Breast cancer survivors may be at risk of experiencing rotator cuff disease after treatment. Biomechanical alterations following surgery potentially predispose survivors to develop this disorder.
To ...examine scapular kinematics in breast cancer survivors with and without impingement pain during an overhead reach task.
A cross-sectional study.
Three surgery groups were included: non-cancer controls, mastectomy-only survivors and post-reconstruction survivors. Breast cancer survivor groups were also categorized by the presence of impingement pain. Scapular motion was tracked during an overhead reach task, performed separately by both arms. Maximum scapular internal rotation, upward rotation and tilt were calculated. Two-way analyses of variance with interactions (p < .05) were used to test the effects of group (control, mastectomy-only, reconstruction) and impingement pain (pain, no pain) on each variable within a (left/right) side.
Scapular kinematics varied with the group by pain interaction. On the right side, the mastectomy-pain group had reduced upward rotation, while the reconstruction-pain group had higher upward rotation (mastectomy-only: 22.9° vs. reconstruction: 31.2°). On the left side, the mastectomy-pain group had higher internal rotation, while the reconstruction-pain group had reduced internal rotation (mastectomy-only: 45.1° vs. reconstruction: 39.3°). However, time since surgery was longer in the mastectomy-pain group than reconstruction-pain group, suggesting there may be a temporal component to kinematic compensations.
There are kinematic alterations in breast cancer survivors that may promote future development of rotator cuff disease. Compensations may begin as protective and progress to more harmful alterations with time.
KEY MESSAGES
Scapular kinematics varied with surgery and pain interaction: upward rotation was lower and internal rotation higher in mastectomy-pain group, while upward rotation was higher and internal rotation lower in reconstruction-pain group.
Kinematics alterations may also be associated with time since surgery, as the mastectomy-pain group had longer time since surgery than the reconstruction-pain group.
Kinematic alterations may transition from protective to harmful over time.
In-depth analyses by reconstruction type are needed to determine surgery-specific effects on kinematics and their potential impact on the development of rotator cuff disease.
Aluminum alloys are in high demand for additive manufacturing (AM) processing. However, the physical properties of Al alloys are less favorable for the production of repeatable and reliable parts, ...with factors such as surface oxide scales, high thermal conductivity, and large solidification shrinkage. Despite these characteristics, processing strategies have been developed to overcome these hurdles. The objective of this article is to highlight the different microstructure–processing–properties characteristics for the three main families of aluminum alloys: pure, casting, and wrought chemistries. The article focuses on AM processes involving solidification, including powder bed and direct energy deposition for both powder and wire feedstock.
Repetitive use of handheld nutrunners contributes to the development of musculoskeletal disorders (MSDs) among assembly operators. Tool-using organizations control the physical exposures resulting ...from nutrunners through their own, company-specific methods and recommendations. The aim of this study was to explore an automotive organization's current practice when conducting ergonomics assessments of nutrunner use. Fourteen employees representing different professional roles within the automotive manufacturing organization were interviewed about their involvement in, and approaches to, ergonomics evaluations of nutrunners. Findings show that the objective criteria tightening torque and tool type are combined with the operators' subjective assessments of the load to identify MSD risks associated with nutrunner use. This way, the effects of factors such as working posture could be integrated into the assessment. Further, it was found that information and knowledge availability could influence the resulting exposures estimates, where for example information about how to appropriately select tool settings is not readily available. In addition, there are negotiating criteria such as quality considerations which need to be balanced with health and safety management, influencing the physical demands associated with power tools.
By providing insight into an automotive manufacturer's approach to managing and assessing handheld tightening tools, policy-makers can form recommended limits and methods for standardized assessments of reaction load exposure from nutrunners.
•Objective and subjective criteria are used to assess nutrunners in the organization•Ergonomics criteria compete against business-critical metrics of safety and quality•Information about how to appropriately program the tools is lacking•Stakeholders desire standard exposure limits for force exposure from nutrunners
To investigate the feasibility, costs and sample representativeness of a recruitment method that used workers with back injuries as the point of entry into diverse working environments.
Workers' ...compensation claims were used to randomly sample workers from five heavy industries and to recruit their employers for ergonomic assessments of the injured worker and up to 2 co-workers.
The final study sample included 54 workers from the workers' compensation registry and 72 co-workers. This sample of 126 workers was based on an initial random sample of 822 workers with a compensation claim, or a ratio of 1 recruited worker to approximately 7 sampled workers. The average recruitment cost was CND$262/injured worker and CND$240/participating worksite including co-workers. The sample was representative of the heavy industry workforce, and was successful in recruiting the self-employed (8.2%), workers from small employers (<20 workers, 38.7%), and workers from diverse working environments (49 worksites, 29 worksite types, and 51 occupations).
The recruitment rate was low but the cost per participant reasonable and the sample representative of workers in small worksites. Small worksites represent a significant portion of the workforce but are typically underrepresented in occupational research despite having distinct working conditions, exposures and health risks worthy of investigation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Alignment of tropoelastin molecules during the process of elastogenesis is thought to require fibrillin-containing microfibrils. In this study, we have demonstrated that amino-terminal domains of two ...microfibrillar proteins, fibrillin-1 and fibrillin-2, interact with tropoelastin in solid phase binding assays. The tropoelastin-binding site was localized to a region beginning at the glycine-rich and proline-rich regions of fibrillin-2 and fibrillin-1, respectively, and continuing through the second 8-cysteine domain. Characterization of the binding requirements using the fibrillin-2 construct found that a folded, secondary structure was necessary for binding. Furthermore, binding between tropoelastin and fibrillin was mediated by ionic interactions involving the lysine side chains of tropoelastin. The importance of the lysine side chains was corroborated by the finding that the fibrillin-2 construct did not bind to mature elastin, whose lysine side chains have been modified to form cross-links. Interestingly, there was no interaction between the fibrillin constructs and tropoelastin in solution phase, suggesting that binding of tropoelastin to a solid substrate exposes a cryptic binding site. These results suggest that fibrillin plays an important role in elastic fiber assembly by binding tropoelastin and perhaps facilitating side chain alignment for efficient cross-linking.
MAGP-1 and fibrillin-1, two protein components of extracellular microfibrils, were shown by immunoprecipitation studies to interact with the chondroitin sulfate proteoglycan decorin in the medium of ...cultured fetal bovine chondrocytes. Decorin interacted with each protein individually and with both proteins together to form a ternary complex. Expression of truncated fibrillin-1 proteins in Chinese hamster ovary cells localized proteoglycan binding to an amino-terminal region near the proline-rich domain. A spatially analogous fibrillin-2 truncated protein did not coprecipitate the same sulfated molecule, suggesting that chondroitin sulfate proteoglycan binding in this region is specific for fibrillin-1. An interaction between fibrillin and MAGP-1 was also observed under culture conditions that abrogated decorin secretion, suggesting that the two microfibrillar proteins can associate in the absence of the proteoglycan. Sulfation of matrix proteins is important for elastic fiber assembly because inhibition of sulfation was shown to prevent microfibrillar protein incorporation into the extracellular matrix of cultured cells.
Using yeast two-hybrid, ligand blotting, and solid phase binding assays, we have shown that microfibril-associated glycoprotein-1 (MAGP-1) interacts with the 8-cysteine motif of fibrillin-2 encoded ...by exon 24. Binding to this sequence was demonstrated for full-length MAGP-1 as well as for the MAGP-1 matrix-binding domain encoded by exons 7 and 8. The matrix-binding domain, but not the full-length protein, also bound to regions of fibrillin-2 defined by exons 16 and 17, exon 20, and exons 23 and 24. Interestingly, no binding was detected to sequences near the N or C terminus where MAGP-1 and MAGP-2, respectively, were shown to interact with fibrillin-1. The localization of MAGP-1 binding to the 8-Cys domain encoded by exon 24 suggests that the bead structure of microfibrils consists of exon 24 and portions of the central region of fibrillin-2. Exon 24 in fibrillin lies in the region of the molecule where mutations produce the most severe phenotypes associated with Marfan syndrome (fibrillin-1) and congenital contractural arachnodactyly (fibrillin-2). It is possible that these mutations alter the ability of fibrillin to bind MAGP-1, which may contribute to the severity of the disease.
The COVID-19 pandemic prompted global public health restrictions that impacted Canadians in multiple ways. The effects of the pandemic are well examined in specific populations and in ...researcher-defined areas (e.g., mental health, physical activity, social connections, and financial impacts). Few studies explore the complex perspectives of adults who experienced and were impacted by the pandemic. The purpose of this study was to understand Canadian adults’ perspectives of pandemic impacts over time. Methods: A sample of 347 Canadian adults were recruited during the first six months of the COVID-19 pandemic to respond to open-ended questions about the pandemic’s impacts, administered every two weeks between April 2020 and January 2021. The responses were amalgamated into epochs, defined by dates that paralleled infection rates and public health responses in Canada. Qualitative thematic analysis identified major themes for each epoch and changes in themes over time. Results: The participants predominately reported adverse impacts of the pandemic during each epoch assessed, particularly with respect to mental health, future-oriented worry, activity restrictions, and social, and employment disruptions. Key concerns were potentially driven by changes in infection rates and public health policy changes. Conclusions: The COVID-19 pandemic impacted individuals in predominantly negative and complex ways that varied over time with public health responses. Findings from the present study may direct future pandemic responses to mitigate adverse effects to best prevent infection while preserving wellbeing.
The multifaceted polycomb group gene Yin-Yang1 (Yy1) has been implicated in a variety of transcriptional regulatory roles both as an activator and silencer of gene expression. Here we examine the ...role of Yy1 during oocyte growth by conditional deletion of the locus in the growing oocyte. Our results indicate that YY1 is required for oocyte maturation and granulosa cell expansion. In mutant oocytes, we observe severely reduced expression of both Gdf9 and Bmp15, suggesting a mechanism underlying the failure of granulosa cell expansion. Consequently, we observe infertility, failure of estrus cycling, and altered reproductive hormone levels in mutant females. Additionally, we find that YY1-deficient oocytes exhibit altered levels of several oocyte-specific factors, including Pou5f1, Figla, Lhx8, Oosp1, and Sohlh2. These results document YY1's involvement in folliculogenesis and ovarian function in the mouse and indicate that YY1 is required specifically in the oocyte for oocyte-granulosa cell communication.
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