Effect of oxygen concentration on nanoindentation-induced phase transformations in ion-implanted amorphous silicon

The effect of the local oxygen concentration in ion-implanted amorphous Si (a-Si) on nanoindentation-inducedphase transformations has been investigated. Implantation of oxygen into the a-Sifilms has been used to controllably introduce an approximately constant concentration of oxygen, ranging from ∼10¹⁸ to ∼10²¹ cm⁻³, over the depth range of the phase transformed zones. Nanoindentation was performed under conditions that ensure a phase transformed zone composed completely of Si-III/XII in the nominally oxygen-free a-Si. The effect of the local oxygen concentration has been investigated by analysis of the unloading curves, Raman microspectroscopy, and cross-sectional transmission electron microscopy (XTEM). The formation of Si-III/XII is suppressed with increasing oxygen concentration, favoring a greater volume of a-Si within the zones. The Raman microspectroscopy and XTEM verify that the volume of Si-III/XII decreases with increasing O concentration. With the smaller volumes of Si-III/XII, the pop-out normally observed on load versus penetration depth curves during unloading decreases in magnitude, becoming more kinklike and is barely discernable at high concentrations of oxygen. The probability of forming any high pressure phases is reduced from 1 to ∼0.1 for a concentration of 10²¹ cm⁻³. We suggest that the bonding of O with Si reduces the formation of Si-III/XII during unloading through a similar mechanism to that of oxygen-retarded solid phase crystallization of a-Si.This project is funded by the Australian Research Council and WRiota Pty Ltd

Effect of hydrogen on nanoindentation-induced phase transformations in amorphous silicon

The effect of local hydrogen concentration on nanoindentation-inducedphase transformations has been investigated in ion-implanted amorphous silicon(a-Si). Elevated concentrations of H ranging from 5×10¹⁸ to 5×10²⁰ cm⁻³, over the depth of indentation-induced phase transformed zones have been formed in the a-Si by H ion-implantation. Indentation has been performed under conditions that result in phase transformed zones composed totally of Si-III/Si-XII in the “H-free” samples. Deformation during indentation and determination of phase transformation behavior has been examined by analysis of load/unload curves, Raman microspectroscopy, and cross-sectional transmission electron microscopy (XTEM). With increasing H content, the probability of forming Si-III/Si-XII and the volume fraction of Si-III/Si-XII decrease. XTEM shows that these reduced volumes are randomly distributed within the phase transformed zone and are surrounded by indentation-induced a-Si. For a H concentration of 5×10²⁰ cm⁻³, the probability of forming Si-III/Si-XII is reduced to 0.5 compared to 1 in “H-free” material and for those indents that exhibit the Si-III/Si-XII end phase the volume fraction is approximately 60 %. We suggest that the monohydride bonding configuration of Si and H in a-Si reduces the formation of the high pressure crystalline phases by retarding growth of the crystallites through a similar mechanism to that of hydrogen-retarded solid phase crystallization of a-Si to diamond cubic crystalline Si-I phase.The authors are grateful to funding from the Australian Research Council

Variasi Kuat Kokoh Tanah Lempung Ekspansif Akibat Perubahan Musim

Tanah lempung ekspansif yang tidak diperhitungkan dengan baik dapat mengakibatkan kerusakan pada struktur bangunan. Wetting dan drying, merupakan sebuah metode yang digunakan untuk mengetahui kondisi tanah pada saat musim hujan dan kemarau. Proses wetting dilakukan dengan cara tanah dibasahi untuk mencari beratnya sedangkan drying dilakukan dengan cara tanah dikeringkan pada ruangan tertutup untuk mencari beratnya. Tujuan dari penelitian ini adalah mengetahui pengaruh indeks plastisitas dan persentase fine aggregate terhadap Perubahan kuat kokoh akibat wetting dan drying. Karakteristik tanah pada kondisi mula-mula dari lima lokasi di Surabaya Barat didapatkan dari pengujian di laboratorium UK Petra. Pada saat proses wetting, tanah dibasahi sampai berat tanah yang diinginkan, sedangkan pada proses drying tanah dibiarkan di ruangan sampai mencapai berat tanah yang diinginkan. Hasil dari penelitian ini menunjukkan bahwa nilai indeks plastisitas yang semakin tinggi mengakibatkan range kuat kokoh yang kecil, dan persentase fine aggregate yang semakin tinggi mengakibatkan range kuat kokoh yang besar

Psychological wellbeing and safety in a global context: a rapid evidence assessment

Psychological wellbeing is a key dimension which impacts on the productivity and work experiences of employees within safety-critical sectors. This rapid evidence assessment has reviewed the academic and grey literature globally to establish key factors that impact on mental health across five sectors responsible for critical social and economic infrastructure – maritime/energy; construction; engineering; food and digital. Structural factors in the organization of workplaces and safety practices impact upon the psychological wellbeing of employees and are in turn affected by the emotional and behavioural consequences and diminished psychological wellbeing. The Power Threat Meaning Framework (PTMF) provides a way of modelling this relationship that avoids some of the difficulties inherent in global approaches to mental health. The evidence clearly shows that psychosocial factors play a central role in mediating the relationship between structural aspects of the working environment and psychological wellbeing. Whilst there is wide variability in the efficacy of interventions attempted across the sectors explored, in general, strategies which employ a holistic approach to psychological wellbeing generally demonstrate better outcomes. On the basis of the available evidence, we recommend that interventions proceed by identifying and modelling the specific configuration of psychosocial factors within a given sector or organization. We further recommend that participation in interventions is facilitated collaboratively, and designed across all levels within the organization. The 4th Industrial Revolution offers many challenges to all the sectors explored and is generally considered in terms of the direct and indirect threats it poses to psychological wellbeing through exacerbating existing workplace inequalities. However, technological changes also offer innovative means through which mental health may be monitored. The evidence base also provides some key lessons for the transitions every sector will have to make during and in recovering from the COVID-19 pandemic

A Victor's History: A Comparative Analysis of the Labour Historiography of Indonesia's New Order

Some observers have identified a common pattern in developing countries whereby unions are transformed from a political force valued for their contribution to the struggle for independence to a state-sponsored ‘tool of development’. A less well-explored question concerns the harnessing of labour historiography to justify such transitions. As this article shows, Suharto’s New Order (1966–98) undertook a conscious and purposeful rewriting of Indonesian labour history in support of a single vehicle of labour representation organized around a narrative of the dangers of political unionism and designed to control and harness the industrial workforce in the name of economic development

Clinical knee findings in floor layers with focus on meniscal status

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to examine the prevalence of self-reported and clinical knee morbidity among floor layers compared to a group of graphic designers, with special attention to meniscal status.</p> <p>Methods</p> <p>We obtained information about knee complaints by questionnaire and conducted a bilateral clinical and radiographic knee examination in 134 male floor layers and 120 male graphic designers. After the exclusion of subjects with reports of earlier knee injuries the odds ratio (OR) with 95% confidence intervals (CI) of knee complaints and clinical findings were computed among floor layers compared to graphic designers, using logistic regression. Estimates were adjusted for effects of body mass index, age and knee straining sports. Using radiographic evaluations, we conducted side-specific sensitivity analyses regarding clinical signs of meniscal lesions after the exclusion of participants with tibiofemoral (TF) osteoarthritis (OA).</p> <p>Results</p> <p>Reports of knee pain (OR = 2.7, 95% CI = 1.5–4.6), pain during stair walking (OR = 2.2, 95% CI = 1.3–3.9) and symptoms of catching of the knee joint (OR = 2.9, 95% CI = 1.4–5.7) were more prevalent among floor layers compared to graphic designers. Additionally, significant more floor layers than graphic designers had clinical signs suggesting possible meniscal lesions: a positive McMurray test (OR = 2.4, 95% CI = 1.1–5.0) and TF joint line tenderness (OR = 5.4, 95% CI = 2.4–12.0). Excluding floor layers (n = 22) and graphic designers (n = 15) with radiographic TF OA did not alter this trend between the two study groups: a positive McMurray test (OR = 2.2, 95% CI = 1.0–4.9), TF joint line tenderness (OR = 5.0, 95% CI = 2.0–12.5).</p> <p>Conclusion</p> <p>Results indicate that floor layers have a high prevalence of both self-reported and clinical knee morbidity. Clinical knee findings suggesting possible meniscal lesions were significant more prevalent among floor layers compared to a group of low-level exposed graphic designers and an association with occupational kneeling could be possible. However, causality cannot be confirmed due to the cross-sectional study design.</p

Estrogen deficiency heterogeneously affects tissue specific stem cells in mice

Postmenopausal disorders are frequently observed in various organs, but their relationship with estrogen deficiency and mechanisms remain unclear. As tissue-specific stem cells have been found to express estrogen receptors, we examined the hypothesis that estrogen deficiency impairs stem cells, which consequently contributes to postmenopausal disorders. Six-week-old C57BL/6 female mice were ovariectomized, following which they received 17β-estradiol replacement or vehicle (control). Sham-operated mice were used as healthy controls. All mice were killed for evaluation 2 months after treatments. Compared with the healthy control, ovariectomy significantly decreased uterine weight, which was partially recovered by 17β-estradiol replacement. Ovariectomy significantly increased the numbers of c-kit-positive hematopoietic stem/progenitor cells in bone marrow, but impaired their capacity to grow mixed cell-type colonies in vitro. Estrogen replacement further increased the numbers of c-kit-positive hematopoietic stem/progenitor cells in bone marrow, without significantly affecting colony growth in vitro. The number of CD105-positive mesenchymal stem cells in bone marrow also significantly decreased after ovariectomy, but completely recovered following estrogen replacement. Otherwise, neither ovariectomy nor estrogen replacement changed the number of Pax7-positive satellite cells, which are a skeletal muscle-type stem cell. Estrogen deficiency heterogeneously affected tissue-specific stem cells, suggesting a likely and direct relationship with postmenopausal disorders

Clinical knee findings in floor layers with focus on meniscal status

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to examine the prevalence of self-reported and clinical knee morbidity among floor layers compared to a group of graphic designers, with special attention to meniscal status.</p> <p>Methods</p> <p>We obtained information about knee complaints by questionnaire and conducted a bilateral clinical and radiographic knee examination in 134 male floor layers and 120 male graphic designers. After the exclusion of subjects with reports of earlier knee injuries the odds ratio (OR) with 95% confidence intervals (CI) of knee complaints and clinical findings were computed among floor layers compared to graphic designers, using logistic regression. Estimates were adjusted for effects of body mass index, age and knee straining sports. Using radiographic evaluations, we conducted side-specific sensitivity analyses regarding clinical signs of meniscal lesions after the exclusion of participants with tibiofemoral (TF) osteoarthritis (OA).</p> <p>Results</p> <p>Reports of knee pain (OR = 2.7, 95% CI = 1.5–4.6), pain during stair walking (OR = 2.2, 95% CI = 1.3–3.9) and symptoms of catching of the knee joint (OR = 2.9, 95% CI = 1.4–5.7) were more prevalent among floor layers compared to graphic designers. Additionally, significant more floor layers than graphic designers had clinical signs suggesting possible meniscal lesions: a positive McMurray test (OR = 2.4, 95% CI = 1.1–5.0) and TF joint line tenderness (OR = 5.4, 95% CI = 2.4–12.0). Excluding floor layers (n = 22) and graphic designers (n = 15) with radiographic TF OA did not alter this trend between the two study groups: a positive McMurray test (OR = 2.2, 95% CI = 1.0–4.9), TF joint line tenderness (OR = 5.0, 95% CI = 2.0–12.5).</p> <p>Conclusion</p> <p>Results indicate that floor layers have a high prevalence of both self-reported and clinical knee morbidity. Clinical knee findings suggesting possible meniscal lesions were significant more prevalent among floor layers compared to a group of low-level exposed graphic designers and an association with occupational kneeling could be possible. However, causality cannot be confirmed due to the cross-sectional study design.</p

The Gene Ontology knowledgebase in 2023

The Gene Ontology (GO) knowledgebase (http://geneontology.org) is a comprehensive resource concerning the functions of genes and gene products (proteins and noncoding RNAs). GO annotations cover genes from organisms across the tree of life as well as viruses, though most gene function knowledge currently derives from experiments carried out in a relatively small number of model organisms. Here, we provide an updated overview of the GO knowledgebase, as well as the efforts of the broad, international consortium of scientists that develops, maintains, and updates the GO knowledgebase. The GO knowledgebase consists of three components: (1) the GO-a computational knowledge structure describing the functional characteristics of genes; (2) GO annotations-evidence-supported statements asserting that a specific gene product has a particular functional characteristic; and (3) GO Causal Activity Models (GO-CAMs)-mechanistic models of molecular "pathways" (GO biological processes) created by linking multiple GO annotations using defined relations. Each of these components is continually expanded, revised, and updated in response to newly published discoveries and receives extensive QA checks, reviews, and user feedback. For each of these components, we provide a description of the current contents, recent developments to keep the knowledgebase up to date with new discoveries, and guidance on how users can best make use of the data that we provide. We conclude with future directions for the project

Trabecular Reorganization in Consecutive Iliac Crest Biopsies when Switching from Bisphosphonate to Strontium Ranelate Treatment

BACKGROUND: Several agents are available to treat osteoporosis while addressing patient-specific medical needs. Individuals' residual risk to severe fracture may require changes in treatment strategy. Data at osseous cellular and microstructural levels due to a therapy switch between agents with different modes of action are rare. Our study on a series of five consecutively taken bone biopsies from an osteoporotic individual over a six-year period analyzes changes in cellular characteristics, bone microstructure and mineralization caused by a therapy switch from an antiresorptive (bisphosphonate) to a dual action bone agent (strontium ranelate). METHODOLOGY/PRINCIPAL FINDINGS: Biopsies were progressively taken from the iliac crest of a female patient. Four biopsies were taken during bisphosphonate therapy and one biopsy was taken after one year of strontium ranelate (SR) treatment. Furthermore, serum bone markers and dual x-ray absorptiometry measurements were acquired. Undecalcified histology was used to assess osteoid parameters and bone turnover. Structural indices and degree of mineralization were determined using microcomputed tomography, quantitative backscattered electron imaging, and combined energy dispersive x-ray/µ-x-ray-fluorescence microanalysis. CONCLUSIONS/SIGNIFICANCE: Microstructural data revealed a notable increase in bone volume fraction after one year of SR treatment compared to the bisphosphonate treatment period. Indices of connectivity density, structure model index and trabecular bone pattern factor were predominantly enhanced indicating that the architectural transformation from trabecular rods to plates was responsible for the bone volume increase and less due to changes in trabecular thickness and number. Administration of SR following bisphosphonates led to a maintained mineralization profile with an uptake of strontium on the bone surface level. Reactivated osteoclasts designed tunneling, hook-like intratrabecular resorption sites. The appearance of tunneling resorption lacunae and the formation of both mini-modeling units and osteon-like structures within increased plate-like cancellous bone mass provides additional information on the mechanisms of strontium ranelate following bisphosphonate treatment, which may deserve special attention when monitoring a treatment switch