Phase Level Assessment of Ergonomic Intervention Effectiveness in Reducing Knee Musculoskeletal Disorder Risks During Residential Roof Shingle Installation.

Background: This study aimed to assess how knee savers (KSs) and knee pads (KPs) alleviate risks of knee musculoskeletal disorders (MSDs) among roofers during various phases of shingle installation. These phases encompass (1) reaching for shingles, (2) placing shingles, (3) grabbing a nail gun, (4) moving to the first nailing position, (5) nailing shingles, (6) replacing the nail gun, and (7) returning to an upright position.

Methods: In a laboratory setting, nine male participants simulated the shingle installation task on a slope-adjustable roof platform (0°, 15°, and 30° slopes) under four intervention conditions: no intervention (NO); with KPs only (KP); with KSs only (KS); and with both KPs and KSs (BO).

AGREEMENT OF HIP KINEMATICS BETWEEN TWO TRACKING MARKER CONFIGURATIONS USED WITH THE CODA PELVIS DURING ERGONOMIC ROOFING TASKS.

The anterior and posterior iliac spine markers frequently used to define the pelvis, are commonly occluded during three-dimensional (3D) motion capture. The occlusion of these markers leads to the use of various tracking marker configurations on the pelvis, which affect kinematic results. The purpose of this investigation was to examine the agreement of CODA pelvis kinematic results when two different tracking marker configurations were used during roofing tasks.

Spatiotemporal gait parameters while cross-slope residential roof walking.

Falls from residential roofs account for 80% of roofing industry fatalities. Furthermore, roofing work represents 44.7% of work in residual construction specialty trades and residential roofers count for 2.

Inclination angles during cross-slope roof walking.

Residential roofers have the highest rate of falls in the construction sector with injuries and fatalities costing billions of dollars annually. The sloped roof surface is the most predominant component within the residential roof work environment. Postural stability on a sloped work environment is not well studied.

Fusing imperfect experimental data for risk assessment of musculoskeletal disorders in construction using canonical polyadic decomposition.

Field or laboratory data collected for work-related musculoskeletal disorder (WMSD) risk assessment in construction often becomes unreliable as a large amount of data go missing due to technology-induced errors, instrument failures or sometimes at random. Missing data can adversely affect the assessment conclusions. This study proposes a method that applies Canonical Polyadic Decomposition (CPD) tensor decomposition to fuse multiple sparse risk-related datasets and fill in missing data by leveraging the correlation among multiple risk indicators within those datasets.

Kneeling trunk kinematics during simulated sloped roof shingle installation.

Trunk musculoskeletal disorders are common among residential roofers. Addressing this problem requires a better understanding of the movements required to complete working tasks, such as affixing shingles on a sloped residential roof. We analyzed the extent to which the trunk kinematics during a shingling process are altered due to different angles of roof slope.

Effects of working posture and roof slope on activation of lower limb muscles during shingle installation.

Awkward and extreme kneeling during roofing generates high muscular tension which can lead to knee musculoskeletal disorders (MSDs) among roofers. However, the combined impact of roof slope and kneeling posture on the activation of the knee postural muscles and their association to potential knee MSD risks among roofers have not been studied. The current study evaluated the effects of kneeling posture and roof slope on the activation of major knee postural muscles during shingle installation via a laboratory assessment.

Are knee savers and knee pads a viable intervention to reduce lower extremity musculoskeletal disorder risk in residential roofers?

One factor commonly associated with musculoskeletal disorder risk is extreme postures. To lessen this risk, individuals must be in an as neutral posture as possible while working. We analyzed how the inclusion of different combinations of two interventions-knee pads and knee savers-can alter lower extremity kinematics during deep or near full flexion kneeling occurs while on different sloped surfaces.

Expansin gene loss is a common occurrence during adaptation to an aquatic environment.

Expansins comprise a superfamily of plant cell wall loosening proteins that can be divided into four individual families (EXPA, EXPB, EXLA and EXLB). Aside from inferred roles in a variety of plant growth and developmental traits, little is known regarding the function of specific expansin clades, for which there are at least 16 in flowering plants (angiosperms); however, there is evidence to suggest that some expansins have cell-specific functions, in root hair and pollen tube development, for example. Recently, two duckweed genomes have been sequenced (Spirodela polyrhiza strains 7498 and 9509), revealing significantly reduced superfamily sizes.

Biomechanical modeling of deep squatting: Effects of the interface contact between posterior thigh and shank.

Epidemiological studies indicate that occupational activities that require extended deep knee flexion or kneeling are associated with a higher prevalence of knee osteoarthritis. In many sport activities, such as a catcher in a baseball or a softball game, athletes have to make repetitive deep squatting motions, which have been associated with the development of osteochondritis dissecans. Excessive deep knee flexion postures may cause excessive loading in the knee joint.

Utility of the Amborella trichopoda expansin superfamily in elucidating the history of angiosperm expansins.

Expansins form a superfamily of plant proteins that assist in cell wall loosening during growth and development. The superfamily is divided into four families: EXPA, EXPB, EXLA, and EXLB (Sampedro and Cosgrove in Genome Biol 6:242, 2005. doi: 10.

Fluoroscopic determination of the tibial insertion of the posterior cruciate ligament in the sagittal plane.

Background: Currently, placement of the tibial tunnel for arthroscopic transtibial posterior cruciate ligament (PCL) reconstruction relies on a limited arthroscopic view of the native insertion or the use of intraoperative imaging. No widely accepted method exists for intraoperative determination of PCL tibial tunnel placement, and current descriptions are cumbersome.

Purpose: To identify the center of the PCL's anatomic tibial insertion site as a percentage of the PCL facet length on a lateral radiograph of the knee so that it may be reliably located in the sagittal plane during surgical reconstruction.

Subject-specific finite element modeling of the tibiofemoral joint based on CT, magnetic resonance imaging and dynamic stereo-radiography data in vivo.

In this paper, we present a new methodology for subject-specific finite element modeling of the tibiofemoral joint based on in vivo computed tomography (CT), magnetic resonance imaging (MRI), and dynamic stereo-radiography (DSX) data. We implemented and compared two techniques to incorporate in vivo skeletal kinematics as boundary conditions: one used MRI-measured tibiofemoral kinematics in a nonweight-bearing supine position and allowed five degrees of freedom (excluding flexion-extension) at the joint in response to an axially applied force; the other used DSX-measured tibiofemoral kinematics in a weight-bearing standing position and permitted only axial translation in response to the same force. Verification and comparison of the model predictions employed data from a meniscus transplantation study subject with a meniscectomized and an intact knee.

Selaginella moellendorffii has a reduced and highly conserved expansin superfamily with genes more closely related to angiosperms than to bryophytes.

Background: Expansins are plant cell wall loosening proteins encoded by a large superfamily of genes, consisting of four families named EXPA, EXPB, EXLA, and EXLB. The evolution of the expansin superfamily is well understood in angiosperms, thanks to synteny-based evolutionary studies of the gene superfamily in Arabidopsis, rice, and Populus. Analysis of the expansin superfamily in the moss Physcomitrella patens revealed a superfamily without EXLA or EXLB genes that has evolved considerably and independently of angiosperm expansins.

Portrait of the expansin superfamily in Physcomitrella patens: comparisons with angiosperm expansins.

Background And Aims: Expansins are plant cell wall loosening proteins important in a variety of physiological processes. They comprise a large superfamily of genes consisting of four families (EXPA, EXPB, EXLA and EXLB) whose evolutionary relationships have been well characterized in angiosperms, but not in basal land plants. This work attempts to connect the expansin superfamily in bryophytes with the evolutionary history of this superfamily in angiosperms.

Genome histories clarify evolution of the expansin superfamily: new insights from the poplar genome and pine ESTs.

Expansins comprise a superfamily of plant cell wall-loosening proteins that has been divided into four distinct families, EXPA, EXPB, EXLA and EXLB. In a recent analysis of Arabidopsis thaliana and Oryza sativa expansins, we proposed a further subdivision of the families into 17 clades, representing independent lineages in the last common ancestor of monocots and eudicots. This division was based on both traditional sequence-based phylogenetic trees and on position-based trees, in which genomic locations and dated segmental duplications were used to reconstruct gene phylogeny.

Use of genomic history to improve phylogeny and understanding of births and deaths in a gene family.

Polyploidy events have played an important role in the evolution of angiosperm genomes. Here, we demonstrate how genomic histories can increase phylogenetic resolution in a gene family, specifically the expansin superfamily of cell wall proteins. There are 36 expansins in Arabidopsis and 58 in rice.