bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis of Spatial Two-Link Coupled Serial Chains
Authors: Krovi Venkat , Ananthasuresh G. K. , Kumar Vijay 
Published: February 2021

Abstract
We address the synthesis of serial chain spatial mechanisms with revolute joints in which the rotations about the joints are coupled via cables and pulleys. Such coupled serial chain mechanisms offer a middle ground between the more versatile and compact serial chains and the simpler closed chains by combining some of the advantages of both types of systems. In particular, we focus on the synthesis of single degree-of-freedom, coupled serial chains with two revolute joints. We derive precision point synthesis equations for two precision points by combining the loop closure equations with the necessary geometric constraints in terms of the unknown mechanism parameters. This system of equations can now be solved linearly for the link vectors after a suitable selection of free choices. We optimize over the free choices to generate an end effector trajectory that closely approximates a desired end effector trajectory for motion generation and path following applications.
Assembly Configurations of Spatial Single-Loop Mechanisms With Revolute, Cylindric, and Prismatic Joints
Authors: Foster David E. , Cipra Raymond J. 
Published: February 2021

Abstract
This paper examines the problem of identifying the assembly configurations (ACs), also called circuits, of certain spatial single-loop mechanisms. First, the spherical mechanism is considered; it is believed that such a mechanism has one AC if every pair of adjacent links can line up; otherwise, it has 2 ACs. Next, general spatial mechanisms with revolute, cylindric, and prismatic points are considered. If the mechanism has three or more sliding (cylindric or prismatic) joints, it is possible to find an equivalent spherical mechanism which has the same angular motions. However, it is also possible that at certain positions, some of the links may have to slide an infinite distance, which is not possible. Therefore, the mechanism may have more ACs than the equivalent spherical mechanism. Several examples are given, and some general conclusions are drawn.
On the Coupler Curve of RCPCR Linkages
Authors: Yan Hong-Sen , Hsieh Wen-Hsiang 
Published: February 2021

Abstract
The purpose of this paper is to investigate the properties of the coupler curves generated by all RCPCR linkages. First, the 3 × 3 matrix with dual elements is used to establish the loop closure equation, the displacement equations are derived, and all joints variables are expressed in terms of input and output variables. Then, the parametric equations of the coupler curve are found by the D-H matrix. Finally, homogeneous coordinate is introduced to those displacement equations, and the order and some critical properties of the coupler curve are investigated based on the theories of algebraic curve and analytical geometry of three dimensions. In addition, RCPCR and RRCPC linkages are used as examples for illustrations. Moreover, the results on the application of dimensional synthesis are discussed.
An Investigation of Screw Systems in the Finite Displacements of Bennett-Based 6R Linkages
Authors: Huang Chintien , Sun Chi-Chih 
Published: February 2021

Abstract
This paper investigates, via numerical simulations, the finite displacements of all the known Bennett-based 6R overconstrained linkages: Goldberg’s linkages, variant Goldberg linkages, Waldron’s linkages, and Wohlhart’s linkages. An investigation of the finite displacements of nine distinct linkages reveals that every Bennett-based linkage, except for Wohlhart’s isomerization linkage, inherits the linear properties of the Bennett mechanism. The relative finite displacement screws of some non-adjacent links of these linkages form screw systems of the second order.
An Investigation Into Compliant Bistable Mechanisms
Authors: Opdahl Patrick G. , Jensen Brian D. , Howell Larry L. 
Published: February 2021

Abstract
This paper proposes a new class of bistable mechanisms: compliant bistable mechanisms. These mechanisms gain their bistable behavior from the energy stored in the flexible segments which deflect to allow mechanism motion. This approach integrates desired mechanism motion and energy storage to create bistable mechanisms with dramatically reduced part count compared to traditional mechanisms incorporating rigid links, joints, and springs. This paper briefly reviews bistable mechanism theory, introduces some additional bistable mechanism characteristics, and integrates this theory with compliant mechanism theory. The resulting theory of bistable compliant mechanisms is validated by measuring the force and motion characteristics of several test mechanisms and comparing them to predicted values.
An Introduction to Burmester Field Theory
Authors: Mlinar John R. , Erdman Arthur G. 
Published: February 2021

Abstract
This paper introduces the Burmester field for motion-generation dyads with four design positions. The Burmester field is the region swept by a Burmester curve as one or more of the design positions varies. The Burmester field’s geometric features are shown to be related to the poles. The most significant feature are anchor poles that remain stationary as the design positions are changed. The envelope of the Burmester field found with the variation of a single design parameter is presented. This work demonstrates that the envelope of the Burmester field consists of segments of Burmester curves and segments found using envelope theory. A number of examples are presented and discussed.
A Computer Implementation of the Position Solution of Planar Linkages Using Vector Loop Decomposition
Authors: Kahler Clint A. , Nisbett J. Keith , Goodin Clement R. 
Published: February 2021

Abstract
A general closed-form approach to the solution of loop equations of planar n-bar linkages is presented. Each loop of a set of canonical independent loops is decomposed to a set of vectors. Several common combinations of revolute and prismatic joints are defined. By evaluating the types of joints at each end of a vector, the magnitude and direction of the vector are determined to be known constants or unknown variables. This leads to an identification of the number of unknowns and the distribution of unknowns in the loop. This identification allows the unknowns to be found by matching the situation to one of the unique, closed-form cases for a solvable loop. A computer software application has been developed and is analyzed for efficiency.
A Proposed Categorization Method and Category Domain Inequality Development Procedure for Ground Joints of Five Bar Linkages
Authors: Lin Chuen-Sen , Lee Terry , Jia Bao-Ping 
Published: February 2021

Abstract
This paper presents a method for the development of sets of symbolic inequalities in terms of link lengths for the prediction of the rotation capabilities of ground joints of single-loop five-bar linkages. The inequalities are obtained from the combination of the loop equation of a five-bar linkage and its derivatives and the application of simple logic operations. The rotation capabilities of ground joints are divided into three categories: the incomplete-rotation ground joints, the conditioned complete-rotation ground joints, and the unconditioned complete-rotation ground joints. The derived sets of inequalities define the domain, in a five-dimension space of the five link lengths, for each of the rotation categories. In this paper, the definition of each category is clearly described and the derivations of sets of inequalities are explained in details. A computer program was constructed to examine the completeness and correctness of the categorization method and to analyze the given five-bar linkages to determine the appropriate categories for their ground joints.
Mass Center of Planar Mechanisms Using Auxiliary Parallelograms
Authors: Gökçe Ali , Agrawal Sunil K. 
Published: February 2021

Abstract
Center of mass is an important characteristic of a mechanism during motion. In some studies of biomechanics, it is necessary to monitor the motion of this point. The physical location of the center of mass during motion may have importance in the development of gravity compensated exercise machines. Also, a mechanism with the center of mass constrained to be inertially fixed has the same motion as if it was in zero gravity. This property may be exploited to develop test beds on earth that mimic the behavior of systems in space.
In this paper, a method is described to augment planar mechanisms with auxiliary parallelograms in order to identify a physical point on the augmented mechanism which is the center of mass of the original mechanism. The original and the augmented mechanisms have the same degrees-of-freedom. If the links of the augmented mechanism are massless, the original and augmented mechanisms have the same motion. During motion, the center of mass is a physical point on the mechanism which can be monitored or used for other purposes motivated from the application. In practice, however, if such an augmented mechanism is constructed, its links will have finite masses. As a result, under the same inputs, the motion of the original and augmented mechanisms will be different. In this paper, the effects of finite masses of the additional links on the original mechanism are also discussed.
Static Balancing of a Class of Spatial Parallel Platform Mechanisms
Authors: Ebert-Uphoff Imme , Gosselin Clément M. , Laliberté Thierry 
Published: February 2021

Abstract
This article discusses the development of statically balanced spatial parallel platform mechanisms. A mechanism is statically balanced if its potential energy is constant for all possible configurations. This property is very important for robotic manipulators with large payloads, since it means that the mechanism is statically stable for any configuration, i.e. zero actuator forces are required whenever the manipulator is at rest. Furthermore, only inertial forces have to be sustained while the manipulator is moving. The application that motivates this research is the use of parallel platform manipulators as motion bases in commercial flight simulators, where the weight of the cockpit results in a large static load.
We first present a class of spatial parallel platform mechanisms of novel architecture that is suitable for static balancing. Then sufficient conditions on the kinematic parameters that guarantee static balancing are derived for this class. Finally a particular mechanism is studied in more detail to show the practicability of its design.
Determination of Individual Foot-Placement Space for Modular Platform Manipulators
Authors: Ji Zhiming , Li Zhenqun 
Published: February 2021

Abstract
Reconfigurability of a modular platform manipulator makes it possible for the manipulator to adapt to different applications. How should the actual configuration be selected? Practical reconfiguration of platform manipulators can only be achieved when users are provided with information to guide their selection process. This paper defines the foot-placement space and presents a method for determining individual Foot-Placement Spaces (FPSs) for a given set of leg modules, based on a desired workspace. Implementation of construction method for Foot-Placement Space is discussed and illustrated with an example.
Differential Geometric Analysis of Singularities of Point Trajectories of Serial and Parallel Manipulators
Authors: Ghosal Ashitava , Ravani Bahram 
Published: February 2021

Abstract
In this paper, we present a differential-geometric analysis of singularities of point trajectories of two and three-degree-of-freedom serial and parallel manipulators. At non-singular configurations, the first order local properties are characterized by the metric coefficients, and, geometrically, by the shape and size of a velocity ellipse and ellipsoid for two and three-degree-of-freedom motions respectively. At singular configurations, the definition of a metric is no longer valid and the velocity ellipsoid degenerates to an ellipse, a line or a point, and the area or the volume of the velocity ellipse or ellipsoid becomes zero. The second and higher order properties, such as curvature, are also not defined at a singularity. In this paper, we use the rate of change of the area or volume to characterize the singularities of the point trajectory. For parallel manipulators, singularities may lead to either loss or gain of one or more degrees-of-freedom. For loss of degree of freedom, the ellipsoid degenerates to an ellipse, a line, or a point as in serial manipulators. For a gain of degree-of-freedom the singularities can be pictured as growth to lines, ellipses, and ellipsoids. The method presented gives a clear geometric picture as to the possible directions and magnitude of motion at a singularity and the local geometry near a singularity. The theoretical results are illustrated with the help of a general spatial 2R manipulator and a three-degree-of-freedom RPSSPR-SPR parallel manipulator.
Determination of Closed Form Solution to the Workspace of Stewart Parallel Manipulators
Authors: Huang T. , Wang J. S. , Yuan J. X. 
Published: February 2021

Abstract
A novel methodology is presented in this paper for the workspace analysis of Stewart parallel manipulators. The workspace is defined in such a way that enables a description to be made in a unified framework of both the position and orientation capabilities of the mobile platform. Given the orientation capability of the mobile platform which is described by the minimum reachable yaw angle, the piecewise closed solution to the position workspace boundary is formulated by means of differential geometry. It is indicated that the workspace boundary is in fact the cap of twelve envelope surfaces, each of which is generated by a family of spherical surfaces with the center moving along a two branch closed spherical curve. Two examples are given to illustrate the effectiveness of this approach.
Robust Design of Gears
Authors: Dippery Richard E. , Echempati Raghu 
Published: February 2021

Abstract
The terms “Robust Design” or sensitivity of a design to variance of design parameters is gaining importance in design of mechanical components and structures. This paper has been written as the result of an introductory investigation to determine the applicability of robust design for a given gear system and development of a model to perform the evaluations. Work has been performed based upon evaluation of a design being performed using AGMA standards.
CRB1-associated retinal dystrophies in a Belgian cohort: genetic characteristics and long-term clinical follow-up
Authors: Talib Mays , Van Cauwenbergh Caroline , De Zaeytijd Julie , Van Wynsberghe David , De Baere Elfride , Boon Camiel J F , Leroy Bart Peter 
Published: February 2021

AimTo investigate the natural history in a Belgian cohort of CRB1-associated retinal dystrophies.MethodsAn in-depth retrospective study focusing on visual function and retinal structure.ResultsForty patients from 35 families were included (ages: 2.5–80.1 years). In patients with a follow-up of >1 year (63%), the mean follow-up time was 12.0 years (range: 2.3–29.2 years). Based on the patient history, symptoms and/or electroretinography, 22 patients (55%) were diagnosed with retinitis pigmentosa (RP), 15 (38%) with Leber congenital amaurosis (LCA) and 3 (8%) with macular dystrophy (MD), the latter being associated with the p.(Ile167_Gly169del) mutation (in compound heterozygosity). MD later developed into a rod-cone dystrophy in one patient. Blindness at initial presentation was seen in the first decade of life in LCA, and in the fifth decade of life in RP. Eventually, 28 patients (70%) reached visual acuity-based blindness (<0.05). Visual field-based blindness (<10°) was documented in 17/25 patients (68%). Five patients (13%) developed Coats-like exudative vasculopathy. Intermediate/posterior uveitis was found in three patients (8%). Cystoid maculopathy was common in RP (9/21; 43%) and MD (3/3; 100%). Macular involvement, varying from retinal pigment epithelium alterations to complete outer retinal atrophy, was observed in all patients.ConclusionBi-allelic CRB1 mutations result in a range of progressive retinal disorders, most of which are generalised, with characteristically early macular involvement. Visual function and retinal structure analysis indicates a window for potential intervention with gene therapy before the fourth decade of life in RP and the first decade in LCA.
Improvement of asymmetric thyroid eye disease with teprotumumab
Authors: Ugradar Shoaib , Wang Yao , Mester Tunde , Kahaly George J , Douglas Raymond 
Published: February 2021

PurposeTeprotumumab, a specific blocking antibody to the insulin like growth factor 1 receptor, significantly reduced proptosis in patients with thyroid eye disease (TED) in recent clinical trials. Given its specificity, we expect it to demonstrate greater efficacy on the worse affected orbit, in patients with asymmetric TED. Herein, we investigate the differential impact of teprotumumab on the orbits of such patients.MethodsIn this pooled analysis of patients who were enrolled in the recent phase 2 (NCT01868997) and phase 3 (NCT03298867) trials, all patients with asymmetric TED (difference in exophthalmometry of ≥3 mm) were screened for eligibility. The primary outcomes of the trials, proptosis, diplopia and Clinical Activity Score (CAS) response, were evaluated in both orbits of patients who had received treatment or placebo, to examine the differential response from baseline to week 24.ResultsFrom a pooled group of 84 patients randomised to receive teprotumumab and 87 randomised to placebo, 10 (12%) and 12 (14%), respectively, met the inclusion criteria. The teprotumumab-treated patients demonstrated significant reductions in proptosis, CAS and diplopia in both orbits of each patient and this was not seen with placebo. The reduction in proptosis and CAS was significantly greater in the worse affected orbit, improving symmetry. In the placebo arm, while the mean CAS in the study eye reduced over time, proptosis and diplopia did not change in either orbit.ConclusionThe findings in this study suggest the differential impact of teprotumumab on orbits that are clinically more affected by TED, suggesting that teprotumumab reduces asymmetry.
A Moving Target: Inactivating BTK Mutations as Drivers of Follicular Lymphoma
Authors: Afaghani Jumana , Taylor Justin 
Published: February 2021

Abstract
Drugs that target Bruton tyrosine kinase (BTK) have been highly successful and changed the landscape of therapies in B-cell lymphomas. However, their lower rates of effectiveness in follicular lymphoma are unexplained. Recent work describes inactivating BTK mutations that show that at least some follicular lymphomas do not require BTK.
See related article by Hu et al., p. 2301
ДОСЛІДЖЕННЯ ФЕНОЛЬНИХ СПОЛУК РИЖІЮ ПОСІВНОГО (CAMELINA SATIVA (L.) CRANTZ) ТА РИЖІЮ ДРІБНОПЛОДОГО (CAMELINA MICROCARPA ANDRZ.)
Authors: Tsykalo T. O. , Trzhetsynskyi S. D. 
Published: February 2021

Мета роботи. Дослідити склад фенольних сполук в траві та насінні видів роду Camelina (L.) Crantz.
Матеріали і методи. Для дослідження використовували траву та насіння рижію посівного сорту Славутич і рижію дрібноплодого. Для досліджень готували водно-спиртові витяжки, як екстрагент використовували 70 % етиловий спирт. Для попередньої оцінки якісного складу витяжок використовували якісні реакції та ТШХ-дослідження у системі розчинників н-бутанол – кислота оцтова льодяна – вода (4:1:2). Хроматограми переглядали у денному та УФ-світлі до і після обробки парами амоніаку. Визначення якісного складу та кількісного вмісту окремих фенольних сполук виконували методом ВЕРХ. Кількісне визначення загального вмісту флавоноїдів, гідроксикоричних кислот і поліфенолів виконували спектрофотометричним методом.
Результати й обговорення. В результаті ТШХ-дослідження встановлено, що у траві та насінні всіх зразків представників роду Camelina (L.) Crantz присутній рутин. В траві обох видів ідентифіковано хлорогенову кислоту. Методом ВЕРХ підтверджено наявність даних сполук і встановлено, що вміст рутину є вищим у насінні рижію дрібноплодого (0,361±0,001) %, а хлорогенової кислоти – в траві рижію дрібноплодого (0,279±0,004) %. У результаті спектрофотометричного визначення вмісту фенольних сполук в сировині даних видів встановлено, що більший вміст флавоноїдів, похідних гідроксикоричних кислот та загальний вміст фенольних сполук характерний для трави рижію посівного і складає (1,17±0,08) %, (1,47±0,03) % і (2,11±0,003) % відповідно.
Висновки. Методом ТШХ ідентифікували та методом ВЕРХ визначили кількісний вміст рутину та хлорогенової кислоти у траві та насінні рижію посівного (Camelina sativa (L.) Crantz) і рижію дрібноплодого (Camelina microcarpa Andrz.). Спектрофотометричним методом визначили загальну суму флавоноїдів, гідроксикоричних кислот та поліфенолів у досліджуваній сировині обох видів.
Professional Competence Among Registered Nurses Working in Hospitals in Saudi Arabia and Their Experiences of Quality of Nursing Care and Patient Safety
Authors: Halabi Jehad O. , Nilsson Jan , Lepp Margret 
Published: February 2021

Introduction: The Kingdom of Saudi Arabia (KSA) plans to become self-sufficient, generating a national nursing workforce. The study’s purpose was to assess nurses’ self-reported professional competence and illuminate experiences of the quality of nursing care and patient safety. Methodology: A cross-sectional design with 469 nurses working in different units from two public hospitals and Regions of the KSA participated. The Nurse Professional Competence Scale short version including six professional areas of nursing care was used. Results: There are significant relationships between self-reported professional competence and the quality of nursing care, patient safety, nurse’s characteristics, and workplace. Discussion: Registered nurses’ professional competence is related to the clinical areas in which they work and the nature of their involvement in patient care. The Nurse Professional Competence Scale can identify professional competence areas for further development, which is important for culturally congruent health care in KSA for their transformation process.
Multiple-testing correction in metabolome-wide association studies
Authors: Peluso Alina , Glen Robert , Ebbels Timothy M. D. 
Published: February 2021

AbstractBackgroundThe search for statistically significant relationships between molecular markers and outcomes is challenging when dealing with high-dimensional, noisy and collinear multivariate omics data, such as metabolomic profiles. Permutation procedures allow for the estimation of adjusted significance levels without assuming independence among metabolomic variables. Nevertheless, the complex non-normal structure of metabolic profiles and outcomes may bias the permutation results leading to overly conservative threshold estimates i.e. lower than those from a Bonferroni or Sidak correction.MethodsWithin a univariate permutation procedure we employ parametric simulation methods based on the multivariate (log-)Normal distribution to obtain adjusted significance levels which are consistent across different outcomes while effectively controlling the type I error rate. Next, we derive an alternative closed-form expression for the estimation of the number of non-redundant metabolic variates based on the spectral decomposition of their correlation matrix. The performance of the method is tested for different model parametrizations and across a wide range of correlation levels of the variates using synthetic and real data sets.ResultsBoth the permutation-based formulation and the more practical closed form expression are found to give an effective indication of the number of independent metabolic effects exhibited by the system, while guaranteeing that the derived adjusted threshold is stable across outcome measures with diverse properties.