Effect of a back-support exoskeleton on internal forces and lumbar spine stability during low load lifting task.

This study assessed the effect of a small-torque generating passive back-support exoskeleton during a low demanding occupational task, namely a repetitive lifting/lowering of an empty crate between the knee and shoulder heights. A comprehensive set of outcomes was considered, ranging from the measured trunk muscle activation and trunk movement to the estimated muscle group forces/coordination, spine loading and spine stability, using a dynamic subject-specific EMG-assisted musculoskeletal model. The exoskeleton decreased back muscle activation and corresponding muscle forces in the lowering phase and reduced spinal loading at larger trunk flexion angles (decreased peak compression and shear forces by ∼ 15%).

A Biomechanics-Aware Robot-Assisted Steerable Drilling Framework for Minimally Invasive Spinal Fixation Procedures.

In this paper, we propose a novel biomechanics-aware robot-assisted steerable drilling framework with the goal of addressing common complications of spinal fixation procedures occurring due to the rigidity of drilling instruments and implants. This framework is composed of two main unique modules to design a robotic system including (i) a Patient-Specific Biomechanics-aware Trajectory Selection Module used to analyze the stress and strain distribution along an implanted pedicle screw in a generic drilling trajectory (linear and/or curved) and obtain an optimal trajectory; and (ii) a complementary semi-autonomous robotic drilling module that consists of a novel Concentric Tube Steerable Drilling Robot (CT-SDR) integrated with a seven degree-of-freedom robotic manipulator. This semi-autonomous robot-assisted steerable drilling system follows a multi-step drilling procedure to accurately and reliably execute the optimal hybrid drilling trajectory (HDT) obtained by the Trajectory Selection Module.

Comparative evaluation of different spinal stability metrics.

Direct in vivo measurements of spinal stability are not possible, leaving computational estimations (such as dynamic time series and structural analyses) as the feasible option. However, differences between different stability assessment approaches and metrics remain unclear. To explore this, we asked 32 participants to perform 35 cycles of repetitive lifts with and without load (4/2.

Validation of an EMG submaximal method to calibrate a novel dynamic EMG-driven musculoskeletal model of the trunk: Effects on model estimates.

Background: Multijoint EMG-assisted optimization models are reliable tools to predict muscle forces as they account for inter- and intra-individual variations in activation. However, the conventional method of normalizing EMG signals using maximum voluntary contractions (MVCs) is problematic and introduces major limitations. The sub-maximal voluntary contraction (SVC) approaches have been proposed as a remedy, but their performance against the MVC approach needs further validation particularly during dynamic tasks.

Submaximal electromyography-driven musculoskeletal modeling of the human trunk during static tasks: Equilibrium and stability analyses.

Conventional electromyography-driven (EMG) musculoskeletal models are calibrated during maximum voluntary contraction (MVC) tasks, but individuals with low back pain cannot perform unbiased MVCs. To address this issue, EMG-driven models can be calibrated in submaximal tasks. However, the effects of maximal (when data points include the maximum contraction) and submaximal calibration techniques on model outputs (e.

Modeling of human intervertebral disc annulus fibrosus with complex multi-fiber networks.

Collagen fibers within the annulus fibrosus (AF) lamellae are unidirectionally aligned with alternating orientations between adjacent layers. AF constitutive models often combine two adjacent lamellae into a single equivalent layer containing two fiber networks with a crisscross pattern. Additionally, AF models overlook the inter-lamellar matrix (ILM) as well as elastic fiber networks in between lamellae.

On the modeling of human intervertebral disc annulus fibrosus: Elastic, permanent deformation and failure responses.

As a primary load-resisting component, annulus fibrosus (AF) maintains structural integrity of the entire intervertebral disc. Experiments have demonstrated that permanent deformation and damage take place in the tissue under mechanical loads. Development of an accurate model to capture the complex behaviour of AF tissue is hence crucial in disc model studies.

The effect of microthread design on magnitude and distribution of stresses in bone: A three-dimensional finite element analysis.

Background: The researches regarding the influence of microthread design variables on the stress distribution in bone and a biomechanically optimal design for implant neck are limited. The aim of the present study is to compare the effect of different microthread designs on crestal bone stress.

Materials And Methods: Six implant models were constructed for three-dimensional finite element analysis including two thread profile (coarse and fine) with three different lengths of microthreaded neck (1 mm, 2 mm, and 3 mm).

Oral Health Knowledge and Attitudes of Community Health Workers in East Azerbaijan, Iran.

Statement Of The Problem: Prevention is the key factor in acquiring dental and oral health. Community health workers, as a part of health care networks in Iran, play an important role in delivering primary care and their knowledge and attitude directly affect the population whom they interact with in their service scope.

Purpose: The aim of this research was to evaluate the knowledge and attitude level of community health workers regarding oral health.

Clinical comparison of coronally-advanced flap plus amniotic membrane or subepithelial connective tissue in the treatment of Miller's class I and II gingival recessions: A split-mouth study.

Background. The aim of the present study was to compare coronally advanced flap (CAF) plus amniotic membrane (AM) to CAF with connective tissue graft (CTG) in the treatment of Miller's class I and II gingival recessions. Methods.

Synthesis, characterization, X-ray crystal structure, DFT calculation and antibacterial activities of new vanadium(IV, V) complexes containing chelidamic acid and novel thiourea derivatives.

Three new thiourea ligands derived from the condensation of aroyl- and aryl-isothiocyanate derivatives with 2,6-diaminopyridine, named 1,1'-(pyridine-2,6-diyl)bis(3-(benzoyl)thiourea) (L1), 1,1'-(pyridine-2,6-diyl)bis(3-(2-chlorobenzoyl)thiourea) (L2) and 1,1'-(pyridine-2,6-diyl)bis(3-(4-chlorophenyl)thiourea) (L3), their oxido-vanadium(IV) complexes, namely [VO(L1('))(H2O)] (C1), [VO(L2('))(H2O)] (C2) and [VO(L3('))(H2O)] (C3), and also, dioxo-vanadium(V) complex containing 4-hydroxy-2,6-pyridine dicarboxylic acid (chelidamic acid, H2dipic-OH) and metformin (N,N-dimethylbiguanide, Met), named [H2Met][VO2(dipic-OH)]2·H2O (C4), were synthesized and characterized by elemental analysis, FTIR and (1)H NMR and UV-visible spectroscopies. Proposed structures for free thiourea ligands and their vanadium complexes were corroborated by applying geometry optimization and conformational analysis. Solid state structure of complex [H2Met][VO2(dipic-OH)]2·H2O (triclinic, Pī) was fully determined by single crystal X-ray diffraction analysis.

Analysis of developmental level of counties of Fars in terms of health infrastructure indicators using standardized scores pattern approach and factor analysis.

Introduction: It is necessary for planning in order to achieve optimal development, to have knowledge and understanding of the current situation. This identification requires separate areas of study into planning and assessing regions of each area with development indicators and analysis and ranking each area in terms of having gifts of development. The study also aims to analyze the development level of counties of Fars in terms of health infrastructure indicators using standardized scores pattern and factor analysis.

The Effects of One-Stage Full-Mouth Disinfection and Qua-drant-Wise Scaling and Root Planing on Serum Levels of IL-17 and IL-1β and Clinical Parameters (A randomized Controlled Trial Study).

Objective: One-stage full-mouth disinfection technique (FMD) has been introduced to avoid cross-contamination between the treated and untreated regions between treatment sessions. Considering the role of inflammatory mediators in periodontitis, the aim of the present study was to compare the effects of FMD with the quadrant-wise scaling and root planing (Q-SRP) on serum levels of IL-17 and IL-1β in patients with moderate-to-severe chronic periodontitis.

Materials And Methods: Twenty patients with chronic periodontitis were selected randomly and based on inclusion criteria in each group.

Evaluation of alteration in mucogingival line location following use of subepithelial connective tissue graft.

Aim And Objective: The aim of this study is to evaluate the positional changes that occur in mucogingival line following the use of subepithelial connective tissue graft (SCTG).

Materials And Methods: In 19 Miller class I or II gingival recession defects, distance between mucogingival line (MGL) and cemento-enamel junction, also width of keratinized and attached gingiva, and clinical attachment level were measured. SCTG were used for covering the exposed roots.

Detection of Helicobacter pylori using PCR in dental plaque of patients with and without gastritis.

Objectives: Helicobacter pylori (H.pylori) accounts for gastritis, peptic ulcer and is a probable cause of gastric cancer. Since its detection in the oral cavity, concerns have been raised about dental plaque as a reservoir for reinfection.

Assessment of the etiologic factors of gingival recession in a group of patients in northwest iran.

Background And Aims: Gingival recession (GR), a common problem in periodontium, is associated with various etiologic factors. There is controversy over the role and importance of these factors. The aim of this study was to evaluate the etiologic factors of GR in a group of subjects in Northwest Iran.

A comparative study of the long term results of root coverage with connective tissue graft or enamel matrix protein: 24-month results.

Background: The objective of this study was to compare the 24 month results of coronally advanced flap + enamel matrix derivates (EMD+CAF) and CAF+ connective tissue graft (CTG+CAF) in the treatment of Miller Class I recession defects.

Methods: Twelve patients with bilateral gingival recessions were treated with EMD+CAF or CTG+CAF. Vertical recession depth (VRD), keratinized tissue width (KTW), clinical attachment level (CAL), and clinical probing depth (CPD) were measured preoperatively, 1 and 2 years post surgery.

Endocarditis Prophylaxis in Cardiac Patients: Knowledge among General Dental Practitioners in Tabriz.

Background And Aims: Dental procedures injuring oral tissues may induce bacterial release to blood stream that can cause infective endocarditis in susceptible patients. The aim of this study was to determine the level of knowledge of general dental practitioners (GDPs) in Tabriz, Northwest of Iran, regarding endocarditis prophylaxis in cardiac pa-tients receiving dental treatments.

Materials And Methods: This was a cross-sectional, descriptive, analytical study that included 150 GDPs.

A Clinical Comparison of Cenobone (A Decalcified Freeze-dried Bone Allograft) with Autogenous Bone Graft in the Treatment of Two- and Three-wall Intrabony Periodontal Defects: A Human Study with Six-month Reentry.

Background And Aims: Complete and predictable regeneration of tissue lost as a result of infection or trauma is the ultimate goal of periodontal therapy. Various graft materials have been successfully used in the treatment of intrabony defects. The purpose of this study was to evaluate the use of a decalcified freeze-dried bone allograft (Cerabone) with the autogenous bone graft as a gold standard in the treatment of human two- or three-wall intrabony periodontal defects.

Assessment of Intra- and Inter-examiner Reproducibility of Probing Depth Measurements with a Manual Periodontal Probe.

Background And Aims: The main purpose of this study was to assess intra- and inter-examiner reproducibility of probing depth measurements with a manual periodontal probe.

Materials And Methods: In this study, 32 dental students in Tabriz Faculty of Dentistry with normal periodontium were evaluated. Each tooth of the upper right quadrants, except the third molars, was examined.