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Osteocyte morphology and orientation in relation to strain in the jaw bone

International Journal of Oral Science 2018年第1期10卷 36-43页

作者： Vivian Wu René F. M. van Oers Engelbert A. J. M. Schulten marco no helder Rommel G. Bacabac Jenneke Klein-Nulend Department of Oral Cell Biology Academic Centre for Dentistry Amsterdam (ACTA) Amsterdam Movement Sciences University of Amsterdam and Vrije Universiteit Amsterdam Amsterdam The Netherlands Department of Dental Materials Science Academic Centre for Dentistry Amsterdam (ACTA) Amsterdam Movement Sciences University of Amsterdam and Vrije Universiteit Amsterdam Amsterdam The Netherlands Department of Oral and Maxillofacial Surgery VU University Medical Center/Academic Centre for Dentistry Amsterdam (ACTA) Amsterdam Movement Sciences Amsterdam The Netherlands Department of Physics Medical Biophysics Group University of San Carlos Cebu City Philippines

Bone mass is important for dental implant success and is regulated by mechanoresponsive osteocytes. We aimed to investigate the relationship between the levels and orientation of tensile strain and morphology and orientation of osteocytes at different dental implant positions in the maxillary bone. Bone biopsies were retrieved from eight patients who underwent maxillary sinus-floor elevation with β-tricalcium phosphate prior to implant placement. Gap versus free-ending locations were compared using 1) a three-dimensional finite-element model of the maxilla to predict the tensile strain magnitude and direction and 2) histology and histomorphometric analyses. The finite-element model predicted larger, differently directed tensile strains in the gap versus freeending locations. The mean percentage of mineralised residual native-tissue volume, osteocyte number(mean ± standard deviations:97 ± 40/region-of-interest), and osteocyte shape(90% elongated,10% round) were similar for both locations. However, the osteocyte surface area was 1.5-times larger in the gap than in the free-ending locations, and the elongated osteocytes in these locations were more cranially caudally oriented. In conclusion, significant differences in the osteocyte surface area and orientation seem to exist locally in the maxillary bone, which may be related to the tensile strain magnitude and orientation. This might reflect local differences in the osteocyte mechanosensitivity and bone quality, suggesting differences in dental implant success based on the location in the maxilla.

关键词： SINUS FLOOR ELEVATION MINERAL DENSITY MAXILLARY HISTOMORPHOMETRY TOMOGRAPHY IMPLANTS SPINE

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There is more to the knee joint than just the quadriceps:A systematic review with meta-analysis and evidence gap map of hamstring strength,flexibility,and morphology in individuals with gradual-onset knee disorders

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Journal of Sport and Health Science 2024年第4期13卷 521-536页

作者： helder S.Lopes Marina C.Waiteman Liliam B.Priore Neal R.Glaviano David M.Bazett-Jones Ronaldo V.Briani Fabio M.Azevedo School of Science and Technology Physical Therapy DepartmentSao Paulo State University(UNESP)Presidente Prudente 19060-900Brazil Department of Kinesiology College of AgricultureHealth and Natural ResourcesUniversity of ConnecticutStorrsCT 06269USA School of Exercise and Rehabilitation Sciences College of Health and Human ServicesUniversity of ToledoToledoOH 43606USA

Background:Impairments in hamstring strength,flexibility,and morphology have been associated with altered knee biomechanics,pain,and *** the presence of these impairments in individuals with gradual-onset knee disorders is important and may indicate targets for assessment and *** systematic review aimed to synthesize the literature to determine the presence of impairments in hamstring strength,flexibility,and morphology in individuals with gradual-onset knee ***:Five databases(MEDLINE,Embase,CINAHL,SPORTDiscus,and Web of Science)were searched from inception to September *** studies comparing hamstring outcomes(e.g.,strength,flexibility,and/or morphology)between individuals with gradual-onset knee disorders and their unaffected limbs or pain-free controls were ***-analyses for each knee disorder were ***-level certainty was assessed using the Grading of Recommendations Assessment,Development,and Evaluation,and evidence gap maps were ***:Seventy-nine studies across 4 different gradual-onset knee disorders(i.e.,knee osteoarthritis(OA),patellofemoral pain(PFP),chondromalacia patellae,and patellar tendinopathy)were *** with knee OA presented with reduced hamstring strength compared to pain-free controls during isometric(standard mean difference(SMD)=-0.76,95%confidence interval(95%CI):-1.32 to-0.21)and concentric contractions(SMD=-0.97,95%CI:-1.49 to-0.45).Individuals with PFP presented with reduced hamstring strength compared to painfree controls during isometric(SMD=-0.48,95%CI:-0.82 to-0.14),concentric(SMD=-1.07,95%CI:-2.08 to-0.06),and eccentric contractions(SMD=-0.59,95%CI:-0.97 to-0.21).No differences were observed in individuals with patellar *** with PFP presented with reduced hamstring flexibility when compared to pain-free controls(SMD=-0.76,95%CI:-1.15 to-0.36).Evidence gap maps identified insufficient evidence for chondromalacia patel

关键词： Chondromalacia patellae Knee flexors Knee osteoarthritis Patellar tendinopathy Patellofemoral pain

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脂肪来源的干细胞单培养或与人脐带血静脉内皮细胞共培养:体外和大鼠颅骨缺损的体内成骨研究

脂肪来源的干细胞单培养或与人脐带血静脉内皮细胞共培养:体外和...

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中华口腔医学会口腔修复学专业委员会第十次全国口腔修复学术大会

作者：马金玲 SanneK Both 纪伟阳芳 Henk-Jan Prins marco N helder 潘巨利陈溯崔福斋 John A Jansen Jeroen JJP van den Beucken Radboud University Nijmegen Medical Center 首都医科大学附属北京口腔医院武汉大学口腔医学院 Academic Centre for Dentistry Amsterdam University of Amsterdam VU University Amsterdam VU University Medical Center/ACTA VU University Medical Center 清华大学材料科学与工程系

目的:口腔种植是当今修复牙缺失的热门方法,然而,口腔种植中经常存在骨量不足的问题。组织工程技术是当今的热门话题,本研究的目的是比较脂肪来源的干细胞(AT-MSCs)单培养或其与人脐带血静脉内皮细胞(HUVECs)共培养的体外和体内成骨能... 详细信息

目的:口腔种植是当今修复牙缺失的热门方法,然而,口腔种植中经常存在骨量不足的问题。组织工程技术是当今的热门话题,本研究的目的是比较脂肪来源的干细胞(AT-MSCs)单培养或其与人脐带血静脉内皮细胞(HUVECs)共培养的体外和体内成骨能力研究。方法:首先,通过把AT-MSCs和HUVECs以不同的比例(100:0:100)接种在细胞培养板上来确定成骨方向分化共培养的最佳细胞比例。之后,AT-MSCs单培养或AT-MSCs/HUVECs(50:50)共培养组被接种于多孔钛纤维网状支架上(Ti)进行体外和体内成骨能力研究。体外,碱性磷酸酶活性和钙含量被用来评估细胞的成骨分化潜能。体内,上述支架材料被移植于大鼠双侧颅骨缺损(5mm直径)中,8周后组织学和定量组织学评估骨形成情况。结果:50:50是共培养的最佳比例,因为此种比例可以用最少的AT-MSCs获得与其他共培养组相似的钙含量。其次,体外研究表明AT-MSCs单培养组的成骨能力优于ATMSCs/HUVECs共培养组。最后,在大鼠颅骨缺损模型中,AT-MSCs的成骨能力优于AT-MSCs/HUVECs。结论:在体外和体内研究中都发现,AT-MSCs的成骨能力优于AT-MSCs/HUVECs。本研究结果为未来口腔种植骨缺损修复的骨组织工程研究方向提供了参考。

关键词：骨再生脂肪干细胞共培养大鼠颅骨缺损

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The effect of drying of Piper hispidinervium bydifferent methods and its influence on the yield ofessential oil and safrole

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Information Processing in Agriculture 2023年第1期10卷 28-39页

作者： helder Kiyoshi Miyagawa Alberdan Silva Santos Systematic Investigation in Biotechnology and Molecular Biodiversity Laboratory Federal University of Para´Bele´m 66075-110PABrazil

The Piper hispidinervium leaves and thin stems were dried under laboratory and field *** drying was performed using a shade dryer operating with and without forced convection and an oven dryer operating at 30 and 40*** experiments were conducted using solar dryers with three different covers,i.e.,transparent,black plastic,and palm straw *** essential oil extraction was performed by steam distillation,and the safrole content was analyzed by gas *** mathematical models(Page,logarithmic,Henderson and Pabis,fractional,and diffusion)were fitted with the experimental data and compared based on the coefficient of determination(R2),root mean square error(RMSE)and *** suggest that the best model was the logarithmic model(R2>0.99,RMSE<0.0005,and v2<0.005).With sufficient drying,the safrole content increased up to 95%of the extracted oil;however,when the drying time was prolonged,both the oil yield and safrole content of the extracted oil decreased.

关键词： Modeling Drying kinetics Essential oil extraction Safrole extraction Piperaceae

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Use of self-organizing suppression and q-Gaussian mutation in artificial immune systems

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International Journal of Intelligent Computing and Cybernetics 2013年第3期6卷 296-322页

作者： helder Ken Shimo Renato Tinòs Department of Computing and Mathematics University of Sa˜o PauloSa˜o PauloBrazil

Purpose-The purpose of this paper is to propose two operators for diversity and mutation control in artificial immune systems(AISs).Design/methodology/approach-The proposed operators are applied in substitution to the suppression and mutation operators used in *** proposed mechanisms were tested in the opt-aiNet,a continuous optimization algorithm inspired in the theories of *** traditional opt-aiNet uses a suppression operator based on the immune network principles to remove similar cells and add random ones to control the diversity of the *** procedure is computationally expensive,as the Euclidean distances between every possible pair of candidate solutions must be *** work proposes a self-organizing suppression mechanism inspired by the self-organizing criticality(SOC)phenomenon,which is less dependent on parameter *** work also proposes the use of the q-Gaussian mutation,which allows controlling the form of the mutation distribution during the optimization *** algorithms were tested in a well-known benchmark for continuous optimization and in a bioinformatics problem:the rigid docking of ***-The proposed suppression operator presented some limitations in unimodal functions,but some interesting results were found in some highly multimodal *** proposed q-Gaussian mutation presented good performance in most of the test cases of the benchmark,and also in the docking ***/value-First,the self-organizing suppression operator was able to reduce the complexity of the suppression stage in the ***,the use of q-Gaussian mutation in AISs presented better compromise between exploitation and exploration of the search space and,as a consequence,a better performance when compared to the traditional Gaussian mutation.

关键词： Artificial immune system Evolutionary computation Self-adjusting systems

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Forecasting and trading cryptocurrencies with machine learning under changing market conditions

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Financial Innovation 2021年第1期7卷 61-90页

作者： helder Sebastiao Pedro Godinho Univ Coimbra CeBERFaculty of EconomicsAv.Dr.Dias da Silva1653004‑512 CoimbraPortugal

This study examines the predictability of three major cryptocurrencies—bitcoin,ethereum,and litecoin—and the profitability of trading strategies devised upon machine learning techniques(e.g.,linear models,random forests,and support vector machines).The models are validated in a period characterized by unprecedented turmoil and tested in a period of bear markets,allowing the assessment of whether the predictions are good even when the market direction changes between the validation and test *** classification and regression methods use attributes from trading and network activity for the period from August 15,2015 to March 03,2019,with the test sample beginning on April 13,*** the test period,five out of 18 individual models have success rates of less than 50%.The trading strategies are built on model *** ensemble assuming that five models produce identical signals(Ensemble 5)achieves the best performance for ethereum and litecoin,with annualized Sharpe ratios of 80.17%and 91.35%and annualized returns(after proportional round-trip trading costs of 0.5%)of 9.62%and 5.73%,*** positive results support the claim that machine learning provides robust techniques for exploring the predictability of cryptocurrencies and for devising profitable trading strategies in these markets,even under adverse market conditions.

关键词： Bitcoin Ethereum Litecoin Machine learning Forecasting Trading

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Identification and Characterization of Natural Anti-breast Cancer Compound:Costunolide

Identification and Characterization of Natural Anti-breast C...

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作者： helder OLIVEIRA 东北师范大学

学位级别：硕士

乳腺癌是女性最常见的恶性肿瘤之一,在新增癌症病例中占23%。乳腺癌在女性癌症患者中的致死率位居第二位,仅次于肺癌。天然化合物与合成化合物相比具有低毒的特点,是许多疾病的治疗药物生产的最初来源。木香烯内酯是一种倍半萜内酯,由... 详细信息

乳腺癌是女性最常见的恶性肿瘤之一,在新增癌症病例中占23%。乳腺癌在女性癌症患者中的致死率位居第二位,仅次于肺癌。天然化合物与合成化合物相比具有低毒的特点,是许多疾病的治疗药物生产的最初来源。木香烯内酯是一种倍半萜内酯,由多种植物化学成分组成,通过细胞毒素作用对多种癌细胞发挥抗癌效应;但木香烯内酯在乳腺癌治疗中的可能作用尚不明确。本研究旨在探索天然化合物对MCF7细胞增殖的影响,研究ROS在由天然化合物诱导的乳腺癌细胞凋亡中潜在的治疗作用。我们首先检测了木香烯内酯对乳腺癌MCF7细胞增殖的影响,并证明其具有高效的抗癌能力。我们发现,木香烯内酯的IC50值为50μM,是强有力的细胞增殖抑制剂。利用荧光探针钙绿化素AV/PI活体实验,我们发现木香烯内酯对MCF细胞的增殖抑制和凋亡诱导效应,降低了 MCF-7细胞在剂量依赖下的生存能力。为了研究木香烯内酯诱导的细胞凋亡,我们采用了流式细胞检测技术。结果显示,在剂量依赖下,木香烯内酯诱导乳腺癌MCF7细胞凋亡。由于ROS的过度表达会诱导氧化压力,导致细胞功能丧失和细胞凋亡。因此,我们利用荧光染色的ROS追踪素—双氯荧光乙酸乙酯来检测细胞内ROS水平,并发现木香烯内酯显著提高ROS水平。有趣的是,细胞被一种特殊的ROS抑制剂乙酰半胱氨酸预处理之后,ROS介导的细胞凋亡效应被消除。所以在本研究中,我们证明木香烯内酯通过提高ROS水平,进而诱导细胞凋亡。然后我们研究了木香烯内酯作为外源诱导剂对乳腺癌MCF7细胞凋亡的影响。通过流式细胞检测技术和蛋白质免疫印记分析了 DNA成分和细胞凋亡相关的蛋白质表达水平。在乳腺癌MCF7细胞中,我们检测了木香烯内酯对凋亡外源途径(死亡受体途径)激活及对凋亡效应蛋白质Caspase-3和PARP的活化作用。结果显示,在25uM和50uM木香烯内酯处理的细胞中,蛋白质Caspase-3分裂为一个17kDa和一个20kDa的片段,蛋白质PARP也被活化剪切。在此基础上,我们进一步检测了木香烯内酯乳腺癌MCF7细胞凋亡过程中对凋亡内源途径(线粒体途径)的激活效应。我们检测了线粒体凋亡途径中抗凋亡蛋白质BcL2和促凋亡蛋白Bax的表达水平,并证明木香烯内酯可下调BcL2蛋白表达和上调Bax蛋白表达,从而证明木香烯内酯通过活化两种凋亡途径从而诱导乳腺癌MCF7细胞产生凋亡。我们的研究结果表明,木香烯内酯对乳腺癌细胞具有增殖抑制和凋亡促进效应,为人类癌症治疗提供了一种可能的新策略。

关键词：乳腺癌木香烯内酯细胞凋亡活性氧

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Industry return lead‑lag relationships between the US and other major countries

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Financial Innovation 2023年第1期9卷 1055-1102页

作者： Ana Monteiro Nuno Silva helder Sebastiao CeBER Faculty of EconomicsUniv CoimbraAv Dias da Silva 1653004‑512 CoimbraPortugal

In this study,we analyze the lead-lag relationships between the US industry index and those of six other major countries from January 1973 to May *** identify the leading role played by the US internationally by showing that the weekly returns of US industries,especially the US basic materials and energy industries,significantly Granger cause the returns of most other countries’industries,suggesting that non-US industries react with some delay to new *** delayed reaction is even more notice-able during periods of recession in the US when cross-country correlations are *** implies that the ability of the lagged returns of US industries to predict industries’returns from other countries is even more pronounced when the US experienced an economic recession.A similar asymmetric relationship is found between the volatil-ity of US industries and that of industries in other *** analysis of causality in the distribution of returns and volatility shows that causality runs mainly from the US to other countries,particularly in the presence of extreme negative ***,we demonstrate that our predictions are valuable to real-world ***-short strategies generate sizable and statistically significant alphas,and a constant relative risk-averse investor obtains certainty equivalent returns well above the risk-free rate.

关键词： International diversification Industry equity indexes Granger causality Causality in distribution

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Nanoparticles-based phototherapy systems for cancer treatment: Current status and clinical potential

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Bioactive Materials 2023年第5期23卷 471-507页

作者： Jiachen Li Shiqi Wang Flavia Fontana Christos Tapeinos Mohammad-Ali Shahbazi Huijie Han helder A.Santos Department of Biomedical Engineering W.J.Kolff Institute for Biomedical Engineering and Materials ScienceUniversity Medical Center GroningenUniversity of GroningenAnt.Deusinglaan 1Groningen9713 AVthe Netherlands W.J.Kolff Institute for Biomedical Engineering and Materials Science University Medical Center GroningenUniversity of GroningenUniversity of GroningenAntonius Deusinglaan 19713 AVGroningenthe Netherlands Drug Research Program Division of Pharmaceutical Chemistry and Technology Faculty of PharmacyUniversity of HelsinkiHelsinkiFI-00014Finland

Remarkable progress in phototherapy has been made in recent decades,due to its non-invasiveness and instant therapeutic *** addition,with the rapid development of nanoscience and nanotechnology,phototherapy systems based on nanoparticles or nanocomposites also evolved as an emerging hotspot in nanomedicine research,especially in *** this review,first we briefly introduce the history of phototherapy,and the mechanisms of phototherapy in cancer ***,we summarize the representative development over the past three to five years in nanoparticle-based phototherapy and highlight the design of the innovative nanoparticles ***,we discuss the feasibility and the potential of the nanoparticle-based phototherapy systems in clinical anticancer therapeutic applications,aiming to predict future research directions in this *** review is a tutorial work,aiming at providing useful insights to researchers in the field of nanotechnology,nanoscience and cancer.

关键词： Phototherapy Cancer Nanoparticles Therapeutic effect Clinical potential

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基于激光雷达的移动机器人实时位姿估计方法研究

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自动化学报 2004年第5期30卷 679-687页

作者：杨明董斌王宏张钹 helder Araújo 清华大学智能技术与系统国家重点实验室北京100084 葡萄牙Coimbra大学系统与机器人研究所

位姿估计是移动机器人研究中的一个关键问题,对于运动目标跟踪、机器人导航、地图生成等具有重要意义.提出了一种基于二维激光雷达的实时位姿估计方法,包括基于Hough变换的切线角度直方图算法和迭代切线加权最近点算法两部分.两种算法... 详细信息

位姿估计是移动机器人研究中的一个关键问题,对于运动目标跟踪、机器人导航、地图生成等具有重要意义.提出了一种基于二维激光雷达的实时位姿估计方法,包括基于Hough变换的切线角度直方图算法和迭代切线加权最近点算法两部分.两种算法的结合和切线信息的引入,有效地解决了传统方法无法解决的局部最小值、类孔径、大计算量等问题.仿真数据和室外环境实际数据的大量实验结果表明它具有精度高、速度快、适用性广和对噪声、遮挡和类孔径问题鲁棒性高的特点.

关键词：位姿估计角度直方图迭代最近点切线信息移动机器人激光雷达

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