματα που προκύπτουν από τη μελέτη είναι ότι η Ανάλυση Σφάλματος εξακολουθεί να είναι ένα ισχυρό εργαλείο για τον εντοπισμό των περιοχών δυσκολίας για τους Έλληνες μαθητές των Αγγλικών και παρέχει στοιχεία για τα καθολικά και τα ιδιαίτερα χαρακτηριστικά των νεοεμφανιζόμενων ποικιλιών της παγκόσμιας αγγλικής γλώσσας.
ФОРМИРОВАНИЕ ОРГАНОВ СОВЕТСКОЙ ВЛАСТИ ДЛЯ ВЗАИМОДЕЙСТВИЯ С АМЕРИКАНСКОЙ АДМИНИСТРАЦИЕЙ ПОМОЩИ (АРА) В ПЕТРОГРАДСКОМ ДИСТРИКТЕ В 1921–1923 ГГ.
Authors: Filippova Maria N. , Romanova Anna N.
Published: November 2021

Цель. Важным аспектом при описании миссии Американской администрации помощи (АРА) в Советской России в 1921–1923 гг., являются действия советских властей, принимавших иностранную помощь для голодающих. Цель работы – проследить формирование государственных органов для работы с АРА в Петрограде и выявить основные направления их деятельности.

Метод проведения работы. Методологическая основа работы – принципы историзма, системности, научности и объективности. Использованы историко-критический, историко-сравнительный, источниковедческие методы. Изучены документы из Центрального государственного архива Санкт-Петербурга, Государственного архива Российской Федерации (Москва), опубликованные исследования.

Результаты. На первых порах в Петрограде миссию АРА принимал Петрогубисполком. Был образован русско-американский исполком. После возникновения представительства советского правительства в Петроградской губернии для работы с АРА Петрогубисполком сотрудничал с ним. Уполномоченным Представителем правительства с ноября 1921 г. был З. И. Жуков. Представительство правительства занималось материальным обеспечением работы АРА, являясь посредником между АРА и советскими учреждениями и организациями. Оно находило источники финансирования для оплаты предоставленных товаров и услуг. С июня 1922 г. Представительство правительства перешло на хозрасчет. Органы советской власти для работы с АРА окончательно сформировались к осени 1922 г. В Петрограде в работе с АРА участвовали имевшиеся представительства наркоматов (НКИД, Внешторг), ПЕПО, а также милиция и ВЧК.

Область применения результатов. Материалы работы могут быть использованы для научных обобщений в теме помощи АРА, при подготовке учебных материалов по отечественной истории. Результаты могут заинтересовать краеведов.
Some Aspects of HR Management in Order to Reduce the Operational Risks of the Company
Authors: Sidorenko O. , Sidorenko G. , Konovalova Valeriya
Published: November 2021

Optimization of management decisions from the point of view of staffing of economic entities is currently the task of minimizing operational risks in order to increase the economic stability of companies. In this connection, the relevance of monitoring the activities of officials in the field of business management increases both before employment and during economic activity on the basis of monitoring the management decisions made, the personal qualities of managers and their competencies, as well as professional development or retraining. In turn, the main problem of the personnel management system of the enterprise as a whole is the redistribution of activities (functions) of managers of all levels, the definition of personal characteristics in accordance with this functional and the formation of a risk culture.
Talent Management and Professional Standards: Research on the Level of Development of University Students' Competencies
Authors: Lysenko E. , Potapov O. , Hoholeva E.
Published: November 2021

The central place in the presented article is devoted to talent management: the theoretical foundations of talent management in the personnel management system are reflected – its concept and essence, its significance in modern conditions are considered. Talent is considered as a set of necessary competencies, on the basis of which the value of the competence approach in identifying talents is established. Within the framework of the study, based on the professional standard of a specialist in personnel management, a competence model was developed, according to which talents were determined among students of the training direction "Personnel Management" of the Ural Federal University named after the first President of Russia B. N. Yeltsin. The results of the study demonstrate that the student training program at the university corresponds to the model of key competencies of a specialist in personnel management, and, therefore, meets the requirements of the professional standard. However, it requires improvement in the development of a number of competencies.
ORDINARY DIFFERENTIAL EQUATIONS WITH MACHINE LEARNING FOR PREDICTION OF SMART COMPOSITE FRACTURE TOUGHNESS
Authors: QHOBOSHEANE RELEBOHILE  GEORGE , ELENCHEZHIAN MUTHU RAM PRABHU , VADLAMUDI VAMSEE , REIFSNIDER KENNETH , RAIHAN RASSEL
Published: November 2021

This work in on the development of an ordinary differential equation (ODE) model coupled with statistical methods for the prediction of fracture toughness of a magnetostrictive, piezoelectric smart self-sensing Fiber Reinforced Polymer (FRP) composite. The smart composite with sensing properties encompasses Terfenol-D alloy nanoparticles and Single Walled Carbon NanoTubes (SWCNT). To explore various configurations the of nanoparticle constituents’ effect on fracture toughness within the FRP composite, the ODE model developed within a finite element analysis (FEA) environment is considered to attain fracture observations across the solution space. The acquired FEA data is then used to feed the machine-learning (ML) algorithms to obtain composite fracture toughness predictions. A comparison and development of artificial neural networks (ANN), decision trees and support vector machines (SVM) models for FRP smart self-sensing composite fracture toughness prediction is done. Qualitative results stating if the sample has fractured or not and quantitative data giving the fracture toughness and strain energy release rate for the smart self-sensing FRP composites is attained. A comparison of all predictions from the developed models for both fracture toughness is corroborated with literature data.
DEEP CONVOLUTIONAL NEURAL NETWORK FOR SEGMENTING CT IMAGES OF FIBER REINFORCEMENTS
Authors: ALI MUHAMMAD A. , UMER REHAN
Published: November 2021

The greatest challenge in creating digital material twins and FE mesh from μCT images of composite reinforcements is the lack of a robust and versatile tool for training μCT images. Here, we have used deep convolutional neural networks (DCNN) for segmenting μCT images of a multi-layer plain-weave fiber reinforcement. A set of raw 2D image slices extracted from the gray-scale volume of a single-layer reinforcement was used to train a DCNN using manually annotated images. The trained network was tested against the manually segmented ground truth images and it performed exceptionally well with a global accuracy of more than 96%. The trained DCNN was then used to segment unseen images from a multilayer stack of the fabric with good accuracy. The work presented here provides a robust and efficient framework of segmenting CT scan images of fiber reinforcements for generating digital material twins and FE mesh of fiber reinforcements.
EFFECT OF PROCESSING PARAMETERS ON THE WIDTHS AND THICKNESSES OF THERMOPLASTIC COMPOSITES MADE BY AUTOMATED FIBER PLACEMENT
Authors: HOANG DUC MINH , HOA SUONG VAN
Published: November 2021

The advent of Automated Fiber Placement (AFP) machine has expanded the capacities to manufacture engineering structures using thermoplastic composites. Structures of cylindrical shapes, flat and curved panels can be easily made using this technique. As more applications and more studies have been made on this technique for thermoplastic composites, many issues have come up. One issue of importance is the variation of the width and thickness of the tow as it is deposited. As the melted thermoplastic composite tow is being pressed under the compression force of the roller, the material flows. This changes the width and the thickness of the tow. The values of the width and thickness depend on many parameters such as the properties of the substrate, the temperature of the material, and the applied pressure. This variation in width and thickness of the individual tow being deposited has an influence on the development of laps and gaps between the deposited tows. This paper presents some of the results on an investigation on the above topic. Widths and thicknesses of carbon/PEEK tows processed using an Automated Fiber Placement machine with a hot gas torch were examined. Preliminary results show that there is significant variation in the width and thickness of the tows upon deposition.
ENHANCED FRACTURE TOUGHNESS OF ADHESIVE JOINTS WITH DOPING EPOXY BY GRAPHENE NANOPLATELETS
Authors: KHAMMASSI10.12783/asc36/35835 SABRINE , TARFAOUI MOSTAPHA
Published: November 2021

It is necessary to enhance the mechanical properties of adhesives to replace conventional joint methods with adhesive bonding. Epoxy in its pure state often suffers catastrophic damage due to its obvious brittleness and low fracture toughness. In this study, the double cantilever beam (DCB - Mode I) was used to characterize the fracture toughness of graphene/DGEBA-epoxy nanocomposite adhesive in bonded aluminium alloy joints and bonded composite joints. Adhesives based on an epoxy adhesive DGEBA (Bisphenol A diglycidyl ether) reinforced with two percentages (1wt.% and 2wt.%) of graphene nanoplatelets (GNP) were prepared. In this study, one shows that the fracture toughness of adhesive nanocomposites was significantly better than neat epoxy-bonded adhesives. Both types of joints contain graphene resulting in increased fracture toughness. Therefore, the maximum fracture toughness was observed until the GNP reached 1wt.%, and then it began to decrease, but it is still higher than that of the pure adhesive joint. On the other hand, this work aims to determine the influence of interfacial interactions on the behavior of enhanced bonded joints and how graphene nanoplatelets can enhance the rigidity of the interface between the substrate and the adhesive. In addition, a numerical study using ABAQUS was performed and compared with the experiments performed on DCB. For the modeling of the damage in an assembly joint, the Cohesive Zone Model (CZM) was used for the fracture behavior of the adhesive.
MOLECULAR DYNAMICS SIMULATIONS OF FURAN RESIN (POLYFURFURYL ALCOHOL): PREDICTING MECHANICAL PROPERTIES
Authors: KEMPPAINEN JOSH , GALLEGOS IVAN , DESHPANDE PRATHAMESH , GISSINGER JACOB , ODEGARD GREGORY
Published: November 2021

Furan resins can be used as precursor resin for Carbon-Carbon Composites but has also been used in adhesives, acid/corrosion resistant materials, and as an alternative fuel precursor [15]. This paper contains the most current understanding of the structure of furan resin and a Molecular Dynamics workflow for computationally simulating its polymerization with the 'fix bond/react' command implemented in LAMMPS. The predicted mechanical properties of the polymerized resin are in good agreement with the literature values.
FRACTURE SIMULATION IN POLYMER NANOCOMPOSITES USING MOLECULAR DYNAMICS
Authors: ROY SAMIT , SOHAIL TANVIR
Published: November 2021

The objective of this paper is to (a) investigate the validity of application of continuum-based linear elastic fracture mechanics (LEFM) methodology, which is often employed by researchers to model fracture processes at the “discrete” atomic scale, and (b) to study the effect of nanographene platelet size on the rupture strength of an edge-cracked polymer block. The material selected for this study is EPON 862 epoxy polymer with 85% cross-link density. Further, an atomistic J-integral is implemented as a nano-scale fracture metric to investigate flaw-tolerance at the nanoscale reported by many researchers, and to develop a methodology to predict the initiation fracture toughness of the material. For this purpose, a bond-order based potential (ReaxFF) available in LAMMPS , a molecular dynamics (MD) software, is utilized. Predictions obtained using the atomistic J-integral are compared with LEFM predictions for the case of a cross-linked epoxy polymer block with a center-crack under uniform far-field loading. Significant deviations from LEFM for crack-lengths below a certain critical crack-length threshold are observed. Further, far-field stress vs. strain plots are obtained for an edge-cracked epoxy polymer block with a single 14 nm graphene nanoplatelet embedded ahead of the crack tip and it is compared with stress vs. strain plot obtained for the same epoxy block with two 7 nm graphene nanoplatelets embedded ahead of the crack tip to study platelet size effect. Significant size effect was observed as shown in the results.
A COMPUTATIONAL MODEL FOR THE PIEZORESISTIVE RESPONSE OF HYBRID CARBON NANOSTRUCTURED NETWORKS
Authors: MORA ANGEL , MEDINA CARLOS , AVILÉS FRANCIS
Published: November 2021

Carbon nanotubes (CNTs) and graphenic sheets (GSs) are commonly used fillers for polymer nanocomposites. These nanocomposites can be used as selfsensing materials (strain and damage sensors) due to their piezoresistive response. CNT/GS hybrid fillers could be used to tune the nanocomposite’s piezoresistive response. The piezoresistive response of polymers filled with hybrid carbon nanofillers is a novel topic being studied recently experimentally, and very few computational works are available. Thus, a computational model is developed to study the piezoresistive response of polymers filled with CNT/GS hybrid fillers, reproducing geometries and conditions similar to those used in experiments. This computational model generates a network of three dimensional (3D) representations of carbon nanostructures inside a cube, which represents the polymer matrix. The network of nanostructures is turned into a network of resistors to obtain the electrical conductivity of the cube, and thus the polymer nanocomposite. Mechanical strain is applied via coupling with a finite element software. To reduce computational time, embedded elements are used in the finite element simulations. Capabilities and limitations of the proposed computational model are explored.
IMPROVEMENT OF FLEXURAL STRENGTH AND FATIGUE PROPERTIES OF GLASS FIBER/EPOXY COMPOSITES BY GRAFTING CELLULOSE NANOFIBERS ONTO THE REINFORCING FIBERS
Authors: SARR, MOUHAMADOU MOUSTAPHA , INOUE HIRAKU , KOSAKA TATSURO
Published: November 2021

Recently, cellulose nanofibers (CNFs) have been added as a modifier to fiber- reinforced polymer composites (FRPs) to improve their mechanical performance. In this study, vacuum impregnation of CNFs onto glass fibers (GF) was proposed to avoid processing high viscosity resin or the formation of aggregations in the matrix. Therefore, different CNF concentrations (from 0 to 0.1 wt%) were prepared and used to investigate the effect of CNFs on flexural properties of GF-CNF/epoxy composites by three-point bending tests. A field-emission scanning electron microscope was used to characterize the strengthening mechanisms. Fatigue tests were conducted at a stress ratio of 0.1 and a frequency of 5 Hz. The results indicated an improvement in flexural properties of glass fiber-reinforced polymer with increasing CNF concentrations. The flexural strength of CNF-modified GF/Epoxy composites (GF-CNF/EP) increased slightly up to 6 %. However, the fatigue life was significantly improved by 5 times in comparison with the neat GF/epoxy composite. This suggested that the use of CNFs onto the GF surface can contribute to improving the flexural fatigue of GFRP. Mouhamadou
NANOPARTICLE MODIFICATION OF NATURAL FIBERS FOR STRUCTURAL COMPOSITES
Authors: LANGHORST AMY , SINGHAL ANSHUL , MIELEWSKI DEBORAH , BANU MIHAELA , TAUB ALAN
Published: November 2021

Natural fibers are a lightweight, carbon negative alternative to synthetic reinforcing agents in polymer composites. However, natural fibers typically exhibit lower mechanical performance than glass fibers due to weak interfacial adhesion between plant cells in the fiber and damage to the fibers during extraction from a plant stem. However, improvement of natural fiber mechanical performance could enable their wide-scale incorporation in structural composite applications, significantly reducing composite weight and carbon footprint. This study seeks to develop a novel, cost-effective method to significantly improve natural fiber stiffness via repair of damage caused by extraction and/ or stiffening of the weak cellular interfaces within a natural fiber. Supercritical fluids have been shown to be capable of swelling and plasticizing amorphous polymers, increasing additive absorption. In this work. supercritical-carbon dioxide (scCO2) was used as a solvent to assist with infusion of nanoparticles into flax fibers at pressures ranging from 1200-4000psi. Fiber analysis with Plasma Focused Ion Beam-Scanning Electron Microscopy (PFIB-SEM) showed that nanoparticles were capable of penetrating and bridging openings between cells, suggesting the ability for nanoparticle treatment to assist with crack repair. Additionally, treated fibers contained uniform surface coatings of nanoparticles, potentially reducing fiber porosity and modifying interfacial properties when embedded in a polymer matrix. Overall, this method of nanoparticle reinforcement of natural fibers could enable development of high-performance lightweight, low-carbon footprint composites for transportation or industrial applications.
FATIGUE DAMAGE MODELING IN LAMINATED COMPOSITES BY USING RX-FEM AND STRENGTH TRACKING METHOD
Authors: LU WEI-TSEN , GAO ZHENJIA , ADLURU HARI K. , HOOS KEVIN H. , SENEVIRATNE WARUNA , MOLLENHAUER DAVID , IARVE ENDEL V.
Published: November 2021

The durability and residual load carrying capacity of composite materials and structures is of critical importance for increasing their application across the industry. Regularized eXtended Finite Element Method (Rx-FEM) framework for discrete modeling of damage evolution and interaction in laminated composite materials under fatigue loading has been extended to include residual Strength Tracking (ST) method in the Mesh Independent Crack (MIC) insertion constitutive modeling as well as in the initiation phase of the fatigue Cohesive Zone Model (CZM). The ST method was initially proposed for semi empirical analysis of IM7/8852 open-hole specimen test S-N data under spectrum loading and variable R -ratios (R = 0.1, 5, and -1). In the present work, the ST method is implemented as a component of high-fidelity progressive damage analysis framework and is combined with damage variable incremental update technique for the propagation phase within the CZM formulation. 3D validation examples investigating the solution stability under constant amplitude fatigue with respect to the cycle increment size are presented and demonstrate the solution stability within a feasible range of cycles per step.
SKIN/STRINGER INTERFACE DAMAGE CHARACTERIZATION OF STIFFENED COMPOSITE STRUCTURES
Authors: SENEVIRATNE WARUNA , SASEENDRAN VISHNU , SHAFIE MOHAMED , TOMBLIN JOHN
Published: November 2021

With stiffened composite panels being widely used in aerostructures, critical failure mechanics of the skin/stringer interface need to be thoroughly understood. The interface is design critical and must demonstrate the ability to sustain design limit load throughout the service life. Buckling and out-of-plane deformations, localized in a stiffened panel can initiate separation at the interface. In addition, presence of inherent manufacturing flaws or operational impact events can lead to premature separation and result in failure. Hence, to ensure structural integrity, thorough damage characterization of skin/stringer interface must be performed. The general building block certification approach used for analysis and test validation does not contain standardized test methods beyond the coupon level. In this study, a Seven-Point Bend (7PB) based test methodology is employed to induce localized buckling-based skin separation. The 7PB methodology is utilized to evaluate panels fabricated using both co-bonding and secondary-bonding methods. The experimental work is complimented by a cohesive zone model (CZM) where the disbond initiation and progressive damage growth at the skin/stringer interface is simulated. Delamination is observed at the interface, originating centrally and progressing asymmetrically along the length of the stringer until failure occurred. The zero-thickness cohesive elements based model implemented within this work was able to capture damage initiation and predicted the final damage map. The 7PB test methodology is demonstrated to be robust and can be introduced as a standard test practice to evaluate sub-elements.
GROWTH MONITORING OF DELAMINATION AND ADHESIVE DEBONDING OF CFRP STRUCTURES BY RAYLEIGH SCATTING-BASED DISTRIBUTION SENSORS
Authors: OHNISHI KAZUKI , KOSAKA TATSURO , FUJIOKA GENKO
Published: November 2021

Since delamination of CFRP laminates is generated by impact or fatigue in aircraft operation, identification method of the delamination is a very important technology to ensure safety of aircraft. Recently, built-in sensors are paid attention as a real-time monitoring method of initiation and growth of delamination. Optical fiber sensors are promised as built-in sensors of FRP due to their high strength, durability and embeddability. In this paper, we applied a Rayleigh scattering-based distribution sensor to detect delamination and debonding of CFRP structures. This optical fiber sensor can measure strain distribution along a fiber with wide area range, high spatial and strain resolutions. The optical fiber sensors attached on the surface of laminates were used to detect delamination and adhesive debonding of DCB, ENF and SLJ (single lap joint) specimens. Pre-crack were formed by inserting a Teflon films between the layers or the laminate and adhesive layer during manufacturing. The experimental results of DCB tests showed that the position of delamination edge could be identified precisely from the measured sharp peak of strain distribution. From the results of ENF tests, it appeared that the strain distribution showed the maximum at the delamination edge and the detected delamination edge positions agreed very well with the observed positions. The measured strain distributions were almost same as simulated results by FEM. From the tensile test results of SLJ specimen, it appeared that strain distribution showed extremum at debonding edge. It was also shown that the measured strain distribution agreed well with simulated results by FEM. From the above results, it appeared that the open delamination and debonding could be easily identified from surface strain distribution measured by the Rayleigh scattering-based sensor.