Quantitative 3D Characterization for Kinetics of Corrosion Initiation and Propagation in Additively Manufactured Austenitic Stainless Steel.

In situ X-ray computed tomography (X-ray CT) is used to investigate the effects of characteristic microstructural features on the pitting initiation and propagation in austenitic stainless steel specimens prepared with laser powder bed fusion (LPBF) additive manufacturing. In situ X-ray CT in probing the mechanism and kinetics of localized corrosion is demonstrated by immersing two LPBF specimens with different porosities in an aggressive ferric chloride solution for the evaluation of corrosion. X-ray CT images are acquired from the specimens after every 8 hours of immersion over an extended period of time (216 hours). Corrosion pit growth is then quantitatively analyzed with a data-constrained modeling method. The pitting growth mechanism of LPBF stainless steel is found to be different from that of conventional stainless steels. More specifically, the mechanism of corrosion pit initiation is closely correlated with the original lack of fusion porosity (LOF) distribution on the surface of the specimens and preferential pit propagation through the LOF pores inside the specimens. Pit growth kinetics are derived from pit volume changes determined through 3D data analysis. The pit growth kinetics in LPBF specimens are found to vary in the initial pit formation, competitive pit propagation, and the dominant pit growth stages.

National trends in sexual health indicators among gay and bisexual men disaggregated by ethnicity: repeated cross-sectional behavioural surveillance in New Zealand.

OBJECTIVES: To assess trends in sexual health outcomes among men who have sex with men (MSM) disaggregated by ethnicity. DESIGN: Repeated cross-sectional. SETTING: Behavioural surveillance data from 2006, 2008, 2011 and 2014 were collected in-person and online across Aotearoa New Zealand. PARTICIPANTS: Eligible participants were self-identified men aged 16 years or older who reported sex with another man in the past 5 years. We classified 10 525 participants' ethnicities: Asian (n=1003, 9.8%), Maori (Indigenous people of Aotearoa New Zealand, n=1058, 10.3%), Pacific (n=424, 4.1%) and European (n=7867, 76.8%). OUTCOME MEASURES: The sexual health outcomes examined were >20 recent (past 6 months) male sexual partners, past-year sexually transmitted infection (STI) testing, past-year STI diagnosis, lifetime and past-year HIV testing, lifetime HIV-positive diagnosis and any recent (past 6 months) condomless anal intercourse with casual or regular partners. RESULTS: When disaggregated, Indigenous and ethnic minority groups reported sexual health trends that diverged from the European MSM and each other. For example, Asian MSM increased lifetime HIV testing (adjusted OR, AOR=1.31 per survey cycle, 95% CI 1.17 to 1.47) and recent HIV testing (AOR=1.14, 95% CI 1.02 to 1.28) with no changes among Maori MSM or Pacific MSM. Condomless anal intercourse with casual partners increased among Maori MSM (AOR=1.13, 95% CI 1.01 to 1.28) with no changes for Asian or Pacific MSM. Condomless anal intercourse with regular partners decreased among Pacific MSM (AOR=0.83, 95% CI 0.69 to 0.99) with no changes for Asian or Maori MSM. CONCLUSIONS: Population-level trends were driven by European MSM, masking important differences for Indigenous and ethnic minority sub-groups. Surveillance data disaggregated by ethnicity highlight inequities in sexual health service access and prevention uptake. Future research should collect, analyse and report disaggregated data by ethnicity to advance health equity.

Ethnicity classification systems for public health surveys: experiences from HIV behavioural surveillance among men who have sex with men.

BACKGROUND: Race and ethnicity classification systems have considerable implications for public health, including the potential to reveal or mask inequities. Given increasing "super-diversity" and multiple racial/ethnic identities in many global settings, especially among younger generations, different ethnicity classification systems can underrepresent population heterogeneity and can misallocate and render invisible Indigenous people and ethnic minorities. We investigated three ethnicity classification methods and their relationship to sample size, socio-demographics and sexual health indicators. METHODS: We examined data from New Zealand's HIV behavioural surveillance programme for men who have sex with men (MSM) in 2006, 2008, 2011, and 2014. Participation was voluntary, anonymous and self-completed; recruitment was via community venues and online. Ethnicity allowed for multiple responses; we investigated three methods of dealing with these: Prioritisation, Single/Combination, and Total Response. Major ethnic groups included Asian, European, indigenous Maori, and Pacific. For each classification method, statistically significant associations with ethnicity for demographic and eight sexual health indicators were assessed using multivariable logistic regression. RESULTS: Overall, 10,525 MSM provided ethnicity data. Classification methods produced different sample sizes, and there were ethnic disparities for every sexual health indicator. In multivariable analysis, when compared with European MSM, ethnic differences were inconsistent across classification systems for two of the eight sexual health outcomes: Maori MSM were less likely to report regular partner condomless anal intercourse using Prioritisation or Total Response but not Single/Combination, and Pacific MSM were more likely to report an STI diagnosis when using Total Response but not Prioritisation or Single/Combination. CONCLUSIONS: Different classification approaches alter sample sizes and identification of health inequities. Future research should strive for equal explanatory power of Indigenous and ethnic minority groups and examine additional measures such as socially-assigned ethnicity and experiences of discrimination and racism. These findings have broad implications for surveillance and research that is used to inform public health responses.

Observations on the Early Stages of Corrosion on AA2099-T83.

An Al­Cu­Li aerospace alloy has been investigated to determine the order in which corrosion at different types of sites occurs in AA2099-T83. Specifically, the sequence of galvanic attack on intermetallic (IM) particles and other sites of AA2099-T83 was determined as a function of time, in 0.1 M NaCl, through the use of scanning electron microscopy and electron backscatter diffraction characterization techniques. The earliest attack occurred at isolated grains and grain boundaries and on Li-containing dispersoids. Similarly, some constituent IM particles showed evidence of trenching in the surrounding alloy matrix. These IM particles included Al7Cu2Fe and another group of unidentified particles which displayed complete trenching within the first 10 min of exposure. Al13(Fe, Mn)4 were next most active followed by Al37Fe12Cu2 with Al6(Fe,Mn) and large TiB2 particles being the least active.

Investigation of the Internal Structure of a Modern Seafloor Hydrothermal Chimney With a Combination of EBSD, EPMA, and XRD.

Samples from the sphalerite-dominated zone of a seafloor massive sulfide chimney, the Satanic Mills Chimney of the PACMANUS hydrothermal field, have been investigated to determine the internal macrostructure and microstructure of this zone, the phases present, and the distribution of metals. A combination of electron probe microanalysis, electron backscattered diffraction, and x-ray diffraction has been used. At the macroscale, this zone of the chimney wall is heavily porous and is comprised primarily of sphalerite, enclosing minor chalcopyrite, pyrite, and wurtzite. A Pb­As sulfosalt layer of possible microbial origins is present at the outer edge of the sphalerite matrix, next to a pore. The sphalerite has grown in globules on the order of 300 µm in diameter. At the microscale, the sphalerite features a colloform texture and a duplex-type grain structure consisting of either fine-grain regions in the center surrounded by coarse-grained regions or radiating coarse grains only. Pb- and As-rich bands have been detected in the colloform sphalerite, and growth twins have been observed in both the sphalerite and chalcopyrite crystals. A qualitative description of the growth of a typical globule is given, including nucleation, crystal growth, and solute redistribution.

Leaching Behavior and Corrosion Inhibition of a Rare Earth Carboxylate Incorporated Epoxy Coating System.

While paint coatings act as important barriers to corrosion, defects can lead to localized, rapid metal loss. The addition of corrosion inhibitors that are capable of leaching from a coating to protect the metal surface at a defect can prevent this type of corrosion. This work investigates the release and corrosion protection capabilities of two rare earth (RE) carboxylate inhibitors from an epoxy coating as an initial step to understanding their leaching behavior and interaction with the coating system. Leaching experiments were performed via inductively coupled plasma mass spectroscopy (ICP-MS) analyses of the solutions in which free-standing coatings loaded with varying concentrations of inhibitor compounds had been immersed. Inhibitor release from the epoxy coating was observed to be dependent on initial inhibitor concentration, inhibitor chemistry, and solution pH conditions. The coating systems with greater initial inhibitor loadings showed higher leaching rates, particularly in acidic environments. Following immersion, the absence of characteristic inhibitor peaks in the FTIR spectra of the coatings also confirmed leaching had taken place. Cross-sectional views of the coatings after exposure to the pH 1 environment presented a chloride infusion zone at the coating/solution interface where the inhibitor had leached out. The RE active inhibition provided by the leached RE carboxylate inhibitors was verified by exposure of a coating defect to a chloride contaminated environment.

A Patient's Perspective: Pairing the Stethoscope with POCUS to Evaluate Acute Dyspnea in the Clinic.

Supplemental digital content is available in the text.

An Examination of the Composition and Microstructure of Coarse Intermetallic Particles in AA2099-T8, Including Li Detection.

Electron and proton microprobes, along with electron backscatter diffraction (EBSD) analysis were used to study the microstructure of the contemporary Al-Cu-Li alloy AA2099-T8. In electron probe microanalysis, wavelength and energy dispersive X-ray spectrometry were used in parallel with soft X-ray emission spectroscopy (SXES) to characterize the microstructure of AA2099-T8. The electron microprobe was able to identify five unique compositions for constituent intermetallic (IM) particles containing combinations of Al, Cu, Fe, Mn, and Zn. A sixth IM type was found to be rich in Ti and B (suggesting TiB2), and a seventh IM type contained Si. EBSD patterns for the five constituent IM particles containing Al, Cu, Fe, Mn, and Zn indicated that they were isomorphous with four phases in the 2xxx series aluminium alloys including Al6(Fe, Mn), Al13(Fe, Mn)4 (two slightly different compositions), Al37Cu2Fe12 and Al7Cu2Fe. SXES revealed that Li was present in some constituent IM particles. Al SXES mapping revealed an Al-enriched (i.e., Cu, Li-depleted) zone in the grain boundary network. From the EBSD analysis, the kernel average misorientation map showed higher levels of localized misorientation in this region, suggesting greater deformation or stored energy. Proton-induced X-ray emission revealed banding of the TiB2 IM particles and Cu inter-band enrichment.

Illicit drug use among New Zealand gay and bisexual men: Prevalence and association with sexual health behaviours.

INTRODUCTION AND AIMS: Data are lacking on drug use among gay and bisexual men (GBM) in New Zealand. We establish a baseline estimate of drug use and investigate associations with sexual health and HIV risk. DESIGN AND METHODS: A cross-sectional survey of GBM was conducted in gay community settings and online. Participants were asked their frequency of using nine drugs (poppers, cannabis, ecstasy, methamphetamine, amphetamine, cocaine, LSD, gamma hydroxybutyrate and ketamine) in the previous 6 months. We examined associations between selected drugs and number of recent partners, unprotected anal intercourse with a casual partner and sexually transmitted infections using adjusted odds ratios (AOR). RESULTS: Overall, 3211 participants provided information of whom 55.8% reported any drug use, and 37.9% cannabis, 36.7% poppers, 16.5% ecstasy, 10.5% amphetamine, 7.4% methamphetamine, 6.6% LSD, 6.1% cocaine, 5.3% gamma hydroxybutyrate and 4.4% ketamine use. A quarter of all respondents (25.6%) reported using one drug, 22.8% two to four and 7.4% five or more drugs (polydrugs). Methamphetamine and polydrug use was independently predictive of reporting >20 recent partners (AOR 1.6 and 7.0, respectively), unprotected anal intercourse with a casual partner (AOR 1.8 and 3.2, respectively) and a sexually transmitted infection (AOR 1.6 and 4.3, respectively). DISCUSSION AND CONCLUSIONS: Drug use was common in this sample of GBM. Polydrug and methamphetamine users had especially high sexual health needs, but risks remained elevated among GBM consuming other drugs. Drug harm reduction programs and HIV prevention should target GBM with problematic drug use. Limitations include an inability to attribute causation. [Saxton P, Newcombe D, Ahmed A, Dickson N, Hughes A. Illicit drug use among New Zealand gay and bisexual men: Prevalence and association with sexual health behaviours. Drug Alcohol Rev 2017;00:000-000].

Frequent condom use with casual partners varies by sexual position among younger gay and bisexual men in New Zealand: national behavioural surveillance 2006-2011.

UNLABELLED: Background Condom promotion remains a cornerstone of HIV/STI control, but must be informed by evidence of uptake and address disparities in use. This study sought to determine the prevalence of, and demographic, behavioural and relational factors associated with, condom use during insertive and receptive anal intercourse with casual partners among younger gay, bisexual and other men who have sex with men (YMSM) in New Zealand. METHODS: The 2006-2011 national HIV behavioural surveillance data for YMSM aged 16-29 years was pooled. Separately for each sexual position, frequent (always/almost always) versus infrequent condom use was regressed onto explanatory variables using manual backward stepwise multivariable logistic regression analysis. RESULTS: Three-quarters of YMSM reported frequent condom use during insertive (76.0%) and receptive (73.8%) anal intercourse. YMSM who were exclusively insertive were more likely to report frequent condom use than versatile YMSM. Factors positively associated with frequent condom use, irrespective of sexual position were: in-person versus web-based recruitment, testing HIV negative versus never testing or testing HIV positive, having no recent sex with women, reporting two to five versus one male sexual partner in the past 6 months, reporting no current regular partner, but if in a regular relationship, reporting a boyfriend-type versus fuckbuddy-type partner, and frequent versus infrequent regular partner condom use. Pacific ethnicity and less formal education were negatively associated with frequent condom use only during receptive anal intercourse. CONCLUSIONS: The findings from this study demonstrate that condom norms can be actively established and maintained among YMSM. Condom promotion efforts must increase YMSM's capacity, agency and skills to negotiate condom use, especially for the receptive partner.

General practitioner awareness of sexual orientation among a community and internet sample of gay and bisexual men in New Zealand.

INTRODUCTION: General practitioners (GPs) can improve HIV and sexually transmitted infection (STI) screening, vaccination and wellbeing among gay, bisexual and other men who have sex with men (GBM) if they are aware of a patient's sexual orientation. AIM: To estimate GP awareness of their GBM patients' sexual orientation and examine whether HIV and STI screening was associated with this. METHODS: We analysed anonymous, self-completed data from 3168 GBM who participated in the community-based Gay Auckland Periodic Sex Survey (GAPSS) and Internet-based Gay men's Online Sex Survey (GOSS) in 2014. Participants were asked if their usual GP was aware of their sexual orientation or that they had sex with men. RESULTS: Half (50.5%) believed their usual GP was aware of their sexual orientation/behaviour, 17.0% were unsure, and 32.6% believed he/she was unaware. In multivariate analysis, GP awareness was significantly lower if the respondent was younger, Asian or an 'Other' ethnicity, bisexual-identified, had never had anal intercourse or had first done so very recently or later in life, and had fewer recent male sexual partners. GBM whose GP was aware of their sexual orientation were more likely to have ever had an HIV test (91.5% vs 57.9%; p<0.001), specific STI tests (91.7% vs 68.9%; p<0.001), and were twice as likely to have had an STI diagnosed. DISCUSSION: Lack of sexual orientation disclosure is resulting in missed opportunities to reduce health inequalities for GBM. More proactive, inclusive and safe environments surrounding the care of sexual orientation minorities are needed in general practice to encourage disclosure.

Younger Gay and Bisexual Men's Condom Use With Main Regular Sexual Partner in New Zealand.

Main partners are a common source of new HIV infections among men who have sex with men (MSM). National behavioral surveillance data (2006-2011) for younger MSM (YMSM, aged 16-29) in New Zealand were analyzed to investigate condom use during anal intercourse with a regular partner (boyfriend/fuckbuddy) by sexual position (insertive/receptive). Backward-stepwise multivariate multinomial logistic regression was used to identify demographic, relational, behavioral, and cognitive factors associated with condom use frequency (high, medium, low). Most YMSM who reported a current regular partner (n=1,221) classified them as a boyfriend (59.5%) versus fuckbuddy (40.5%), though condom use was higher with the latter partner type. Condom use or nonuse was habitual across partners, although insertive sexual position was positively associated with condom use. YMSM who believed condoms reduce sensitivity reported lower condom use. Condoms remain the leading HIV/STI prevention tool for YMSM; efforts to improve condom use must consider sexual position and relationship factors.

Trends in web-based HIV behavioural surveillance among gay and bisexual men in New Zealand: complementing location-based surveillance.

Most HIV behavioural surveillance programmes for gay, bisexual and other men who have sex with men (MSM) sample from location-based (offline) or web-based (online) populations, but few combine these two streams. MSM sampled online have been found to differ demographically and behaviourally from those sampled offline, meaning trends identified in one system may not hold for the other. The aim was to examine trends among MSM responding to supplementary repeat online behavioural surveillance surveys who had not participated in offline surveillance earlier that year in the same city, to see whether trends were parallel, converged or diverged. We recruited a total of 1613 MSM from an Internet dating site in Auckland, New Zealand in 2006, 2008 and 2011 using identical questionnaires and eligibility criteria to offline surveillance. Condom use was stable over time, HIV testing rates rose, the proportion reporting over 20 recent male partners declined, and anal intercourse rates increased, consistent with trends in offline surveillance conducted concomitantly and reported elsewhere. Variant trends included greater stability in condom use with casual partners among online-recruited MSM, and a rise in regular fuckbuddy partnering not identified among offline-recruited MSM. Among MSM recruited online, the frequency of checking Internet dating profiles increased between 2008 and 2011. In conclusion, supplementary web-based behavioural surveillance among MSM generally corroborates trends identified in offline surveillance. There are however some divergent trends, that would have been overlooked if only one form of surveillance had been conducted. As MSM populations increasingly shift their socialising patterns online and diversify, multiple forms of HIV behavioural monitoring may be required.

Thirty years of condom-based HIV prevention by gay men in New Zealand.

Three decades after the first government-funded HIV prevention campaign in 1985, gay and bisexual men (GBM) remain the population most at risk of infection in New Zealand. We review the major determinants of the elevated HIV risk for GBM, describe New Zealand's prevention response over the first 30 years, and summarise the public health record. HIV incidence among GBM is driven by the heightened biological efficiency of HIV transmission during unprotected anal intercourse, dense sexual partnering networks, and endemic HIV prevalence. Responses in New Zealand have emphasised evidence-based primary prevention by condom use, which were implemented in communities and supported by comprehensive public health action. New Zealand has a good international HIV prevention record among GBM, however HIV diagnosis rates are now higher than they were during the epidemic nadir of the late 1990s. Lessons from the first three decades must underpin future HIV control efforts.

Infrequent condom use with casual partners among New Zealand gay and bisexual men.

AIMS: To identify predictors of non-condom use among gay and bisexual men (GBM) in New Zealand with casual male partners. METHODS: We analysed anonymous self-completed data from GBM who participated in the communitybased Gay Auckland Periodic Sex Survey (GAPSS) and Internet-based Gay Online Sex Survey (GOSS), undertaken in 2014. Infrequent condom use was defined as not using condoms "always" or "almost always" during anal intercourse in the prior six months. RESULTS: Of the 1,912 GBM reporting anal intercourse with a casual partner, 27.2% reported infrequent condom use. Being recruited from Internet dating sites, Pacific ethnicity, having over 20 recent male partners, infrequent condom use with a current regular partner, or being HIV-positive were independently predictive of infrequent condom use. Conversely, being older, having a tertiary degree, using a condom at first anal intercourse, being exclusively receptive with a casual partner/s, and seeing condoms promoted through multiple channels predicted frequent condom use. Attitudes to condoms and safe sex were strongly predictive of actual condom use. CONCLUSIONS: Social marketing should target the modifiable predictors of condom use, such as attitudes to safe sex. Interventions also need to engage successfully with GBM reporting non-modifiable traits such as HIV-positive GBM.

Self-reported STIs and sexual health checks in a cross-sectional study of gay and bisexual men in New Zealand.

OBJECTIVES: To determine the incidence of self-reported sexually transmitted infections (STIs) and sexual health checks in community and internet samples of New Zealand gay, bisexual and other men who have sex with men (MSM) and factors associated with these. METHODS: We analysed anonymous self-completed data from 3138 MSM who participated in the location-based Gay Auckland Periodic Sex Survey (GAPSS) and the internet-based Gay Online Sex Survey (GOSS) undertaken in February 2011. RESULTS: Overall 8.2% of the participants reported at least one STI in the previous 12 months, which did not differ significantly by demographic factors or HIV status. While having anal sex and more partners were associated with more STI, after adjustment for the number of partners, the type of partner (regular or casual) was not. Medium and low condom users reported STIs more than high condom users, regardless of partner type. Overall 40% had a sexual health check-up without an STI diagnosed in the past year, with similar numbers attending general practice and sexual health clinics. Having a check-up was lower among Pacific and Asian men, those identifying as bisexual and recruited online. While those with more partners, having anal intercourse and diagnosed with HIV were more likely to go for a check-up, those using condoms less often were not. CONCLUSIONS: STIs are commonly reported in this community sample of MSM but will underestimate the true incidence due to asymptomatic infection. Screening for STIs outside sexual health clinics should be normalised for MSM and made accessible, safe and relevant.

Atom probe tomography study of the nanoscale heterostructure around an Al20Mn3Cu2 dispersoid in aluminum alloy 2024.

Atom probe tomography (APT) has been used to investigate the surface and sub-surface microstructures of aluminum alloy 2024 (AA2024) in the T3 condition (solution heat treated, cold worked, and naturally aged to a substantially stable condition). This study revealed surface Cu enrichment on the alloy matrix, local chemical structure around a dispersoid Al20Mn3Cu2 particle including a Cu-rich particle and S-phase particle on its external surface. Moreover, there was a significant level of hydrogen within the dispersoid, indicating that it is a hydrogen sink. These observations of the nanoscale structure around the dispersoid particle have considerable implications for understanding both corrosion and hydrogen embrittlement in high-strength aluminum alloys.

Factors associated with recent HIV testing among younger gay and bisexual men in New Zealand, 2006-2011.

BACKGROUND: Understanding HIV testing behaviour is vital to developing evidence-based policy and programming that supports optimal HIV care, support, and prevention. This has not been investigated among younger gay, bisexual, and other men who have sex with men (YMSM, aged 16-29) in New Zealand. METHODS: National HIV sociobehavioural surveillance data from 2006, 2008, and 2011 was pooled to determine the prevalence of recent HIV testing (in the last 12 months) among YMSM. Factors associated with recent testing were determined using manual backward stepwise multivariate logistic regression. RESULTS: Of 3,352 eligible YMSM, 1,338 (39.9%) reported a recent HIV test. In the final adjusted model, the odds of having a recent HIV test were higher for YMSM who were older, spent more time with other gay men, reported multiple sex partners, had a regular partner for 6-12 months, reported high condom use with casual partners, and disagreed that HIV is a less serious threat nowadays and that an HIV-positive man would disclose before sex. The odds of having a recent HIV test were lower for YMSM who were bisexual, recruited online, reported Pacific Islander or Asian ethnicities, reported no regular partner or one for >3 years, were insertive-only during anal intercourse with a regular partner, and who had less HIV-related knowledge. CONCLUSION: A priority for HIV management should be connecting YMSM at risk of infection, but unlikely to test with appropriate testing services. New generations of YMSM require targeted, culturally relevant health promotion that provides accurate understandings about HIV transmission and prevention.

Reducing ZnO nanoparticle cytotoxicity by surface modification.

Nanoparticulate zinc oxide (ZnO) is one of the most widely used engineered nanomaterials and its toxicology has gained considerable recent attention. A key aspect for controlling biological interactions at the nanoscale is understanding the relevant nanoparticle surface chemistry. In this study, we have determined the disposition of ZnO nanoparticles within human immune cells by measurement of total Zn, as well as the proportions of extra- and intracellular dissolved Zn as a function of dose and surface coating. From this mass balance, the intracellular soluble Zn levels showed little difference in regard to dose above a certain minimal level or to different surface coatings. PEGylation of ZnO NPs reduced their cytotoxicity as a result of decreased cellular uptake arising from a minimal protein corona. We conclude that the key role of the surface properties of ZnO NPs in controlling cytotoxicity is to regulate cellular nanoparticle uptake rather than altering either intracellular or extracellular Zn dissolution.