bluuebunny/crossref_metadata_2025 huggingface dataset:
Image Stabilization for a Camera on a Moving Platform
Authors: Tucker Joseph C. , de Sam Lazaro Anthony
Published: March 2021

The problem of video tele-operation of a moving vehicle is compounded by the fact that a camera mounted on such a vehicle moves rather violently and randomly depending on the terrain. This contributes to motion sickness of the operator who is controlling the vehicle from a stationary platform. In order to correct this problem, motion of the camera is counteracted by a stabilization routine that can account for all unwanted vibrations. A possibilistic model is described. The experimental set-up and preliminary results are presented.
Artificial Neural Networks Used As a Rule Selector for Fuzzy Logic Controllers
Authors: Huang Shou-Heng , Nelson Ron M.
Published: March 2021

A feedforward, three-layer, partially-connected artificial neural network (ANN) is proposed to be used as a rule selector for a rule-based fuzzy logic controller. This will allow the controller to adapt to various control modes and operating conditions for different plants. A principal advantage of an ANN over a look up table is that the ANN can make good estimates to fill in for missing data. The control modes, operating conditions, and control rule sets are encoded into binary numbers as the inputs and outputs for the ANN. The General Delta Rule is used in the backpropagation learning process to update the ANN weights. The proposed ANN has a simple topological structure and results in a simple analysis and relatively easy implementation. The average square error and the maximal absolute error are used to judge if the correct connections between neurons are set up. Computer simulations are used to demonstrate the effectiveness of this ANN as a rule selector.
Teaching the Finite Element Method As a Design Tool for Mechanical Engineering
Authors: Grimm T. R.
Published: March 2021

The importance of the finite element method as an engineering tool for design and analysis is emphasized in a senior level elective course taught at Michigan Technological University. The course emphasizes hands-on experience with computers and the pre- and post-analysis of results to establish confidence in solutions obtained. The students learn by using the finite element method to “solve” several design projects, rather than by being told about the method without significant actual experience. They also learn about the basis of the method, including formation of the matrix equations required and the numerical methods used in their solution. Intelligent use of the method requires that engineers understand both the mechanics of how to apply the method, i.e modeling requirements, and the limitations imposed by the basic solution process. The course provides the students with important experience in using the powerful finite element method as a design tool. It requires a strong background of fundamentals and stimulates the problem solving thinking skills so essential to industry.
Solving Large Linear Equations Using PVM System
Authors: Li Qiang , Liu Jyh-chum , Yip T. Gary
Published: March 2021

This paper presents a solution to large simultaneous linear equations on a distributed system. The solution is a parallel version of Gauss-Jordan elimination that runs on a network of workstations. The software platform is the PVM system (Parallel Virtual Machine). The goal is to achieve computational speedup for large tasks by utilizing idle time on available workstations. Since the system is a loosely coupled system, we are not striving for the linear speedup as one would do in the case of a tightly coupled parallel machine. The solution is based on dense coefficient matrices. Gauss-Jordan elimination is nicely parallelized into large grain parallel subtasks suitable for the distributed system. Performance evaluation results are presented.
Hilbert Transform Generalization of a Classical Random Vibration Integral
Authors: Spanos Pol D. , Miller Scott M.
Published: March 2021

Integrals which represent the spectral moments of the stationary response of a linear, time-invariant system under random excitation are considered. It is shown that these integrals can be determined through the solution of linear algebraic equations. These equations are derived by considering differential equations for both the autocorrelation function of the system response and its Hilbert transform. The method can be applied to determine both even order and odd order spectral moments. Furthermore, it provides a potent generalization of a classical formula used in control engineering and applied mathematics. The applicability of the derived formula is demonstrated by considering random excitations with, among others, the white noise, “Gaussian”, and Kanai-Tajimi seismic spectra. The results for the classical problem of a randomly excited single-degree-of-freedom oscillator are given in a concise and readily applicable format.
Linear and Nonlinear Instabilities in a Flexible Mechanism
Authors: Beale David G. , Lee Shyr Wen
Published: March 2021

An analytical and experimental comparison is made between the stability of the linear and nonlinear equation response of a flexible rod in a slider crank mechanism, using a one mode approximation. It is shown that there is strong correlation between the onset of parametric resonance regions from the linear equation and the bifurcation of a stable period 1 solution from the nonlinear equation, both regions plotted on a crank length-crank speed parameter plane. But within the unstable zones, an estimate of response requires a nonlinear equation representation. Amplified oscillations, not associated with any instability and called irregular resonance when pertaining to the nonlinear equations, are also present as harmonics in the linear equation analysis. The nonlinearities effect these resonances by pulling the peak amplification to lower speeds.
Control of Dynamic Systems With Nonlinearities and Time Varying Parameters
Authors: Söffker Dirk , Müller Peter C.
Published: March 2021

The well-known theory of disturbance rejection control and the experience of using a generalized technique with universal fault model for building observers and regulators for the estimation and compensation of disturbances and unmodeled or uncertain effects as well, could be used for controlling dynamic systems with time varying parameters and nonlinearities.

Based on a linear time-invariant model the effects of non-linearities and unmodeled dynamics are estimated by an extended observer scheme. Using this information these dynamic effects will be compensated by the developed compensation scheme.

Here also different compensation techniques of disturbance rejection control are discussed, compared, and modified.

The simulation example of an inverted flexible pendulum shows the efficiency of the method controlling an unstable mechanical system without exact knowledge of structure and parameters of nonlinearity and time-variance.
On Dynamic Stability and Nonlinear Modal Interaction of Parametrically-Excited Rectangular Plates
Authors: Ostiguy Germain L. , Evan-Iwanowski Ross M.
Published: March 2021

The authors review recent developments on the dynamic stability and nonlinear parametric vibrations of general rectangular plates. Emphasis is placed on nonlinear modal interaction in parametncally excited plates and various types of resonances are investigated. Analytical predictions are compared to experimental data to form a qualitative and quantitative verification of the solutions. Experimental results indicate that the presence of initial geometric imperfections can modify considerably the dynamic behavior of the plate and produce various types of resonances highly unpredictable beforehand and differing from those generally assumed in analytical studies.
Modeling of a Finger-Follower Cam System With Verification in Contact Forces
Authors: Hsu Wensyang , Pisano Albert P.
Published: March 2021

A lumped/distributed-parameter, dynamic model is developed to investigate the dynamic responses of a finger-follower valve train with the effects of an oscillating pivot, frictional forces between sliding surfaces, and a hydraulic lash adjuster.

Based on the measured force data at low speed, an algorithm is derived to determine the dynamic Coulomb friction coefficients around maximum valve lift simultaneously at three contact points. A constraint equation is formulated to find the contact position between the cam and the follower kinematically. This makes it possible for the model to simulate the dynamic response of the cam system when the pivot is moving. A hydraulic lash adjuster acting as the pivot of the follower is also modeled with the effects of oil compressibility and oil refill mechanism.

The model is numerically integrated and shown to have good agreement between simulation results and experimental data of contact forces at three different speeds. The maximum operating speed is limited by valve toss, loss contact between components. The model predicts toss between the hydraulic lash adjuster and the follower at 2535 rpm, and experiment indicates toss starting at 2520 rpm of camshaft speed.
Steady-State Unbalance Response of Continuous Rotors on Anisotropic Supports
Authors: Curti Graziano , Raffa Francesco A. , Vatta Furio
Published: March 2021

An analytical investigation of the steady-state unbalance response of axisymmetric rotor systems with anisotropic, flexible and damped bearings is presented. According to the exact approach of the dynamic stiffness method, the rotor is modelled by means of continuous beam elements.

In this work, the expression of the 8 × 8 dynamic stiffness matrix of a rotating Timoshenko beam is derived and it is shown that it is related, by means of a simple law, to the previously published 4 × 4 dynamic stiffness matrix, which holds for the isotropic bearings case. The effects of concentrated disks and bearings are included into the formulation; in particular, each bearing is described by eight constant coefficients, according to the well-known linearized model of the bearing forces.

The unbalance response of a typical rotor system taken from the literature is analyzed. A comparison is presented with the finite element results reported by other authors.
An Integrated Approach Toward the Dynamic Analysis of High-Speed Spindles: Part I — System Model
Authors: Chen C. H. , Wang K. W. , Shin Y. C.
Published: March 2021

Experimental evidence [Shin, 1992] has shown that the natural frequencies of high speed spindles with angular contact ball bearings decrease with increasing rotational speed. A recent study [Wang, et al., 1991] illustrated that this phenomenon is caused by stiffness change of the bearings. A simplified approximation was used in the analysis to examine the bearing radial stiffness at high speeds. While the investigation explained the experimental observations in a qualitative sense, the analytical results so far are not sufficient to quantitatively describe the spindle behavior under high speed operations due to the approximations made in the modeling process. This paper presents an integrated approach toward the modelling of flexible spindles with angular contact ball bearings from basic principles. The local dynamics of the bearings are coupled with the global shaft motion. The model derived includes both the longitudinal and transverse vibrations of the shaft interacting with the nonlinear bearings. The influences of shaft speed on the bearing stiffness matrix and the system frequencies have been studied. It is shown that the spindle dynamic behavior can vary substantially as speed increases due to the bearing gyroscopic moment and centrifugal force. These effects have been ignored in most of the previous spindle models. Lab tests were conducted to validate the model. The analytical predictions are quantitatively verified by the experimental results.
Comparison of Linear and Nonlinear Control on a Distributed Parameter System
Authors: Rietz Ralph W. , Inman Daniel J.
Published: March 2021

The performance of a single link, very flexible manipulator using two different position control systems was studied. A standard PD feedback control was considered along with PD plus position times velocity feedback. An analytical model of the plant was identified and computer simulations using the two controllers were performed. The results clearly showed a decrease in control effort for the system using nonlinear control when compared to a similar response for the system using PD control. Experimental results on a slewing beam system verified this result. The system using the proposed nonlinear feedback control required significantly less energy to complete the same maneuver as the system using the standard PD feedback control. Other measures of performance (e.g. rise time, settling time, overshoot) were slightly improved when the nonlinear feedback was added to the controller.
Simultaneous Trajectory Tracking and Vibration Reduction of Distributed Parameter Systems Through Inverse Dynamics
Authors: Ledesma R. , Devasia S. , Bayo E.
Published: March 2021

This paper addresses the problem of inverse dynamics for three-dimensional articulated flexible structures with both lumped and distributed actuators. A recursive procedure is presented for computing the lumped inverse dynamic torques and the distributed piezoelectric actuator inputs for simultaneously tracking a prescribed end-point trajectory and reducing motion-induced vibrations in the articulated structure. The procedure sequentially solves for the non-causal inverse dynamic torques and piezoelectric voltages applied to each link in the open-chain articulated structure, starting from the last element in the chain and proceeding to the base element. The method allows trajectory tracking wherein controllability of the structural vibrations is assured in all possible configurations through the use of only one motor at each intermediate joint and three motors at the ground. Numerical simulation shows that the elastic vibrations can be reduced significantly through the use of distributed actuators while at the same time satisfying the trajectory tracking requirement through the use of inverse dynamics.
System Identification for Boring Bar Chatter Control
Authors: Embry Jonathan A. , Smith Suzanne Weaver , Walcott Bruce L.
Published: March 2021

The boring bar is used to provide smooth, accurate cuts in materials. However, when the length to diameter (L/D) ratio of the boring bar becomes large, low-frequency vibration, or chatter, results. Initial attempts to control this unwanted vibration with an active absorber have been successful, but in some configurations problems remain. In this paper, algorithms for flexible structure identification widely used in the aerospace industry are applied to a number of boring bar setups to identify the vibration characteristics of each system. Emphasis is placed on one class of methods which includes the Eigensystem Realization Algorithm (ERA), developed for identification of flexible space structures. The resulting identified characteristics are compared and contrasted. Results are also compared to finite element analysis predictions. From the current identification results, implications for chatter control are discussed, including the possibility of nonlinear modal interactions.
The Origins of Engineering Design
Authors: Dimarogonas Andrew D.
Published: March 2021

Engineering is distinguished from craft or invention by systematic development and use of intelligence and scientific knowledge. Elements of engineering design can be found in the great Potamic civilizations but systematic engineering design activity started in the ancient Greek and Hellenistic world and matured under the Romans. The renaissance and the industrial revolution revived Engineering and modern engineering design was eventually defined during the 19th Century.
On the Dynamics of a Rotary Compressor: Part 2 — Experimental Validation and Sensitivity Analysis
Authors: Padhy Sisir K.
Published: March 2021

This paper describes the experimental validation of the rotary compressor dynamics model [1]. Roller velocity is measured using video technology and a very good agreement is found with the theoretical results. A sensitivity study using different variables that affect the compressor dynamics is also carried out. It is found that the coefficient of friction at the vane and roller plays an important role in roller velocity. The dynamics of roller is influenced by the clearances, the roller radius, the vane radius, eccentricity of the shaft, the frictional behavior between the roller ends and the bearing plates, the discharge pressure of the compressor as well as the moment of inertia of roller.
An Improved Model for the Dynamics of Spur Gear Systems With Backlash Consideration
Authors: Shing Tai-Kang , Tsai Lung-Wen , Krishnaprasad P. S.
Published: March 2021

An improved model which accounts for backlash effects is proposed for the dynamics of spur gear systems. This dynamic model is mainly developed for the purpose of real time control. The complicated variation of the meshing stiffness as a function of contact point along the line of action is studied. Then the mean value is used as the stiffness constant in the improved model. Two simulations, free vibration and constant load operation, are performed to illustrate the effects of backlash on gear dynamics. Also given are comparisons of the simulation results with that of the Yang and Sun’s model. This model is judged to be more realistic which can be used in real time control to achieve high precision.
Development and Real Time Implementation of a Collision Detection Algorithm for an Automated Guided Vehicle
Authors: Majumder Indranil , Naganathan Nagi G. , Kim Young-Gon
Published: March 2021

An algorithm has been developed for detecting a collision-free path for an Automated Guided Vehicle (AGV) when it is required to navigate in an unstructured environment. Real time implementation issues are discussed and investigated experimentally using an ultrasonic sensor system. Concepts of obstacle matrix and path penalty are used in the guidance of the vehicle in a work area discretized as matrix cells. Two search methods namely, the arc searching method and obstacle crawling method, are developed for the AGV to facilitate navigation. The algorithm is capable of admitting the appropriate search method depending on the nature of the obstacles in the work area. Case studies using real time data from ultrasonic sensors demonstrate an excellent level of performance for the algorithm.
Shape Optimization Using a Variable Number of Conic Patches
Authors: Widmann James M. , Sheppard Sheri D.
Published: March 2021

Shape Optimization is a branch of structural optimization in which the boundaries of geometry are varied. The shape of the boundary is determined by optimizing a set of design variables that form the geometric description of the shape. This paper presents a method of two dimensional shape optimization in which the number of design variables is allowed to change during the optimization process. First an initial design representation is chosen and optimized. Next a new mathematical description of the optimized design is created with an increased number of design variables. This new design is subsequently optimized. This allows the optimization process to work within a larger design space that includes a greater variety of shapes. The process of adding design variables is repeated until no additional improvements in the design are made. Several design examples are solved with this procedure and presented.
A Decomposition Method for Concurrent Design of Mixed Discrete/Continuous Systems
Authors: Ford Jeffrey M. , Bloebaum Christina L.
Published: March 2021

Interest in Concurrent Engineering (CE) has increased as industry looks for more efficient means of product design. Design optimization methods that facilitate the CE approach are an important aspect of current research. Among the methods that have been proposed is the Concurrent Subspace Optimization (CSSO) method, which allows the optimization problem to be decomposed into coupled subproblems. These subproblems may correspond to the different disciplines involved in the design process or to participating organizational design or manufacturing groups. The decomposition allows each discipline to apply their own optimization criteria to the problem. While this method may not be as computationally efficient as other methods, it allows the design process to conform to the departmental divisions that already exist in industry.

The method development to date has focused on continuous systems only. However, problems that can not be modeled as continuous systems, such as those involving the placement of active controllers in CSI applications, would benefit from a method that allows the use of discrete parameters. The paper presents a decomposition method (based on CSSO) for the optimal design of mixed discrete/continuous systems. The method is applied to the design of a composite plate for minimum weight, with design variables contributed from sizing variables (continuous) and material combinations (discrete).
A Client/Server Implementation of the Design Process Using PDES/STEP “Level 3” Data Sharing Architecture
Authors: Edwards-lwe Esther A.
Published: March 2021

The ability to exchange and share product data between and within enterprises is essential for implementing the concepts of concurrent engineering as well as operating in a global market economy. STEP, the STandard for the Exchange of Product Model Data, is an international effort to standardize product information. Product information is used by manufacturing enterprise to design, produce, and maintain a product. The purpose of STEP is to prescribe a neutral mechanism capable of completely representing product data throughout the life cycle of a product.

Data sharing can only be discussed in the context of a specific application. The scope of STEP data sharing architecture has progressed from a single shared facility to sharing multiple distributed facilities. This paper discusses the lessons learned from a prototype implementation of the mechanical part design process(es) captured in a network of heterogeneous computers and database management systems to allow for data exchange and sharing between and within an enterprise.
Automation of Wind Pressure Computation Using a Data Management Approach
Authors: Gourishankar Yamini , Weisgerber Frank
Published: March 2021

It is observed that calculating the wind pressures on structures involves more data retrieval from the ASCE standard than any subjective reasoning on the designer’s part. Once the initial design requirements are established, the procedure involved in the computation is straightforward. This paper discusses an approach to automate the process associated with wind pressure computation on one story and multi-story buildings using a data management strategy (implemented using the ORACLE database management system). In the prototype system developed herein, the designer supplies the design requirements in the form of the structure’s exposure type, its dimensions and the nature of occupancy of the structure. Using these requirements, the program retrieves the necessary standards data from an independently maintained database, and computes the wind pressures. The final output contains the wind pressures on the main wind force resisting system, and on the components and claddings, for wind blowing parallel and perpendicular to the ridge.

The knowledge encoded in the system was gained from ASCE codes, design guidelines and as a result of interviews with various experts and practitioners. Several information modeling methodologies such as the entity relationship model, IDEF 1X, etc. were employed in the system analysis and design phase of this project. The prototype is implemented on an IBM PC using the ORACLE DBMS and the ‘C’ programming language. Appendix A illustrates a sample run.
Targeting metastatic NETs
Authors: Ferrarelli Leslie K.
Published: March 2021

Blocking tumor-to-neutrophil cross-talk by cathepsin C may prevent lung metastasis.
Two Functionally Redundant FK506-Binding Proteins Regulate Multidrug Resistance Gene Expression and Govern Azole Antifungal Resistance
Authors: Moirangthem Romila , Kumar Kundan , Kaur Rupinder
Published: March 2021

Increasing resistance to antifungal therapy is an impediment to the effective treatment of fungal infections.
Candida glabrata
is an opportunistic human fungal pathogen that is inherently less susceptible to cost-effective azole antifungals. Gain-of-function mutations in the Zn finger pleiotropic drug resistance transcriptional activator-encoding gene
CgPDR1
are the most prevalent causes of azole resistance in clinical settings.
CgPDR1
is also transcriptionally activated upon azole exposure; however, factors governing
CgPDR1
gene expression are not yet fully understood.
Identification of a Novel Hybrid Plasmid Encoding KPC-2 and Virulence Factors in Klebsiella pneumoniae Sequence Type 11
Authors: Jin Longyang , Wang Ruobing , Gao Hua , Wang Qi , Wang Hui
Published: March 2021

Recent emergence of carbapenem-resistant
Klebsiella pneumoniae
(CRKP) coharboring
bla
KPC-2
and pLVPK-like virulence plasmids represented a novel clinical challenge. In the present study, we characterized a
bla
KPC-2
and virulence hybrid plasmid, designated pCRHV-C2244, from a clinical ST11-K64 CRKP strain. pCRHV-C2244 was non-self-transmissible due to incomplete conjugative elements but mobilizable together with a conjugative helper.
IFN-γ
–/–
Mice Resist Actinobacillus pleuropneumoniae Infection by Promoting Early Lung IL-18 Release and PMN-I Accumulation
Authors: Bao Chuntong , Liu Baijun , Zhu Rining , Xiao Jiameng , Li Ziheng , Jiang Hexiang , Wang Beinan , Langford P. R. , Fei Rui , Li Na , Lei Liancheng
Published: March 2021

Porcine pleuropneumonia is a common infectious disease of pigs caused by
Actinobacillus pleuropneumoniae
. Interferon gamma (IFN-γ) expression increases in the lung of pigs after
A. pleuropneumoniae
infection, but the role of IFN-γ during the infection is still obscure.
c-di-AMP-Regulated K
+
Importer KtrAB Affects Biofilm Formation, Stress Response, and SpeB Expression in Streptococcus pyogenes
Authors: Faozia Sabrina , Fahmi Tazin , Port Gary C. , Cho Kyu Hong
Published: March 2021

The second messenger cyclic di-AMP (c-di-AMP) controls biofilm formation, stress response, and virulence in
Streptococcus pyogenes
. The deletion of the c-di-AMP synthase gene,
dacA
, results in pleiotropic effects including reduced expression of the secreted protease SpeB.
Ectopic Expression of Human Thymosin β4 Confers Resistance to Legionella pneumophila during Pulmonary and Systemic Infection in Mice
Authors: Park Bonggoo , Shin Min Hwa , Kim Jiyoung , Park Gayoung , Ryu Yun-Kyoung , Lee Jae-Wook , Kim Tae Jin , Moon Eun-Yi , Lee Kyung-Mi
Published: March 2021

Thymosin beta-4 (Tβ4) is an actin-sequestering peptide that plays important roles in regeneration and remodeling of injured tissues. However, its function in a naturally occurring pathogenic bacterial infection model has remained elusive.
Laboratory Diagnosis of 37 Cases of
Bartonella
Endocarditis Based on Enzyme Immunoassay and Real-Time PCR
Authors: Shapira Lev , Rasis Michal , Binsky Ehrenreich Inbal , Maor Yasmin , Katchman Eugene A. , Treves Adi , Velan Ariel , Halutz Ora , Graidy-Varon Merav , Leibovitch Cecilia , Maisler Noam , Ephros Moshe , Giladi Michael
Published: March 2021

Bartonella
spp., mostly
Bartonella quintana
and
B. henselae
, are a common cause of culture-negative endocarditis. Serology using immunofluorescence assay (IFA) and PCR performed on cardiac tissues are the mainstays of diagnosis.
Evolutionary Divergence in DNA Damage Responses among Fungi
Authors: Steenwyk Jacob L.
Published: March 2021

Cell cycle checkpoints and DNA repair pathways contribute to maintaining genome integrity and are thought to be evolutionarily ancient and broadly conserved. For example, in the yeast
Saccharomyces cerevisiae
and humans, DNA damage induces activation of a checkpoint effector kinase, Rad53p (human homolog Chk2), to promote cell cycle arrest and transcription of DNA repair genes.
Take a Walk to the Wild Side of
Caenorhabditis elegans
-Pathogen Interactions
Authors: Radeke Leah J. , Herman Michael A.
Published: March 2021

Microbiomes form intimate functional associations with their hosts. Much has been learned from correlating changes in microbiome composition to host organismal functions.
Microbial Diversity and Mercury Methylation Activity in Periphytic Biofilms at a Run-of-River Hydroelectric Dam and Constructed Wetlands
Authors: Leclerc Maxime , Harrison Makayla C. , Storck Veronika , Planas Dolors , Amyot Marc , Walsh David A.
Published: March 2021

Monomethylmercury (MMHg) is a biomagnifiable neurotoxin of global concern with risks to human health mostly associated with fish consumption. Hydroelectric reservoirs are known to be sources of MMHg many years after their impoundment.
Broadly Reactive H2 Hemagglutinin Vaccines Elicit Cross-Reactive Antibodies in Ferrets Preimmune to Seasonal Influenza A Viruses
Authors: Reneer Z. Beau , Skarlupka Amanda L. , Jamieson Parker J. , Ross Ted M.
Published: March 2021

H1N1 and H3N2 influenza viruses have cocirculated in the human population since 1977. Nearly every human alive today has antibodies and memory B and T cells against these two subtypes of influenza viruses.
Flow of Devonian anatectic crust in the accretionary Altai Orogenic Belt, central Asia: Insights into horizontal and vertical magma transfer
Authors: Wang Sheng , Jiang Yingde , Weinberg Roberto , Schulmann Karel , Zhang Jian , Li Pengfei , Xiao Ming , Xia Xiao-Ping
Published: March 2021

Flow of partially molten crust is a key contributor to mass and heat redistribution within orogenic systems, however, this process has not yet been fully understood in accretionary orogens. This issue is addressed in a Devonian migmatite-granite complex from the Chinese Altai through structural, petrological, and geochronological investigations presented in this study. The migmatite-granite complex records a gradual evolution from metatexite, diatexite to granite and preserves a record of two main Devonian phases of deformation designated D1 and D2. The D1 phase was subdivided into an early crustal thickening episode (D1B) and a later extensional episode (D1M) followed by D2 upright folding. The D1M episode is associated with anatexis in the deep crust. Vertical shortening, associated with D1M, gave rise to the segregation of melt and formation of a sub-horizontal layering of stromatic metatexite. This fabric was reworked by the D2 deformation associated with the migration of anatectic magma in the cores of F2 antiforms. Geochronological investigations combined with petro-structural analysis reveal that: (1) D1M partial melting started probably at 420–410 Ma and formed sub-horizontal stromatic metatexites at ∼30 km depth; (2) The anatectic magma accumulated and migrated when a drainage network developed, as attested by the pervasive formation of massive diatexite migmatites, at 410–400 Ma; (3) Soon after, massive flow of the partially molten crust from orogenic lower to orogenic upper crustal levels, assisted by the interplay between D2 upright folding and magma diapirism, led to migmatite-granite emplacement in the cores of regional F2 antiforms that lasted until at least 390 Ma; (4) a terminal stage was manifested by the emplacement of 370–360 Ma granite dykes into the surrounding metamorphic envelope. We propose that Devonian anatexis assisted by deformation governed first the horizontal and then the vertical flow of partially molten orogenic lower crust, which drove crustal flow, mass redistribution, and crustal differentiation in the accretionary system of the Chinese Altai.
Risk factors for intellectual disability in children with spastic cerebral palsy
Authors: Cummins David , Kerr Claire , McConnell Karen , Perra Oliver
Published: March 2021

Background

Cerebral palsy (CP) is a non-progressive disorder of posture and movement caused by prenatal or perinatal lesions of the brain. Children with CP are also at increased risk of other disabilities, for example, intellectual disability. Previous studies suggest the risk of intellectual disability varies in complex ways according to the type of motor impairment and perinatal factors such as gestational age.

Objective

To determine the patterns of risk of intellectual disability in children with spastic CP.

Design

Cross-sectional, population-based study using the Northern Ireland Cerebral Palsy Register.

Participants

Persons born in 1981–2008 with congenital bilateral or unilateral spastic CP (N=1452).

Outcome measure

The outcome measure was severe intellectual disability (IQ <50), as reported by clinicians known to the child. Data pertaining to CP subtype, sex, gestational age, birth weight and functional level were included in analyses.

Results

Severe intellectual disability was significantly more prevalent in children with bilateral spastic CP (BSCP) compared with children with unilateral spastic CP (χ² (2)=162.60, p<0.001). Compared with very preterm infants with BSCP, the risk of intellectual disability increased in moderately preterm (OR=3.97, 95% CI 1.04 to 15.23) and at-term (OR=2.51, 95% CI 1.16 to 5.44) children with BSCP.

Conclusions

Children with BSCP are at increased risk of intellectual disability, with those born at term at the highest risk. The findings highlight the importance of early screening, particularly for children with BSCP born at term.
Influence of agents and mechanisms of injury on anatomical burn locations in children <5 years old with a scald
Authors: Javaid Assim Ali , Johnson Emma , Hollén Linda , Kemp Alison Mary
Published: March 2021

Objective

To demonstrate how the mechanism and agent of injury can influence the anatomical location of a scald.

Design

Prospective multicentre cross-sectional study.

Setting

20 hospital sites across England and Wales including emergency departments, minor injury units and regional burns units.

Patients

Children aged 5 years and younger who attended hospital with a scald.

Main outcome measures

Primary outcome: a descriptive analysis of the mechanism, agent and anatomical location of accidental scalds. Secondary outcome: a comparison of these factors between children with and without child protection (CP) referral.

Results

Of 1041 cases of accidental scalds, the most common narrative leading to this injury was a cup or mug of hot beverage being pulled down and scalding the head or trunk (132/1041; 32.9% of cases). Accidental scalds in baths/showers were rare (1.4% of cases). Accidental immersion injuries were mainly distributed on hands and feet (76.7%). There were differences in the presentation between children with accidental scalds and the 103 who were referred for CP assessment; children with scalds caused by hot water in baths/showers were more likely to get referred for CP assessment (p<0.0001), as were those with symmetrically distributed (p<0.0001) and unwitnessed (p=0.007) scalds.

Conclusions

An understanding of the distributions of scalds and its relationship to different mechanisms of injury and causative agents will help clinicians assess scalds in young children, particularly those new to the emergency department who may be unfamiliar with expected scald patterns or with the importance of using appropriate terminology when describing scalds.
Palatal flap in bilateral inferior partial maxillectomy
Authors: Selvaraj Daniel Sathiya Sundaram , Gaikwad Pranay , Ebenezer Jagadish
Published: March 2021

Maxillectomy is done for a variety of disease conditions. Reconstruction following maxillectomy is done to restore the form and function. One of the important goals that are to be achieved in reconstruction is the separation of the oral and nasal cavities. In this article, we report the use of palatal flap by preserving the descending palatine artery during bilateral inferior partial maxillectomy, for separating the nasal cavity from the oral cavity. This technique eliminates the need for an obturator or another free or local flap for this purpose.
Surgical management of an odontogenic cutaneous fistula
Authors: Kelly Mairéad Sarah , Murray Dylan J
Published: March 2021

A patient presented to our unit with a long history of a discharging skin infection on his left cheek, which came and went. He had been seen by numerous healthcare practitioners including his general practitioner, general dental practitioner and dermatologist, with no resolution. He was eventually diagnosed with an odontogenic cutaneous fistula (OCF), for which he underwent surgical management. The purpose of the study is to describe the diagnosis and surgical management of an OCF, from initial assessment through to postoperative review and discharge. Following surgical management of the OCF and treatment of the source of infection by dental extraction, the patient is no longer experiencing purulent discharge through his left cheek. The extraoral skin site of drainage at his left cheek has resolved completely, with minimal residual scarring. OCF can be managed by a number of different treatment modalities. The treatment of an OCF by surgical excision is presented.
Additive manufacturing in community pharmacies: a framework for business model innovation
Authors: Feldmann Carsten , Rose Olaf
Published: March 2021

Background

Additive manufacturing offers new opportunities in that it brings the preindustrial production back into community pharmacies.

Methods

This study was based on the qualitative research methodology of action research. The 55 domains of the St. Gallen Business Model Navigator were applied to three-dimensional drug printing (3DDP) from the pharmaceutical and the economic perspectives. Results were synthesised and applied to a model of potential customer drivers.

Results

This study classified 55 relevant business models into a framework to systematise business model innovations. Out of the potential 55 business model patterns, 27 have been identified as suitable for implementation. Promising examples of business model characteristics are to foster customer loyalty by convenience and therapeutic benefits, to offer an individualised shopping experience, to provide a guaranteed availability, to leverage customer data for selling additive services, to create value in a specialised niche, to create mass customisation and to offer ultimate luxury.

Conclusion

A reference model to systematise promising business model patterns for practitioners was developed, providing initial indications for implementation of 3DDP in community pharmacies. Pharmacies innovating or extending their business models can strengthen their positions in the value chain, create competitive advantages and expand into new markets.
Risk of dispersion or aerosol generation and infection transmission with nasopharyngeal and oropharyngeal swabs for detection of COVID-19: a systematic review
Authors: Agarwal Arnav , Fernando Shannon M , Honarmand Kimia , Bakaa Layla , Brar Sonia , Granton David , Chaudhuri Dipayan , Chetan Devin , Hu Malini , Basmaji John , Muttalib Fiona , Rochwerg Bram , Adhikari Neill K J , Lamontagne Francois , Murthy Srinivas , Hui David S , Gomersall Charles D , Mubareka Samira , Diaz Janet , Burns Karen EA , Couban Rachel , Vandvik Per O
Published: March 2021

Objectives

SARS-CoV-2-related disease, referred to as COVID-19, has emerged as a global pandemic since December 2019. While there is growing recognition regarding possible airborne transmission, particularly in the setting of aerosol-generating procedures and treatments, whether nasopharyngeal and oropharyngeal swabs for SARS-CoV-2 generate aerosols remains unclear.

Design

Systematic review.

Data sources

We searched Ovid MEDLINE and EMBASE up to 3 November 2020. We also searched the China National Knowledge Infrastructure, Chinese Medical Journal Network, medRxiv and ClinicalTrials.gov up to 29 March 2020.

Eligibility criteria

All comparative and non-comparative studies that evaluated dispersion or aerosolisation of viable airborne organisms, or transmission of infection associated with nasopharyngeal or oropharyngeal swab testing.

Results

Of 7702 citations, only one study was deemed eligible. Using a dedicated sampling room with negative pressure isolation room, personal protective equipment including N95 or higher masks, strict sterilisation protocols, structured training with standardised collection methods and a structured collection and delivery system, a tertiary care hospital proved a 0% healthcare worker infection rate among eight nurses conducting over 11 000 nasopharyngeal swabs. No studies examining transmissibility with other safety protocols, nor any studies quantifying the risk of aerosol generation with nasopharyngeal or oropharyngeal swabs for detection of SARS-CoV-2, were identified.

Conclusions

There is limited to no published data regarding aerosol generation and risk of transmission with nasopharyngeal and oropharyngeal swabs for the detection of SARS-CoV-2. Field experiments to quantify this risk are warranted. Vigilance in adhering to current standards for infection control is suggested.
Cardiometabolic risk factors and early indicators of vascular dysfunction: a cross-sectional cohort study in South African adolescents
Authors: Letswalo Boitumelo Prescilla , Schmid-Zalaudek Karin , Brix Bianca , Matjuda Edna Ngoakoana , Klosz Fabian , Obernhumer Natalie , Gaisl Michael , Engwa Godwill Azeh , Sewani-Rusike Constance , Fredriksen Per Morten , Nkeh-Chungag Benedicta , Goswami Nandu
Published: March 2021

Objectives

Prevalence of child and adolescents’ overweight and obesity in low- and middle-income countries has increased dramatically. Simultaneously, the incidence of pre-hypertension/hypertension is also increasing in children, which, in turn, predisposes these children to the risk of cardiovascular disease (CVD) in later life. The present study assessed cardiometabolic risk factors and early indicators of vascular dysfunction in adolescents from a low socio-economic rural area in South Africa.

Design

Cross-sectional cohort study.

Setting

The study was conducted in public schools in Mthatha, OR Tambo district municipality, Eastern Cape Province, South Africa.

Participants

A total of 244 adolescents (188 females) of African ancestry aged 13–16 years were enrolled.

Primary and secondary outcome measures

Anthropometric and haemodynamic measures and pulse wave velocity (PWV) were related to overweight/obesity and hypertension. Blood markers of cardiometabolic syndrome were assessed as well as vascular function (via PWV).

Results

One-third (33.0%) of the adolescents exceeded the age and sex-specific body mass index percentiles for overweight (≥85th) or obesity (>95th) with a prevalence of 61.1% pre-hypertensives in this group. Overweight/obesity and hypertension were associated with higher triglycerides (lean:overweight: 0.79<1.01 mmol/L; normotensive:hypertensive: 0.82<0.89 mmol/L). Fasting glucose was higher in hypertensive as compared to normotensive adolescents (4.85>4.69 mmol/L, p<0.05). PWV was elevated in 25.9% of the children and significantly correlated with asymmetric dimethylarginine and systolic blood pressure (p<0.001).

Conclusion

Overweight/obesity and hypertension show a high prevalence in rural South African youth. Almost half of the studied adolescents are at risk for developing CVD. The high association between cardiometabolic risk factors and PWV further suggests that hypertension in adolescents may promote the progression of CVD in adulthood. Early detection of those at risk and the implementation of preventive strategies in underprivileged young people is urgently needed to stop the progression of vascular damage and manifestation of CVD in rural African children.
Do neurocritical care units improve outcomes for brain-injured adults: a protocol for a systematic review and meta-analysis
Authors: Pham Xiuxian , Ray Jason , Serpa Neto Ary , Udy Andrew
Published: March 2021

Introduction

Neurocritical care is a rapidly developing subspecialty within intensive care medicine which aims to improve outcomes of critically ill neurological patients. This has inspired the formation of specialised intensive care units or services to provide dedicated care of brain-injured patients, as well as new training pathways for physicians. However, expansion has been variable worldwide and it is yet to be determined if there are clear benefits in regard to patient outcomes. We are planning a systematic review with meta-analysis to assess whether the introduction of neurocritical care units or services, or neurointensivists have favourable effects on survival.

Methods and analysis

We will include all observational and interventional studies comparing specialised neurocritical care units or services with general or non-specialised units in the care of acutely brain-injured adults. The primary outcome will be all-cause mortality at the longest follow-up, and secondary outcomes will be intensive care unit and hospital length of stay, and functional outcomes. All relevant studies will be identified through database searches. All study selection and data extraction will be conducted by two independent reviewers. We will conduct a random-effects meta-analysis to synthesise evidence for all outcomes. In addition, we will perform a subgroup analysis by disease process. We will assess confidence in the cumulative evidence using the Grading of Recommendations, Assessment, Development and Evaluations framework.

Ethics and dissemination

This systematic review and meta-analysis does not require ethical approval. We will publish findings from this systematic review in a peer-reviewed scientific journal and present these at conferences. It will be included in the primary author’s higher degree research thesis.

PROSPERO registration number

CRD42020177190.
Incidence of occupational injuries and diseases among seafarers: a descriptive epidemiological study based on contacts from onboard ships to the Italian Telemedical Maritime Assistance Service in Rome, Italy
Authors: Sagaro Getu Gamo , Dicanio Marzio , Battineni Gopi , Samad Marc Abdul , Amenta Francesco
Published: March 2021

Objectives

Workers at sea have high mortality, injuries and illnesses and work in a hazardous environment compared to ashore workers. The present study was designed to measure the incidence of occupational injuries and diseases among seafarers and quantify the contribution of differences in rank and job onboard on seafarers’ diseases and injuries rates.

Design

Descriptive epidemiological study.

Setting and participants

This study’s data were based on contacts (n=423) for medical requests from Compagnie Maritime d'Affrètement/Compagnie Générale Maritime (CMA-CGM) container ships to the Italian Telemedical Maritime Assistance Service in Rome from 2016 to 2019, supplemented by data on the estimated total at-risk seafarer population on container ships (n=13 475) over the study period.

Outcome measures

Distribution of injuries by anatomic location and types of diseases across seafarers’ ranks and worksites. We determined the incidence rate and incidence rate ratio (IRR) with a 95% CI.

Results

The total disease rate was 25 per 1000 seafarer-years, and the overall injury rate was 6.31 per 1000 seafarer-years over the 4 years study period. Non-officers were more likely than officers to have reported gastrointestinal (IRR 2.12, 95% CI 1.13 to 4.26), dermatological (IRR 3.66, 95% CI 1.27 to 14.42) and musculoskeletal (IRR 2.25, 95% CI 1.11 to 5.05) disorders onboard container ships. Deck workers were more likely than engine workers to be injured in the wrist and hand (IRR 3.25, 95% CI 1.19 to 10.23).

Conclusions

Rates of reported injury and disease were significantly higher among non- officers than officers; thus, this study suggests the need for rank-specific preventative measures. Future studies should consider risk factors for injury and disease among seafarers in order to propose further preventive measures.