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Artificial neural network model for predicting drill cuttings settling velocity

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Petroleum 2020年第4期6卷 340-352页

作者： Okorie e.Agwu julius U.Akpabio Adewale Dosunmu Department of Chemical and Petroleum engineering University of UyoAkwa Ibom StateNigeria Department of Petroleum and Gas engineering University of PortHarcourtRivers StateNigeria

The traditional method of using the coefficient of drag–Reynolds number relationship to predict cuttings settling velocity involves an implicit procedure that requires repeated,time-consuming and tedious iterations using Newtonian or mostly non-Newtonian ***,these correlations are limited to certain fluid flow ***,most of the explicit and direct cuttings settling velocity models that exist are based on the assumption that the cuttings are spherical ***,in the field,the cuttings are a mixture of various shapes and are hardly spherical,hence these models when applied to field conditions come off with huge *** objective of this work was to use a nature-inspired algorithm(artificial neural network-ANN)to develop a model for estimating cuttings settling velocity that would be robust and useful in the field that would take into account the shape of the *** data used for this work was obtained from research experiments in the *** model was then evaluated using four performance metrics namely:mean squared error(MSe),root mean square error(RMSe),sum of squares error(SSe)and goodness of fit(R2).It was found that the model's predictions obtained in this work agreed with experimental ***,the developed model possesses the capacity to generalize across new input datasets and can be applied to particles of any shape,hence,defining the novelty of this research and bridging the gap between theory and *** compared with state-of-the-art models,the developed models show a high degree of robustness,as the ANN model performed reasonably well with an MSe of 7.5×10−4,an R2 of 0.978,RMSe of 0.0274 and SSe of *** generalize the results across new input datasets,the developed model was cross-validated with new data that was not part of the training *** was found that the ANN model had an MSe value 0.00807,RMSe of 0.0898,MAe of 0.065,SSe of 2.74 and MAPe of 0.675%.To ensure the replicabi

关键词： Drill cuttings Artificial neural network Mud Cuttings settling velocity

Hypoxic pre-conditioned adipose-derived stem/progenitor cells embedded in fibrin conduits promote peripheral nerve regeneration in a sciatic nerve graft model

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Neural Regeneration Research 2023年第3期18卷 652-656页

作者： julius M.Mayer Christian Krug Maximilian M.Saller Annette Feuchtinger Riccardo e.Giunta elias Volkmer Thomas Holzbach Department of Hand-and Plastic Surgery Spital ThurgauFrauenfeldSwitzerland Musculoskeletal University Center Munich(MUM) Department of Orthopedics and Trauma SurgeryLudwig-Maximilians-University(LMU)Planegg-MartinsriedGermany Research Unit Analytical Pathology MunichHelmholtz Zentrum München-German Research Center for Environmental Health(GmbH)NeuherbergGermany Division of Hand- Plastic-and Aesthetic SurgeryLudwig-Maximilians-University(LMU)MunichGermany Division of Hand Surgery Helios Klinikum München WestMunichGermany

Recent results emphasize the supportive effects of adipose-derived multipotent stem/progenitor cells(ADSPCs)in peripheral nerve *** under hypoxia is considered to enhance the release of the regenerative potential of *** study aimed to examine whether peripheral nerve regeneration in a rat model of autologous sciatic nerve graft benefits from an additional custom-made fibrin conduit seeded with hypoxic pre-conditioned(2%oxygen for 72 hours)autologous ADSPCs(n=9).This treatment mode was compared with three others:fibrin conduit seeded with ADSPCs cultivated under normoxic conditions(n=9);non-cell-carrying conduit(n=9);and nerve autograft only(n=9).A 16-week follow-up included functional testing(sciatic functional index and static sciatic index)as well as postmortem muscle mass analyses and morphometric nerve evaluations(histology,g-ratio,axon density,and diameter).At 8 weeks,the hypoxic pre-conditioned group achieved significantly higher sciatic functional index/static sciatic index scores than the other three groups,indicating faster functional ***,histologic evaluation showed significantly increased axon outgrowth/branching,axon density,remyelination,and a reduced relative connective tissue *** pre-conditioned ADSPCs seeded in fibrin conduits are a promising adjunct to current nerve *** studies are needed to understand the underlying cellular mechanism and to investigate a potential application in clinical practice.

关键词： adipose-derived progenitor cells adipose-derived multipotent stem/progenitor cell autologous nerve graft fibrin conduit hypoxia hypoxic pre-conditioning nerve defect nerve tissue engineering peripheral nerve regeneration regenerative medicine

evaluation of the gastrointestinal anti-motility effect of Anacardium occidentale stem bark extract:A mechanistic study of antidiarrheal activity

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Journal of Pharmaceutical Analysis 2021年第6期11卷 776-782页

作者： Blessing O.Omolaso Francis S.Oluwole Olugbenga A.Odukanmi julius K.Adesanwo Ahmed A.Ishola Kayode e.Adewole Department of Physiology Faculty of Basic Medical SciencesUniversity of Medical SciencesOndo City340001Ondo StateNigeria Department of Physiology College of MedicineUniversity of IbadanIbadan200001Nigeria Department of Chemistry Obafemi Awolowo UniversityIle-Ife230001Osun StateNigeria Central Research Laboratories Limited University Road IlorinKwara State240001Nigeria Department of Biochemistry Faculty of Basic Medical SciencesUniversity of Medical Sciences340001Ondo StateNigeria

Diarrhea is a prevalent gastrointestinal problem associated with fatal *** is a huge public health concern that requires better alternatives to current *** study investigated the mechanisms involved in the antidiarrheal activity of Anacardium occidentale(Ao) stem bark extract,a plant commonly used in the management of diarrhea in *** stem bark extract of the plant was partitioned into three fractions:hexane fraction,ethyl acetate fraction(Ao eF) and methanol *** vitro studies on the effect of these fractions on guinea pig ileum(GPI) strips,as well as the modulatory effect of Ao eF on standard agonists-and antagonists-induced GPI contraction and relaxation,revealed Ao eF as the most active *** vivo studies to assess the effect of Ao eF on the dopaminergic,muscarinic,and serotonergic pathways were carried out using gastric emptying(Ge) and gastrointestinal transit(GT) as experimental end *** eF was subjected to GC-MS analysis,while the identified compounds were docked with the muscarinic acetylcholine receptor M3(CHRM3) using Autodock *** indicated that Ao eF inhibited Ge and GT via inhibition of *** addition,GC-MS analysis revealed the presence of 24 compounds in Ao eF,while docking indicated that octadecanoic acid 2-(2-hydroxylethoxy)ethyl ester exhibited the highest binding affinity to *** study indicated that the antidiarrheal activity of Ao is through its antimotility effect via the inhibition of the muscarinic *** since none of the identified compounds exhibited higher binding affinity to CHRM3 relative to loperamide,the antimotility activity of these phytoconstituents may be via synergism.

关键词： Anacardium occidentale Antidiarrheal Muscarinic receptor Gastric emptying Gut motility GC-MS analysis

Relationship between Adiposity, Low-Density Lipoprotein Particles Size and Cardiovascular Risk among Adult Obese Cameroonians

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Open Journal of epidemiology 2022年第2期12卷 185-206页

作者： Jacob Tchinda Nkougni Françoise Raissa Ntentie Martin Fonkoua Boris Gabin Kingue Azantsa Guy Roussel Takuissu Nguemto evelyn Ngwa Lumngwena Judith Laure Ngondi julius enyong oben Laboratory of Nutrition and Nutritional Biochemistry Department of Biochemistry University of Yaounde 1 Yaounde Cameroon Department of earth and Life Sciences Higher Teachers’ Training College University of Maroua Maroua Cameroon Centre for Food Food Security and Nutrition Research (CRASAN) Institute for the Medical Research and Medicinal Plant Studies (IMPM) Ministry of Scientific Research and Innovation Yaoundé Cameroon School of Clinical Medicine University of Witwatersrand Johannesburg South Africa Centre for the Study of emerging and Re-emerging Infections (CReMeR) Institute for the Medical Research and Medicinal Plant Studies (IMPM) Ministry of Scientific Research and Innovation Yaoundé Cameroon

Background: Despite the evidence about the increasing prevalence of dyslipidemia among adult obese Cameroonians, little is known about the Low-Density Lipoprotein (LDL) particles which influence lipid metabolism and affect cardiovascular status. The present study aims to assess the relationship between adiposity, LDL particles size and cardiovascular risk (CVR) among adult obese Cameroonians. Methods: A cross-sectional study was conducted from September 2015 to March 2016 on apparently healthy adults (n = 1006), aged 20 - 70 years and living in the West and North-West regions of Cameroon. Anthropometric measurements, blood pressure (BP), fasting blood glucose (FBG) and lipid profile markers were analyzed and LDL particle phenotypes (LDL phenotype A;LDL phenotype I;LDL phenotype B) were characterized using small, dense LDL-cholesterol (sdLDL-c) levels. Abdominal fat accumulation (AFA) was defined as waist circumference (WC) ≥ 88 cm (men) and ≥90 cm (women) and the CVR was assessed using Framingham score method. Results: In the overall population, 36.6% were overweight, 33.1% were obese and 69.1% were overweight/obese with AFA. The prevalence of LDL phenotype B was 19.8%, 37.5% and 42.8% respectively in normal-weight, overweight and obese. Among the obese, sdLDL and triglycerides levels correlated significantly with WC (r = 0.768;p Conclusion: Among obese Cameroonians, anthropometric markers of adiposity (BMI and WC) were strongly correlated to LDL phenotype B which was associated with high CVR dependently of AFA. SdLDL particles could exacerbate the CVR in obese Cameroonians subjects.

关键词： Obese Cameroonians LDL Particle Size Adiposity Markers Cardiovascular Risk

Assessment of Dietary Habits and Nutritional Status of Women of Childbearing Age in Cameroon: A Cross Sectional Study

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Open Journal of epidemiology 2020年第4期10卷 369-392页

作者： Christelle Momdjo M’bobda Judith Laure Ngondi Françoise Raïssa Ntentie Boris Ronald Tonou Tchuente Maxwell Wandji Nguedjo Boris Gabin Kingue Azantsa julius enyong oben Laboratory of Nutrition and Nutritional Biochemistry Department of Biochemistry Faculty of Science University of Yaoundé I Yaounde Cameroon Higher Teacher’s and Training College University of Maroua Maroua Cameroon Centre for Food and Nutrition Research IMPM Ministry of Scientific Research and Innovation Yaounde Cameroon

Background: Malnutrition due to poor feeding habits, is still a serious public health issue in Cameroon. The objective of this study was to assess the dietary patterns and nutritional status of women of childbearing age in various geographical settings in Cameroon so as to propose intervention strategies. Methods: In a cross sectional study conducted from January 2014 to August 2015, women aged 14 - 49 years were randomly selected from the capital city Yaounde and four regions of Cameroon. Anthropometric measures were collected for nutritional status assessment. Data on diet habits and socio-demographic parameters were collected. Results: 608 women of reproductive age with average age 34.68 ± 0.39 years made up the study. Dietary patterns assessment revealed that, most study participants had a frequent intake of carbohydrate rich foods and fats and oils rich foods;but an infrequent intake of protein rich foods and vitamin and minerals rich foods in a week. Nutritional status assessment revealed that, 2.1% were underweight, 28.6% had a normal weight, 30.8% overweight, and 38.5% obese. The grass field regions presented the highest prevalence of underweight, overweight and obesity. Higher malnutrition levels were linked to low intakes of pulses and beans;milk and dairy products;vegetables and fruits food groups. Conclusion: Women of the study population had an unhealthy dietary pattern and a poor nutritional status. Therefore, strategies such as nutritional education are warranted and should be age and region specific, so as to target specific groups of women and ensure adequate nutritional status and health.

关键词： Diet Pattern Nutritional Status Childbearing Age Women Cameroon

Understanding electricity prices beyond the merit order principle using explainable AI

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energy and AI 2023年第3期13卷 149-159页

作者： julius Trebbien Leonardo Rydin Gorjao Aaron Praktiknjo Benjamin Schafer Dirk Witthaut Forschungszentrum Julich Institute for Energy and Climate Research–Systems Analysis and Technology Evaluation(IEK-STE)52428 JülichGermany University of Cologne Institute for Theoretical PhysicsZülpicher Str.7750937 CologneGermany Faculty of Science and Technology Norwegian University of Life Sciences1432 AsNorway Chair for energy System economics Institute for Future Energy Consumer Needs and Behavior(FCN)E.ON Energy Research CenterRWTH Aachen UniversityMathieustr.1052074 AachenGermany Institute for Automation and Applied Informatics Karlsruhe Institute of Technology76344 Eggenstein-LeopoldshafenGermany JARA-eNeRGY 52074 AachenGermany

electricity prices in liberalized markets are determined by the supply and demand for electric power,which are in turn driven by various external influences that vary strongly in *** perfect competition,the merit order principle describes that dispatchable power plants enter the market in the order of their marginal costs to meet the residual load,*** difference of load and renewable *** market models are based on this principle when attempting to predict electricity prices,yet the principle is fraught with assumptions and simplifications and thus is limited in accurately predicting *** this article,we present an explainable machine learning model for the electricity prices on the German day-ahead market which foregoes of the aforementioned assumptions of the merit order *** model is designed for an ex-post analysis of prices and builds on various external *** SHapley Additive exPlanation(SHAP)values we disentangle the role of the different features and quantify their importance from empiric data,and therein circumvent the limitations inherent to the merit order *** show that load,wind and solar generation are the central external features driving prices,as expected,wherein wind generation affects prices more than solar ***,fuel prices also highly affect prices,and do so in a nontrivial ***,large generation ramps are correlated with high prices due to the limited flexibility of nuclear and lignite ***,we offer a model that describes the influence of the main drivers of electricity prices in Germany,taking us a step beyond the limited merit order principle in explaining the drivers of electricity prices and their relation to each other.

关键词： electricity prices Merit order principle explainable artificial intelligence Machine learning Fuel prices energy market

Monolithic ultrasound fingerprint sensor

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Microsystems & Nanoengineering 2017年第1期3卷 37-44页

作者： Xiaoyue Jiang Yipeng Lu Hao-Yen Tang julius M.Tsai eldwin J.Ng Michael J.Daneman Bernhard e.Boser David A.Horsley Department of Mechanical engineering University of CaliforniaBerkeleyCA 94720USA Department of Mechanical and Aerospace engineering University of CaliforniaDavisCA 95616USA Department of electrical engineering and Computer Sciences University of CaliforniaBerkeleyCA 94720USA Invensense Inc. San JoseCA 95110USA

This paper presents a 591×438-DPI ultrasonic fingerprint *** sensor is based on a piezoelectric micromachined ultrasonic transducer(PMUT)array that is bonded at wafer-level to complementary metal oxide semiconductor(CMOS)signal processing electronics to produce a pulse-echo ultrasonic imager on a *** meet the 500-DPI standard for consumer fingerprint sensors,the PMUT pitch was reduced by approximately a factor of two relative to an earlier *** conducted a systematic design study of the individual PMUT and array to achieve this scaling while maintaining a high *** resulting 110×56-PMUT array,composed of 30×43-μm^(2) rectangular PMUTs,achieved a 51.7% fill-factor,three times greater than that of the previous *** with the custom CMOS ASIC,the sensor achieves 2 mV kPa^(−1) sensitivity,15 kPa pressure output,75μm lateral resolution,and 150μm axial resolution in a 4.6 mm×3.2 mm *** the best of our knowledge,we have demonstrated the first MeMS ultrasonic fingerprint sensor capable of imaging epidermis and sub-surface layer fingerprints.

关键词： piezoelectric micromachined ultrasonic transducer(PMUT) fingerprint sensors ultrasound

Metabolic Abnormalities and Metabolic Syndrome among Cameroonian Women: Comparative Study between Pre- and Post-Menopausal Women

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Journal of Biosciences and Medicines 2020年第7期8卷 76-89页

作者： Françoise Raïssa Ntentie Mary-Ann Angie Mbong Maxwell Wandji Nguedjo Boris Rornald Tonou Tchuenté Ousmane Mfopou Mboindi Boris Gabin Kingue Azantsa Judith Laure Ngondi julius enyong oben Department of earth and Life Sciences Higher Teachers’ Training College University of Maroua Maroua Cameroon Laboratory of Nutrition and Nutritional Biochemistry Department of Biochemistry University of Yaounde 1 Yaounde Cameroon Centre for Food and Nutrition Research Institute of Medical Research and Medicinal Plants Study Ministry of Scientific Research and Innovation Yaounde Cameroon

The high prevalence of non-communicable diseases is a challenging problem in the Cameroonian population and women are the most affected. The aim of the present study was to determine and compare the prevalence of metabolic abnormalities and metabolic syndrome (MetS) among pre- and post-men- opausal women living in urban areas in Cameroon. A total of 499 women were recruited during a mass health campaign in 2018. Metabolic abnormalities were diagnosed using International Diabetes Federation (IDF) criteria. MetS was defined using IDF criteria with slight modification (total cholesterol used instead of HDL cholesterol). Logistic regression was used to estimate the association between menopausal status and metabolic abnormalities and MetS in age control and non-control models. The prevalence of high waist- to-hip ratio (56.8% vs 36.3%, p elevated fasting blood glucose (glycemia ≥ 100 mg/dL) (38.7% vs 26.9%, p = 0.006);diabetes (14.6% vs 5.7%, p = 0.001);high triglycerides level (29.7% vs 17.1%, p = 0.002);hyperlipidemia (high total cholesterol and or triglycerides levels) (45.0% vs 30.8%, p = 0.002);and elevated blood pressure (67.9% vs 56.1%, p = 0.007) were higher among post-menopausal than pre-menopausal women. The overall prevalence of MetS was 30.1% and post-menopausal women were more affected (33.8% vs 25.0%;p = 0.034). The odds ratio of MetS was 1.888 (95% CI: 1.016 - 3.507) when age was covariate, but was slightly reduced without age control (OR = 1.532;95% CI: 1.031 - 2.275). Metabolic abnormalities seem to be a major health problem among Cameroonian women and menopausal status increased the risk of developing a cardiovascular event.

关键词： Metabolic Abnormalities MetS Menopausal Status Cameroonian Women

Characterization of Dyslipidemia and Assessment of Atherogenic Risk amongst Cameroonian Living in Yaounde: A Cross Sectional Study

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Journal of Biosciences and Medicines 2019年第7期7卷 35-50页

作者： Huguette Cecile Mafo Yangoua Boris Gabin Kingue Azantsa Dieudonne Kuate Fran&ccedil oise Raissa Ntentie Maxwell Wandji Nguedjo Jacob Tchinda Nkougni Boris Ronald Tonou Tchuente Judith Laure Ngondi julius oben Laboratory of Nutrition and Nutritional Biochemistry Department of Biochemistry Faculty of Science University of Yaounde 1 Yaounde Cameroon Centre for Food and Nutrition Research IMPM Ministry of Scientific Research and Innovation Yaounde Cameroon Department of Biochemistry Faculty of Science University of Dschang Dschang Cameroon Higher Teaching’ Training College University of Maroua Maroua Cameroon

Background: This study was conducted to evaluate the lipid profile in nutritional categories, to characterize dyslipidemia and assess cardiovascular risk, to describe association between anthropometric markers, incidence of dyslipidemia and cardiovascular risk in Cameroonian adults. Methods: A cross-sectional survey was conducted in Yaoundé from April 2014-June 2015. It included 1986 individuals, aged 20 - 65 years, both males (30.7%) and females (69.3%). Blood pressure, anthropometric measurement including weight, height, body fat, waist and hip circumference were performed. BMI was used to define nutritional status. Blood analysis included total cholesterol, HDL-cholesterol and triglycerides, insulin. Dyslipidemia was defined as hypercholesterolemia, hypertriglyceridemia, low HDL-cholesterolemia and combined dyslipidemia. Atherogenic indexes were calculated for assessment of the cardiovascular risk. Results: Out of the 1986 participants, 544 (27.4%), 616 (31%), and 826 (41.6%) were normal weight, overweight and obese respectively. In obese, lipid profile varied according to gender (p 5) was (40.50%). Low HDL-cholesterolemia (75.4%) was the main lipid abnormality found, independently of gender, age, fat location. Waist circumference (WC) unlike body mass index (BMI) and body fatness was associated to hypercholesterolemia. Conclusion: Low HDL-cholesterolemia and high atherogenic risk profile are more prevalent amongst Cameroonian adults. Promotion of healthy lifestyle including good eating habits shall be encouraged to reduce mortality from cardiovascular disease complications.

关键词： Dyslipidemia Obesity Atherognic Risk Lipid Markers Cameroon