Effect of detonator position on fragmentation at Kevitsa open pit mine

Abstract. Blasting is one of the main operations in open pit mining and effective rock blasting can have a major impact on the overall economy of the mine. To obtain optimal rock fragmentation by blasting, explosive energy must be well-utilized, well-distributed, and targeted to the rock mass that we aim to fragment. A position of a detonator in a blasthole affects all of the above. The aim of this thesis was to study the effect of detonator position on fragmentation at the Kevitsa open pit mine. The theoretical optimum for the detonator position in the explosive column was defined and tested in practice. In addition, the effects on bench floor conditions were investigated. The practical study consisted of blasted test fields within production blasts, where the current blasting practice used in Kevitsa was compared to the test design representing the theoretical optimum. The effects were measured and studied with shovel-mounted machine vision cameras, test drillings, and loading machine operator feedback forms. Considering optimal fragmentation and less damage below the bench floor level, both theoretical and field studies indicated that the detonator position plays an important role in rock fragmentation, and that the detonator position in the middle of the explosive column allows for significant improvement in rock fragmentation and bench floor conditions. The results of this study can be applied more generally in open pit blasting

PCB and PBDE levels in southern and northern resident killer whales: update on contaminant levels and related health effects

Salish Sea’s killer whale populations are among the most contaminated marine mammals in the world and face risks related to the effects of polychlorinated biphenyls (PCBs) and related contaminants such as polybrominated diphenylethers (PBDEs). While PCBs have long been banned, they continue to present toxic risks to marine mammals, along with a number of other, emerging persistent, bioaccumulative and toxic (PBT) contaminants. Since PBTs have been identified as a threat to the recovery of resident killer whale populations under the auspices of the US Endangered Species Act and the Canadian Species at Risk Act (SARA), documenting the presence, trends and health effects of emerging PBT contaminants represents an important line of research. In the summer of 2016 and 2017, we collected blubber biopsies from 10 southern resident and nine northern resident killer whales. PCB and PBDE analyses were conducted using high resolution gas chromatography/high resolution mass spectrometry. Given the likelihood of significant temporal changes in the concentrations of these contaminants, this study will provide updated contaminant concentration data and strengthen our ability to prioritize contaminants of concern in resident killer whales. In addition, stable isotope and fatty acid analyses will provide important information on diet and nutritional status. Together with analyses of the expression of essential genes involved in immune response, hormone regulation and lipid metabolism, this study provides new essential information on the health status of resident killer whales as it relates to contaminant exposure and will help inform the development and application of recovery action plans

Burnout and Substance Use in Collegiate Athletic Trainers

CONTEXT: The Smith Cognitive-Affective Model of Athletic Burnout suggests that athletic trainers (ATs) suffering from burnout may engage in substance use as a coping behavior. Increases in self-reported burnout symptoms are often associated with increases in heavy episodic drinking and tobacco use among various health care providers. However, this relationship has not been examined thoroughly. OBJECTIVE: To investigate the prevalence of substance use in ATs and identify relationships between symptoms of burnout and substance use among ATs. DESIGN: Cross-sectional study. SETTING: Web-based survey. PATIENTS OR OTHER PARTICIPANTS: A total of 783 certified ATs working full time in the collegiate or university setting were sampled for this study. Graduate assistant and other part-time ATs were excluded. The survey was distributed via the National Athletic Trainers\u27 Association membership directory e-mail broadcast service. MAIN OUTCOME MEASURE(S): A 100-item online questionnaire consisting of items from previously used scales was used for this study. The survey included the Maslach Burnout Inventory and questions on substance use from the Monitoring the Future study. Multiple regression analyses were performed to analyze the survey data. All independent (Maslach Burnout Inventory subscales) and dependent (use of alcohol, tobacco, and marijuana) variables were mapped to the Smith Cognitive-Affective Model of Athletic Burnout to determine which dimensions of burnout altered the odds of self-reported substance use. RESULTS: Almost half (46.3%) of participants admitted to at least 1 binge-drinking episode. However, the use of cigarettes, smokeless tobacco, marijuana, and energy drinks during the previous month was less pronounced in the sample. Emotional exhaustion (B = .008, P = .023) and personal accomplishment (B = -.016, P = .02) were significantly correlated with binge drinking. Emotional exhaustion (Exp[B] = 1.017, P \u3c .001) was also significantly positively correlated with energy-drink consumption. CONCLUSIONS: Some ATs engaged in heavy episodic drinking. Emotional exhaustion and a decreased sense of personal accomplishment were significantly correlated with this behavior

Determining collagen distribution in articular cartilage using contrast-enhanced micro-computed tomography

Objective: Collagen distribution within articular cartilage (AC) is typically evaluated from histological sections, e.g., using collagen staining and light microscopy (LM). Unfortunately, all techniques based on histological sections are time-consuming, destructive, and without extraordinary effort, limited to two dimensions. This study investigates whether phosphotungstic acid (PTA) and phosphomolybdic acid (PMA), two collagen-specific markers and X-ray absorbers, could (1) produce contrast for AC X-ray imaging or (2) be used to detect collagen distribution within AC. Method: We labeled equine AC samples with PTA or PMA and imaged them with micro-computed tomography (micro-CT) at pre-defined time points 0, 18, 36, 54, 72, 90, 180, 270 h during staining. The micro-CT image intensity was compared with collagen distributions obtained with a reference technique, i.e., Fourier-transform infrared imaging (FTIRI). The labeling time and contrast agent producing highest association (Pearson correlation, BlandeAltman analysis) between FTIRI collagen distribution and micro-CT -determined PTA distribution was selected for human AC. Results: Both, PTA and PMA labeling permitted visualization of AC features using micro-CT in non-calcified cartilage. After labeling the samples for 36 h in PTA, the spatial distribution of X-ray attenuation correlated highly with the collagen distribution determined by FTIRI in both equine (mean +/- S.D. of the Pearson correlation coefficients, r = 0.96 +/- 0.03, n = 12) and human AC (r = 0.82 +/- 0.15, n = 4). Conclusions: PTA-induced X-ray attenuation is a potential marker for non-destructive detection of AC collagen distributions in 3D. This approach opens new possibilities in development of non-destructive 3D histopathological techniques for characterization of OA. (C) 2015 The Authors. Published by Elsevier Ltd and Osteoarthritis Research Society International.Peer reviewe

Mechanisms of Esophago-Pharyngeal Acid Regurgitation in Human Subjects

Esophago-pharyngeal regurgitation is implicated in various otolaryngologic and respiratory disorders. The pathophysiological mechanisms causing regurgitation are still largely unknown

Harbor seal pup dispersal and individual morphology, hematology, and contaminant factors affecting survival

This work was funded by The Valentine Family Foundation and the John H. Prescott Marine Mammal Rescue Assistance Grant Program.Understanding the factors affecting individual harbor seal (Phoca vitulina) survival is essential for determining population level health risks. We estimated postweaning dispersal, and modeled the effects of morphology, hematology, and blubber contaminants on the survival of recently weaned harbor seal pups using a mark recapture framework. We deployed satellite transmitters on apparently healthy pups captured in San Francisco Bay (SFB, n = 19) and Tomales Bay (TB, n = 7), and pups released after rehabilitation that stranded along the central California coast preweaning (n = 21). Dispersal distances were further than previously reported for harbor seal pups (maximum = 802 km) which has implications for understanding risks to this vulnerable age class. We found differences in body condition, serum immunoglobulin and thyroxine (T4) concentrations, white blood cell count, and blubber organohalogen contamination (OH) among the three groups. Overall, increased T4, decreased OH, and increased mass were associated with greater survival probabilities; whereas, among stranded seals, greater mass gain, shorter time in rehabilitation, and admission to rehabilitation earlier in the season were associated with greater survival probabilities. Attention to these latter factors may improve the success of rehabilitation efforts. For wild pups, reduction of legacy contaminants and direct causes of mortality, such as ship strike, may enhance pup survival.Publisher PDFPeer reviewe

Expression of Androgen Receptor Splice Variants in Prostate Cancer Bone Metastases is Associated with Castration-Resistance and Short Survival

Background: Constitutively active androgen receptor variants (AR-V) lacking the ligand binding domain (LBD) may promote  the development of castration-resistant prostate cancer (CRPC). The expression of AR-Vs in the clinically most important metastatic site, the bone, has, however, not been well documented. Our aim was therefore to compare levels of AR-Vs in hormone-naive (HN) and CRPC bone metastases in comparison to primary PC and non-malignant prostate tissue, as well as in relation to AR protein expression, whole-genome transcription profiles and patient survival. Methodology/Principal Findings: Hormone-naı¨ve (n = 10) and CRPC bone metastases samples (n = 30) were obtained from  40 patients at metastasis surgery. Non-malignant and malignant prostate samples were acquired from 13 prostatectomized men. Levels of full length AR (ARfl) and AR-Vs termed AR-V1, AR-V7, and AR-V567es mRNA were measured with RT-PCR and whole-genome transcription profiles with an Illumina Beadchip array. Protein levels were examined by Western blotting and immunohistochemistry. Transcripts for ARfl, AR-V1, and AR-V7 were detected in most primary tumors and metastases, and levels were significantly increased in CRPC bone metastases. The AR-V567es transcript was detected in 23% of the CRPC bone metastases only. A sub-group of CRPC bone metastases expressed LBD-truncated AR proteins at levels comparable to the ARfl. Detectable AR-V567es and/or AR-V7 mRNA in the upper quartile, seen in 1/3 of all CRPC bone metastases, was associated with a high nuclear AR immunostaining score, disturbed cell cycle regulation and short survival. Conclusions/Significance: Expression of AR-Vs is increased in CRPC compared to HN bone metastases and associated with a particularly poor prognosis. Further studies are needed to test if patients expressing such AR-Vs in their bone metastases benefit more from drugs acting on or down-stream of these AR-Vs than from therapies inhibiting androgen synthesis

Human papillomavirus infection and use of oral contraceptives

Human papillomavirus (HPV) infection is thought to be a necessary but not sufficient cause of most cases of cervical cancer. Since oral contraceptive use for long durations is associated with an increased risk of cervical cancer, it is important to know whether HPV infection is more common in oral contraceptive users. We present a systematic review of 19 epidemiological studies of the risk of genital HPV infection and oral contraceptive use. There was no evidence for a strong positive or negative association between HPV positivity and ever use or long duration use of oral contraceptives. The limited data available, the presence of heterogeneity between studies and the possibility of bias and confounding mean, however, that these results must be interpreted cautiously. Further studies are needed to confirm these findings and to investigate possible relations between oral contraceptive use and the persistence and detectability of cervical HPV infection

Assessing Perceived Risk and STI Prevention Behavior: A National Population-Based Study with Special Reference to HPV

Aim: This thesis aims to provide a multidimensional assessment of infection risks and to evaluate strategies for HPV prevention including vaccination with quadrivalent HPVvaccines, dose-level vaccine effectiveness and condom use in high STI risk situations. Methods: Multiple population-based registers and questionnaire responses provided data for this thesis. Various multivariable and univariate regression models were fit. Findings: Overall, quadrivalent HPV-vaccination was highly effective against genital warts (GW) also referred to as condyloma, which is the first HPV disease endpoint possible to measure. However, effectiveness was contingent upon young age-at-first vaccination, with effectiveness declining steadily the older the age-at-first vaccination. Among women above 20 years of age there was low to immeasurable effectiveness and suggestive evidence vaccinations in this age group tended to reach women at high GW risk. There were marked socioeconomic disparities in the opportunistic (on-demand with co-pay) vaccination strategy evaluated, with women and girls who have parents with the highest education level compared to the lowest having a 15 times greater likelihood to be vaccinated (Study III). Once vaccination was initiated, however, high parental education level was unrelated to vaccination completion. Maximum protection against GW was found among girls vaccinated under the age of 17 who had received three doses of the vaccine. No differences in effectiveness were found for girls who received twodoses between ages 10-16 with that of those who received three-doses between ages 17- 19 (Study IV). GW affects more men than women in Sweden as of 2010 with 453 per 100 000 men and 365 per 100 000 women treated. A decline between 25-30% was seen between 2006 and 2010 among women in the age groups with the highest vaccination coverage. No decline was found amongst men and their GW incidence has steadily increased between 2006 and 2010 (Study II). Reported condom use in high risk situations was low among both men and women, with 41% of men and 34% of women reporting always/almost always condom use with temporary partners. STI risk perception was also low, with approximately 10% of sexually active respondents considering themselves at large risk of contracting an STI. There was no association between men’s condom use and their STI risk perception but there was an association for women (Study I). Conclusions: Results suggest that males bear a substantial burden of HPV-related condyloma where incidence has dropped among women. When planning HPVvaccination among females, efforts should target girls under age 14 for maximum effectiveness. Quadrivalent HPV-vaccination offers most protection against condyloma at three doses. Gross social inequity was found with opportunistic HPV-vaccination. There were large gender differences in factors associated with condom use in high risk situations and STI risk perceptions

Sympathetic Activation and Baroreflex Function during Intradialytic Hypertensive Episodes

BACKGROUND: The mechanisms of intradialytic increases in blood pressure are not well defined. The present study was undertaken to assess the role of autonomic nervous system activation during intradialytic hypertensive episodes. METHODOLOGY/PRINCIPAL FINDINGS: Continuous interbeat intervals (IBI) and systolic blood pressure (SBP) were monitored during hemodialysis in 108 chronic patients. Intradialytic hypertensive episodes defined as a period of at least 10 mmHg increase in SBP between the beginning and the end of a dialysis session or hypertension resistant to ultrafiltration occurring during or immediately after the dialysis procedure, were detected in 62 out of 113 hemodialysis sessions. SBP variability, IBI variability and baroreceptor sensitivity (BRS) in the low (LF) and high (HF) frequency ranges were assessed using the complex demodulation technique (CDM). Intradialytic hypertensive episodes were associated with an increased (n = 45) or decreased (n = 17) heart rate. The maximal blood pressure was similar in both groups. In patients with increased heart rate the increase in blood pressure was associated with marked increases in SBP and IBI variability, with suppressed BRS indices and enhanced sympatho-vagal balance. In contrast, in those with decreased heart rate, there were no significant changes in the above parameters. End-of-dialysis blood pressure in all sessions associated with hypertensive episode was significantly higher than in those without such episodes. In logistic regression analysis, predialysis BRS in the low frequency range was found to be the main predictor of intradialytic hypertension. CONCLUSION/SIGNIFICANCE: Our data point to sympathetic overactivity with feed-forward blood pressure enhancement as an important mechanism of intradialytic hypertension in a significant proportion of patients. The triggers of increased sympathetic activity during hemodialysis remain to be determined. Intradialytic hypertensive episodes are associated with higher end-of-dialysis blood pressure, suggesting that intradialytic hypertension may play a role in generation of interdialytic hypertension