Foam stability in filtered lubricants containing antifoams.

Lubricant formulations are filtered to remove deleterious particulate matter. An unintended consequence of this important process is the detrimental effect of fine filtration on the foaming performance of lubricants with antifoam additives. Here we outline a method to study this phenomenon in detail by probing the coalescence stability of single bubbles in filtered antifoam laden lubricants. Initially, we establish the validity of Garrett's hypothesis for the tested antifoam laden lubricants. Subsequently, we show that the bubble stability in filtered lubricants are positively correlated to the number of filtration cycles - with the most dramatic changes in bubble stability accompanying the initial few cycles of filtration. Further, we show that post filtration, the stability of bubbles in lubricants is inversely correlated to the pore size of the filter and the volume fraction of antifoam in the lubricant prior to filtration. The results also reveal that in the presence of antifoam additives, the bubble coalescence times span multiple Rayleigh distributions. We also provide visual evidence that shows the tested antifoams employ a bridging-stretching mechanism to rupture non-aqueous foams. Finally, a simple probabilistic model is introduced that helps in analyzing the distribution of coalescence times of single bubbles to obtain insights into the volume fraction of antifoams in the lubricant. We believe these results are valuable in guiding the design of lubricants with robust and superior foaming performance.

Graft Preparation with Intraoperative Vancomycin Decreases Infection After ACL Reconstruction: A Review of 1,640 Cases.

BACKGROUND: Reported infection rates following anterior cruciate ligament (ACL) reconstruction are low, but infections are associated with high morbidity including reoperations and inferior clinical outcomes. The purpose of the current study was to investigate the rate of infection after ACL reconstruction with and without graft preparation with a vancomycin irrigant. METHODS: All ACL reconstructions performed between May 2009 and August 2018 at a single academic institution were reviewed and categorized based on vancomycin use. Patients with <90-day follow-up, intraoperative graft preparation with an antibiotic other than vancomycin, or previous ipsilateral knee infection were excluded. Infection was defined as a return to the operating room for irrigation and debridement within 90 days after ACL reconstruction. Descriptive and inferential statistical analysis using t tests and Poisson regression were performed, with significance defined as p < 0.05. RESULTS: In total, 1,640 patients (952 males; 58.0%) with a mean age (and standard deviation) of 27.7 ± 11.4 years underwent ACL reconstruction (1,379 primary procedures; 84.1%) and were included for analysis. Intraoperative vancomycin was used in 798 cases (48.7%), whereas 842 ACL reconstructions (51.3%) were performed without intraoperative vancomycin. In total, 11 reconstructions (0.7%) were followed by infection, which occurred in 10 (1.2%) of the patients in whom the graft was not soaked in vancomycin and in 1 (0.1%) of the patients in whom the graft was soaked in vancomycin (p = 0.032). Age (p = 0.571), sex (p = 0.707), smoking (p = 0.407), surgeon (p = 0.124), and insurance type (p = 0.616) were not associated with postoperative infection risk. Autograft use was associated with decreased infections (p = 0.045). There was an 89.4% relative risk reduction with the use of intraoperative vancomycin. An increased body mass index (BMI) (p = 0.029), increased operative time (p = 0.001), and the absence of ACL graft preparation with vancomycin (p = 0.032) independently predicted postoperative infection. CONCLUSIONS: The use of vancomycin-soaked grafts was associated with a 10-fold reduction in infection after ACL reconstruction (0.1% versus 1.2%; p = 0.032). Other risk factors for infection after ACL reconstruction included increased BMI and increased operative time. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Evaporation-induced foam stabilization in lubricating oils.

Foaming in liquids is ubiquitous in nature. Whereas the mechanism of foaming in aqueous systems has been thoroughly studied, nonaqueous systems have not enjoyed the same level of examination. Here we study the mechanism of foaming in a widely used class of nonaqueous liquids: lubricant base oils. Using a newly developed experimental technique, we show that the stability of lubricant foams can be evaluated at the level of single bubbles. The results obtained with this single-bubble technique indicate that solutocapillary flows are central to lubricant foam stabilization. These solutocapillary flows are shown to originate from the differential evaporation of multicomponent lubricants-an unexpected result given the low volatility of nonaqueous liquids. Further, we show that mixing of some combinations of different lubricant base oils, a common practice in the industry, exacerbates solutocapillary flows and hence leads to increased foaming.

Contraception to prevent HIV-positive births: current contribution and potential cost savings in PEPFAR countries.

OBJECTIVES: To estimate the number of HIV-positive births currently prevented by contraceptive use in the President's Emergency Plan for AIDS Relief (PEPFAR) focus countries and to estimate the first year cost savings to each country if unintended and unwanted HIV-positive births were prevented via contraceptive use rather than providing antiretroviral prophylaxis for HIV-positive pregnant women ("PMTCT services"). METHODS: Data from publicly available sources yielded estimates of (1) contraceptive and HIV prevalence; (2) the number of women of reproductive age; (3) the number of annual births to HIV-infected women; (4) the rates of pregnancy and vertical HIV transmission; (5) the proportions of unintended and unwanted births; and (6) the cost per HIV-positive birth averted by family planning and PMTCT services. The number of HIV-positive births currently averted by contraceptive use and the number of unwanted and unintended HIV-positive births are the product of these estimates. Cost savings are the difference in the costs of family planning and PMTCT services. RESULTS: The annual number of unintended HIV-positive births currently averted by contraceptive use ranges from 178 in Guyana to over 120 000 in South Africa. The minimum annual cost savings to prevent just the unwanted HIV-positive births ranges from $26 000 in Vietnam to over $2.2 million in South Africa. CONCLUSIONS: Contraception is already having an important effect on reducing the number of infant HIV infections. This contribution could be strengthened by additional efforts to provide contraception to HIV-infected women who do not wish to become pregnant. Moreover, the effect of contraception can be achieved at a cost savings compared with PMTCT services.

From effectiveness to impact: contraception as an HIV prevention intervention.

BACKGROUND: Most efforts to date to prevent mother-to-child transmission of HIV have focused on provision of antiretroviral prophylaxis to HIV-infected pregnant women. Increasing voluntary contraceptive use has been an underused approach, despite clear evidence that preventing pregnancies in HIV-infected women who do not wish to become pregnant is an effective strategy for reducing HIV-positive births. This paper reviews international, country and service delivery level opportunities for and obstacles to translating contraceptive efficacy into interventions that will have an impact on the effectiveness of HIV prevention. METHODS: The integration of family planning services and HIV programmes as a potential intervention were specifically reviewed. RESULTS AND CONCLUSIONS: Despite substantial policy support for the integration of family planning and HIV programmes, burgeoning resources for HIV ignore the potential impact of contraception on HIV prevention. Moreover, separate funding for these two programmes and the resulting vertical organisation of health ministries and service facilities undermine coordination between departments and limit providers' ability to address the contraceptive needs of HIV-positive clients. Projects integrating family planning and HIV services are being implemented, allowing for documentation of factors that facilitate or impede integrated service delivery. However, few have been evaluated to demonstrate impact on contraceptive uptake and HIV-positive births averted.

Abortion surveillance at CDC: creating public health light out of political heat.

In the late 1960s, states began to liberalize their abortion laws, and a new era in women's health began. Under the leadership of Jack Smith, the Centers for Disease Control and Prevention (CDC) established a voluntary abortion surveillance system that provided the first nationwide information on the numbers and characteristics of women having abortions. Studies of abortion morbidity done by the CDC revealed that suction curettage was safer than sharp curettage, local anesthesia was safer than general anesthesia, free-standing clinics were safer than hospitals, and dilation and evacuation (D&E) was safer than the alternative of labor induction for early second-trimester abortions. This evidence, which contradicted traditional medical tenets, rapidly changed the practice of abortion in the United States. CDC also established a surveillance system for abortion deaths. This demonstrated a rapid improvement in the safety of abortion in the early 1970s. Lessons learned from mortality investigations helped to change practice as well.Today, more is known about the epidemiology of abortion than any other operation in the history of medicine. In the midst of strident debate over the abortion issue, CDC abortion surveillance data have helped to guide judicial rulings, legislative actions, and Surgeon General's reports, which have supported safer choices for women of reproductive age. When medical historians of the future look back on this century, the increasing availability of safe, legal abortion will stand out as a public health triumph.

The real problem with male condoms is nonuse.

PIP: Male latex condoms are considered to be the most effective method in reducing the risk of sexually transmitted disease (STD) and HIV transmission if properly used during sexual intercourse. Several studies were documented citing the effectiveness of latex condoms. Although one study reported condom failure due to breakage and slippage, this does not put the user at risk of STD/HIV transmission, because such mechanical failure occurs before intercourse or during removal (nonclinical breakage and slippage). Most importantly, condom users who report more frequent condom breakage and slippage can be counseled to develop skills to avoid behaviors that may place them at increased risk. Aside from condom breakage and slippage, a possible explanation for the observed failure of condoms to protect against STD/HIV transmission is the respondent's behavior of not providing valid information about their consistency in use. Based on the studies conducted on STD/HIV transmission, a frequently listed cause of condom failure was the type of condom being used during sexual intercourse and the user's failure to properly use the condom.^ieng

Estimates of the incidence and prevalence of sexually transmitted diseases in the United States. American Social Health Association Panel.

BACKGROUND: Accurate, updated estimates of the incidence and prevalence of sexually transmitted infections in the United States remain elusive. The most widely quoted number of new sexually transmitted disease (STD) cases each year is 12 million. However, this figure has not changed in more than a decade, despite improvements in detection methods and the effects of STD control programs. GOALS: To propose a system for weighing the strength of STD surveillance data and to estimate the incidence and prevalence of STDs in the United States for 1996, using the available published data. RESULTS: We estimate that more than 15 million STD infections occurred in the United States in 1996. This number exceeds the earlier estimate primarily because improved detection techniques have allowed an assessment of previously undiagnosed infections. CONCLUSIONS: Large numbers of new STDs continue to occur each year in the United States, with serious health and economic consequences. More than two thirds of our current estimate of 15 million STDs annually consists of two infections--trichomoniasis and human papillomavirus--for which we have only level III surveillance data. As the quality of our surveillance data improves, we can further refine the precision of our national estimates.