Environmental significance of lubricant oil: A systematic study of photooxidation and its consequences

Lubricant (lube) oil discharge from ships has been widely considered as normal "operational consumption", but is now deemed to be oil pollution. Despite the chronic contamination of the marine environment by lube oil, the number of studies related to its environmental impact, characteristics, and toxicity is limited. This study is the first attempt to investigate the environmental fate of lube oil subjected to photooxidation using in situ mesocosms. A tiered approach using thin-layer chromatography-flame ionization detection (TLC-FID), Fourier-transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) demonstrated compositional changes in lube oil and the water-soluble fraction (WSF). Total polycyclic aromatic hydrocarbons (ΣPAHs) in lube oil after 96 h of photooxidation were measured at 79.8 and 41 μg/g in the control (Con) and exposure (Exp) groups, respectively. Meanwhile, the ΣPAHs concentration in WSF after 96 h was very low, at 0.25 and 0.45 μg/L in Con and Exp, respectively. FTIR and GC-MS helped identify bond changes and photoproducts in WSF. A wide range of photoproducts, including carboxylic acids, esters, anhydrides, aldehydes and ketones, were identified in WSF. Toxic effects of WSF in both the Con and Exp groups obtained after 96 h of photooxidation were evaluated on olive flounder (Paralichthys olivaceus) embryos. Morphological defects, especially tail fin fold defects, were found to be significantly elevated in both the Con and Exp groups, with marginally higher frequency in Exp. The results of this study demonstrate the need for further research on lube oil weathering, including monitoring over prolonged periods of time.

Upcycling of Spent Lithium Cobalt Oxide Cathodes from Discarded Lithium-Ion Batteries as Solid Lubricant Additive

This work provides an alternative solution to the challenge of battery recycling via the upcycling of spent lithium cobalt oxide (LCO) as a new promising solid lubricant additive. An advanced solid lubricant mixture of graphene, Aremco binder, and recycled LCO was formulated into a spray with the use of excess volatile organic solvent. Numerous flat steel disks were spray-coated with the new lubricant formulation and naturally dried followed by curing at 180 °C. When tested on a ball-on-disk up to 230 m in distance, the composite new solid lubricant reduced the coefficient of friction (COF) by 85% between two steel surfaces compared to unlubricated surfaces under a constant 1 GPa Hertzian pressure in an ambient environment. The tribofilm composition, particle size, and type of contact are identified as important parameters in the improvement of the COF. Scanning electron microscopy was used to study its morphology, and energy dispersive X-ray spectroscopy was used to analyze the composition of pristine and tested tribofilms. Upcycled spent low value LCO powder was used as a lubricant additive in tribology for the first time with exceptional lubricious properties.

Time to change the paradigm: limited condom and lubricant use among Nigerian men who have sex with men and transgender women despite availability and counseling

PURPOSE

This study characterized availability and uptake of condoms and condom-compatible lubricants (CCLs) at community-engaged condom education and distribution programs serving cisgender men who have sex with men and transgender women in Abuja and Lagos, Nigeria.

METHODS

Condoms and water-based CCLs were freely available to participants in the TRUST/RV368 cohort. Factors associated with their consistent use were assessed using Poisson regression with robust error variance to estimate relative risks (RRs) and 95% confidence intervals (CIs).

RESULTS

From March 2013-November 2017, 2090 cisgender men who have sex with men and transgender women enrolled with HIV prevalence 40.4% and incidence 12.8 cases per 100 person-years. Fifteen months after enrollment, the proportion who reported consistent condom and CCL use increased during receptive anal sex (21.7%-67.1%, P < .001) and insertive anal sex (25.4%-67.8%, P < .001). Multivariable analyses demonstrated independent impact of 15 months in care on uptake during both receptive (RR 2.62 [95% CI 2.29-3.00]) and insertive (RR 2.27 [95% CI 2.01-2.57]) sex.

CONCLUSIONS

Engagement in care improved condom and CCL uptake over time but inconsistent use remained common. Novel approaches to further increase uptake must be pursued alongside complementary strategies, such as sustained access to antiretroviral therapy for those living with HIV and provision of pre and postexposure prophylaxis for those at risk.

Lubricant use during intercourse and time to pregnancy: a prospective cohort study

OBJECTIVE

To assess the extent to which lubricant use during intercourse is associated with time to pregnancy (TTP).

DESIGN

Prospective cohort study.

SETTING

Denmark and North America.

POPULATION

A total of 6467 women aged 18-49 years who were not using contraception or fertility treatment.

METHODS

We pooled data from two continuing prospective cohort studies of pregnancy planners in Denmark (2011-2017) and North America (2013-2017). Female participants completed bimonthly questionnaires for 12 months or until they reported pregnancy. After restricting the study to women without a history of infertility who had been trying to conceive for six or fewer cycles at enrollment, 6467 women were retained for analysis. Self-reported lubricant use was categorised as water-based/not pH balanced, water-based/pH balanced 'fertility friendly', silicone-based, oil-based, or a combination of these. We used proportional probability models to calculate fecundability ratios (FRs) and 95% confidence intervals (95% CIs) for the association between lubricant use and fecundability, after adjusting for cohort and sociodemographic and lifestyle factors.

MAIN OUTCOME MEASURE

Fecundability.

RESULTS

At baseline, 17.5% of participants reported the use of lubricants, most commonly water-based/not pH balanced (11.4%). Compared with non-use of lubricants, FRs were 1.02 (95% CI 0.93-1.11) for water-based/not pH-balanced lubricant use, 1.01 (95% CI 0.86-1.18) for water-based/pH balanced 'fertility friendly' lubricant use, 1.23 (95% CI 0.94-1.61) for oil-based lubricant use, and 1.27 (95% CI 0.93-1.73) for silicone-based lubricant use. Associations between oil-based lubricant use and fecundability were inconsistent across subgroups of study cohort, age, parity, and intercourse frequency.

CONCLUSIONS

Lubricant use was not associated with reduced fecundability in the preconception cohorts of pregnancy planners studied.

TWEETABLE ABSTRACT

Lubricant use during intercourse was not associated with time to pregnancy in a study of pregnancy planners.

Repeated rectal application of a hyperosmolar lubricant is associated with microbiota shifts but does not affect PrEP drug concentrations: results from a randomized trial in men who have sex with men

INTRODUCTION

Oral pre-exposure prophylaxis (PrEP) with tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC) is highly effective in preventing HIV infection among men who have sex with men (MSM). The effects of consistent personal lubricant use in the rectum on tissue PrEP drug concentrations and the rectal microbiota are unknown. We investigated rectal PrEP drug concentrations and the microbiota in MSM before and after repeated rectal application of a hyperosmolar lubricant.

METHODS

We randomized 60 HIV-negative MSM to apply 4 mL of hyperosmolar rectal lubricant daily (n = 20), take daily oral TDF/FTC (n = 19), or both (n = 21) for seven days. Blood, rectal biopsies and rectal secretions were collected via rigid sigmoidoscopy before and on day 8 after product use. Tenofovir (TFV) and FTC as well as their intracellular metabolites tenofovir-diphosphate (TFV-DP), FTC-triphosphate (FTC-TP) were measured by HPLC-mass spectrometry. Rectal mucosal microbiota was sequenced with 16S rRNA sequencing using Illumina MiSeq.

RESULTS

Seven days of lubricant application was not associated with differences in PrEP drug concentrations in rectal tissue or secretions. Lubricant use was associated with a decrease in the relative abundance of the Bacteroides genus (p = 0.01) and a non-significant increase in the Prevotella genus (p = 0.09) in the rectum. PrEP drug concentrations in rectal tissue and secretions were not associated with microbiota composition or diversity either before or after lubricant use.

CONCLUSIONS

Repeated rectal application of a hyperosmolar lubricant does not affect mucosal PrEP drug concentrations but is associated with changes in the rectal microbiome.

Performance and emission characteristics of a bio-lubricated two-stroke gasoline engine

Two-stroke petrol engines find wide applications in the areas like chain saws, weed cutters, and power sprayers because of their compactness and higher power to weight ratio. In the present study, the feasibility of using vegetable-based lubricant instead of ordinary mineral 2 T oil is investigated. M15 (85% petrol + 15% methanol) and E15 (85% petrol + 15% ethanol) blend with gasoline are used as the fuel. Experiments were carried out in a two-stroke air-cooled engine equipped with a rope brake dynamometer. It is observed that the vegetable-based lubricant (sunflower oil) is miscible with the tested fuels. The frictional power for the vegetable-based lubricant was found to be less than that of mineral 2 T oil. The brake thermal efficiency improved and the brake-specific fuel consumption decreased for the sunflower oil-based lubricant. The combination of E15 + sunflower oil lubricant exhibited the greatest benefits, raising the brake thermal efficiency by 3.4% and reducing the brake-specific fuel consumption by 1.4%. Hydrocarbon and carbon monoxide emissions were lower for the vegetable-based lubricant than the 2 T mineral oil.

Impact of Drug Formulation Variables on Silicone Oil Structure and Functionality of Prefilled Syringe System

Use of prefilled syringes to self-administer biologics via subcutaneous administration provides convenience to patients. The barrel interior of prefilled syringes is typically coated with silicone oil for lubrication to aid plunger movement at the time of administration. This study intended to evaluate the impact of formulation variables on the silicone oil on the barrel interior surface. Characterization techniques including syringe glide force, break loose force, Schlieren imaging, contact angle, inductively coupled plasma spectrometry, and thin film interference reflectometry were used in assessing the interactions. Data indicated that formulation variables such as pH, buffer/tonicity agent type and concentration, and surfactant present in the formulation can effect silicone oil lubrication of prefilled syringes, leading to changes in functional properties of the syringe over time. Syringe samples containing acetate and histidine buffers showed an increase in glide force at accelerated storage temperature conditions, but the change was minimal at 5 °C. The samples with the highest glide force correlated with the presence of mannitol in combination with sodium acetate buffer. Sodium chloride had lesser impact on glide force than mannitol. Samples with higher glide force exhibited a substantial change in the silicone oil layer of the syringe, as observed with Schlieren imaging, as well as a significant reduction in surface hydrophobicity, as demonstrated through contact angle measurement. These data indicated that the structure of the siliconized surface can change over time in contact with different formulations. During formulation development of drug products in prefilled syringes, in addition to potential impact on molecule stability, the selection of formulation variables should also be guided by assessing the impact to syringe functionality with the glide force as one of the key parameters.LAY ABSTRACT: Self-administering drug products packaged in prefilled syringes provides convenience to patients. The interior of a prefilled glass syringe is typically lubricated with silicone oil for easy plunger movement during injection. This article discusses the impact of formulation excipients on silicone oil coating inside the syringe. Characterization techniques were used to assess the ease of plunger movement and structure of the silicone coating. Data indicate formulation excipients can affect silicone oil distribution of prefilled syringes, leading to an increase in plunger glide force at accelerated storage temperature conditions. The increase in glide force within a prefilled syringe with or without an auto-injector can have an impact on dose accuracy and user experience. Syringes with a higher plunger glide force appeared to exhibit a change over time in surface energy and structure of the silicone oil layer in contact with particular formulations.

Improved hearing protector attenuation through the use of a lubricant

A study of 40 novice hearing protection users was conducted to determine if the use of a lubricant with hearing protective plugs would enhance their attenuation. Three types of hearing protection devices (i.e., earplugs) were evaluated: roll-down PVC foam, mushroom-style polyurethane foam, and elastomeric flanged. For each earplug type, the right and left ear (dry and lubricated, respectively) personal attenuation rating was determined using a commercially available microphone in real-ear apparatus. Earplug efficacy was observed to increase in the presence of a lubricant for all 3 plug types, with average mean elevations by earplug type ranging from 1.5-5.1 dB. Two of three earplug types saw statistically significant improvements when used with lubrication, demonstrating heightened mean personal attenuation ratings of 2.8 dB and 5.1 dB. The issues of handedness and gender differences (vis à vis ear canal size) are explored, and the importance of proper fitting is discussed in detail. Several specific questions yet to be answered are posed, and directions for further research indicated.

Reducing Friction in the Eye: A Comparative Study of Lubrication by Surface-Anchored Synthetic and Natural Ocular Mucin Analogues

Biomaterials used in the ocular environment should exhibit specific tribological behavior to avoid discomfort and stress-induced epithelial damage during blinking. In this study, two macromolecules that are commonly employed as ocular biomaterials, namely, poly(vinylpyrrolidone) (PVP) and hyaluronan (HA), are compared with two known model glycoproteins, namely bovine submaxillary mucin (BSM) and α₁-acid glycoprotein (AGP), with regard to their nonfouling efficiency, wettability, and tribological properties when freely present in the lubricant, enabling spontaneous adsorption, and when chemisorbed under low contact pressures. Chemisorbed coatings were prepared by means of photochemically triggered nitrene insertion reactions. BSM and AGP provided boundary lubrication when spontaneously adsorbed in a hydrophobic contact with a coefficient of friction (CoF) of ∼0.03-0.04. PVP and HA were found to be excellent boundary lubricants when chemisorbed (CoF ≤ 0.01). Notably, high-molecular-weight PVP generated thick adlayers, typically around 14 nm, and was able to reduce the CoF below 0.005 when slid against a BSM-coated poly(dimethylsiloxane) pin in a tearlike fluid.

Phosphorus Depletion as a Green Alternative to Biocides for Controlling Biodegradation of Metalworking Fluids

Metalworking fluids (MWFs) are used as lubricants and coolants in the manufacturing operations. Their biodeterioration, while in operation, is a widespread problem leading to poor performance and worker health issues. Adding biocides, though effective in reducing microbial growth, leads to the production of more recalcitrant wastewaters that are difficult to dispose or recycle on-site. Increasing environmental concerns have led to robust legislation for reducing/eliminating the use of toxic biocides in MWFs, stimulating a growing interest in the development/application of alternative biological preservation strategies. In this study, inducing nutrient imbalance was investigated for controlling microbial growth in MWFs. Phosphorus was immobilized employing insoluble La₂O₃ to form LaPO₄. Concentrations of La₂O₃ greater than 0.08%w (%w = weight percent) completely inhibited microbial growth (from 1.4 × 10⁷ to 0 CFU/mL) and hindered biodegradation. Raman spectroscopy suggested that La₂O₃ converted intracellular phosphorus into LaPO₄. The growth inhibition potentials of both 0.06%w La(NO₃)₃ and La₂O₃ were found to be superior to formaldehyde. The antimicrobial property of La₂O₃ (i.e., inhibition) was tenable by adding sufficient phosphate, acting as an on/off switch for controlling microbial growth in MWFs. This technology offers the potential to reduce/eliminate the use of biocides in MWFs, improves the feasibility of end-of-life biological treatment, and closes the water loop.

Breakage is the norm: use of condoms and lubrication in anal sex among Black South African men who have sex with men

This paper explores condom use and lubrication practices among Black men who have sex with men in South African townships. Results are from 81 in-depth individual interviews conducted among a purposive sample from four townships surrounding Pretoria as part of a larger qualitative study. Awareness that condoms should be used to have safer anal sex was ubiquitous. Fewer men reported that lubricants should be used to facilitate anal intercourse. Partner pressure and partner distrust were the most common barriers cited for not using condoms and lubricants. Knowledge about condom-lubricant compatibility was rare. Condom problems were a norm, with widespread expectations of condom failure. Men's subjectivities - their perceptions of and preferences for specific brands, types and flavours of condoms and lubricants - influenced engagement with such safer-sex technologies. However, what was available in these settings was often neither what men needed nor preferred. Findings show the need to enhance access to appropriate and comprehensive: safer-sex supplies, health services and health education, and underline the importance of efforts to develop targeted programmes relevant to experiences of men who have sex with men in the South African context.

Adhesion of Microdroplets on Water-Repellent Surfaces toward the Prevention of Surface Fouling and Pathogen Spreading by Respiratory Droplets

Biofouling caused by the adhesion of respiratory microdroplets generated in sneezing and coughing plays an important role in the spread of many infectious diseases. Although water-repellent surfaces are widely used for the long-term repellency of aqueous solutions, their repellency to pathogen-containing microdroplets is elusive. In this work, microdroplets from picoliter to nanoliter were successfully generated in a controlled manner to mimic the exhaled microdroplets in sneezing and coughing, which allowed us to evaluate the adhesion of microdroplets on both superhydrophobic and lubricant-infused "slippery" surfaces for the first time. The impact and retention of water microdroplets on the two water-repellent surfaces are compared and investigated. Microdroplet-mediated surface biofouling and pathogen transmission were also demonstrated. Our results suggested that the adhesion of microdroplets should be duly considered in the design and application of water-repellent surfaces on biofouling prevention.

Acceptability of Three Novel HIV Prevention Methods Among Young Male and Transgender Female Sex Workers in Puerto Rico

Sex workers need HIV-prevention methods they can control and incorporate easily in their work. We studied the acceptability of three methods: HIV self-test use with clients, oral pre-exposure prophylaxis (PrEP), and rectal microbicide gel. Four male and eight transgender female (TGF) sex workers in Puerto Rico completed a baseline survey with a quantitative measure of likelihood of use. From them, one male and four TGF also completed a 12-week study of rectal microbicide placebo gel use prior to receptive anal intercourse with male clients and evaluated via qualitative in-depth interviews and follow-up quantitative assessments how each method could be incorporated into their work. Most were interested in a rectal microbicide gel and able to use it covertly with clients. Challenges to using the HIV self-test with clients included the potential for both breach of confidentiality and confronting violent situations. Participants also expressed interest in oral PrEP, but raised concerns about side effects.

Valorization of lubricant-based wastewater for bacterial neutral lipids production: Growth-linked biosynthesis

Lipids produced by microorganisms are currently of great interest as raw material for either biofuels or oleochemicals production. Significant biosynthesis of neutral lipids, such as triacylglycerol (TAG) and wax esters (WE) are thought to be limited to a few strains. Hydrocarbonoclastic bacteria (HCB), key players in bioremediation of hydrocarbon contaminated ecosystems, are among this group of strains. Hydrocarbon rich wastewaters have been overlooked concerning their potential as raw material for microbial lipids production. In this study, lubricant-based wastewater was fed, as sole carbon source, to two HCB representative wild strains: Alcanivorax borkumensis SK2, and Rhodococcus opacus PD630. Neutral lipid production was observed with both strains cultivated under uncontrolled conditions of pH and dissolved oxygen. A. borkumensis SK2 was further investigated in a pH- and OD-controlled fermenter. Different phases were assessed separately in terms of lipids production and alkanes removal. The maximum TAG production rate occurred during stationary phase (4 mg-TAG/L h). The maximum production rate of WE-like compounds was 15 mg/L h, and was observed during exponential growth phase. Hydrocarbons removal was 97% of the gas chromatography (GC) resolved straight-chain alkanes. The maximum removal rate was observed during exponential growth phase (6 mg-alkanes/L h). This investigation proposes a novel approach for the management of lubricant waste oil, aiming at its conversion into valuable lipids. The feasibility of the concept is demonstrated under low salt (0.3%) and saline (3.3%) conditions, and presents clues for its technological development, since growth associated oil production opens the possibility for establishing continuous fermentation processes.

Sources of hydrocarbons in urban road dust: Identification, quantification and prediction

Among urban stormwater pollutants, hydrocarbons are a significant environmental concern due to their toxicity and relatively stable chemical structure. This study focused on the identification of hydrocarbon contributing sources to urban road dust and approaches for the quantification of pollutant loads to enhance the design of source control measures. The study confirmed the validity of the use of mathematical techniques of principal component analysis (PCA) and hierarchical cluster analysis (HCA) for source identification and principal component analysis/absolute principal component scores (PCA/APCS) receptor model for pollutant load quantification. Study outcomes identified non-combusted lubrication oils, non-combusted diesel fuels and tyre and asphalt wear as the three most critical urban hydrocarbon sources. The site specific variabilities of contributions from sources were replicated using three mathematical models. The models employed predictor variables of daily traffic volume (DTV), road surface texture depth (TD), slope of the road section (SLP), effective population (EPOP) and effective impervious fraction (EIF), which can be considered as the five governing parameters of pollutant generation, deposition and redistribution. Models were developed such that they can be applicable in determining hydrocarbon contributions from urban sites enabling effective design of source control measures.

Liquid-Infused Poly(styrene-b-isobutylene-b-styrene) Microfiber Coating Prevents Bacterial Attachment and Thrombosis

Infection and thrombosis associated with medical implants cause significant morbidity and mortality worldwide. As we know, current technologies to prevent infection and thrombosis may cause severe side effects. To overcome these complications without using antimicrobial and anticoagulant drugs, we attempt to prepare a liquid-infused poly(styrene-b-isobutylene-b-styrene) (SIBS) microfiber coating, which can be directly coated onto medical devices. Notably, the SIBS microfiber was fabricated through solution blow spinning. Compared to electrospinning, the solution blow spinning method is faster and less expensive, and it is easy to spray fibers onto different targets. The lubricating liquids then wick into and strongly adhere the microfiber coating. These slippery coatings can effectively suppress blood cell adhesion, reduce hemolysis, and inhibit blood coagulation in vitro. In addition, Pseudomonas aeruginosa (P. aeruginosa) on the lubricant infused coatings slides readily, and no visible residue is left after tilting. We furthermore confirm that the lubricants have no effects on bacterial growth. The slippery coatings are also not cytotoxic to L929 cells. This liquid-infused SIBS microfiber coating could reduce the infection and thrombosis of medical devices, thus benefiting human health.

Inequities in access to HIV prevention services for transgender men: results of a global survey of men who have sex with men

INTRODUCTION

Free or low-cost HIV testing, condoms, and lubricants are foundational HIV prevention strategies, yet are often inaccessible for men who have sex with men (MSM). In the global context of stigma and poor healthcare access, transgender (trans) MSM may face additional barriers to HIV prevention services. Drawing on data from a global survey of MSM, we aimed to describe perceived access to prevention services among trans MSM, examine associations between stigma and access, and compare access between trans MSM and cisgender (non-transgender) MSM.

METHODS

The 2014 Global Men's Health and Rights online survey was open to MSM (inclusive of trans MSM) from any country and available in seven languages. Baseline data (n=3857) were collected from July to October 2014. Among trans MSM, correlations were calculated between perceived service accessibility and anti-transgender violence, healthcare provider stigma, and discrimination. Using a nested matched-pair study design, trans MSM were matched 4:1 to cisgender MSM on age group, region, and HIV status, and conditional logistic regression models compared perceived access to prevention services by transgender status.

RESULTS

About 3.4% of respondents were trans men, of whom 69 were included in the present analysis. The average trans MSM participant was 26 to 35 years old (56.5%); lived in western Europe, North America, or Oceania (75.4%); and reported being HIV-negative (98.6%). HIV testing, condoms, and lubricants were accessible for 43.5, 53.6, and 26.1% of trans MSM, respectively. Ever having been arrested or convicted due to being trans and higher exposure to healthcare provider stigma in the past six months were associated with less access to some prevention services. Compared to matched cisgender controls, trans MSM reported significantly lower odds of perceived access to HIV testing (OR=0.57, 95% CI=0.33, 0.98) and condom-compatible lubricants (OR=0.54, 95% CI=0.30, 0.98).

CONCLUSIONS

This first look at access to HIV prevention services for trans MSM globally found that most reported inadequate access to basic prevention services and that they were less likely than cisgender MSM to have access to HIV testing and lubricants. Results indicate the need to enhance access to basic HIV prevention services for trans MSM, including MSM-specific services.

Lubricant Use Among Men Who Have Sex With Men Reporting Anal Intercourse in Bangkok, Thailand: Impact of HIV Status and Implications for Prevention

This analysis measures prevalence and correlates of consistent lubricant use among a cohort of Thai men who have sex with men (MSM). Lubricant use was queried at the 12-month follow-up visit. Consistent lubricant use was evaluated with logistic regression. Consistent lubricant use was reported by 77.0% of men and was associated with consistent condom use with casual partners, while binge drinking, payment for sex, and inconsistent condom use with casual, and steady, partners were negatively associated. Though consistent lubricant use is common among this Thai MSM cohort, further promotion is needed with MSM engaging in risky sexual practices.

"This will not enter me": painful anal intercourse among Black men who have sex with men in South African townships

Little is known about painful receptive anal intercourse (RAI) and its relationship to HIV risk and protective behaviors among men who have sex with men (MSM). The purpose of this study was to identify attributions for and responses to painful RAI among Black MSM in South African townships. In-depth interviews were conducted with 81 Black MSM (ages 20-39 years) who were purposively recruited from four townships. The semi-structured interviews addressed sexual behavior and identity, alcohol use, and safer sex. Pain during RAI was brought up by many participants without specific prompting from the interviewer. Analysis of the interview transcripts revealed that pain was a common feature of first RAI experiences but was not limited to first-time experiences. The participants attributed pain during RAI to partner characteristics, interpersonal dynamics, lack of lubricant, and alcohol use or non-use. The main strategies participants used to address pain during RAI were setting sexual boundaries and lubricant use; a small number of participants reported purposefully consuming alcohol to prevent the pain associated with RAI. Black South African MSM can be supported to reduce pain during RAI in ways that reduce their HIV/STI risk. Culturally specific sexual health education, supportive sexual health services, and improved access to condom-compatible lubricants are important components of HIV/STI interventions for this population.

Enema use among men who have sex with men: a behavioral epidemiologic study with implications for HIV/STI prevention

Enema use or douching is a risk factor for HIV/STI in men who have sex with men (MSM). However, few studies have explored enema use practices. We examined the frequency of enema use, type of products used, and reasons to use and not to use before and after receptive anal sex in a large sample of MSM (N = 4,992) recruited from 16 U.S. cities. Through online surveys, we examined personal, behavioral, and environmental factors associated with enema use. Most (52 %) participants reported having douched at least once and 35 % reported douching within the last 3 months. While most (88 %) reported enema use before receptive anal sex, 28 % douched after receptive anal sex. Most participants (65 %) used water to douche, 24 % added salt, soap, and/or antibacterial products to water, and 30 % reported using commercially available products. Being a man of color, HIV-positive, diagnosed with an STI, identifying as "versatile" in sex, and having more than two unprotected sex partners were significantly associated with recent enema use. Douching behavior appears closely associated with HIV/STI risk. Douching with water may be a concern since it may increase HIV/STI infection by damaging the epithelium. Development and promotion of a non-damaging, non-water based enema specifically for use in anal sex are recommended. In addition, the seemingly contradictory recommendations that water-based lubricant is recommended for anal sex but water-based enemas are dangerous need to be reconciled into a single consistent message.

What is the value of incorporating tear osmolarity measurement in assessing patient response to therapy in dry eye disease?

PURPOSE

To evaluate the correlation between changes in tear osmolarity, symptoms, and corneal fluorescein staining in patients with dry eye disease (DED).

DESIGN

Retrospective, clinic-based cohort study.

METHODS

In this single-institution study, we reviewed the charts of 186 patients with DED from whom we had data on tear osmolarity, symptoms, and corneal fluorescein staining from 2 separate visits. Main outcomes included the correlation of the changes between the 2 visits for tear osmolarity (TearLab system), symptoms (Ocular Surface Disease Index), and corneal fluorescein staining (modified Oxford scheme). For tear osmolarity and corneal fluorescein staining the scores from the eye with highest readings were analyzed. The correlations were repeated on subgroups based on proposed cutoffs for DED severity and on patients' treatment.

RESULTS

We found a modest, though statistically significant, correlation between changes in corneal fluorescein staining and symptoms of DED (R = 0.31; P < .001). However, there was no correlation between the recorded change in tear osmolarity and symptoms (R = -0.091; P = .38) or between changes in tear osmolarity and corneal fluorescein staining (R = -0.02; P = .80). This lack of correlation was consistent in all the subgroups studied. A multivariate analysis revealed that changes in corneal fluorescein staining had predictive value on symptom changes, whereas tear osmolarity changes did not.

CONCLUSIONS

Changes in tear osmolarity do not correlate significantly with changes in patient symptoms or corneal fluorescein staining in dry eye disease.

The role of gel application in decreasing pain during speculum examination and its effects on papanicolaou smear results

PURPOSE

This study aimed to investigate the effects of water-based gel application in reducing pain or discomfort associated with speculum examination, and compared the presence of unsatisfactory Papanicolaou smear results between gel-applied and control groups.

METHODS

In this prospective randomized controlled study, a total of 1,580 patients were analyzed. The subjects were randomized to a gel group and a control group. For the collection of the smear sample, water-based gel was used in the gel group and dry speculum was used in the control group. All patients were asked to score their pain on a numeric pain scale at two time points during the procedure (insertion and opening phase of speculum). Cytopathologists who analyzed the smear cytology were blinded to the study. Pain intensity during speculum examination, as well as unsatisfactory smear results, were analyzed between the groups.

RESULTS

The pain scores obtained at two different time points of speculum application were significantly lower in the gel group compared to the control group both in premenopausal and postmenopausal women (p < 0.001). The ratios of unsatisfactory cytopathologic examination results were 1.13 and 1.39% for the gel-applied and control groups, which were not significantly different.

CONCLUSION

Lubrication of the outer superior and inferior blade of the plastic vaginal speculum with a small amount of a water-soluble lubricant gel decreases the pain associated with insertion and opening of the vaginal speculum in both premenopausal and postmenopausal women without affecting the quality of the cytology results during the collection of Papanicolaou test specimens.

Thermo-chemical extraction of fuel oil from waste lubricating grease

This study investigated the recovery of oil from waste grease through the process of thermal degradation in an aqueous solution of potassium hydroxide (KOH) followed by solvent extraction. Waste high temperature metal bearing grease was dissolved in a 15 w/w% KOH solution at 80°C while being agitated at 2000 rpm using a shear action agitator for a period of 15 min. Two distinct layers were observed after 8 min of settling time. The top layer being of dark brown oil and the bottom layer was a heterogeneous mixture. The two layers were separated by decantation. The bottom layer was cooled down to 45°C followed by slow addition of toluene (C7H8) while agitating at 1200 rpm for 15 min to prevent solids settling and minimise rapid volatilisation of the organic compounds in the mixture. Two distinct layers were also formed, the top homogeneous mixture of light brown oil-toluene mixture and the bottom sludge layer. The solvent was recovered from the oil for re-use by fractional distillation of the homogenous mixture. It was observed that 15 w/w% potassium hydroxide solution can chemically degrade the soap matrix in the grease and extract up to 49 w/w% of the fuel oil when subjected to high shear stress at a temperature of 80°C. The 26 w/w% extraction of oil in the remaining sludge was obtained by solvent extraction process with mass ratios of sludge to solvent of 2:1. Solvent recovery of 88% by mass was obtained via fractional distillation method. The combined extraction processes brought an overall oil yield of 75 w/w% from the waste grease. The fuel oil obtained from this process has similar properties to paraffin oil and can be blended with other oils as an alternative energy source.