bluuebunny/crossref_metadata_2025 huggingface dataset:
Predictors of real‐world utilisation of docetaxel combined with androgen deprivation therapy in metastatic hormone‐sensitive prostate cancer
Authors: Azad Arun A. , Tran Ben , Davis Ian D. , Parente Phillip , Evans Melanie , Wong Shirley , Brown Stephen , Evans Sue , Millar Jeremy , Murphy Declan G. , Papa Nathan
Published: March 2021

Background

Docetaxel has emerged as a standard‐of‐care for metastatic hormone‐sensitive prostate cancer (mHSPC). Uptake of docetaxel for mHSPC in Australia has not previously been reported.

Aims

To investigate the real‐world uptake of docetaxel in mHSPC and to identify predictors of utilisation of docetaxel in mHSPC.

Methods

Men diagnosed from June 2014 to December 2018 and enrolled in the Prostate Cancer Outcomes Registry‐Victoria (PCOR‐Vic) were included. Data collected include demographics, diagnosis method and institution, staging investigations and treatments within 12 months of diagnosis. Wilcoxon rank‐sum, Chi‐squared and trend tests were used to identify predictors of docetaxel utilisation. All predictors were entered as covariates simultaneously into a multivariable logistic regression model. Statistical significance was set at 0.05 (two sided).

Results

In all, 1014 men with mHSPC were analysed, 25% of whom received docetaxel with androgen deprivation therapy. Uptake of docetaxel increased from 20% in 2014 to 33% in 2018. Predictors of higher usage of docetaxel were younger age and treatment in a private hospital, with both remaining significant on multivariable analysis. Notably, the proportion of men aged <70 years receiving docetaxel increased from 54% in 2014–2015 to 64% in 2016–2018, while in men aged ≥70 years the comparative figures were 15% and 22% respectively.

Conclusions

Although docetaxel was not used in the majority of cases, there was a clear increase in docetaxel uptake, especially in younger men following publication of the CHAARTED and STAMPEDE trials. Identifying barriers to real‐world implementation of pivotal clinical trial data is critical to improving outcomes in mHSPC.
Big in the tropics: Ecogeographical clines in peccary size reveal the converse of Bergmann’s rule
Authors: Hendges Carla Deonisia , Patterson Bruce D. , Cáceres Nilton C.
Published: March 2021

Aim

Bergmann's rule is an ecogeographical rule that describes a negative relationship between body size and temperature. Here, we used a multivariate measure of skull size (centroid size) as a proxy for body size to test the influence of temperature, precipitation, elevation, human influence and competition on size in Dicotyles tajacu and Tayassu pecari.

Location

American tropics and sub‐tropics.

Taxon

Tayassuidae.

Methods

Using geometric morphometric methods, we measured 426 adult skulls of both peccary species from 174 different localities south of the equator and 83 in the north. We explored the effects of temperature, precipitation, altitude and human influence, controlling for spatial autocorrelation, using ordinary least squares models and the Akaike information criterion. Size differences where the species occur allopatrically or sympatrically, where competition could be a factor, were investigated using ANCOVA models.

Results

We found that peccaries were larger in the tropics. Temperature and precipitation explained the size variation of both peccaries in the southern hemisphere, whereas human influence is a predictor of size only for T. pecari. Size variation of northern D. tajacu is mainly explained by elevation and temperature. Tayassu pecari is consistently larger than D. tajacu in both hemispheres. Peccaries did not exhibit significant shifts in either rate of change in size or size–latitude relationships between allopatric and sympatric areas.

Main conclusions

Geographical variation in size of these peccaries does not support Bergmann's rule. In the tropics, precipitation and human influence appear to exert strong selective pressures on body size of peccaries, whose resource utilization patterns are shaped by group living. Size differences of the two species across the continents may contribute to their stable coexistence via interference rather than exploitative competition.
Artificial intelligence in prediction of non‐alcoholic fatty liver disease and fibrosis
Authors: Wong Grace Lai‐Hung , Yuen Pong‐Chi , Ma Andy Jinhua , Chan Anthony Wing‐Hung , Leung Howard Ho‐Wai , Wong Vincent Wai‐Sun
Published: March 2021

Artificial intelligence (AI) has become increasingly widespread in our daily lives, including healthcare applications. AI has brought many new insights into better ways we care for our patients with chronic liver disease, including non‐alcoholic fatty liver disease and liver fibrosis. There are multiple ways to apply the AI technology on top of the conventional invasive (liver biopsy) and noninvasive (transient elastography, serum biomarkers, or clinical prediction models) approaches. In this review article, we discuss the principles of applying AI on electronic health records, liver biopsy, and liver images. A few common AI approaches include logistic regression, decision tree, random forest, and XGBoost for data at a single time stamp, recurrent neural networks for sequential data, and deep neural networks for histology and images.
Artificial intelligence in liver disease
Authors: Lee Hye Won , Sung Joseph J Y , Ahn Sang Hoon
Published: March 2021

Artificial intelligence (AI) is a branch of computer science that attempts to mimic human intelligence, such as learning and problem‐solving skills. The use of AI in hepatology occurred later than in gastroenterology. Nevertheless, studies on applying AI to liver disease have recently increased. AI in hepatology can be applied for detecting liver fibrosis, differentiating focal liver lesions, predicting prognosis of chronic liver disease, and diagnosing of nonalcoholic fatty liver disease. We expect that AI will eventually help manage patients with liver disease, predict the clinical outcomes, and reduce medical errors. However, there are several hurdles that need to be overcome. Here, we will briefly review the areas of liver disease to which AI can be applied.
Artificial intelligence in the diagnosis and management of hepatocellular carcinoma
Authors: Sato Masaya , Tateishi Ryosuke , Yatomi Yutaka , Koike Kazuhiko
Published: March 2021

Despite recent improvements in therapeutic interventions, hepatocellular carcinoma is still associated with a poor prognosis in patients with an advanced disease at diagnosis. Recently, significant progress has been made in image recognition through advances in the field of artificial intelligence (AI) (or machine learning), especially deep learning. AI is a multidisciplinary field that draws on the fields of computer science and mathematics for developing and implementing computer algorithms capable of maximizing the predictive accuracy from static or dynamic data sources using analytic or probabilistic models. Because of the multifactorial and complex nature of liver diseases, the machine learning approach to integrate multiple factors would appear to be an advantageous approach to improve the likelihood of making a precise diagnosis and predicting the response of treatment and prognosis of liver diseases. In this review, we attempted to summarize the potential use of AI in the diagnosis and management of liver diseases, especially hepatocellular carcinoma.
Radiomics and deep learning in liver diseases
Authors: Sung Yu Sub , Park Bumwoo , Park Hyo Jung , Lee Seung Soo
Published: March 2021

Recently, radiomics and deep learning have gained attention as methods for computerized image analysis. Radiomics and deep learning can perform diagnostic or predictive tasks using high‐dimensional image‐derived features and have the potential to expand the capabilities of liver imaging beyond the scope of traditional visual image analysis. Recent research has demonstrated the potential of these techniques in various fields of liver imaging, including staging of liver fibrosis, prognostication of malignant liver tumors, automated detection and characterization of liver tumors, automated abdominal organ segmentation, and body composition analysis. However, because most of the previous studies were preliminary and focused mainly on technical feasibility, further clinical validation is required for the application of radiomics and deep learning in clinical practice. In this review, we introduce the technical aspects of radiomics and deep learning and summarize the recent studies on the application of these techniques in liver radiology.
Artificial intelligence in precision medicine in hepatology
Authors: Su Tung‐Hung , Wu Chih‐Horng , Kao Jia‐Horng
Published: March 2021

The advancement of investigation tools and electronic health records (EHR) enables a paradigm shift from guideline‐specific therapy toward patient‐specific precision medicine. The multiparametric and large detailed information necessitates novel analyses to explore the insight of diseases and to aid the diagnosis, monitoring, and outcome prediction. Artificial intelligence (AI), machine learning, and deep learning (DL) provide various models of supervised, or unsupervised algorithms, and sophisticated neural networks to generate predictive models more precisely than conventional ones. The data, application tasks, and algorithms are three key components in AI. Various data formats are available in daily clinical practice of hepatology, including radiological imaging, EHR, liver pathology, data from wearable devices, and multi‐omics measurements. The images of abdominal ultrasonography, computed tomography, and magnetic resonance imaging can be used to predict liver fibrosis, cirrhosis, non‐alcoholic fatty liver disease (NAFLD), and differentiation of benign tumors from hepatocellular carcinoma (HCC). Using EHR, the AI algorithms help predict the diagnosis and outcomes of liver cirrhosis, HCC, NAFLD, portal hypertension, varices, liver transplantation, and acute liver failure. AI helps to predict severity and patterns of fibrosis, steatosis, activity of NAFLD, and survival of HCC by using pathological data. Despite of these high potentials of AI application, data preparation, collection, quality, labeling, and sampling biases of data are major concerns. The selection, evaluation, and validation of algorithms, as well as real‐world application of these AI models, are also challenging. Nevertheless, AI opens the new era of precision medicine in hepatology, which will change our future practice.
The efficacy of linked color imaging for the endoscopic diagnosis of mucosal healing in quiescent ulcerative colitis
Authors: Takagi Tomohisa , Uchiyama Kazuhiko , Kajiwara‐Kubota Mariko , Kashiwagi Saori , Toyokawa Yuki , Hotta Yuma , Tanaka Makoto , Inoue Ken , Dohi Osamu , Yoshida Naohisa , Kamada Kazuhiro , Ishikawa Takeshi , Konishi Hideyuki , Kishimoto Mitsuo , Yagi Nobuaki , Naito Yuji , Itoh Yoshito
Published: March 2021

Background and Aim

The Mayo Endoscopic Subscore (MES) and the Ulcerative Colitis Endoscopic Index of Severity (UCEIS) are used to assess endoscopic mucosal healing in patients suffering from ulcerative colitis. Although mucosal healing is defined by MES 0, relapse of ulcerative colitis is often observed. Over a 48‐month period, this study investigated the efficacy of linked color imaging (LCI) in predicting the long‐term prognosis of ulcerative colitis patients diagnosed with MES 0.

Methods

Overall, 26 patients in ulcerative colitis remission, diagnosed with MES 0, were enrolled. Using a LASEREO endoscopic system (Fujifilm Co., Tokyo, Japan), endoscopic colonic images were assessed with linked color imaging and the colitis endoscopic index of severity. Endoscopic LCI images were separated into three subgroups (A, no redness; B, redness with visible vessels; and C, redness without visible vessels). The Geboes score was used to evaluate histology; active mucosa was defined as GS > 2B.1.

Results

Linked color imaging classification subdivided colonic mucosa, which had been diagnosed with MES 0, into two classes. The LCI‐A group did not relapse, and the non‐relapse rate was significantly higher (P = 0.018) than that in the LCI‐B group. No difference in relapse rates was observed between patients with a colitis endoscopic index of severity of 0 and 1 (P = 0.655). There was no statistical difference between the composition of LCI‐A group and the relapse rate between active and inactive mucosa diagnosed by Geboes score.

Conclusions

This methodology can be used to evaluate mucosal healing and predict long‐term outcomes in ulcerative colitis patients.
Region‐specific effects of the cysteine protease papain on gastric motility
Authors: Annaházi Anita , Schröder Alexandra , Schemann Michael
Published: March 2021

Background

Papaya is a traditional remedy for gastrointestinal complaints in the folk medicine. On this basis, papain, a cysteine protease of the fruit, is sold as a nutritional supplement, although scientific data on its effects in the gastrointestinal tract are lacking. We aimed to explore the effect of papain on gastric motility in vitro.

Methods

Guinea pig antrum and corpus strips were mounted in organ bath.

Key results

Papain reversibly increased the amplitude of ongoing phasic contractions in both circular and longitudinal antrum strips without having an effect on the frequency or on the muscle tone. All three tested doses of papain (end cc.: 12.5 mg L−1, 50 mg L−1, 100 mg L−1) were similarly effective. Contrarily, in the corpus circular and longitudinal muscle strips, papain caused a dose‐dependent relaxation, which was preceded by a transient contraction in most tissues. The effect was resistant to tetrodotoxin (1 µM), but diminished by the cysteine protease inhibitor E64 (4.5 µM) in both regions. In the corpus, L‐NAME (100 µM) and the protease‐activated receptor (PAR)‐1 antagonist SCH79797 (5 µM) or the PAR‐2 antagonist GB 83 (3 µM) did not change the effect of papain significantly. This demonstrates that the effects of papain are not neurally mediated and nitrergic pathways are not involved in the mechanism. The effects are linked to the enzymatic activity, but not executed via PAR‐1 or 2.

Conclusions and inferences

Papain alters gastric motility in a region‐specific manner, which could at least partly explain its claimed beneficial effects in functional gastrointestinal disorders.
Association between maternal diabetes mellitus and allergic diseases in children — A systematic review and meta‐analysis
Authors: Li Zhi , Yu Mei , Wang Pin , Qian Hong , Fan Yun , Li Xiuzhu , Xu Qiaoqiao , Wang Xinru , Wang Xu , Lu Chuncheng
Published: March 2021

Background

Existing knowledge suggests that gestational diabetes mellitus was inconsistently associated with offspring allergic diseases. The aim of this study was to identify the association between maternal diabetes mellitus and the risk of offspring allergic diseases by systematic review.

Methods

We searched and retrieved three databases (PubMed, Web of Science, and Cochrane Library) for articles on the association between maternal diabetes mellitus and offspring allergic diseases published before December 31, 2019. Stata software version 16.0 was used for statistical analysis.

Results

Eight published studies were included in this meta‐analysis. The pooled effect estimates showed the association between maternal diabetes mellitus and allergic outcomes, including asthma (OR: 1.13, 95% CI: 1.01‐1.27), wheezing (OR: 1.13, 95% CI: 1.07‐1.21), and atopic dermatitis (OR: 1.43, 95% CI: 1.22‐1.57). Maternal diabetes mellitus was not associated with the risk of allergic sensitization, with a pooled effect estimate of 1.07 (95% CI: 0.45, 2.58).

Conclusion

Maternal diabetes mellitus may increase the risk of allergic diseases in their children. However, this finding should be validated with future large‐sample epidemiological studies covering a wider spectrum of allergic diseases.
NordAqua, a Nordic Center of Excellence to develop an algae‐based photosynthetic production platform
Authors: Allahverdiyeva Yagut , Aro Eva‐Mari , van Bavel Bert , Escudero Carlos , Funk Christiane , Heinonen Jarna , Herfindal Lars , Lindblad Peter , Mäkinen Sari , Penttilä Merja , Sivonen Kaarina , Skogen Chauton Matilde , Skomedal Hanne , Skjermo Jorunn
Published: March 2021

NordAqua is a multidisciplinary Nordic Center of Excellence funded by NordForsk Bioeconomy program (2017–2022). The research center promotes Blue Bioeconomy and endeavours to reform the use of natural resources in a environmentally sustainable way. In this short communication, we summarize particular outcomes of the consortium. The key research progress of NordAqua includes (1) improving of photosynthetisis, (2) developing novel photosynthetic cell factories that function in a “solar‐driven direct CO2 capture to target bioproducts” mode, (3) promoting the diversity of Nordic cyanobacteria and algae as an abundant and resilient alternative for less sustainable forest biomass and for innovative production of biochemicals, and (4) improving the bio‐based wastewater purification and nutrient recycling technologies to provide new tools for integrative circular economy platforms.
Regional Scale Risk to the Ecological Sustainability and Ecosystem Services of an African Floodplain System
Authors: O'Brien Gordon , Smit Nico J , Wepener Victor
Published: March 2021

The Phongolo floodplain is one of southern Africa's most important systems. In this study, we carried out a regional scale ecological risk assessment to evaluate the risk of multiple stressors associated with the use of the aquatic resources in the floodplain to selected social and ecological endpoints representing its sustainability. The floodplain has undergone significant changes as a result of the impacts of multiple stressors. This includes high risk of impact and threatened sustainability between the Pongolapoort Dam and the Ndumo Game Reserve (NGR). This compares to relatively low risk to the maintenance of the endpoints within the NGR. The reserve provides a protection and refuge function for regional biodiversity maintenance and ecosystem sustainability processes. In the study a range of scenarios were considered and demonstrate that the system will respond to protection measures and or increased resource use options. Should flood reductions or water quality pollution drivers continue on increasing trajectories, the condition of the Phongolo River and floodplain will probably deteriorate into an unacceptable, unsustainable state. Removal of the protection services of the NGR would result in an unsustainable ecosystem and loss of ecosystem services for regional vulnerable African communities. Additional evidence should be obtained from monitoring and research to refine, validate, and update the assessment in an adaptive management context. The risk assessment framework approach implemented in the Phongolo floodplain can contribute to the management of other floodplains ecosystems and the sustainability management of social and ecological attributes and processes of these important ecosystems.
The role of double‐step advancement genioplasty and bilateral coronoidectomy in Nager Syndrome: A case report
Authors: Trindade Paulo Alceu Kiemle , Bueno Patricia Martins , Scomparin Leandro , Marzano‐Rodrigues Maria Noel , Trindade‐Suedam Ivy Kiemle
Published: March 2021

Aim

To report the surgical management of bilateral mandibular coronoid processes hyperplasia and mandibular retrognathism associated with trismus and convex facial profile in an individual diagnosed with Nager syndrome (NS).

Case report

A 21 years old female was referred to the Department of Oral and Maxillofacial Surgery, presenting limited mouth opening and an unpleasant convex facial profile. The tomography exhibited hyperplasia of mandibular coronoid processes with no evidence of intracapsular ankylosis of the temporomandibular joint. The treatment objectives were to increase mouth opening through a bilateral coronoidectomy and gain chin projection using the double‐step advancement genioplasty technique. The 9‐month postoperative follow‐up revealed a 22.22% (6 mm) gain in jaw opening, improved masticatory function, and facial profile.

Conclusions

The NS is a complex craniofacial anomaly due to its clinical heterogeneity. Thus, treatment planning must be done individually, considering the patients' main complaints and respecting the limitations regarding anatomy and availability of proper surgical materials. In the present case, a bilateral coronoidectomy associated with immediate physiotherapy improved the patient's mouth opening, and the double‐step genioplasty promoted a much more significant chin advancement than would be obtained with the single‐step traditional osteotomy.
Characterization of the novel HLA‐A*26:208 allele by sequencing‐based typing
Authors: Dard Celine , Walencik Alexandre , Oukasse Imad , Bardy Béatrice , Masson Dominique
Published: March 2021

The novel HLA‐A*26:208 allele was characterized using two next generation sequencing technologies.
Intravenous lipid emulsion treatment in rabbits with ivermectin toxicosis
Authors: Branco Stephanie Elise Muniz Tavares , Mattoso Claudio Roberto Scabelo , Botelho Ana Flávia Machado , Soto‐Blanco Benito , Melo Marília Martins
Published: March 2021

Objective

To determine the effect and safety of IV lipid emulsion in rabbits with acute ivermectin toxicosis.

Design

Randomized controlled trial.

Setting

University research facility.

Animals

Twenty‐four healthy male adult New Zealand rabbits.

Interventions

Three groups of rabbits (IV, IV_RL, and IV_LE) received 80 mg/kg of ivermectin (8 mL/kg) through a nasogastric tube, and 1 group (LE) received an equivalent volume (8 mL/kg) of 0.9% sodium chloride. Group IV_RL was treated with Ringer's lactate (2 mL/kg bolus, followed by 0.25 mL/kg/min for 60 minutes), whereas groups IV_LE and LE received 20% lipid emulsion. The rabbits were submitted to clinical and neurological evaluation, and blood samples were collected for biochemical analysis. All animals were euthanized, and tissue samples were collected and processed for histopathological evaluation and ivermectin quantification.

Measurements and main results

All animals exposed to ivermectin manifested clinical changes consistent with toxicosis, but the ones that received IV lipid emulsion infusion showed no significant clinical improvement. Intense increase in serum glucose and triglyceride concentrations was seen after ivermectin exposure, along with increased urea and creatinine concentrations, but the last 2 remained within the reference range. Lipid emulsion caused an intense increase in triglycerides and cholesterol concentrations. No pathological abnormalities were seen in the organs sampled. Toxicological analysis showed greater ivermectin concentration in adipose tissue and liver, followed by kidney and, finally, brain. The treatments did not change ivermectin tissue concentration.

Conclusions

When given to rabbits intoxicated with ivermectin, IV lipid emulsion was biochemically and histologically safe but was not effective in treating, delaying, or reversing clinical signs and progression, nor did it alter ivermectin tissue concentration.
Comparison of left fourth and fifth intercostal space thoracotomy for open‐chest cardiopulmonary resuscitation in dogs
Authors: Warang Anushri M. , Mann F. A. , Middleton John R. , Wagner‐Mann Colette , Branson Keith
Published: March 2021

Objective

To determine whether ease of access to thoracic structures for performing open‐chest cardiopulmonary resuscitation (OC‐CPR) differed between fourth and fifth intercostal space (ICS) left lateral thoracotomies in dogs, and to determine if “shingling” improved access for OC‐CPR manipulations.

Design

Prospective single‐blinded study.

Setting

Laboratory.

Animals

Twelve mixed breed canine cadavers weighing approximately 20 kg.

Interventions

Left lateral thoracotomies were performed at the 4th ICS (n = 6) or 5th ICS (n = 6). Shingling at the 4th or 5th ICS, as applicable, was performed after initial data collection and outcomes were reassessed.

Measurements and main results

Three evaluators blinded to the surgical approach scored the following parameters on a 0 to 10 scale (0 = easiest, 10 = most difficult): ease of access of the phrenicopericardial ligament, ease of pericardial incision, ease of appropriate hand position, ease of aortic access, ease of Rumel tourniquet application, and ease of proper placement of defibrillation paddles. Objective measurements (time to completion or number of attempts) were made for all but ease of pericardial incision and ease of appropriate hand position. Outcomes were reassessed after shingling.

The 5th ICS was superior for ease of aortic access (P = 0.042), time to visualization of aorta (P = 0.009), and ease of application of a Rumel tourniquet (P = 0.019). When comparing scores pre‐ and post‐shingling, shingling improved time to visualization of the aorta (P < 0.001), time to placement of Rumel tourniquet (P < 0.001), ease of paddle placement (P = 0.017), and time to paddle placement (P < 0.001).

Conclusions

Either 4th or 5th ICS thoracotomy may provide adequate access to intrathoracic structures pertinent to performing OC‐CPR in dogs weighing approximately 20 kg, but 5th ICS was preferred for most manipulations, and shingling improved access for most of the measured parameters.
Mesenchymal stem cell transplantation into the spinal cord of healthy adult horses undergoing cervical ventral interbody fusion
Authors: François Isé , Lepage Olivier M. , Carpenter Elaine , Desjardins Isabelle , De Guio Cécile , Benedetti Inga‐Catalina Cruz , Maddens Stéphane , Saulnier Nathalie , Grant Barrie D.
Published: March 2021

Objective

To determine the feasibility of umbilical cord‐derived mesenchymal stem cell (UC‐MSC) transplantation into the cervical spinal cord of horses by using fluoroscopy with or without endoscopic guidance and to evaluate the neurological signs and tissue reaction after injection.

Study design

Experimental study.

Animals

Eight healthy adult horses with no clinical signs of neurological disease.

Methods

After cervical ventral interbody fusion (CVIF), ten million fluorescently labeled allogeneic UC‐MSC were injected into the spinal cord under endoscopic and fluoroscopic guidance (n = 5) or fluoroscopic guidance only (n = 3). Postoperative neurological examinations were performed, and horses were humanely killed 48 hours (n = 4) or 14 days (n = 4) postoperatively. Spinal tissues were examined after gross dissection and with bright field and fluorescent microscopy.

Results

Needle endoscopy of the cervical canal by ventral approach was associated with intraoperative spinal cord puncture (2/5) and postoperative ataxia (3/5). No intraoperative complications occurred, and one (1/3) horse developed ataxia with cell transplantation under fluoroscopy alone. Umbilical cord‐derived MSC were associated with small vessels and detected up to 14 days in the spinal cord. Demyelination was observed in six of eight cases.

Conclusion

Fluoroscopically guided intramedullary UC‐MSC transplantation during CVIF avoids spinal cord trauma and decreases risk of ataxia from endoscopy. Umbilical cord‐derived MSC persist in the spinal cord for up to 14 days. Cell injection promotes angiogenesis and induces demyelination of the spinal tissue.

Clinical significance

Umbilical cord‐derived MSC transplantation into the spinal cord during CVIF without endoscopy is recommended for future evaluation of cell therapy in horses affected by cervical vertebral compressive myelopathy.
The Absolute Calibration of Electro-Mechanical Pickups
Authors: Trent H. M.
Published: March 2021

A new method of calibrating electromechanical pickups is presented in this paper. Given two linear indicators, one of which is bilateral, it is shown that the sensitivities of the units can be established in both magnitude and phase by three experiments which do not involve the direct measurement of oscillating mechanical quantities. It is shown, also, that the technique does not depend upon the specific designs of the units.
Square Plates Fixed at Points
Authors: Thorne C. J.
Published: March 2021

Deflection functions for thin plates with symmetric loads are given as a sum of biharmonic polynominals with coefficients determined by the slopes and deflections at five equally spaced points on each edge of the plate. The coefficients are given numerically for a point load and a uniform load, for zero slope and deflection at the five points, for the tangential slope at two of the five points not specified, for a particular slope, and for a particular deflection at the mid-points of the edges. Deflections are plotted at the edges, the center line, and the diagonal. Slopes are plotted at the edges. Moments and stresses are given at the mid-point of the edges.
The Hydrosphere—A New Hydrodynamic Bearing
Authors: Shaw M. C. , Strang C. D.
Published: March 2021

A fitted spherical bearing has been found to operate hydrodynamically when subjected to large values of thrust or radial-thrust load. An examination of the geometry of this bearing fails to reveal the usual wedge-shaped oil film in the direction of motion of the moving bearing surface. However, a wedge does exist normal to the direction of motion. When Reynolds differential equation is applied to the bearing it is not evident whether this normal wedge is capable of producing positive pressure. When the differential equation for pressure is written with respect to co-ordinates directed along and perpendicular to a “mean streamline,” it is apparent that a wedge normal to the direction of motion may produce positive pressure, provided there is flow in the normal direction. The results of several experimental tests are analyzed with respect to the qualitative theory presented, and the unique characteristics of this bearing are compared with those of other existing hydrodynamic bearings.
Some Properties of a Mechanical Model of Plasticity
Authors: Bohnenblust H. F. , Duwez Pol
Published: March 2021

Various mechanical models explaining the plastic deformation of metals have been proposed. One of the present authors has shown that in some cases an analytical expression for the stress-strain curve and the hysteresis curve of a metal in the plastic range can be deduced from such a model. The present investigation is a further analysis of the model leading to the computation of the change in potential energy of the metal due to work-hardening.
The Stress-Strain Laws of the Mathematical Theory of Plasticity—a Survey of Recent Progress
Authors: Prager William
Published: March 2021

Typical stress-strain laws of flow and deformation types are discussed with particular reference to the conditions of continuity and uniqueness which these laws must fulfill if they are to make sense physically. Alternative forms of some of these laws are presented, and conditions are discussed under which different laws yield identical results. It is shown how these laws may be generalized so as to fit test data more readily. Methods of integration are indicated and the use of variational principles is stressed.
The Propagation of Plasticity in Uniaxial Compression
Authors: White M. P. , Griffis LeVan
Published: March 2021

A theoretical investigation of the mechanism of uniaxial compression impact on elastic-plastic materials is described in this paper. The method of analysis is similar in some respects to that previously given for tension impact on such materials. It is concluded that four different kinds of behavior can occur, depending upon the impact velocity. In the lowest velocity range the behavior in compression is similar to that found in tension. In this case stress and strain are propagated from the point of impact as a zone or wave front of ever-increasing length. This type of behavior ends at a velocity corresponding to the “critical” velocity found in tension impact. Within the next higher velocity range, stress and strain are propagated as a shock-type wave, or wave of very small length in which the transition from low to high stress and strain is very abrupt. At still higher impact velocities, there occurs “flowing deformation” in which the material is too weak to maintain coherency. Here there is a steady flow of the material toward and against the hammer, after which it flows in a thin sheet radially outward over the face of the hammer. The final possible state occurs at impact velocities greater than the speed of an elastic wave, so that no disturbance can escape from the hammer into the medium. Here the behavior is essentially that of a fluid, impact force being independent of strength of material.
The Decay of Isotropic Turbulence
Authors: Frenkiel F. N.
Published: March 2021

The equation of decay of isotropic turbulence is determined in the two cases of large and small Reynolds number of turbulence by using the von Kármán-Howarth equations and applying Loitsianskii’s theorem of the conservation of the disturbance moment. The theoretical curves are compared with the results of measurements behind grids, made by various experimenters in the United States and in England. The decay of the longitudinal turbulent energy seems to agree quite well with the theoretical equations for large Reynolds number of turbulence. The theory does not give the variation of the transverse scale of turbulence measured in the experiments, but only the “disturbance length,” which is a function of the longitudinal correlation. Thus the comparison for the scale is only qualitative. It is not possible to show agreement with the theoretical variation of the scale deduced from the equations. The difference is explained by the imperfect isotropy, which has a much greater influence on the variation of the scale than it has on the energy decay. The present comparison of the theory with the experiments differs from similar prior comparisons by the fact that the decay is given as a function of the initial conditions of the turbulence at a chosen moment, without using arbitrary constants.
Transient Large Eddy Simulation of Slurry Erosion in Submerged Impinging Jets
Authors: Wang Qiuchen , Huang Qiyu , Sun Xu , Zhang Jun , Karimi Soroor , Shirazi Siamack A.
Published: March 2021

Submerged impingement jets are widely used in erosion/corrosion experiments as it is easy to control jet standoff distance, jet angle, and flow velocities in experiments. In addition to experiments, typically computational fluid dynamics (CFD) technique has been used to simulate slurry flow in this geometry to investigate erosion process and develop erosion models or equations. The traditional CFD simulations of erosion in this geometry use the Reynolds-averaged Navier–Stokes (RANS) equations with turbulence models. By using this technique, time-averaged fluid flow is revealed, and thus, time-averaged erosion rate can be obtained by tracking particles in the fluid flow field. However, this seemingly simple flow displays unsteady flow structures in the stagnation zone of the flow field and its effects on the erosion process were previously unclear. In this study, large eddy simulation (LES) is used to simulate unsteady fluid flow in different impingement jets in an Eulerian scheme. Then, transient particle tracking is performed in a Lagrangian scheme. Particles are injected randomly at the inlet plane and tracked to simulate unsteady erosion that occurs on the target surface. Finally, an erosion equation is used to calculate solid particle erosion rates. The LES Eulerian–Lagrangian erosion modeling is further validated by available experimental data for fluid velocities and an erosion profile. The results show that the accuracy of erosion prediction of small particles is improved significantly by using the LES method. In addition, the unsteady particle motion and erosion process can be revealed by using this method.
Study of Pressure Pulsations in a Francis Turbine Designed for Frequent Start-Stop
Authors: Trivedi Chirag
Published: March 2021

The energy market aims for high flexibility that allows guaranteed power to the consumers with minimum carbon footprint. Over the last three decades, hydropower has been a reliable and an efficient option to meet the fluctuating energy demand as it allows high-ramping rate and quick start-stop. However, such critical operations bring certain challenges for hydro turbines, i.e., high-amplitude stochastic loading and the fatigue. Credible investigation of unsteady pressure pulsations and their signature is important to understand the consequences. The present work aims to study pressure pulsations in a model Francis turbine, which is designed for the frequent start–stop operations. A total of 112 numerical simulations, across the hill diagram, are conducted. Pressure pulsations in the vaneless space, blade channels, and draft tube are investigated. The results show distinct patterns of rotor-stator interaction frequencies in the turbine. In the regions of high rotational speed and low flow rate, stochastic pulsations are predominant.
Quantitative Characterization of Shale Porosities of Different Origins by Integrating Pore Genesis and Logging Analysis
Authors: Wang Jianguo , Gu Daihong , Meng Xiaoyan , Yang Daoyong
Published: March 2021

In this paper, a new and pragmatic technique has been developed to identify pore types and characterize porosities of shales with various origins. By comparing the genesis of pore types (i.e., organic, brittle, and clay mineral porosities) in shales, the corresponding pore volumes per unit mass are determined as a function of the total porosity, density, and the content of each pore type from core samples. Subsequently, a new inverse framework was proposed and successfully applied to quantify different types of porosities in the Silurian Longmaxi formation shale in the Zhaotong area. The pore volume per unit mass of organic matter is calculated to be around 0.185–0.190 cm3/g, which is 10–21 and 8–19 times more than that of brittle mineral and clay mineral, respectively, indicating that pore space of organic matter contributes greater to the total porosity than that of the clay and brittle minerals. Using single well data, the porosity in organic matter is found to follow the same pattern as the total porosity in the vertical direction. Such an identified porosity type leads to more accurate sweet spots as well as more appropriate drilling locations for horizontal wells in shale reservoirs.
A Review on Corrosion and Wear of Additively Manufactured Alloys
Authors: Renner Peter , Jha Swarn , Chen Yan , Raut Ajinkya , Mehta Siddhi G. , Liang Hong
Published: March 2021

Products made from additive manufacturing processes have attracted great attention in engineering, health care, and society at large. However, there is little knowledge about the failure of additively manufactured alloys, in particular, corrosion and wear seen in most engineering applications. The haphazard and inefficient usage of such alloys raised concerns about safety, compatibility, reliability, cost, and consumer satisfaction. To address those concerns, we studied the mechanisms of the most common failure modes, corrosion and wear, of alloys fabricated through additive manufacturing based on published literature. It was found that the processing conditions have profound influence on microstructure and thus corrosion and wear resistance of alloys. Because of the layered structure, the initiation and growth of both corrosion and wear exhibited anisotropic behavior. The insights from this review could be used as a reference of the state-of-the art and to help in the development of future additively manufactured alloys with improved corrosion and wear properties.
Dynamic Analysis of the Optimized Savonius Vertical Axis Wind Turbine Composite Blades
Authors: Ghoneam Sobhy M. , Hamada Ahmed A. , Sherif Taha S.
Published: March 2021

This article presents a comprehensive study of the dynamic behavior of small vertical-axis wind turbines (VAWTs) based on local fabricated Savonius VAWTs, which is suitable for countries that have a moderate wind speed. The merits of this design are cleanliness, silent, start-up under low wind speed, independent wind directions, adaptability, and ease of manufacturing. Also, this article presents an experimental validation study for the optimized Savonius VAWT. Four verification test configurations of the optimized VAWT composite blades are designed, simulated, and fabricated of Glass—Polyester with different stacking sequence layout for each. Modified mechanical parameters are introduced to improve the scalability, reliability, and accuracy of the developed models. Based on wind energy conversion system basics, aerodynamic characteristics (tip speed ratio (λ) and coefficient of power (Cp)) and dynamic characteristics (natural frequencies and mode shapes) of Savonius rotor models are presented and simulated within solidworks simulation 2020 software. The dynamic characteristics such as frequency, mode shape, and damping factor are extensively investigated using fast Fourier transform (FFT) analyzer. The results show that the role of composite material blades in improving the dynamic performance of a wind turbine is significant.
Optimization of Herringbone Grooved Thrust Air Bearings for Maximum Load Capacity
Authors: Yu Yunluo , Pu Guang , Jiang Tianchu , Jiang Kyle
Published: March 2021

Many studies in herringbone grooved thrust bearings are focused on searching for the optimal groove parameters to improve the load capacity, but none of them adopt different grooves in different sections. In this study, a novel optimization method of herringbone grooved thrust air bearings is proposed for maximum load capacity by seeking the optimal groove parameters in each section of the bearing independently. An example of an optimized thrust air bearing is presented, and its performance is compared with a non-optimized bearing and a conventionally optimized bearing without dividing grooves into sections. The resultant herringbone grooves are found to have different parameters in the inner and outer sections, which is uncommon in existing grooves. Numerical results show that the novel bearing has a higher load capacity than the non-optimized reference bearing and conventionally optimized bearing. The study shows that the new design can increase load capacity by 30.77%, verified by experiments.
Triboinformatics Approach for Friction and Wear Prediction of Al-Graphite Composites Using Machine Learning Methods
Authors: Hasan Md Syam , Kordijazi Amir , Rohatgi Pradeep K. , Nosonovsky Michael
Published: March 2021

Data-driven analysis and machine learning (ML) algorithms can offer novel insights into tribological phenomena by establishing correlations between material and tribological properties. We developed ML algorithms using tribological data available in the literature for predicting the coefficient of friction (COF) and wear-rate of self-lubricating aluminum graphite (Al/Gr) composites. We collected data on effects of material variables (graphite content, hardness, ductility, yield strength, silicon carbide content, and tensile strength), processing procedure, heat treatment and tribological test variables (normal load, sliding speed, and sliding distance) on tribological properties and established two-parameter relationships. These data are analyzed using several ML algorithms: artificial neural network (ANN), K nearest neighbor (KNN), support vector machine (SVM), gradient boosting machine (GBM), and random forest (RF). The trained ML models can predict the tribological behavior from material variables and test conditions, beyond what is possible from two-parameter correlations. GBM outperformed other ML algorithms in predicting friction behavior, while RF had the best prediction of the wear behavior. ML analysis identified graphite content and hardness and as the most significant variables in predicting the COF, while graphite content and sliding speed were the most dominant variables for wear-rates.
Feature Recognition for Manufacturability Analysis
Authors: Regli William C. , Gupta Satyandra K. , Nau Dana S.
Published: March 2021

While automated recognition of features has been attempted for a wide range of applications, no single existing approach possesses the functionality required to perform manufacturability analysis. In this paper, we present a methodology for taking a CAD model of a part and extracting a set of machinable features that contains the complete set of alternative interpretations of the part as collections of MRSEVs (Material Removal Shape Element Volumes, a STEP-based library of machining features). The approach handles a variety of features including those describing holes, pockets, slots, and chamfering and filleting operations. In addition, the approach considers accessibility constraints for these features, has an worst-case algorithmic time complexity quadratic in the number of solid modeling operations, and modifies features recognized to account for available tooling and produce more realistic volumes for manufacturability analysis.
Decomposing a Delta Volume Into Maximal Convex Volumes and Sequencing Them for Machining
Authors: Sakurai Hiroshi
Published: March 2021

A method has been developed to decompose a polyhedral delta volume, which is the volume difference between the raw material and the finished part, into maximal convex volumes by intersecting the halfspaces of the faces of the delta volume. The hypothesis behind this effort is that in machining a delta volume of complex shape it is more efficient to divide it into volumes of simple shapes and remove volume by volume with large cutters than to remove it as a single volume with a single small cutter. The maximality of a maximal convex volume represents the possibility of using a large cutter and its convexity represents the simplicity of the shape of the volume. To prove the utility of maximal convex volumes, a small computer program was developed that sequences the maximal convex volumes based on a few heuristics on machining efficiency and tested it with a few objects. It generated good machining sequences.

The basic idea of the decomposition method is to intersect a polyhedral delta volume with the halfspaces of its faces having concave edges. The combinations of such halfspaces that result in maximal convex volumes when they are intersected with the delta volume are determined efficiently by examining the relationships among the halfspaces. This basic idea works well for polyhedral delta volumes but does not work for delta volumes having curved faces since curved faces cannot always be extended infinitely. To cope with the delta volumes having cylindrical faces, a separate decomposition method has been developed. This method works only for the delta volumes that can be decomposed into 2½D machining volumes.
Reducing Setup Cost by Automated Generation of Redesign Suggestions
Authors: Das Diganta , Gupta Satyandra K. , Nau Dana S.
Published: March 2021

All mechanical designs pass through a series of forma] and informal redesign steps, involving the analysis of functionality, manufacturability, cost and other life-cycle factors. The speed and efficacy of these steps has a major influence on the lead time of the product from conceptualization to launching.

In this paper we propose a methodology for automatically generating redesign suggestions for reducing setup costs for machined parts. Our approach is based on interpreting the design as a collection of machinable features. Our methodology generates alternate machining features by making geometric changes to the part, and adds them to the feature set of the original part. The designer may provide restrictions indicating that certain surfaces and volumes should not be changed, in which case all redesign suggestions generated by our approach honor those restrictions. Using features from the extended feature set generated above, one or more new designs may be found that need fewer setups than the original part.