bluuebunny/crossref_metadata_2025 huggingface dataset:
A Digital Perspective on Machine Tool Calibration
Authors: Montavon Benjamin ,   Laboratory for Machine Tools and Production Engineering (WZL), RWTH Aachen University Campus-Boulevard 30, Aachen 52074, Germany, Dahlem Philipp , Peterek Martin , Schmitt Robert H.
Published: May 2020

Machine tool calibration and subsequent controller-based compensation are industrially established and research-intensive techniques used to monitor and increase the volumetric performance in high-precision manufacturing. Moreover, a variety of interim performance checks and integrated sensor approaches have been developed to predict volumetric performance degradation and avoid an economically undesirable downtime. However, the fragmentation of data acquisition and management limits the potential for additional insights with respect to the value creation based on existing methods in the field of machine tool calibration. The authors reviewed the former from the perspective of data sources according to the frequency of their contribution to the digital twin of a machine tool, adopting a digital view regarding machine tool calibration within theInternet of Productionconcept. The latter proposes a semantic separation of cyber physical production systems into four layers: data sources, data access and provisioning, storage and analytics, and user respective agent feedback. To achieve a common representation across different layers, devices, and industrial Internet protocols, a model-based abstraction layer is required, which must be compatible with existing standards within the field, e.g., the ISO 230 series. Utilizing different Internet of Production architectures and platforms, a multitude of parallel analytic applications and an evaluation of complex models are enabled owing to the availability of ample computing resources, among which the machine tool’s numerical controller takes the role of an edge-device injecting the feedback into the production process. A proof-of-concept of a digital approach to machine tool calibration data storage and processing was established based on the software prototypeVoluSoft, which implements an ISO 230-1:2012 based abstraction layer in JavaScript Object Notation format, and an evaluation of the kinematic models to estimate the volumetric performance at the functional point. Apart from generating compensation tables, the results are used to project the expected deviation at the tool tip to the computer-aided design-model of a work piece, correlate the error motions using the temperature data acquired by integrated sensors, and estimate the contribution of the volumetric performance limitation to the uncertainty budget of on-machine measurements.
Impact of Model Complexity in the Monitoring of Machine Tools Condition Using Volumetric Errors
Authors: Xing Kanglin ,   Department of Mechanical Engineering, Polytechnique Montréal 2500 Chemin de Polytechnique, Montréal, Québec H3T 1J4, Canada, Mayer J. R. R. , Achiche Sofiane
Published: May 2020

The scale and master ball artefact (SAMBA) method allows estimating the inter- and intra-axis error parameters as well as volumetric errors (VEs) of a five-axis machine tool by using simple ball artefacts and the machine tool’s own touch-trigger probe. The SAMBA method can use two different machine error models named after the number of model parameters, i.e., the “13” and “84” machine error models, to estimate the VEs. In this study, we compare these two machine error models when using VE vector directions and values for monitoring the machine tool condition for three cases of machine malfunctions: 1) a C-axis encoder fault, 2) an induced X-axis linear positioning error, and 3) an induced straightness error simulated fault. The results show that the “13” machine error model produces more focused concentrated VE directions but smaller VE values when compared with the “84” machine error model; furthermore, although both models can recognize the three faults and are effective in monitoring the machine tool condition, the “13” machine error model achieves a better recognition rate of the machine condition. This paper provides guidelines for selecting machine error models for the SAMBA method when using VEs to monitor the machine tool condition.
Automating Accuracy Evaluation of 5-Axis Machine Tools
Authors: Florussen Guido ,   IBS Precision Engineering BV 201 Esp, Eindhoven 5633AD, Netherlands, Houben Koen , Spaan Henny , Spaan-Burke Theresa
Published: May 2020

A wireless non-contact 3D measuring head is used to determine the accuracy of 5-axis machine tools. The measuring head is inserted in the spindle by the tool exchanger automating the measurement routine used. For checking the linear machine axes, a cross shaped artefact containing 13 precision balls is introduced, named Position Inspector, enabling the determination of positioning and straightness errors of two linear axes in one setup. The squareness error between both axes is also determined in this setup. This artefact can be mounted on a pallet system for automatic loading and is measured in a bi-directional run. This artefact can be measured in different orientations (i.e., horizontal, inclined, vertical) and is pre-calibrated with a CMM. The measurement sequence using this artefact is executed in eight minutes and its design and support system is addressed in this paper. The location errors and orientation errors of the axis average line (or pivot line) of both rotary axes are determined with the Rotary Inspector using the same measuring head with a single precision ball. For this, kinematic tests are used from ISO10791-6, e.g., the BK1 test, BK2 test which apply for trunnion or swivel table machines. Derived parameters can be used for machine correction resulting in a significantly improved machine accuracy. An example is given where this correction is performed automatically by implementing this measurement system in the machine’s controller. Finally the machine tool is tested using the BK4 test. For this test all 5-axes are moved simultaneously and the measured displacements between the machine’s spindle and table in X-, Y-, and Z-directions are compared to tolerance levels. This final test reveals the machine’s overall accuracy and dynamic behavior.
Development of Scanning Line Tool Path Generation Algorithm Using Boundary Position Information of Approximate Polyhedron of Complex Molds
Authors: Saito Yuki ,   Saitama University 255 Shimo-okubo, Sakura-ku, Saitama City, Saitama 338-8570, Japan, Kaneko Jun’ichi , Abe Takeyuki , Horio Kenichiro
Published: May 2020

In the manufacturing industry, molds are required for mass production operations, and the industry’s recent small lot, multi-product production systems call for such molds to be made by NC machine tools in short periods of time. The tool path point coordinates of NC machine tools are derived by geometric computations, which are used in turn to derive the polyhedron-approximated mold surface and the contact positions of the tool. In the conventional method, however, placing surplus tool path points on the planar section makes it difficult to acquire the boundary position coordinate values in the vicinity of the boundaries of the polyhedrons that constitute the curved surface, resulting in errors in the path point coordinates for the polyhedron-approximated shape of the mold surface. In this study, therefore, we have developed CAM algorithms that can reduce the tool path errors and suppress the number of tool path points by not deriving the path point coordinates in the linearly approximated section. This is done by using the boundary information of the approximate polyhedrons that constitute the concave section of the mold model.
Hilbert-Huang Transform Analysis of Machining Stability in Ball-Nose End-Milling of Curved Surface
Authors: Azka Muizuddin , Yamada Keiji , Huda Mahfudz Al , Mani Kyosuke , Tanaka Ryutaro , Sekiya Katsuhiko ,   Graduate School of Engineering, Hiroshima University 1-4-1 Kagamiyama, Higashi-hiroshima, Hiroshima 739-8527, Japan,   Agency for the Assessment and Application of Technology (BPPT), Central Jakarta, Indonesia,   Ground Systems Research Center, Acquisition, Technology & Logistics Agency (ATLA), Sagamihara, Japan
Published: May 2020

This paper investigates the machining stability in ball-end-milling of curved surface in which the inclination of tool continuously changes. Initially, the influence of inclination angle is geometrically investigated on the parameters such as immersion angle and cutting velocity. Then, the paper presents the stability lobe diagrams of the process. Curved surface milling is simulated by slot milling on a cylindrical workpiece using a ball-end-mill to obtain the cutting force and vibration, which are used for fast-Fourier transform and Hilbert-Huang transform (HHT) analyses. Experimental results show that the cutting force increases, and the stability becomes worse with the inclination angle, while the machining errors decrease with the inclination. The vibration analysis showed that the HHT can detect the transition from stable to unstable during milling of curved surface in the time-frequency plots.
Development of Tool Shape Estimation Method Integrating Multidirectional Optical Measurement
Authors: Kaneko Mayumi , Kaminaga Takahiro , Kaneko Jun’ichi , Katano Kiyohiko , Abe Takeyuki , Horio Kenichiro ,   Saitama University 255 Shimo-okubo, Sakura-ku, Saitama City, Saitama 338-8570, Japan,   Kuraki Co., Ltd., Nagaoka, Japan
Published: May 2020

Advance avoidance of machine collision by means of computer simulation is now common in NC machining. However, human errors from the tool shape mounted in the machine tool main shaft not matching the simulation data and the actual tool have become a problem. Therefore, in this research, we have developed a high-speed method of comparing the shape of a tool mounted on a machine tool main shaft and an estimated shape in a simulation. This is done by capturing an image of the tool with a camera and estimating the tool shape from multiple images.
Periprosthetic Joint Infection in Patients Who Have Multiple Prostheses in Place
Authors: Komnos George A. , Manrique Jorge , Goswami Karan , Tan Timothy L. , Restrepo Camilo , Sherman Matthew B. , Parvizi Javad
Published: May 2020

Background:

Although periprosthetic joint infection (PJI) can affect multiple joints concurrently, the majority of patients with multiple prosthetic joints present with PJI of a single joint. Data regarding the optimal management of these patients are limited. We aimed to identify the prevalence, risk factors for a subsequent PJI, and clinical circumstances of PJI in patients with multiple prosthetic joints.

Methods:

We retrospectively reviewed the clinical records of 197 patients with ≥2 total joint prostheses in place who presented with PJI from 2000 to 2017. The average follow-up was 3.6 years (range, 0.5 to 17 years). Demographic data and risk factors for synchronous or metachronous PJI were identified. The time from the initial to the second PJI and organism profile data were collected as well. The workup for other joints with a prosthesis in place at the time of the initial PJI was noted.

Results:

Among the 197 patients with PJI and multiple joint prostheses in situ, 37 (19%) developed PJI in another joint; 11 had a synchronous PJI and 26 had a metachronous PJI. The average time between the first and the second infection in the metachronous cases was 848 days (range, 20 to 3,656 days). Females and patients with an initial PJI with methicillin-resistant Staphylococcus aureus (MRSA) were more likely to have a metachronous PJI, and patients with rheumatoid arthritis had an increased risk of a second (metachronous or synchronous) PJI. Three of 11 patients in the synchronous group and 19% (5) of the 26 in the metachronous group had bacteremia at the time of the initial PJI compared with 12% (19) of the 160 with a single PJI. The percentage of negative cultures increased from 10% for the initial PJIs to 38% for the metachronous PJIs.

Conclusions:

Patients who have multiple prosthetic joints in place and present with PJI of a single joint are at risk of developing PJI in another joint. Female sex, rheumatoid arthritis, bacteremia at presentation, and infection with MRSA appear to be risk factors for PJI of another joint. Clinical evaluation of the other prosthetic joint(s) should be carried out in all patients and aspiration of those joint(s) should be considered for patients with any of the above risk factors.

Level of Evidence:

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
Pengaruh Agroekosistem Pertanaman Kopi terhadap Keanekaragaman dan Kelimpahan Semut (Formicidae)
Authors: Susilawati Susilawati , Indriati Gusti
Published: May 2020

Ant (Formicidae: Hymenoptera) is one of the dominant groups of insects and has significant biological and ecological properties. The presence of ants in coffee plantations plays an important role as it functions as a predator. The study aimed to investigate the effect of coffee plantation agroecosystem on the diversity and abundance of ant species. The study was conducted from February to June 2018 at Pakuwon Experimental Station. The coffee plants were divided into 4 groups, based on their locations and agroecosystems, where each group consisted of 4 observation plots. Ants sampling were taken from 15 sample plants in each plot.   Observation was conducted on ants found in the stems, leaves, twigs and fruits of coffee plants. The ants were taken for 5 to 10 minutes from each plant. The differences in coffee agroecosystem were  grouped based on location, altitude, coffee species, shade plant, and vegetation around the observation site. The study found 59 ant morphospecies with a total of 2,535 individuals. The dominant ant was Dolichoderus sp1. There were 4 ant species that were found in all four locations, namely Camponotus sp1., Crematogaster sp1., Dolichoderus sp1., Polyrhachis sp1. which are predatory. The analysis result showed that different coffee agroecosystem affects diversity and abundance of ants.
Programme du Colloque "Des Mouflettes d’Atropos aux Sorcières de la République : le parcours et l’œuvre de Chloé Delaume"
Authors: Cornelio Dawn
Published: May 2020

Les communications et activités du colloque qui a eu lieu à l'University de Guelph en avril 2018.
Ego Hugo : « Hauteville House », de la maison-musée au miroir de l’écrivain
Authors: Bourgeois Bertrand
Published: May 2020

Victor Hugo achète « Hauteville House » en 1856 grâce aux gains des Contemplations et c’est dans cette même demeure qu’il finit Les Misérables en 1862 : « Hauteville House » est donc intrinsèquement liée à sa création littéraire. C’est en outre la première maison dont il est propriétaire et dans laquelle il vivra pendant quinze ans. De 1857 à 1862, il façonne la décoration intérieure de la maison, pour laquelle il fabrique même certains meubles.

Cet article démontre qu’Hugo transforme ce lieu de vie en « maison-musée » qui constitue une autre de ses œuvres d’art, la maison-livre de l’écrivain-architecte. Finalement, Hugo met en scène une véritable architecture du moi dans cette maison-miroir narcissique, car ses initiales et sa signature sont partout inscrites à « Hauteville House ».
La représentation du livre dans Comment faire l’amour avec un Nègre sans se fatiguer de Dany Laferrière
Authors: Basabose Philippe
Published: May 2020

Cet article analyse le premier roman de Dany Laferrière, Comment faire l’amour avec un Nègre sans se fatiguer. Il démontre que lu du point de vue de son architecture narrative, son organisation de l’espace, de la place qu’il accorde à la production, à la circulation et à la réception de l’œuvre artistique, ce roman est une représentation claire de l’objet-livre. Il entend ainsi contribuer à compléter les analyses qui se sont limitées aux facettes subsidiaires de cet élément clé qui donne matière et forme au roman.

 

Mots clés: représentation, objet-livre, architecture narrative, lieux, réception
IMPLEMENTATION OF EDPUZZLE TO IMPROVE STUDENTS’ ANALYTICAL THINKING SKILL IN NARRATIVE TEXT
Authors: Amaliah Amaliah
Published: May 2020

Digital learning has become one of the demands of life to prepare students to become part of global society 5.0. as cultured human being. For this reason, it is very important that students learn to be creative, collaborative, communicative, and able to think critically. However, to achieve those all, the teacher really has to work hard in designing 4C learning. The purpose of this research is to describe the implementation of Edpuzzle to improve the students’analytical thinking skill in Narrative text at SMPN 2 Sidoarjo in the academic year 2018/2019 by using  Edpuzzle in the even semester. The method used in this research is case study. It develops a detail background, case, investigation to solve a problem. The results obtained are: (1) The use of Edpuzzle can improve students’ analytical thinking skill, especially in Narrative text at SMPN 2 Sidoarjo (2) The use of Edpuzzle in the classroom is conducted and implemented with PISA method (Preliminarily, Intensive learning, Self-study and Assessment). This application is specifically used to overcome students' understanding and analytical thinking skills at a higher level. Students also increase their creativity in creating writing content that educates and promotes the Indonesian stories to the international languages.
VLOG AS LEARNING MEDIA TO TRAIN ENGLISH FLUENCY AND PUBLIC SPEAKING SKILL
Authors: Mufidah Zakiyatul , Roifah Miftahur
Published: May 2020

The collaboration of technology and media can have positive effects on teaching and learning. In modern teaching traditions, teachers must include technology into their teaching and must be able to select a suitable media so they can deliver lessons in the classroom effectively and can achieve the learning goal. This study is going to explore and elaborate the effectiveness of incorporating technology in learning process by using a media to get more engaging learning situation and to know its impacts to the students’ learning achievements, especially to their fluency and public speaking skill. To be specific, this study is trying to implement Video Blog (Vlog) as learning media in English speaking subject. The results of the observation show that, training students’ fluency and public speaking by implementing Vlog as learning media give positive impacts to the students. Vlog increases students’ encouragement in speaking. Vlog can provide fun and enjoyable learning process and it can build confidence.
AN ANALYSIS OF IMPLICATURES FOUND IN WHATSAPP STORIES
Authors: Rosyiidah Afiifah Al
Published: May 2020

This study focuses on implicatures found in the WhatsApp stories. This study aims to find and explain types of implicatures found in WhatsApp stories using the theory proposed by Yule (1996). This study employs qualitative design as the research design. In addition, content analysis is applied to obtain the data in which the writer becomes the key instrument of the study. Interactive data analysis, then, is conducted to analyze and explain the data. The data of the study are taken from WhatsApp stories that appears in the writer’s WhatsApp application. This study shows the findings of the types of implicatures. The data are classified into four types of implicatures: generalized conversational implicatures (5 data), particularized conversational implicatures (7 data), scalar implicature (2 data), and conventional implicatures (1 datum).
Efectividad de un programa de fisioterapia multimodal en la capacidad funcional y emocional de adultos mayores con discapacidad intelectual severa
Authors: Arrizabalaga Otaegui Asier
Published: May 2020

Antecedentes: El aumento de la esperanza de vida de las personas con discapacidad intelectual severa acelera un proceso de envejecimiento prematuro que favorece la presencia de un proceso de fragilidad física y psicológica que afecta a la calidad de vida.
Objetivos: Este estudio pretende investigar los efectos de una intervención de fisioterapia multimodal en la capacidad funcional de adultos mayores con discapacidad intelectual. Este estudio se realizó durante seis meses y consistió en la realización de sesiones de masoterapia adaptada, ejercicio físico terapéutico en un entorno natural y fisioterapia acuática.
Método: Ensayo clínico controlado aleatorizado. Los criterios de inclusión fueron ser mayores de 50 años, presentar diagnóstico de discapacidad intelectual severa teniendo en cuenta los criterios de la DSM-V y presentar alto riesgo de presentar demencias según el NTG-EDSD. Los participantes fueron asignados al azar en el grupo experimental y en el grupo control. Las variables físicas se midieron por medio del Test de Alusti Abreviado, 10MWT, 6MWT, TUG, SCPT, las variables psicológicas por medio del NPI-Q y las variables relacionadas con la calidad de vida por medio del QUALID.
Resultados: La muestra final estuvo compuesto por 20 adultos mayores, de los cuales 10 formaron parte del grupo experimental en el cual se obtuvieron diferencias significativas con una p inferior a 0,005, una mejoría en la movilidad (16,5%), en la potencia muscular de la extremidad inferior (90,2%), en el equilibrio dinámico (7,2%), en la capacidad cardio-respiratoria (19,3%), en la velocidad de la marcha (19,4%), en la disminución de los síntomas neuropsiquiátricos (54,45%) y en la mejoría de la calidad de vida (57,8%).
Conclusiones: La intervención de fisioterapia multimodal basada en la combinación de sesiones de terapia manual, sesiones de ejercicio físico en un circuito al aire libre y las sesiones de fisioterapia acuática del programa AquaCap fue capaz de mejorar la capacidad funcional, disminuir los síntomas neuropsiquiátricos mejorando la capacidad de expresión emocional y mejorar la calidad de vida de adultos mayores con discapacidad intelectual grave con alto riesgo de demencias.
Palabras clave: terapia manual, ejercicio físico, fisioterapia acuática, demencia.
Carbonaceous composite materials from calcination of azo dye-adsorbed layered doubled hydroxide with enhanced photocatalytic efficiency for removal of Ibuprofen in water
Authors: Shen Xiaolin , Zhiliang ZHU , Zhang Hua , Di Guanglan , Chen Ting , Qiu Yanling , Yin Daqiang
Published: May 2020

Background: The discard of used adsorbents may pose a great threat to human health and ecological environment. This work herein reported a facile and feasible method, with aims of (i) reusing the calcined layered double hydroxide (CLDH) adsorbent after azo dye adsorption, and (ii) being further used as a photocatalyst to enhance the degradation of typical pharmaceuticals. Calcination under inner gas flow has been utilized to carbonize adsorbed azo dye and a kind of novel carbonaceous CLDH composite material (CM-CLDH) was synthesized. This fabricated material was used as a catalyst for Ibuprofen removal in water samples under simulated sunlight irradiation. Results: According to our experimental results, combination of carbonaceous material with CLDH showed an enhanced photocatalytic performance compared to original CLDH materials. More than 90 % of Ibuprofen could be removed in less than 180 min. Introduction of carbon material narrowed catalyst’s band gap and turned its conduct band potential to a more negative state, which brought considerable light absorption and higher oxidation ability of photo-induced electrons. Furthermore, photoluminescent spectra and transient photocurrent examination confirmed that carbon material suppressed recombination of photo-induced electrons and holes through faster electron transportation. Under experimental conditions, the removal efficiency of Ibuprofen by CM-CLDH composite kept above 90 % during five cycles. Conclusion: Calcination under inner gas flow can transform organic pollutant-adsorbed CLDH to CM-CLDH composite with higher photocatalytic performance. A feasible way to reuse spent LDH adsorbents was proposed, which is benefit to reduce second pollution of spent adsorbents in environment.
Stigma and utilization of treatment for adolescent perinatal depression in Ibadan Nigeria
Authors: Kola Lola , Bennett Ian M , Bhat Amritha , Ayinde Olatunde O. , Oladeji Bibilola D. , Abiona Dolapo , Abdulmalik Jibril , Faregh Neda , Collins Pamela Y. , Gureje Oye
Published: May 2020

Background. Depression is a common and severe disorder among low-income adolescent mothers in low-and middle-income countries where resources for treatment are limited. We wished to identify factors influencing health service utilization for adolescent perinatal depression, in Nigeria to inform new strategies of care delivery.Methods. Focus Group Discussions (FGDs) were conducted among purposively selected low-income young mothers (with medical histories of adolescent perinatal depression), and separately with primary care clinicians treating this condition in Ibadan, Nigeria. Participants from this community-based study were from the database of respondents who participated in a previous randomized control trial (RCT) conducted between 2014 and 2016 in 28 primary health care facilities in the 11 Local government areas in Ibadan. Semi-structured interview guides, framed by themes of the Behavioral Model for Vulnerable Populations, was developed to obtain views of participants on the factors that promote or hinder help-seeking and engagement (see additional files 1 & 2). FGDs were conducted, and saturation of themes was achieved after discussions with six groups. Transcripts were analyzed using content analysis.Results. A total of 42 participants, 17 mothers (who were adolescents at the time of the RCT), and 25 care providers participated in 6 FGDs. The availability of care for perinatal depression at the primary care level was an important enabling factor in healthcare utilization for the adolescents. Perceived health benefits of treatment received for perinatal depression were strong motivation for service use. Significant stigma and negative stereotypes expressed by care providers towards adolescent pregnancy and perinatal depression were obstacles to care. However, individual patient resilience was a major enabling factor, facilitating service engagement. Providers trained in the management of perinatal depression were perceived to deliver more tolerant and supportive care that adolescent mothers valued. Conclusions. Participants identified unsupportive and stigmatizing clinic environments towards pregnant and parenting adolescents as significant barriers to accessing available care. Interventions to reduce stigma among healthcare providers may improve services for this vulnerable population.
Comparison of radiological and clinical outcomes, complications, and implant removals in anatomically pre-contoured clavicle plates versus reconstruction plates - a propensity score matched retrospective cohort study of 106 patients
Authors: Fang Christian , Liu Ruiping , Yee Dennis King Hang , Chau Jackie , Lau Tak-Wing , Chan Rebecca , Woo Siu-Bon , Wong Tak-Man , Fang Evan , Leung Frankie
Published: May 2020

Background: Plate fixation is frequently used to treat displaced midshaft clavicular fractures, however the ideal plate choice remains subject to discussion; reconstruction locking compression plates (RLCPs) are cheaper and can be easily contoured, whereas anatomically pre-contoured locking compression plates (ALCPs) are thought to provide better stability and therefore lower rates of mechanical failure.Objective: To compare the incidence of mechanical failures, functional and radiological outcomes in patients with midshaft clavicular fractures treated with ALCPs versus RLCPs. Methods: A propensity score matched retrospective cohort study was conducted across two trauma centers. 106 consecutively recruited patients with displaced midshaft clavicular fractures, who were treated with plate fixation and had a minimum follow-up of 6 months, were matched on gender, age, fracture grading, energy of injury, and fracture location. The resulting groups included 53 ALCP-treated fractures and 53 matched controls treated with RLCPs. Results: During a mean follow-up of 20.5 months, there were no implant deformities in the ALCP group whereas the RLCP group had 6 patients (11.3%, p=0.012) with implant deformities (5 occurrences of plate bending with fracture union, and 1 plate breakage with nonunion). Despite the higher rate of plate deformities in the RLCP group, there were no statistically significant differences in number of patients recovering full shoulder range of motion (ALCP 90.6%, RLCP 88.7%, p=0.751), incidence of rest pain (ALCP 13.2%, RLCP 9.4%, p=0.542), or implant removals (ALCP 49.1%, RLCP 56.6%, p=0.439). Conclusion: ALCPs may be superior to RLCPs in terms of implant stability but appear to produce similar clinical results.
Effect and potential risks of using multilevel cement-augmented pedicle screw fixation in osteoporotic spine with lumbar degenerative disease
Authors: Tang Yong-chao , Guo Hui-zhi , Guo Dan-qing , Luo Pei-jie , Li Yong-xian , Mo Guo-ye , Ma Yan-huai , Peng Jian-cheng , Liang De , Zhang Shun-cong
Published: May 2020

Background: The increase of augmented level and bone cement dose are accompanied by the rising incidence of cement leakage (CL) of cement-augmented pedicle screw instrumentation (CAPSI). But the effect and potential risks of the application of CAPSI to osteoporotic lumbar degenerative disease (LDD) have not been studied in the case of multilevel fixation. This study aimed to investigate the effectiveness and potential complications of using multilevel CAPSI for patients with osteoporotic LDD.Methods: A total of 93 patients with multilevel LDD were divided into the CAPSI group (46 subjects) and the conventional pedicle screw (CPS) group (47 subjects), including 75 cases for three levels and 18 cases for four levels. Relevant data were compared between two groups, including baseline data, clinical results, and complications.Results: In the CAPSI group, a total of 336 augmented screws was placed bilaterally. The CL was observed in 116 screws (34.52%). Three cemented screws (0.89%) were found loosened during the follow-up and the overall fusion rate was 93.47%. For perioperative complications, two patients (4.35%) experienced pulmonary cement embolism (PCE), one patient augmented vertebral fracture, and three patients (6.52%) wound infection. And in the CPS group, thirty-three screws (8.46%) suffered loosening in cranial and caudal vertebra with a fusion rate of 91.49%. The operation time and hospital stay of CAPSI group were longer than the CPS group, but CAPSI group has a lower screw loosening percentage (P＜0. 05). And in terms of blood loss, perioperative complications, fusion rate, and VAS and ODI scores at the follow-up times, there were no significant differences between the two groups.Conclusions: Patients with osteoporotic LDD underwent multilevel CPS fixation have a higher rate of screw loosening in the cranial and caudal vertebra. The application of cemented pedicle screws for multilevel LDD can achieve better stability and less screw loosening, but it also accompanied by longer operating time, higher incidence of CL, PCE and wound infections. Selective cement augmentation of cranial and caudal pedicle screws may be a worthy strategy to decrease the complications.
Comparative Study of Imaging and Pathology of Sacroiliac Joint in Normal Rats Based on IVIM-DWI and DCE-MRI
Authors: Qin Jian , Yao Qianqian , Ge Xubo , Zhu Jianzhong , Yin Zhaoliang , Li Xiaoqian , Li changqin
Published: May 2020

Background : There are few reports describing the relationship between functional MRI findings and pathology of normal sacroiliac joint (SIJ). Furthermore, the pathology of SIJ is difficult to access, so animal models have special value. Aims:We undertook this study to explore the changes of parameters of Intravoxel Incoherent Motion Diffusion Weighted Imaging(IVIM-DWI), Dynamic Contrast Enhanced Magnetic Resonance Imaging(DCE-MRI) and compare them with pathology in the SIJ of normal rats in different ages.Methods: Thirty 7 week-old male wistar rats were included in the study. The parameters of IVIM-DWI and DCE-MRI in bone marrow and the joint space of SIJ were measured respectively at 8, 13, 18, 23, 28 and 33 weeks, then histological specimen of the SIJ were examined with light microscopy. One-way ANOVA were used for statistical analysis. Results: The values of D in the sacral and iliac bone marrow of normal rats in different age groups decreased with the increase of age, and ANOVA indicated a significant difference in D values among different age groups(P＜0.005). The normal values of D*, f, Fenh(%), Senh(%/s) in the sacral bone marrow, the iliac bone marrow and in the joint space in SIJ of normal rats were obtained. In six groups of rats with different weeks of age, the pathology of the SIJ surface was smooth and clear, the cartilage cells were intact, and no thickening or pannus formation was found. Conclusions: The range of IVIM-DWI and DCE-MRI parameters of the sacral and iliac bone marrow and of the synovial area of the joint space in normal rats were obtained. It provides a basis for further clinical study of SIJ lesions.
Healing Pattern Classification for Thoracolumbar Burst Fractures after Posterior Short-segment Fixation
Authors: Liang Changxiang , Liu Guihua , Liang Guoyan , Zheng Xiaoqing , Yin Dong , Xiao Dan , Zeng Shixing , Cai Honghua , Chang Yunbing
Published: May 2020

Background: Thoracolumbar burst fractures can be treated with posterior short-segment fixation. However, no classification can help to estimate whether the healed vertebral body will have sufficient stability after implant removal. We aimed to develop a Healing Pattern Classification (HPC) to evaluate the stability of the healed vertebra based on cavity size and location.Methods: Fifty-two thoracolumbar burst fracture patients treated with posterior short-segmental fixation without fusion and followed up for an average of 3.2 years were retrospectively studied. The HPC was divided into 4 types: type I - no cavity; type II - a small cavity with or without the violation of one endplate; type III - a large cavity with or without the violation of one endplate; and type IV - a burst cavity with the violation of both endplates or the lateral cortical shell. The intraobserver and interobserver intraclass correlation coefficients (ICCs) of the HPC were assessed. The demographic characteristics and clinical outcomes of the cohort were compared between the stable group (types I and II) and the unstable group (types III and IV). Logistic regression was conducted to evaluate risk factors for unstable healing.Results: The intraobserver and interobserver ICCs of the HPC were 0.86 (95% CI=0.74-0.90) and 0.77 (95% CI=0.59-0.86), respectively. While the unstable healing group (types III and IV) accounted for 59.6% of the patients, most of these patients were asymptomatic. The preoperative Load Sharing Classification (LSC) comminution score may predict the occurrence of unstable healing (OR=8.4, 95% CI=2.4-29.7).Conclusions: A reliable classification for assessing the stability of a healed vertebra was developed. With type I and II healing, the vertebra is considered stable, and the implant can be removed. With type III healing, the vertebra may have healing potential, but the implant should not be removed unless type II healing is achieved. With type IV healing, the vertebra is considered extremely unstable, and instrumentation should be maintained. Assessing the LSC comminution score preoperatively may help to predict unstable healing after surgery.
Asymmetrical fatiguing of the gluteus maximus muscles in the elite short-track female skaters.
Authors: Konieczny Mariusz , Pakosz Paweł , Witkowski Mateusz
Published: May 2020

Background According to research, fast skating on short distances increases functional asymmetry of leg muscles. As has been proven in many sporting disciplines, this asymmetry can increase the risk of injury. The aim of the study was to analyze the level of right and left fatigue asymmetry of gluteus maximus muscle in elite skaters on a short track and to compare this phenomenon to a control group. The muscles were chosen deliberately, due to their influence in maintaining the right position during training on ice.Methods The experiment compared a group of eight members of the Polish Women’s National Team in short track with a group of eight non-training people. The subjects did the Biering-Sorensen test, in which sEMG (surface electromyography) signal frequency was measured in the gluteus maximus muscles during an isometric contraction. Fatigue slopes were analyzed with a ANOVA with repeated measures. In the skaters, the fatigue differed between the right and the left gluteus maximus muscles. All the skaters had higher fatigue in the right leg. This phenomenon was not observed in the non-training subjects, who on average had similar fatigue in both legs. Results Results showed that the right and the left muscles of the skaters in the experimental group differed in fatigue, but this difference was non-significant in the control group.The subjects from the two groups did not differ in the fatigue of the left muscle, they did in the fatigue of the right muscle. The elite speed-track skaters had higher fatigue in the right muscle than the non-training subjects.Conclusions Training should thus be planned in a way that minimizes the risk of causing muscle fatigue asymmetry in skaters despite the typically asymmetrical muscle work during training on ice and competition, thus new training protocols should be developed or considered to decrease that asymmetry.Trial registration The tests were previously approved by the Bioethical Commission of the Chamber of Physicians in Opole. (Resolution No. 235 of 13 December 2016).
Complications of bone transport technique using the Ilizarov method in the lower extremity: a retrospective analysis of 282 consecutive cases over 10 years
Authors: Liu Yanshi , Yushan Maimaiaili , Liu Zhenhui , Liu Jialin , Ma Chuang , Ahemaitijiang Yusufu
Published: May 2020

Background: The treatment of large bone defects in lower limbs is a serious challenge for orthopedic surgeons and patients. The bone transport technique using the Ilizarov method has become the main treatment option for the reconstruction of bone defect. However, inevitable difficulties and complications related to bone transport technique have been reported by many studies. The purpose of this study was to evaluate the effectiveness and complications of bone transport technique using Ilizarov method in the treatment of bone defect of lower extremity.Methods: The study was conducted on 282 patients who underwent bone transport procedures using Ilizarov method at our institution from January 2007 to June 2017. Patient’s demographic data, complications and clinical outcomes at minimum of two years follow-up were collected and retrospectively analyzed. All difficulties that related to bone transport were documented according to Paley’s classification. The clinical outcomes were evaluated using Association for the Study and Application of the Method of Ilizarov criteria (ASAMI) at last clinical visit. Results: There were 243 male and 39 females with a mean age of 40 years (range 18-65 years). The mean defect was 6.56±2.15 cm, whereas single level transport in 221 cases and double level transport in 61 cases. There were 189 problems, 166 obstacles and 406 complications (257 minor and 149 major complications), and the average complication rate per patients consists of 0.91 minor and 0.53 major complications. The top five complications were pin-site infection (65.96%), axial deviation (40.78%), joint stiffness (23.76%), soft tissue incarceration (22.34%) and delayed union of the docking site (13.48%).The ASAMI bony result was excellent in 233 patients, good in 32, fair in 5 and poor in 12. The ASAMI functional result was excellent in 136 patients, good in 88, fair in 47, poor in 11.Conclusion: Bone transport is a reliable method for reconstruction of bone defects in the femur and tibia. Awareness of predictable complications is beneficial to prevent or early detection of the expected complication which can improve the risk-benefit balance.
Blinding in electric current stimulation in subacute neglect patients with current densities of 0.8 A/m²: A cross-over pilot study
Authors: Gorsler Anna , Grittner Ulrike , Külzow Nadine , Rackoll Torsten
Published: May 2020

Objective Transcranial direct current stimulation (tDCS) is a promising adjuvant technique to improve standard care neglect therapy in patients suffering from stroke. Current densities in tDCS are modeled by tissue distribution in the brain. Therefore, we hypothesized that higher current densities are needed in aged stroke population to counteract age related brain volume loss. Here it is still unresolved whether blinding of participants can be achieved. Our aim was to test whether stroke patients with left-sided hemineglect are able to differentiate beyond chance active tDCS from sham stimulation at a current density of 0.8 A/m². Therefore, we investigated 12 early subacute stroke patients with left-sided hemineglect in a cross-over design with two stimulation settings (active/sham stimulation in randomized order). Stimulation was performed simultaneous to standard care neglect therapy with 0.8 A/m² and progress of neglect symptomatology was monitored during inpatient rehabilitation.Results Our sample exhibited higher odds of correct guessing an active tDCS condition compared to wrongly judge an active tDCS condition as sham stimulation (Odds ratio 10.00, 95%CI: 0.65 - 154.40, p = 0.099). Therefore, we must question the feasibility of blinding success in studies with current densities of 0.8 A/m². Assessment in multisession protocols still warrants further investigation.
Life-conditions and anthropometric variables as risk factors for caries in children in Ladakh: A cross- sectional survey.
Authors: Cagetti MariaGrazia , Cocco Fabio , Calzavara Ezio , Augello Davide , Zagpoo Phunchok , Campus Guglielmo Giuseppe
Published: May 2020

Backgrounds

The aim of this survey was to evaluate the severity of dental caries among Ladakh children and its association with anthropometric and background variables.

Methods

This cross‐sectional epidemiological survey was conducted on Ladakh schoolchildren divided into four age groups (<6, ≥6<11, ≥11≤14 and >14 years of age). A total of 1474 schoolchildren (607 males 41.18% and 867 females 58.82%) were examined. Actual dental caries prevalence (dt/DT) and gingival bleeding were recorded by four calibrated examiners. An ad hoc questionnaire evaluated general health, eating habits, oral hygiene and the self-perception of oral conditions. Height, weight, waist circumference, heart-rate and oxygen-saturation were also collected. Responses to questionnaire items were treated as categorical or ordinal variables. Relation between children’s caries data, gingival bleeding, gender, Body Mass Index (BMI) following the International Obesity Task Force, waist circumference and questionnaire items were assessed using the Kruskal–Wallis test. Conditional ordinal logistic regression was used to analyse associations among caries severity, gender, BMI, waist circumference, oxygen saturation and questionnaire. A forward stepwise logistic regression procedure was also assessed to estimate the ORs of gingival bleeding prevalence and the covariates derived from examination or questionnaire.

Results

Caries was almost ubiquitarian with only 10.04% of caries-free children (dt/DT=0). Caries severity, in both primary and permanent dentitions was statistically significantly related to gender, waist circumference, BMI, oral hygiene frequency and self-reported chewing problems (p<0.01 in both dentitions). An increasing relative risk for caries in permanent dentition compared to caries-free subjects was observed in children with a low BMI (RRR=1.67, 95% CI=1.54/2.83 for subjects with 1-3 caries lesions and RRR=1.52, 95% CI=1.36/1.74 for subjects with more than 3 caries lesions); also children with reduced waist circumference had a higher relative risk to have 1-3 caries lesions (RRR=2.16, 95% CI=1.84 / 2.53) and an even higher risk to have more than 3 caries lesions (RRR=4.22, 95% CI=3.33 / 5.34).

Conclusion

A significant impact of untreated caries lesions was observed; low BMI values and reduced waist circumference showed to be the main caries risk predictors. Preventive and intervention programmes should be implemented to improve children's oral health living in Ladakh.
Enhancing the Lubricity of Gas-to-Liquid (GTL) Paraffinic Kerosene: Impact of the Additives on the Physicochemical Properties
Authors: Ababnah Hani , Mohamed Nasr , Choudhury Hanif , Zhang Lei Lei , Gani Rafiqul , McKay Gordon , Elbashir Nimir
Published: May 2020

Synthetic paraffinic kerosene (SPK) is an ultra-clean fuel with low aromatic content and negligible quantities of sulfur compounds. Although, SPK has a good potential to replace the conventional fuel Jet A-1, it also has some deficiencies. One of them is the low lubricity compared to its conventional counterpart Jet A-1. To improve the lubricity of SPK, three selected additives have been mixed with SPK at different concentrations. The lubricity of the samples was determined experimentally and the samples that meet the industry specifications have been studied further. The effect of the additives on the physicochemical properties, such as, density, flash point, freezing point, viscosity, and heat content, were investigated. Linoleic acid was found to be an excellent lubricity improver even at a very low concentration and its negative impact on the other physicochemical properties was found to be insignificant. Ethyl oleate also demonstrated significant improvement in lubricity at low concentrations but had a negative impact on the fuel’s freezing point at high concentrations. Quinoline, at high concentrations, elevated the blend’s freezing point above the acceptable limits. In parallel to the experimental campaign, a pre-existing mathematical modelling tool was utilized to predict the properties of interest. The lubricity model was successfully introduced into the mathematical model in order to improve the capabilities of the model. Linoleic acid sample showed the best improvement in lubricity of SPK with wear scar diameter of 417 µm; well below the ASTM D7566 maximum limit of 850 µm. The dual nature of this study facilitated the optimization of the physicochemical properties of the fuel samples.
MicroRNA-381 inhibits bladder cancer pathogenesis through directly controlling BMI1 and triggering the Rho/ROCK signaling pathway defect
Authors: Chen Dayin , Cheng Liang , Cao Huifeng , Liu Wensi
Published: May 2020

Background
Emerging evidence has noted the important participation of microRNAs (miRNAs) in several human diseases including cancer control. This research was launched to probe the function of miR-381 in bladder cancer (BCs) progression.
Methods
Aberrantly expressed miRNAs in BCs tissues were analyzed using miRNA microarrays. miR-381 expression in the bladder and paired tumor tissues, and in BCs and normal cell lines was determined. The target relationship between miR-381 and BMI1 was predicted online and validated through a luciferase assay. Gain-of-functions of miR-381 and BMI1 were performed to identify their functions on BCs cell behaviors as well as tumor growth in vivo.
Results
miR-381 was poor regulated in BCs tissues and cells. A higher miR-381 level indicates a better prognosis of patients with BCs. Artificial up-regulation of miR-381 inhibited proliferation, invasion, migration, resistance to apoptosis, and tumor formation ability of BCs cells. miR-381 directly binds to BMI1 expression. Overexpression of BMI1 partially blocked the tumor suppressing roles of miR-381 in cell malignancy and tumor growth. In addition, miR-381 led to decreased RhoA phosphorylation and ROCK2 activation, which were also reversed by BMI1.
Conclusion
The study evidenced that miR-381 may act as a beneficiary biomarker in BCs patients. Up-regulation of miR-381 could suppress BCs development both in vivo and in vitro through BMI1 down-regulation and the Rho/ROCK inactivation.