11,554 research outputs found
Fatigue testing a plurality of test specimens and method
Described is a fatigue testing apparatus for simultaneously subjecting a plurality of material test specimens to cyclical tension loading to determine the fatigue strength of the material. The fatigue testing apparatus includes a pulling head having cylinders defined therein which carry reciprocating pistons. The reciprocation of the pistons is determined by cyclical supplies of pressurized fluid to the cylinders. Piston rods extend from the pistons through the pulling head and are attachable to one end of the test specimens, the other end of the test specimens being attachable to a fixed base, causing test specimens attached between the piston rods and the base to be subjected to cyclical tension loading. Because all the cylinders share a common pressurized fluid supply, the breaking of a test specimen does not substantially affect the pressure of the fluid supplied to the other cylinders nor the tension applied to the other test specimens
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Effect of Rectal Hygiene on Sexually Transmitted Infections Among HIV-Negative Men Who Have Sex with Men (MSM)
Abstract
Background
Rectal gonorrhea (NG) and chlamydia (Connecticut) infections are common among men who have sex with men (MSM). Rectal douching/enema (RDE) is a common practice among MSM that can affect the rectal microbiome. It is unclear if this practice is associated with acquiring rectal infections (RI) with either NG or CT.
Methods
From 2013–2015, 398 adult HIV-negative MSM and transwomen were enrolled in a randomized controlled study on text messaging for adherence to pre-exposure prophylaxis (PrEP). Participants were surveyed on sexual behavior, frequency of RDE, drug use, and nutritional habits in conjunction with routine sexually transmitted infection testing. Pearson’s χ 2 and two sample t-tests were used to measure significance of RDE and other risk factors with RI. Multivariable logistic regression model was used to control for confounding and assess the association of RDE with RIs. Confounders (i.e., age, number anal receptive sex, number sex partners) were selected a priori for inclusion in the final model based on a causal model and statistical significance.
Results
Of 397 participants, 262 (67%) performed RDE and 132 (33%) had at least one NG or CT rectal infection over 48 weeks. Number of condomless anal receptive sex acts (mean = 19, P < 0.001), condom use for anal receptive sex (P = 0.017), number of male sex partners in past 3 months (mean = 14, P = 0.001), and the use of poppers (P < 0.001) were associated with RI. There was no significant association between nutritional habits, probiotic foods or supplements and RI, with the exception of energy bars (P = 0.029). Controlling for confounders, RI was associated with RDE less than weekly with OR = 1.02 (95% CI 0.52–1.99) while RDE weekly or more had OR = 2.08 (95% CI 1.03–4.17). Stratified by number of partners, MSMs with more than the median (>6) number of partners had OR = 4.96 (95% CI 1.29–19.03) if performing RDE less than weekly, and OR = 6.03 (95% CI 1.55–23.49) if weekly or more.
Conclusion
Rectal hygiene with douching/enemas is a common practice among MSMs on PrEP, which increases the odds of acquiring rectal NG and/or CT. This finding is suggestive for the use of rectal hygiene products/practices as potential targets for sexually transmitted infection prevention.
Disclosures
All authors: No reported disclosures
Study of the application of hydrogen fuel to long-range subsonic transport aircraft, volume 2
The feasibility, practicability, and potential advantages/disadvantages of using liquid hydrogen as fuel in long range, subsonic transport aircraft of advanced design were studied. Both passenger and cargo-type aircraft were investigated. To provide a valid basis for comparison, conventional hydrocarbon (Jet A) fueled aircraft were designed to perform identical missions using the same advanced technology and meeting the same operational constraints. The liquid hydrogen and Jet A fueled aircraft were compared on the basis of weight, size, energy utilization, cost, noise, emissions, safety, and operational characteristics. A program of technology development was formulated
Initial observations of plastic-lined ponds for fingerling walleye production
Fish culture ponds are commonly fertilized to increase fish production through enhancement of the plankton forage base. Many fish culture facilities rely on natural production of zooplankton and aquatic insects as food sources for larval fish. Literature on pond fertilization regimes varies; recommendations range from no fertilization to a combination of inorganic and organic fertilizers. More research on the interactions among water quality, nutrients, plankton (phytoplankton and zooplankton) and fertilizers of the appropriate nutrient ratios is needed to move fertilization from an art to a science
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Frame me if you must: PrEP framing and the impact on adherence to HIV Pre-exposure Prophylaxis
Abstract
Background
“PrEP whore” has been used both as a pejorative by PrEP opponents in the gay community and, reactively, by PrEP advocates as a method to reclaim the label from stigmatization and “slut-shaming.” The actual prevalence and impact of such PrEP-directed stigma on adherence have been insufficiently studied.
Methods
CCTG 595 was a randomized controlled PrEP demonstration project in 398 HIV-uninfected MSM and transwomen. Intracellular tenofovir-diphosphate (TFV-DP) levels at weeks 12 and 48 were used as a continuous measure of adherence. At study visits, participants were asked to describe how they perceived others’ reactions to them being on PrEP. These perceptions were categorized a priori as either “positively framed,” “negatively framed,” or both. We used Wilcoxon rank-sum to determine the association between positive and negative framing and TFV-DP levels at weeks 12 and 48.
Results
By week 4, 29% of participants reported perceiving positive reactions from members of their social groups, 5% negative, and 6% both. Reporting decreased over 48 weeks, but positive reactions were consistently reported more than negative. At week 12, no differences in mean TFV-DP levels were observed in participants with positively-framed reactions compared with those reporting no outcome or only negatively-framed (1338 [IQR, 1036-1609] vs. 1281 [946-1489] fmol/punch, P = 0.17). Additionally, no differences were observed in those with negative reactions vs. those without (1209 [977–1427] vs. 1303 [964–1545], P = 0.58). At week 48, mean TFV-DP levels trended toward being higher among those that report any reaction, regardless if positive (1335 [909–1665] vs. 1179 [841–1455], P = 0.09) or negative (1377 [1054–1603] vs. 1192 [838–1486], P = 0.10) than those reporting no reaction. At week 48, 46% of participants reported experiencing some form of PrEP-directed judgment, 23% reported being called “PrEP whore,” and 21% avoiding disclosing PrEP use.
Conclusion
Over 48 weeks, nearly half of participants reported some form of judgment or stigmatization as a consequence of PrEP use. However, individuals more frequently perceived positively framed reactions to being on PrEP than negative. Importantly, long-term PrEP adherence does not appear to suffer as a result of negative PrEP framing.
Disclosures
All authors: No reported disclosures
Studies on fusobacteria associated with periodontal diseases
The document attached has been archived with permission from the Australian Dental Association. An external link to the publisher’s copy is included.The physiological and metabolic characteristics of representative isolates of the various subspecies of Fusobacterium nucleatum were investigated by growing them in continuous culture in chemically-defined media. Behaving almost identically, these organisms were found to obtain energy from the fermentation of simple carbohydrates such as glucose or fructose or from the fermentation of certain amino acids, free or in the form of small peptides. The latter can be attacked by aminopeptidase activity which was shown to be essential for the growth of the organism in an environment lacking fermentable carbohydrate and free amino acids but replete with small peptides. This metabolic versatility may explain the presence of F nucleatum in both supra- and sub-gingival dental plaque and why it is often found together with organisms such as Porphyromonas gingivalis which display powerful endopeptidase activities. Using the technique of allozyme electrophoresis, the current subspeciation of F. nucleatum was shown to be of doubtful validity and evidence, based upon physiological and metabolic properties, for differences in pathogenicity between isolates was not detected. While this organism is a member of various bacterial consortia associated with periodontal diseases, its contribution to the disease process remains unclear.AH Roger
Recent HIV Risk Behavior and Partnership Type Predict PrEP Adherence in Men Who Have Sex with Men
Abstract
Background
Individuals engaging in higher risk behavior are often more adherent to PrEP but it is unclear if partnership type itself affects PrEP adherence. We examined the effect of recent HIV risk behaviors and partnership type on PrEP adherence in men who have sex with men (MSM) taking PrEP.
Methods
CCTG 595 is a 48-week PrEP demonstration study of 398 HIV− at-risk MSM. At baseline and week 48, HIV risk score was estimated as the probability of seroconversion over the next year based on number of condomless anal sex acts with HIV+/unknown partners in the last month and any STI diagnosed at study visit. HIV risk score was categorized as low (<0.12), moderate (0.12−0.59) and high (>0.59) risk based on population seroconversion probabilities. Partnership type was assigned as no/single HIV− partner, single HIV+ partner, or multiple partners of any serostatus in the past 3 months. PrEP adherence was estimated by intracellular tenofovir-diphosphate (TFV-DP) levels as a continuous variable at week 48. Statistical methods included McNemar’s test, Wilcoxon rank-sum test, and linear regression model where appropriate.
Results
Of 313 MSM who completed week 48, there was no significant change in HIV risk category from baseline to week 48 (low: 44 to 42%; moderate: 27 to 24%; high: 28 to 34%; P = 0.25). There was a significant change in partnership type, with the proportion of those with no or single HIV− partnerships increasing (1 to 9%, P < 0.001). In univariate analysis, moderate and high-risk groups had higher TFV-DP levels than the low-risk group at week 48 (P = 0.018). Participants with no/single HIV− partner had significantly lower TFV-DP levels than those with one HIV+ partner or multiple partners (P = 0.007). In a multivariable linear regression model, only low-risk partnerships remained significant where no/single HIV− partnerships were associated with lower TFV-DP levels (mean difference = −344fmol/punch [−617, −71], P = 0.014).
Conclusion
Although there was a shift in partnership type towards lower risk partnerships, objective HIV risk behavior remained stable over time. Individuals with higher HIV risk behaviors and risk partnerships had higher TFV-DP levels suggesting maintained strong motivation for PrEP adherence. Thus, recent sexual risk behavior and partnership type may be important predictors of PrEP adherence in MSM.
Disclosures
All authors: No reported disclosures
Time for change: a new training programme for morpho-molecular pathologists?
The evolution of cellular pathology as a specialty has always been driven by technological developments and the clinical relevance of incorporating novel investigations into diagnostic practice. In recent years, the molecular characterisation of cancer has become of crucial relevance in patient treatment both for predictive testing and subclassification of certain tumours. Much of this has become possible due to the availability of next-generation sequencing technologies and the whole-genome sequencing of tumours is now being rolled out into clinical practice in England via the 100 000 Genome Project. The effective integration of cellular pathology reporting and genomic characterisation is crucial to ensure the morphological and genomic data are interpreted in the relevant context, though despite this, in many UK centres molecular testing is entirely detached from cellular pathology departments. The CM-Path initiative recognises there is a genomics knowledge and skills gap within cellular pathology that needs to be bridged through an upskilling of the current workforce and a redesign of pathology training. Bridging this gap will allow the development of an integrated 'morphomolecular pathology' specialty, which can maintain the relevance of cellular pathology at the centre of cancer patient management and allow the pathology community to continue to be a major influence in cancer discovery as well as playing a driving role in the delivery of precision medicine approaches. Here, several alternative models of pathology training, designed to address this challenge, are presented and appraised
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