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1.
Annu Int Conf IEEE Eng Med Biol Soc ; 2022: 3628-3631, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-36085878

RESUMEN

In the expanding field of robotic prosthetics, surface electromyography (sEMG) signals can be decoded to seamlessly control a robotic prosthesis to perform the desired gesture. It is essential to create a pipeline, which can acquire, process, and accurately classify sEMG signals in order to replicate the desired hand gesture in near real-time and in a reliable manner. In this study, an optimised pipeline is proposed. This pipeline encompasses the main stages of sEMG signal processing and hand gesture classification and implements a sliding window approach, which is the main focus of the optimisation. In this study, a range of different parameters and modelling approaches are evaluated. The main contributions of this work are a robust and extensive analysis of sliding window parameter selection and an optimised pipeline that could be implemented in practice with minimal overheads. The optimum pipeline is efficient and achieves accurate prediction of hand gestures with an uninterrupted processing pipeline.


Asunto(s)
Miembros Artificiales , Gestos , Electromiografía , Implantación de Prótesis , Extremidad Superior
2.
Pediatr Emerg Care ; 36(12): e671-e676, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-33181793

RESUMEN

STUDY OBJECTIVE: To estimate the minimum dose and total sedation time of rapidly infused ketamine that achieves 3 to 5 minutes of effective sedation in children undergoing abscess incision and drainage in the emergency department. METHODS: The Up-Down method was used to estimate the dose of intravenous ketamine infused over 5 seconds or less that provided effective sedation in 50% (ED50) and 95% (ED95) for healthy children aged 2 to 5 years and 6 to 11 years undergoing abscess incision and drainage. None were pretreated with opioids. Three investigators blinded to ketamine dose independently graded sedation effectiveness by viewing a video recording of the first 5 minutes of sedation. Recovery was determined when patients reached a Modified Aldrete score of 10. RESULTS: We enrolled 20 children in each age group. The estimated ED50 was 0.9 and 0.6 mg/kg for the 2 to 5 years and 6 to 11 years' groups and the estimated ED95 was 1.1 mg/kg for both groups. The median time to full recovery for the 2 groups was 20.5 and 17.5 minutes when only 1 dose of ketamine was administered and 27.5 and 35 minutes when additional doses of ketamine were administered. No participants experienced serious adverse events. CONCLUSIONS: We estimated ED50 and ED95 for rapidly infused ketamine for 2 age groups undergoing abscess incision and drainage. Further studies are needed to get a more precise estimate of ED95. The total sedation time with this technique in the abscess group was shorter than most previous studies and is consistent with our previous observations in patients undergoing fracture reduction.


Asunto(s)
Absceso/cirugía , Anestésicos Disociativos , Drenaje , Ketamina , Anestésicos Disociativos/administración & dosificación , Niño , Preescolar , Sedación Consciente , Humanos , Ketamina/administración & dosificación
3.
Sex Health ; 16(6): 548-553, 2019 11.
Artículo en Inglés | MEDLINE | ID: mdl-31514798

RESUMEN

Background A substantial minority of patients living with HIV refuse or cease antiretroviral therapy (ART), have virological failure (VF) or develop an AIDS-defining condition (ADC) or serious non-AIDS event (SNAE). It is not understood which socioeconomic and psychosocial factors may be associated with these poor outcomes. METHODS: Thirty-nine patients with poor HIV treatment outcomes, defined as those who refused or ceased ART, had VF or were hospitalised with an ADC or SNAE (cases), were compared with 120 controls on suppressive ART. A self-report survey recorded demographics, physical health, life stressors, social supports, HIV disclosure, stigma or discrimination, health care access, treatment adherence, side effects, health and treatment perceptions and financial and employment status. Socioeconomic and psychosocial covariates significant in bivariate analyses were assessed with conditional multivariable logistic regression, adjusted for year of HIV diagnosis. RESULTS: Cases and controls did not differ significantly with regard to sex (96.2% (n = 153) male) or age (mean (± s.d.) 51 ± 11 years). Twenty cases (51%) had refused or ceased ART, 35 (90%) had an HIV viral load >50 copies mL-1, 12 (31%) were hospitalised with an ADC and five (13%) were hospitalised with a new SNAE. Three covariates were independently associated with poor outcomes: foregoing necessities for financial reasons (adjusted odds ratio (aOR) 3.1, 95% confidence interval (95% CI) 1.3-7.6, P = 0.014), cost barriers to accessing HIV care (aOR 3.1, 95% CI 1.0-9.6, P = 0.049) and lower quality of life (aOR 3.8, 95% CI 1.5-9.7, P = 0.004). CONCLUSIONS: Despite universal health care, socioeconomic and psychosocial factors are associated with poor HIV outcomes in adults in Australia. These factors should be addressed through targeted interventions to improve long-term successful treatment.


Asunto(s)
Infecciones por VIH/psicología , Aceptación de la Atención de Salud/psicología , Negativa del Paciente al Tratamiento/psicología , Fármacos Anti-VIH/uso terapéutico , Australia , Estudios de Casos y Controles , Femenino , Infecciones por VIH/tratamiento farmacológico , Humanos , Masculino , Persona de Mediana Edad , Aceptación de la Atención de Salud/estadística & datos numéricos , Psicología , Factores Socioeconómicos , Encuestas y Cuestionarios , Resultado del Tratamiento , Negativa del Paciente al Tratamiento/estadística & datos numéricos
4.
Biomacromolecules ; 19(3): 816-824, 2018 03 12.
Artículo en Inglés | MEDLINE | ID: mdl-29489329

RESUMEN

The thermoresponsive behavior of a hydroxypropylmethylcellulose (HPMC) sample in aqueous solutions has been studied by a powerful combination of characterization tools, including rheology, turbidimetry, cryogenic transmission electron microscopy (cryoTEM), light scattering, small-angle neutron scattering (SANS), and small-angle X-ray scattering (SAXS). Consistent with prior literature, solutions with concentrations ranging from 0.3 to 3 wt % exhibit a sharp drop in the dynamic viscoelastic moduli G' and G″ upon heating near 57 °C. The drop in moduli is accompanied by an abrupt increase in turbidity. All the evidence is consistent with this corresponding to liquid-liquid phase separation, leading to polymer-rich droplets in a polymer-depleted matrix. Upon further heating, the moduli increase, and G' exceeds G″, corresponding to gelation. CryoTEM in dilute solutions reveals that HPMC forms fibrils at the same temperature range where the moduli increase. SANS and SAXS confirm the appearance of fibrils over a range of concentration, and that their average diameter is ca. 18 nm; thus gelation is attributable to formation of a sample-spanning network of fibrils. These results are compared in detail with the closely related and well-studied methylcellulose (MC). The HPMC fibrils are generally shorter, more flexible, and contain more water than with MC, and the resulting gel at high temperatures has a much lower modulus. In addition to the differences in fibril structure, the key distinction between HPMC and MC is that the former undergoes liquid-liquid phase separation prior to forming fibrils and associated gelation, whereas the latter forms fibrils first. These results and their interpretation are compared with the prior literature, in light of the relatively recent discovery of the propensity of MC and HPMC to self-assemble into fibrils on heating.


Asunto(s)
Metilcelulosa/análogos & derivados , Metilcelulosa/química , Nanofibras , Difracción de Neutrones , Difracción de Rayos X , Microscopía por Crioelectrón , Nanofibras/química , Nanofibras/ultraestructura
5.
PLoS One ; 12(4): e0174613, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28369066

RESUMEN

BACKGROUND: Missing more than one tablet of contemporary antiretroviral therapy (ART) per month increases the risk of virological failure. Recent studies evaluating a comprehensive range of potential risk factors for suboptimal adherence are not available for high-income settings. METHODS: Adults on ART with undetectable viral load (UDVL) were recruited into a national, multi-centre cohort, completing a comprehensive survey assessing demographics, socio-economic indicators, physical health, well-being, life stressors, social supports, HIV disclosure, HIV-related stigma and discrimination, healthcare access, ART regimen, adherence, side effects, costs and treatment beliefs. Baseline data were assessed, and suboptimal adherence was defined as self-reported missing ≥1 ART dose/month over the previous 3-months; associated factors were identified using bivariate and multivariate binary logistic regression. RESULTS: We assessed 522 participants (494 [94.5%] men, mean age = 50.8 years, median duration UDVL = 3.3 years [IQR = 1.2-6.8]) at 17 sexual health, hospital, and general practice clinics across Australia. Seventy-eight participants (14.9%) reported missing ≥1 dose/month over the previous three months, which was independently associated with: being Australian-born (AOR [adjusted odds ratio] = 2.4 [95%CI = 1.2-4.9], p = 0.014), not being in a relationship (AOR = 3.3 [95%CI = 1.5-7.3], p = 0.004), reaching the "Medicare safety net" (capping annual medical/pharmaceutical costs) (AOR = 2.2 [95%CI = 1.1-4.5], p = 0.024), living in subsidised housing (AOR = 2.5 [95%CI = 1.0-6.2], p = 0.045), receiving home-care services (AOR = 4.4 [95%CI = 1.0-18.8], p = 0.046), HIV community/outreach services linkage (AOR = 2.4 [95%CI = 1.1-5.4], p = 0.033), and starting ART following self-request (AOR = 3.0 [95%CI = 1.3-7.0], p = 0.012). CONCLUSIONS: In this population, 15% reported recent suboptimal ART adherence at levels associated in prospective studies with subsequent virological failure, despite all having an undetectable viral load. Associations were with social/economic/cultural/patient engagement factors, but not ART regimen/clinical factors. These associations may help identify those at higher risk of future virological failure and guide patient education and support.


Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Infecciones por VIH/tratamiento farmacológico , Cumplimiento de la Medicación/estadística & datos numéricos , Factores Socioeconómicos , Adulto , Terapia Antirretroviral Altamente Activa , Australia , Recuento de Linfocito CD4 , Estudios Transversales , Femenino , Humanos , Renta , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Encuestas y Cuestionarios , Insuficiencia del Tratamiento , Carga Viral
6.
AIDS ; 31(9): 1291-1295, 2017 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-28301425

RESUMEN

OBJECTIVES: Completion rates for HIV postexposure prophylaxis (PEP) are often low. We investigated the adherence and safety of dolutegravir (DTG; 50 mg daily) with tenofovir disoproxil fumarate-emtricitabine (TDF-FTC; 300/200 mg, respectively) as three-drug PEP in gay and bisexual men. DESIGN: Open-label, single-arm study at three sexual health clinics and two emergency departments in Australia. METHODS: In total, 100 HIV-uninfected gay and bisexual men requiring PEP received DTG and TDF-FTC for 28 days. The primary end point was PEP failure (premature PEP cessation or primary HIV infection through week 12). Additional end points were adherence by self-report (n = 98) and pill count (n = 55), safety, and plasma drug levels at day 28. RESULTS: PEP completion was 90% (95% confidence interval 84-96%). Failures (occurring at a median 9 days, interquartile range 3-16) comprised loss to follow-up (9%) and adverse event resulting in study drug discontinuation (headache, 1%). No participant was found to acquire HIV through week 12. Adherence to PEP was 98% by self-report and in the 55 participants with corresponding pill count data. The most common clinical adverse events were fatigue (26%), nausea (25%), diarrhoea (21%), and headache (10%). There were only four grade 3-4 subjective adverse events. The most common laboratory adverse event was raised alanine aminotransferase (22%), but there was no case of clinical hepatitis. At day 28, the mean estimated glomerular filtration rate decrease was 14 ml/min/1.73m (SD 17, P = 0.001); an estimated glomerular filtration rate of less than 60 ml/min/1.73m occurred in 3%. CONCLUSIONS: DTG with TDF-FTC is a well tolerated option for once-daily PEP.


Asunto(s)
Fármacos Anti-VIH/administración & dosificación , Quimioprevención/métodos , Emtricitabina/administración & dosificación , Infecciones por VIH/prevención & control , Compuestos Heterocíclicos con 3 Anillos/administración & dosificación , Profilaxis Posexposición/métodos , Tenofovir/administración & dosificación , Fármacos Anti-VIH/efectos adversos , Australia , Quimioprevención/efectos adversos , Transmisión de Enfermedad Infecciosa/prevención & control , Emtricitabina/efectos adversos , Infecciones por VIH/transmisión , Compuestos Heterocíclicos con 3 Anillos/efectos adversos , Humanos , Masculino , Cumplimiento de la Medicación , Oxazinas , Piperazinas , Piridonas , Minorías Sexuales y de Género , Tenofovir/efectos adversos , Insuficiencia del Tratamiento
7.
Clin Infect Dis ; 61(8): 1336-41, 2015 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-26123937

RESUMEN

BACKGROUND: Completion rates for human immunodeficiency virus (HIV) postexposure prophylaxis (PEP) are low. We investigated the adherence and safety of coformulated emtricitabine (FTC), rilpivirine (RPV), and tenofovir disoproxil fumarate (TDF) as a 3-drug, single-tablet regimen for PEP in men who have sex with men (MSM). METHODS: In an open-label, single-arm study at 2 public sexual health clinics and 2 hospital emergency departments in urban Australia, 100 HIV-uninfected MSM requiring 3-drug PEP received single-tablet FTC-RPV-TDF once daily for 28 days. The primary endpoint was premature PEP cessation or primary HIV infection through week 12. Additional endpoints were adherence (by self-report of doses missed or not ingested with a meal, by pill count, and by plasma concentrations of tenofovir and FTC at week 4); and safety (clinical and laboratory adverse events [AEs]). RESULTS: PEP completion was 92% (95% confidence interval, 85%-96%); premature cessation resulted from loss to follow-up (6%), AEs (1%), or study burden (1%). No participant was found to acquire HIV through week 12. Adherence was 98.6% (standard deviation [SD], 2.4) by pill count and 98.5% (SD, 2.7) by self-report; 86% reported taking all doses with food, and 88% of the subset tested had plasma tenofovir levels suggesting full adherence (>40 ng/mL). Eighty-eight participants experienced at least 1 clinical AE; 4 had grade 3 AEs or higher, possibly attributable to study drug. Fifty-six participants experienced at least 1 laboratory AE; 4 had AEs of grade 3 or higher, possibly attributable to study drug. CONCLUSIONS: A single-tablet regimen of FTC-RPV-TDF was well tolerated as once-daily PEP, with high levels of adherence and completion. CLINICAL TRIALS REGISTRATION: NCT01715636.


Asunto(s)
Fármacos Anti-VIH/administración & dosificación , Combinación Emtricitabina, Rilpivirina y Tenofovir/administración & dosificación , Infecciones por VIH/prevención & control , Homosexualidad Masculina , Profilaxis Posexposición , Adulto , Fármacos Anti-VIH/sangre , Fármacos Anti-VIH/uso terapéutico , Australia , Esquema de Medicación , Combinación Emtricitabina, Rilpivirina y Tenofovir/sangre , Combinación Emtricitabina, Rilpivirina y Tenofovir/uso terapéutico , Humanos , Masculino , Cumplimiento de la Medicación , Persona de Mediana Edad , Comprimidos , Adulto Joven
8.
J Pediatr Ophthalmol Strabismus ; 52(3): 167-72, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26053207

RESUMEN

PURPOSE: A hallmark of albinism is foveal hypoplasia. However, literature suggests variable foveal development. This study evaluates the association between ocular phenotype and foveal morphology to demonstrate the broad structural and functional spectrum. METHODS: Best-corrected visual acuity (BCVA), nystagmus, angle kappa, stereoacuity, iris transillumination, macular melanin presence, foveal avascular zone, and annular reflex were recorded in 14 patients with albinism. Spectral-domain optical coherence tomography provided macular images. RESULTS: The clinical phenotype was broad, with BCVA varying from 20/20 to 20/100. Better BCVA was associated with a preserved foveal avascular zone, annular macular reflex, stereoacuity, and macular melanin. Imaging demonstrated a continuum of foveal development correlating with BCVA. Individuals with a rudimentary pit had normal inner and outer segment lengthening and better BCVA. CONCLUSIONS: The spectrum of ocular structure and visual function in albinism is broad, suggesting a possible diagnosis of albinism in a patient with an even more normal clinical presentation.


Asunto(s)
Albinismo Ocular/diagnóstico , Albinismo Oculocutáneo/diagnóstico , Anomalías del Ojo/diagnóstico , Fóvea Central/patología , Adolescente , Adulto , Anciano de 80 o más Años , Albinismo Ocular/genética , Albinismo Ocular/fisiopatología , Albinismo Oculocutáneo/genética , Albinismo Oculocutáneo/fisiopatología , Niño , Análisis Mutacional de ADN , Percepción de Profundidad/fisiología , Potenciales Evocados Visuales , Anomalías del Ojo/genética , Anomalías del Ojo/fisiopatología , Proteínas del Ojo/genética , Femenino , Fóvea Central/anomalías , Humanos , Masculino , Proteínas de la Membrana/genética , Nistagmo Patológico/diagnóstico , Fenotipo , Reacción en Cadena de la Polimerasa , Estudios Prospectivos , Tomografía de Coherencia Óptica , Agudeza Visual/fisiología , Adulto Joven
9.
Paediatr Anaesth ; 25(4): 363-71, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25677176

RESUMEN

BACKGROUND: Failed airway management remains one of the most common causes of cardiopulmonary arrest in the pediatric population. Practice guidelines addressing the difficult airway (DAW) in adults provide anesthesiologists a framework for managing the airway during the perioperative period; however, similar consensus guidelines are lacking in the pediatric population. Many of the adverse events associated with difficult pediatric airway management occur outside the perioperative setting and often result in worse outcomes. The lower frequency of DAW management required in children, lesser awareness of pediatric health care professionals about DAW management, and the need for guiding principles led us to develop a DAW consultative service. This report outlines the steps to establish the Difficult Airway Service (DAS) and the initial experiences with this new consultation service. METHODS: The mission of the DAS is to identify children with known or anticipated DAWs, communicate the diagnosis and collaborate with referring medical and surgical services, and to manage children in those settings that airway management might be required in the context of the patient's ongoing medical care. RESULTS: The initial 3-month experience confirmed that a majority of pediatric DAW events are associated with congenital or acquired abnormalities. Through appropriate consultation and leadership, the DAS was able to physically and electronically identify pediatric patients with a DAW and provide management. Hospital-wide participation was instrumental in the success and exponential growth of DAS: planned preoperative tracheostomy in complicated posterior spinal fusion candidates, participation in EXIT procedures, standardization of airway carts, and implementation of education forums. CONCLUSION: In developing the DAS, our goal was to provide a more comprehensive approach to caring for a child with a DAW that included their entire hospital stay and follow-up care. We believe this approach has improved health care professional awareness as well as the safe management of routine and difficult pediatric airway. Additional studies are needed to determine whether measurable changes in morbidity and mortality are observed over time.


Asunto(s)
Manejo de la Vía Aérea/métodos , Anestesia/métodos , Derivación y Consulta , Adolescente , Manejo de la Vía Aérea/efectos adversos , Manejo de la Vía Aérea/instrumentación , Anestesia/efectos adversos , Niño , Preescolar , Humanos , Lactante , Liderazgo , Grupo de Atención al Paciente , Respiración Artificial/efectos adversos , Respiración Artificial/métodos , Anomalías del Sistema Respiratorio/complicaciones , Factores de Riesgo , Traqueostomía , Adulto Joven
10.
Ann Emerg Med ; 65(6): 640-648.e2, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25595951

RESUMEN

STUDY OBJECTIVE: We estimate the minimum dose and total sedation time of rapidly infused ketamine that achieves 3 to 5 minutes of effective sedation in children undergoing forearm fracture reduction in the emergency department. METHODS: We used the up-down method to estimate the median dose of intravenous ketamine infused during less than or equal to 5 seconds that provided effective sedation in 50% (ED50) and 95% (ED95) of healthy children aged 2 to 5, 6 to 11, or 12 to 17 years who were undergoing forearm fracture reduction. Most patients were pretreated with opioids. Three investigators blinded to ketamine dose independently graded sedation effectiveness by viewing a video recording of the first 5 minutes of sedation. Recovery was assessed by modified Aldrete score. RESULTS: We enrolled 20 children in each age group. The estimated ED50 was 0.7, 0.5, and 0.6 mg/kg and the estimated ED95 was 0.7, 0.7, and 0.8 mg/kg for the groups aged 2 to 5, 6 to 11, and 12 to 17 years, respectively. For the group aged 2 to 5 years, an empirically derived ED95 was 0.8 mg/kg. All patients who received the empirically derived ED95 in the group aged 2 to 5 years or the estimated ED95 in the groups aged 6 to 11 and 12 to 17 years had effective sedation. The median total sedation time for the 3 age groups, respectively, was 25, 22.5, and 25 minutes if 1 dose of ketamine was administered and 35, 25, and 45 minutes if additional doses were administered. No participant experienced serious adverse events. CONCLUSION: We estimated ED50 and ED95 for rapidly infused ketamine for 3 age groups undergoing fracture reduction. Total sedation time was shorter than that in most previous studies.


Asunto(s)
Sedación Consciente/métodos , Traumatismos del Antebrazo , Fijación de Fractura , Hipnóticos y Sedantes/administración & dosificación , Ketamina/administración & dosificación , Adolescente , Factores de Edad , Niño , Preescolar , Servicio de Urgencia en Hospital , Femenino , Traumatismos del Antebrazo/terapia , Humanos , Infusiones Intravenosas , Masculino
11.
J Infect Dis ; 211(5): 736-43, 2015 Mar 01.
Artículo en Inglés | MEDLINE | ID: mdl-25293369

RESUMEN

BACKGROUND: We aimed to characterize seminal hepatitis C virus (HCV) RNA dynamics in human immunodeficiency virus (HIV)-positive men with acute HCV infection given its potential role in sexual transmission of HCV. METHODS: Men with acute HCV infection (duration, ≤12 months) or chronic HCV infection (duration, >12 months) were prospectively recruited. Paired semen and blood samples were assayed for HCV RNA levels. Results were analyzed using χ(2), Fisher exact, Mann-Whitney U, and Kruskal-Wallis tests. RESULTS: Eighteen men (27.3%) had acute HCV and HIV coinfection, 22 (33.3%) had chronic HCV infection and HIV coinfection, and 26 (39.4%) had chronic HCV monoinfection. HCV RNA was detected in semen specimens from 29 of 66 men (43.9%). The median HCV RNA level in blood was 4.0 log IU/mL higher than that in semen. HCV RNA levels were correlated in semen and blood (r(2) = 0.142). Neither HIV positivity nor acute HCV infection was associated with an increased frequency of seminal HCV RNA detection. Among men with acute HCV and HIV coinfection, the median HCV RNA level in blood specimens from those with seminal HCV RNA was higher than that in blood specimens from those without seminal HCV RNA (P = .001). Seminal HCV RNA was detected in ≥1 sample for 26 of 35 men (74.3%) attending follow up. CONCLUSIONS: HCV RNA was detected in semen during both acute and chronic HCV infection. This was unaffected by HIV positivity or the phase of HCV infection. Elevated seminal HCV RNA levels could contribute to sexual transmission of HCV, but other factors, including high-risk behaviors, may be the main drivers for HCV transmission in HIV-infected individuals.


Asunto(s)
Hepacivirus/aislamiento & purificación , Semen/virología , Carga Viral , Adulto , Sangre/virología , Estudios de Cohortes , Infecciones por VIH/complicaciones , Hepatitis C/complicaciones , Hepatitis C/virología , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Estudios Prospectivos , ARN Viral/aislamiento & purificación
12.
ACS Macro Lett ; 4(5): 538-542, 2015 May 19.
Artículo en Inglés | MEDLINE | ID: mdl-35596304

RESUMEN

Cryogenic transmission electron microscopy and small-angle neutron scattering recently have revealed that the well-known thermoreversible gelation of methylcellulose (MC) in water is due to the formation of fibrils, with a diameter of 15 ± 2 nm. Here we report that both the linear and nonlinear viscoelastic response of MC solutions and gels can be described by a filament-based mechanical model. In particular, large-amplitude oscillatory shear experiments show that aqueous MC materials transition from shear thinning to shear thickening behavior at the gelation temperature. The critical stress at which MC gels depart from the linear viscoelastic regime and begin to stiffen is well predicted from the filament model over a concentration range of 0.18-2.0 wt %. These predictions are based on fibril densities and persistence lengths obtained experimentally from neutron scattering, combined with cross-link spacings inferred from the gel modulus via the same model.

13.
Invest Ophthalmol Vis Sci ; 55(7): 4186-98, 2014 May 20.
Artículo en Inglés | MEDLINE | ID: mdl-24845642

RESUMEN

PURPOSE: Albinism is associated with disrupted foveal development, though intersubject variability is becoming appreciated. We sought to quantify this variability, and examine the relationship between foveal cone specialization and pit morphology in patients with a clinical diagnosis of albinism. METHODS: We recruited 32 subjects with a clinical diagnosis of albinism. DNA was obtained from 25 subjects, and known albinism genes were analyzed for mutations. Relative inner and outer segment (IS and OS) lengthening (fovea-to-perifovea ratio) was determined from manually segmented spectral domain-optical coherence tomography (SD-OCT) B-scans. Foveal pit morphology was quantified for eight subjects from macular SD-OCT volumes. Ten subjects underwent imaging with adaptive optics scanning light ophthalmoscopy (AOSLO), and cone density was measured. RESULTS: We found mutations in 22 of 25 subjects, including five novel mutations. All subjects lacked complete excavation of inner retinal layers at the fovea, though four subjects had foveal pits with normal diameter and/or volume. Peak cone density and OS lengthening were variable and overlapped with that observed in normal controls. A fifth hyper-reflective band was observed in the outer retina on SD-OCT in the majority of the subjects with albinism. CONCLUSIONS: Foveal cone specialization and pit morphology vary greatly in albinism. Normal cone packing was observed in the absence of a foveal pit, suggesting a pit is not required for packing to occur. The degree to which retinal anatomy correlates with genotype or visual function remains unclear, and future examination of larger patient groups will provide important insight on this issue.


Asunto(s)
Albinismo Oculocutáneo/diagnóstico , Fóvea Central/patología , Células Fotorreceptoras Retinianas Conos/patología , Agudeza Visual , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Albinismo Oculocutáneo/genética , Albinismo Oculocutáneo/fisiopatología , Recuento de Células , Niño , ADN/genética , Electrorretinografía , Proteínas del Ojo/genética , Femenino , Fóvea Central/fisiopatología , Pruebas Genéticas , Humanos , Masculino , Persona de Mediana Edad , Mutación , Oftalmoscopía , Células Fotorreceptoras Retinianas Conos/metabolismo , Tomografía de Coherencia Óptica , Adulto Joven
14.
PLoS One ; 8(8): e71436, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-24009661

RESUMEN

BACKGROUND: Since 2005, Australian clinicians were advised to undertake quarterly syphilis testing for all sexually active HIV-positive men who have sex with men (MSM). We describe differences in syphilis testing frequency among HIV-positive MSM by clinic testing policies since this recommendation. METHODS: Three general practices, two sexual health clinics and two hospital HIV outpatient clinics provided data on HIV viral load and syphilis testing from 2006-2010. Men having ≥1 viral load test per year were included; >95% were MSM. We used Chi-2 tests to assess changes in syphilis testing frequency over time, and differences by clinic testing policy (opt-out, opt-in and risk-based). RESULTS: The proportion of men having HIV viral loads with same-day syphilis tests increased from 37% in 2006 to 63% in 2007 (p<0.01) and 68-69% thereafter. In 2010, same-day syphilis testing was highest in four clinics with opt-out strategies (87%, range:84-91%) compared with one clinic with opt-in (74%, p = 0.121) and two clinics with risk-based strategies (22%, range:20-24%, p<0.01). The proportion of men having ≥3 syphilis tests per year increased from 15% in 2006 to 36% in 2007 (p<0.01) and 36-38% thereafter. In 2010, the proportion of men having ≥3 syphilis tests in a year was highest in clinics with opt-out strategies (48%, range:35-59%), compared with opt-in (39%, p = 0.121) and risk-based strategies (8.4%, range:5.4-12%, p<0.01). CONCLUSION: Over five years the proportion of HIV-positive men undergoing syphilis testing at recommended frequencies more than doubled, and was 5-6 times higher in clinics with opt-out and opt-in strategies compared with risk-based policies.


Asunto(s)
Seropositividad para VIH , Homosexualidad Masculina , Sífilis/diagnóstico , Sífilis/epidemiología , Adulto , Australia/epidemiología , Coinfección , Seropositividad para VIH/virología , Humanos , Masculino , Tamizaje Masivo , Persona de Mediana Edad , Prevalencia , Carga Viral , Adulto Joven
15.
Biomacromolecules ; 14(8): 2484-8, 2013 Aug 12.
Artículo en Inglés | MEDLINE | ID: mdl-23889145

RESUMEN

It is well established that aqueous solutions of methylcellulose (MC) can form hydrogels on heating, with the rheological gel point closely correlated to the appearance of optical turbidity. However, the detailed gelation mechanism and the resulting gel structure remain poorly understood. Herein the fibrillar structure of aqueous MC gels was precisely quantified with a powerful combination of (real space) cryogenic transmission electron microscopy (cryo-TEM) and (reciprocal space) small-angle neutron scattering (SANS) techniques. The cryo-TEM images reveal that MC chains with a molecular weight of 300 000 g/mol associate into fibrils upon heating, with a remarkably uniform diameter of 15 ± 2 nm over a range of concentrations. Vitrified gels also exhibit heterogeneity in the fibril density on the length scale of hundreds of nanometers, consistent with the observed optical turbidity of MC hydrogels. The SANS curves of gels exhibit no characteristic peaks or plateaus over a broad range of wavevector, q, from 0.001-0.2 Å(-1). The major feature is a change in slope from I ∼ q(-1.7) in the intermediate q range (0.001 - 0.01 Å(-1)) to I ∼ q(-4) above q ≈ 0.015 Å(-1). The fibrillar nature of the gel structure was confirmed by fitting the SANS data consistently with a model based on the form factor for flexible cylinders with a polydisperse radius. This model was found to capture the scattering features quantitatively for MC gels varying in concentration from 0.09-1.3 wt %. In agreement with the microscopy results, the flexible cylinder model indicated fibril diameters of 14 ± 1 nm for samples at elevated temperatures. This combination of complementary experimental techniques provides a comprehensive nanoscale depiction of fibrillar morphology for MC gels, which correlates very well with macro-scale rheological behavior and optical turbidity previously observed for such systems.


Asunto(s)
Hidrogeles/química , Metilcelulosa/química , Microscopía por Crioelectrón , Microscopía Electrónica de Transmisión , Conformación Molecular , Difracción de Neutrones , Dispersión del Ángulo Pequeño , Propiedades de Superficie , Viscosidad
16.
Cult Health Sex ; 15 Suppl: 88-101, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23171131

RESUMEN

This paper is a strategic intervention in the debate over the value of globalised gay identity for emerging sexual minority communities in the South. Focusing on self-identifying gay men in Botswana using semi-structured interviews, it explores their views of what characterises 'modern gay culture' and relates these to international media clichés of a glamorous, stylish, hedonistic gayness. I argue that identifying with what is so visibly a Western image of gayness exposes sexual minority communities to the most dangerous of the justifications for homophobia in Africa, the argument that sexual dissidence is a neo-colonial conspiracy to subvert 'African values'. The 'unAfrican' argument has to be taken very seriously, not only because it taps into the intense, conflicted emotions at the heart of the post-colonial condition, but also because it contains an undeniable germ of truth. This poses a dilemma, since global gay discourses, including the media clichés, are an important source of inspiration for African sexual minorities. A communication activism strategy is proposed to undermine the unAfrican argument by cultivating and asserting the 'tswanarisation' of gay culture in Botswana that is already taking place. A similar strategy may also be effective in other African societies.


Asunto(s)
Colonialismo , Características Culturales , Homosexualidad Masculina , Medios de Comunicación de Masas , Botswana , Humanos , Masculino , Investigación Cualitativa , Identificación Social , Valores Sociales
17.
J Acquir Immune Defic Syndr ; 58(4): 424-8, 2011 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-21857349

RESUMEN

BACKGROUND: Gay men who request nonoccupational postexposure prophylaxis (PEP) may seek preexposure prophylaxis (PrEP) should this become available. We explored trends and predictors of PEP use among Australian gay men to inform future biomedical prevention programs. METHODS: We used 2001-2010 data from Gay Community Periodic Surveys in 3 Eastern Australian states and assessed PEP awareness and use in the 6 months before each survey, and among HIV-uninfected men in all surveys predictors of PEP use. Analytical methods included chi-square test for trend and multivariate log-binomial estimation of associations. RESULTS: The awareness of PEP significantly increased from 23% in 2001 to 64% in 2010. PEP use also increased from 2.3% to 3.9%, respectively. PEP use was significantly associated with being in a regular relationship with an HIV-serodiscordant partner, higher number of sex partners, engaging in anal intercourse with casual partners, and regularly testing for HIV/sexually transmitted infections. However, fewer than 8% of men who engaged in these practices reported PEP use. CONCLUSIONS: Our findings highlight the profiles of current PEP users: men in HIV-serodiscordant relationships, and men having high numbers of casual partners and unprotected anal intercourse with them. These men are in need of effective HIV prevention strategies and may be receptive to preexposure prophylaxis in the future. Presently, targeted HIV education to improve risk assessment skills may prevent some seroconversions through the appropriate use of PEP.


Asunto(s)
Infecciones por VIH/prevención & control , Homosexualidad Masculina/estadística & datos numéricos , Adulto , Fármacos Anti-VIH/uso terapéutico , Australia/epidemiología , Infecciones por VIH/tratamiento farmacológico , Infecciones por VIH/psicología , Conocimientos, Actitudes y Práctica en Salud , Encuestas Epidemiológicas/estadística & datos numéricos , Humanos , Masculino , Persona de Mediana Edad , Profilaxis Posexposición/estadística & datos numéricos , Conducta Sexual/psicología , Conducta Sexual/estadística & datos numéricos , Parejas Sexuales/psicología , Enfermedades de Transmisión Sexual/tratamiento farmacológico , Enfermedades de Transmisión Sexual/prevención & control , Enfermedades de Transmisión Sexual/psicología
18.
Sex Health ; 8(1): 76-8, 2011 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-21371387

RESUMEN

OBJECTIVES: To evaluate whether the introduction of an anal cytology screening program (ACSP) targeting HIV-positive men who have sex with men (MSM) affected rates of sexually transmissible infection (STI) testing and detection in an urban HIV outpatient clinic. METHODS: STI testing was offered as part of an ACSP. Uptake of STI testing and diagnoses were compared before and after the introduction of an ACSP. RESULTS: The number of men undergoing STI testing increased significantly from 67 (20.4%) to 123 (34.8%) (relative risk 1.7, 95% confidence interval (CI) 1.40-2.07), but the increase in the total number of patients with any STI did not achieve significance (from 7 to 11, prevalence ratio 0.86, 95% CI 0.33-2.21). Rates of STI diagnosed in men participating in the ACSP were no different (11.3% v. 7.7%, P=0.557) from those men declining screening. CONCLUSIONS: STI testing, when combined with an ACSP in HIV-positive MSM, may lead to an increase in STI testing and increased opportunities for risk reduction interventions. Men participating in an ACSP appear to have similar risk of STIs to those who decline participation in an ACSP. The inclusion of STI testing could potentially enhance the public health benefit of ACSPs.


Asunto(s)
Canal Anal/microbiología , Canal Anal/virología , Infecciones por VIH/epidemiología , Homosexualidad Masculina/estadística & datos numéricos , Aceptación de la Atención de Salud/estadística & datos numéricos , Enfermedades de Transmisión Sexual/diagnóstico , Enfermedades de Transmisión Sexual/epidemiología , Instituciones de Atención Ambulatoria , Humanos , Masculino , Nueva Gales del Sur , Medición de Riesgo/estadística & datos numéricos , Enfermedades de Transmisión Sexual/prevención & control
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