251 research outputs found
Damage from Collapsed Backfill Rock and Soils Behind Retaining Walls Caused by Earthquake Shaking
The 17 January 1994 Northridge Earthquake caused extensive damage to thousands of buildings and condominiums throughout the San Fernando Valley. Not only to the buildings’ structure, but also to the foundations and subdrain systems. This author investigated and documented hundreds of cases where condominium units experienced similar symptoms of damage resulting from collapsed backfill rock and soils from the earthquake forces. A typical condominium building investigated was of three story construction with an 8 to 10 foot high retaining wall on three sides of the 4 to 10 unit building to contain the garages and utility rooms. Some building slabs and other ancillary features, ie. patios, wing walls, decks, steps, walks were constructed directly over the backfill rock and soil. The earthquake shaking especially the vertical acceleration caused the backfill behind the retaining walls to collapse as much as eight inches resulting in failure not only to the retaining walls and surface features, but also to the underlying subdrain pipes behind the building’s retaining wall. Detailed subsurface investigations found in almost every case collapsed backfill rock and cracked, crushed or deformed perforated and solid PVC drain pipes. Other investigations suggested that the crushed pipes were caused by improper installation during original construction. This author conduced lab testing and full scale field testing to demonstrate that the resulting failures were caused by the earthquake shaking and not installation. These failures resulted in millions of dollars in insurance claims and reconstruction of retaining wall backfills and reinstallation of subdrains
Ariel - Volume 5 Number 5
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Decreased varicella and increased herpes zoster incidence at a sentinel medical deputising service in a setting of increasing varicella vaccine coverage in Victoria, Australia, 1998 to 2012
We performed an ecological study using sentinel consultation data from a medical deputising service to assess the impact of increasing coverage with childhood varicella vaccine on the incidence risk of varicella and zoster in the population served by th
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Epitope Specificity Appears To Be an Important Determinant of In Vivo Killing Ability of Simian Immunodeficiency Virus (SIV)-Specific CD8+ T Cells
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ADCC Develops Over Time during Persistent Infection with Live-Attenuated SIV and Is Associated with Complete Protection against Challenge
Live-attenuated strains of simian immunodeficiency virus (SIV) routinely confer apparent sterilizing immunity against pathogenic SIV challenge in rhesus macaques. Understanding the mechanisms of protection by live-attenuated SIV may provide important insights into the immune responses needed for protection against HIV-1. Here we investigated the development of antibodies that are functional against neutralization-resistant SIV challenge strains, and tested the hypothesis that these antibodies are associated with protection. In the absence of detectable neutralizing antibodies, Env-specific antibody-dependent cell-mediated cytotoxicity (ADCC) emerged by three weeks after inoculation with SIVΔnef, increased progressively over time, and was proportional to SIVΔnef replication. Persistent infection with SIVΔnef elicited significantly higher ADCC titers than immunization with a non-persistent SIV strain that is limited to a single cycle of infection. ADCC titers were higher against viruses matched to the vaccine strain in Env, but were measurable against viruses expressing heterologous Env proteins. In two separate experiments, which took advantage of either the strain-specificity or the time-dependent maturation of immunity to overcome complete protection against challenge, measures of ADCC activity were higher among the SIVΔnef-inoculated macaques that remained uninfected than among those that became infected. These observations show that features of the antibody response elicited by SIVΔnef are consistent with hallmarks of protection by live-attenuated SIV, and reveal an association between Env-specific antibodies that direct ADCC and apparent sterilizing protection by SIVΔnef
Clonal expansion of new penicillin-resistant clade of neisseria meningitidis serogroup w clonal complex 11, Australia
In Western Australia, Neisseria meningitidis serogroup W clonal complex 11 became the predominant cause of invasive meningococcal disease in 2016. We used core-genome analysis to show emergence of a penicillin-resistant clade that had the penA_253 allele. This new penicillin-resistant clade might affect treatment regimens for this disease
Prevalence of fibromyalgia in France: a multi-step study research combining national screening and clinical confirmation: The DEFI study (Determination of Epidemiology of FIbromyalgia)
<p>Abstract</p> <p>Background</p> <p>Fibromyalgia is a common disease, but little is known on its real prevalence in France. This epidemiological study aimed to assess fibromyalgia (FM) prevalence in the French metropolitan population, based on a multi-step sampling analysis, combining national screening and clinical confirmation by trained specialists.</p> <p>Methods</p> <p>a sampling method on the entire national territory was used: patients over 18 years of age accepting to take part in the study were contacted by telephone using the LFES Questionnaire, a screening test for FM. The, for patients detected by the LFESQ, a visit with a FM-trained rheumatologist was proposed to confirm FM, based on 1990 ACR criteria. Each detected patient completed the following self-questionnaires: SF36, HADS, stress VAS, Co-morbidities and Regional pain score.</p> <p>Results</p> <p>3081 patients were contacted in 5 representative French regions, of which 232 patients were screened for FM. A fibromyalgia diagnosis was then confirmed by rheumatologist in 20 cases (17 female and 3 male, 56.9 ± 13.2 years). The final estimated FM prevalence was 1.6 (CI95: 1.2%; 2.0%). No significant difference was detected between the patients accepting (CS+) and refusing (CS-) rheumatologist visit for the SF36 score, regional pain score, stress VAS scale and co-morbidities. In patients detected for FM by the LFESQ, we found a statistically significant decrease in quality of life and a statistically significant increase in stress level in patients with a confirmed diagnosis (FM+) (6.3 ± 1.9) compared to patients with an invalidated diagnosis (FM-) (4.4 ± 2.8; p = 0.007). The study also demonstrated a significant association, independently of ACR criteria, between the diagnosis of FM and several factors such as regional pain score > 10, elevated stress level, low SF36 scale score and presence of gastro-intestinal disorder co-morbidities.</p> <p>Conclusion</p> <p>Fibromyalgia is a common condition; the 1.6% prevalence calculated in the French population in our study corroborates the figures published in the European literature. Our results also suggest that criteria such as regional pain score, stress level or SF36 quality of life, could represent useful tools in fibromyalgia diagnosis.</p
Sick-listed employees with severe medically unexplained physical symptoms: burden or routine for the occupational health physician? A cross sectional study
Background: The two primary objectives of this study were to the assess consultation load of occupational health physicians (OHPs), and their difficulties and needs with regard to their sickness certification tasks in sick-listed employees with severe medical unexplained physical symptoms (MUPS). Third objective was to determine which disease-, patient-, doctor- and practice-related factors are associated with the difficulties and needs of the OHPs. Methods: In this cross-sectional study, 43 participating OHPs from 5 group practices assessed 489 sick-listed employees with and without severe MUPS. The OHPs filled in a questionnaire about difficulties concerning sickness certification tasks, consultation time, their needs with regard to consultation with or referral to a psychiatrist or psychologist, and communication with GPs. The OHPs also completed a questionnaire about their personal characteristics. Results: OHPs only experienced task difficulties in employees with severe MUPS in relation to their communication with the treating physician. This only occured in cases in which the OHP attributed the physical symptoms to somatoform causes. If they attributed the physical symptoms to mental causes, the OHPs reported a need to consultate a psychiatrist about the diagnosis and treatment. Conclusions: OHPs experience few difficulties with their sickness certification tasks and consultation load concerning employees with severe MUPS. However, they encounter problems if the diagnostic uncertainties of the treating physician interfere with the return to work process. OHPs have a need for psychiatric expertise whenever they are uncertain about the psychiatric causes of a delayed return to work process. We recommend further training programs for OHPs. They should also have more opportunity for consultation and referral to a psychiatrist, and their communication with treating physicians should be improved
Contribution of Hepatic Cytochrome P450 3A4 Metabolic Activity to the Phenomenon of Clopidogrel Resistance
Background— Interindividual variability of platelet inhibition after aspirin or clopidogrel administration has been described. Additionally, aspirin resistance and clopidogrel resistance occur in some individuals. Because the prodrug clopidogrel is activated by hepatic cytochrome P450 (CYP) 3A4, we hypothesized that interindividual variability in clopidogrel efficacy might be related to interindividual differences in CYP3A4 metabolic activity. Methods and Results— Platelet aggregation was measured before and after clopidogrel treatment in 32 patients undergoing coronary artery stent implantation and in 35 healthy volunteers. The erythromycin breath test was used to measure CYP3A4 activity in vivo in 25 of the healthy volunteers. Individual platelet aggregation was studied in 10 healthy volunteers after the coadministration of clopidogrel and rifampin (a CYP3A4 inducer). Clopidogrel nonresponders, low responders, and responders were defined by a relative inhibition of adenosine diphosphate (20 μmol/L)–induced platelet aggregation of less than 10%, 10% to 29%, and ≥30%, respectively. Among patients, 22% were clopidogrel nonresponders, 32% were low responders, and 47% were responders. Among volunteers, 16% were nonresponders, 12% were low responders, and 72% were responders. Percent platelet aggregation after clopidogrel inversely correlated with CYP3A4 activity (r=−0.6, P=0.003). Improved platelet inhibition in volunteers resistant to clopidogrel was observed with the coadministration of clopidogrel and rifampin. Conclusions— Clopidogrel administration results in interindividual variability in platelet inhibition, which correlates with CYP3A4 metabolic activity. Measurement of antiplatelet drug efficacy with a point-of-care device and alternative antithrombotic strategies for aspirin or clopidogrel nonresponders and low responders could reduce the incidence of thrombotic events that continue to occur despite oral antiplatelet therapy
Effects of cigarette smoke on endothelial function of pulmonary arteries in the guinea pig
<p>Abstract</p> <p>Background</p> <p>Cigarette smoking may contribute to pulmonary hypertension in chronic obstructive pulmonary disease by altering the structure and function of pulmonary vessels at early disease stages. The objectives of this study were to evaluate the effects of long-term exposure to cigarette smoke on endothelial function and smooth muscle-cell proliferation in pulmonary arteries of guinea pigs.</p> <p>Methods</p> <p>19 male Hartley guinea pigs were exposed to the smoke of 7 cigarettes/day, 5 days/week, for 3 and 6 months. 17 control guinea pigs were sham-exposed for the same periods. Endothelial function was evaluated in rings of pulmonary artery and aorta as the relaxation induced by ADP. The proliferation of smooth muscle cells and their phenotype in small pulmonary vessels were evaluated by immunohistochemical expression of α-actin and desmin. Vessel wall thickness, arteriolar muscularization and emphysema were assessed morphometrically. The expression of endothelial nitric oxide synthase (eNOS) was evaluated by Real Time-PCR.</p> <p>Results</p> <p>Exposure to cigarette smoke reduced endothelium-dependent vasodilatation in pulmonary arteries (ANOVA p < 0.05) but not in the aorta. Endothelial dysfunction was apparent at 3 months of exposure and did not increase further after 6 months of exposure. Smoke-exposed animals showed proliferation of poorly differentiated smooth muscle cells in small vessels (p < 0.05) after 3 months of exposure. Prolonged exposure resulted in full muscularization of small pulmonary vessels (p < 0.05), wall thickening (p < 0.01) and increased contractility of the main pulmonary artery (p < 0.05), and enlargement of the alveolar spaces. Lung expression of eNOS was decreased in animals exposed to cigarette smoke.</p> <p>Conclusion</p> <p>In the guinea pig, exposure to cigarette smoke induces selective endothelial dysfunction in pulmonary arteries, smooth muscle cell proliferation in small pulmonary vessels and reduced lung expression of eNOS. These changes appear after 3 months of exposure and precede the development of pulmonary emphysema.</p
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