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1.
Sex Transm Infect ; 99(8): 534-540, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37607814

RESUMO

BACKGROUND: The potential of HIV self-testing (HIVST) to cause harm is a concern hindering widespread implementation. The aim of this paper is to understand the relationship between HIVST and harm in SELPHI (An HIV Self-testing Public Health Intervention), the largest randomised trial of HIVST in a high-income country to date. METHODS: 10 111 cis and trans men who have sex with men (MSM) recruited online (geolocation social/sexual networking apps, social media), aged 16+, reporting previous anal intercourse and resident in England or Wales were first randomised 60/40 to baseline HIVST (baseline testing, BT) or not (no baseline testing, nBT) (randomisation A). BT participants reporting negative baseline test, sexual risk at 3 months and interest in further HIVST were randomised to three-monthly HIVST (repeat testing, RT) or not (no repeat testing, nRT) (randomisation B). All received an exit survey collecting data on harms (to relationships, well-being, false results or being pressured/persuaded to test). Nine participants reporting harm were interviewed in-depth about their experiences in an exploratory substudy; qualitative data were analysed narratively. RESULTS: Baseline: predominantly cis MSM, 90% white, 88% gay, 47% university educated and 7% current/former pre-exposure prophylaxis (PrEP) users. Final survey response rate was: nBT=26% (1056/4062), BT=45% (1674/3741), nRT=41% (471/1147), RT=50% (581/1161).Harms were rare and reported by 4% (n=138/3691) in exit surveys, with an additional two false positive results captured in other study surveys. 1% reported harm to relationships and to well-being in BT, nRT and RT combined. In all arms combined, being pressured or persuaded to test was reported by 1% (n=54/3678) and false positive results in 0.7% (n=34/4665).Qualitative analysis revealed harms arose from the kit itself (technological harms), the intervention (intervention harms) or from the social context of the participant (socially emergent harms). Intervention and socially emergent harms did not reduce HIVST acceptability, whereas technological harms did. DISCUSSION: HIVST harms were rare but strategies to link individuals experiencing harms with psychosocial support should be considered for HIVST scale-up. TRIAL REGISTRATION NUMBER: ISRCTN20312003.


Assuntos
Infecções por HIV , Minorias Sexuais e de Gênero , Masculino , Humanos , Homossexualidade Masculina , Autoteste , HIV , País de Gales , Infecções por HIV/diagnóstico , Infecções por HIV/prevenção & controle , Infecções por HIV/psicologia , Inglaterra
2.
Proc Natl Acad Sci U S A ; 115(30): E7081-E7090, 2018 07 24.
Artigo em Inglês | MEDLINE | ID: mdl-29987005

RESUMO

The huntingtin N17 domain is a modulator of mutant huntingtin toxicity and is hypophosphorylated in Huntington's disease (HD). We conducted high-content analysis to find compounds that could restore N17 phosphorylation. One lead compound from this screen was N6-furfuryladenine (N6FFA). N6FFA was protective in HD model neurons, and N6FFA treatment of an HD mouse model corrects HD phenotypes and eliminates cortical mutant huntingtin inclusions. We show that N6FFA restores N17 phosphorylation levels by being salvaged to a triphosphate form by adenine phosphoribosyltransferase (APRT) and used as a phosphate donor by casein kinase 2 (CK2). N6FFA is a naturally occurring product of oxidative DNA damage. Phosphorylated huntingtin functionally redistributes and colocalizes with CK2, APRT, and N6FFA DNA adducts at sites of induced DNA damage. We present a model in which this natural product compound is salvaged to provide a triphosphate substrate to signal huntingtin phosphorylation via CK2 during low-ATP stress under conditions of DNA damage, with protective effects in HD model systems.


Assuntos
Adenina , Adutos de DNA/metabolismo , Dano ao DNA , Doença de Huntington/tratamento farmacológico , Neurônios/metabolismo , Transdução de Sinais/efeitos dos fármacos , Adenina/análogos & derivados , Adenina/farmacocinética , Adenina/farmacologia , Adenina Fosforribosiltransferase/genética , Adenina Fosforribosiltransferase/metabolismo , Animais , Caseína Quinase II/genética , Caseína Quinase II/metabolismo , Linhagem Celular Transformada , Adutos de DNA/genética , Modelos Animais de Doenças , Humanos , Doença de Huntington/genética , Doença de Huntington/metabolismo , Doença de Huntington/patologia , Camundongos , Camundongos Transgênicos , Neurônios/patologia , Fosforilação/efeitos dos fármacos , Fosforilação/genética , Transdução de Sinais/genética
3.
Nanotechnology ; 30(33): 335706, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-31026844

RESUMO

Phase-change random access memory is a promising approach to non-volatile memory. However, the inability to secure consistent, reliable switching on a nanometre scale may limit its practical use for high density applications. Here, we report on the switching behaviour of PCRAM cells comprised of single crystalline Ge9Sb1Te5 (GST) nanowires. We show that device switching is dominated by the contacts and does not result in a resistance change within the bulk of the wire. For the devices studied, the typical contact resistance was ∼30 kΩ, whereas the resistance of the GST channel was 1.8 kΩ. The applied voltage was predominately dropped across the passivating oxide on the surface of the GST nanowires, resulting in local resistive switching at the contacts and local power dissipation, which limited the endurance of the devices produced. The optimal device must balance low resistance contacts with a more resistive channel, to facilitate phase change switching within the nanowires. These results highlight the importance of contact formation on the switching properties in phase change devices and help guide the future design of more reliable neuromorphic devices.

4.
BMC Infect Dis ; 19(1): 699, 2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31391003

RESUMO

BACKGROUND: The SELPHI study (An HIV Self-Testing Public Health Intervention) is an online randomised controlled trial (RCT) of HIV self-testing (HIVST). The aim of this study was to assess the feasibility of recruiting UK men who have sex with men (cis and trans) and trans women who have sex with men to the SELPHI pilot, and the acceptability of the HIVST intervention used among those randomised to receive a kit. METHODS: A mixed-methods approach to assessing trial feasibility and intervention acceptability was taken, using quantitative data from advertising sources and RCT surveys alongside qualitative data from a nested sub-study. RESULTS: Online recruitment and intervention delivery was feasible. The recruitment strategy led to the registration of 1370 participants of whom 76% (1035) successfully enrolled and were randomised 60/40 to baseline testing vs no baseline testing. Advertising platforms performed variably. Reported HIVST kit use increased from 83% at two weeks to 96% at three months. Acceptability was very high across all quantitative measures. Participants described the instructions as easy to use, and the testing process as simple. The support structures in SELPHI were felt to be adequate. Described emotional responses to HIVST varied. CONCLUSIONS: Recruiting to a modest sized HIVST pilot RCT is feasible, and the recruitment, intervention and HIVST kit were acceptable. Research on support needs of individuals with reactive results is warranted.


Assuntos
Infecções por HIV/diagnóstico , Homossexualidade Masculina , Marketing de Serviços de Saúde , Aceitação pelo Paciente de Cuidados de Saúde , Pessoas Transgênero , Adolescente , Adulto , Inglaterra , Estudos de Viabilidade , Infecções por HIV/psicologia , Inquéritos Epidemiológicos , Homossexualidade Masculina/estatística & dados numéricos , Humanos , Internet , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Autocuidado , Minorias Sexuais e de Gênero , Pessoas Transgênero/psicologia , País de Gales
5.
BMC Infect Dis ; 18(1): 531, 2018 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-30352556

RESUMO

BACKGROUND: Among men who have sex with men (MSM) in the UK, an estimated 28% have never tested for HIV and only 27% of those at higher risk test at least every 6 months. HIV self-testing (HIVST), where the person takes their own blood/saliva sample and processes it themselves, offers the opportunity to remove many structural and social barriers to testing. Although several randomised controlled trials are assessing the impact of providing HIVST on rates of HIV testing, none are addressing whether this results in increased rates of HIV diagnoses that link to clinical care. Linking to care is the critical outcome because it is the only way to access antiretroviral treatment (ART). We describe here the design of a large, internet-based randomised controlled trial of HIVST, called SELPHI, which aims to inform this key question. METHODS/DESIGN: The SELPHI study, which is ongoing is promoted via social networking website and app advertising, and aims to enroll HIV negative men, trans men and trans women, aged over 16 years, who are living in England and Wales. Apart from the physical delivery of the test kits, all trial processes, including recruitment, take place online. In a two-stage randomisation, participants are first randomised (3:2) to receive a free baseline HIVST or no free baseline HIVST. At 3 months, participants allocated to receive a baseline HIVST (and meeting further eligibility criteria) are subsequently randomised (1:1) to receive the offer of regular (every 3 months) free HIVST, with testing reminders, versus no such offer. The primary outcome from both randomisations is a laboratory-confirmed HIV diagnosis, ascertained via linkage to a national HIV surveillance database. DISCUSSION: SELPHI will provide the first reliable evidence on whether offering free HIVST via the internet increases rates of confirmed HIV diagnoses and linkage to clinical care. The two randomisations reflect the dual objectives of detecting prevalent infections (possibly long-standing) and the more rapid diagnosis of incident HIV infections. It is anticipated that the results of SELPHI will inform future access to HIV self-testing provision in the UK. TRIAL REGISTRATION: DOI 10.1186/ISRCTN20312003 registered 24/10/2016.


Assuntos
Infecções por HIV/diagnóstico , Programas de Rastreamento/métodos , Adolescente , Adulto , Inglaterra , Feminino , Homossexualidade Masculina , Humanos , Internet , Masculino , Testes Sorológicos , Minorias Sexuais e de Gênero , Rede Social , Inquéritos e Questionários
6.
Environ Sci Technol ; 51(21): 12302-12309, 2017 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-29028327

RESUMO

In this work, recovery of aluminum from coagulated primary sludge and its reuse potential as secondary coagulant were investigated. The recovery process consisted of releasing the particle-bound aluminum from primary sludge by acidification (HCl or H2SO4), followed by separation using centrifugation for dissolved coagulant recovery. The recovered coagulant was then reused for treating primary wastewater and overall coagulation efficiency was determined. While with fresh alum, the removal efficiencies of total suspended solids, chemical oxygen demand, total phosphorus, and total nitrogen were 85%, 65%, 80% and 33%, respectively, a drop in removal efficiency of total suspended solids and chemical oxygen demand was observed for recovered aluminum (85-60% and 65-50%, respectively). Nitrogen concentration remained almost constant with each cycle, while phosphorus in the effluent increased by 1 mg/L and 3 mg/L in the first and second cycle, respectively. Precipitation of various aluminum species was modeled for determining the recovery potential of aluminum at low pH. Preliminary cost analysis indicates that optimum recovery of aluminum occurred at a pH of 1.5 for both acids. Struvite precipitation effectively removed increased phosphorus solubilized by acidification at the end of second cycle, however, it also decreased the amount of aluminum available for recycle.


Assuntos
Carbono , Fósforo , Águas Residuárias , Alumínio , Nitrogênio , Esgotos , Eliminação de Resíduos Líquidos , Purificação da Água
7.
Nano Lett ; 16(1): 434-9, 2016 Jan 13.
Artigo em Inglês | MEDLINE | ID: mdl-26629610

RESUMO

Thermal management is an important consideration for most nanoelectronic devices, and an understanding of the thermal conductivity of individual device components is critical for the design of thermally efficient systems. However, it can be difficult to directly probe local changes in thermal conductivity within a nanoscale system. Here, we utilize the time-resolved and diffraction-limited imaging capabilities of ultrafast pump-probe microscopy to determine, in a contact-free configuration, the local thermal conductivity in individual Si nanowires (NWs). By suspending single NWs across microfabricated trenches in a quartz substrate, the properties of the same NW both on and off the substrate are directly compared. We find the substrate has no effect on the recombination lifetime or diffusion length of photogenerated charge carriers; however, it significantly impacts the thermal relaxation properties of the NW. In substrate-supported regions, thermal energy deposited into the lattice by the ultrafast laser pulse dissipates within ∼10 ns through thermal diffusion and coupling to the substrate. In suspended regions, the thermal energy persists for over 100 ns, and we directly image the time-resolved spatial motion of the thermal signal. Quantitative analysis of the transient images permits direct determination of the NW's local thermal conductivity, which we find to be a factor of ∼4 smaller than in bulk Si. Our results point to the strong potential of pump-probe microscopy to be used as an all-optical method to quantify the effects of localized environment and morphology on the thermal transport characteristics of individual nanostructured components.

8.
N Engl J Med ; 368(3): 207-17, 2013 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-23323897

RESUMO

BACKGROUND: Short-course antiretroviral therapy (ART) in primary human immunodeficiency virus (HIV) infection may delay disease progression but has not been adequately evaluated. METHODS: We randomly assigned adults with primary HIV infection to ART for 48 weeks, ART for 12 weeks, or no ART (standard of care), with treatment initiated within 6 months after seroconversion. The primary end point was a CD4+ count of less than 350 cells per cubic millimeter or long-term ART initiation. RESULTS: A total of 366 participants (60% men) underwent randomization to 48-week ART (123 participants), 12-week ART (120), or standard care (123), with an average follow-up of 4.2 years. The primary end point was reached in 50% of the 48-week ART group, as compared with 61% in each of the 12-week ART and standard-care groups. The average hazard ratio was 0.63 (95% confidence interval [CI], 0.45 to 0.90; P=0.01) for 48-week ART as compared with standard care and was 0.93 (95% CI, 0.67 to 1.29; P=0.67) for 12-week ART as compared with standard care. The proportion of participants who had a CD4+ count of less than 350 cells per cubic millimeter was 28% in the 48-week ART group, 40% in the 12-week group, and 40% in the standard-care group. Corresponding values for long-term ART initiation were 22%, 21%, and 22%. The median time to the primary end point was 65 weeks (95% CI, 17 to 114) longer with 48-week ART than with standard care. Post hoc analysis identified a trend toward a greater interval between ART initiation and the primary end point the closer that ART was initiated to estimated seroconversion (P=0.09), and 48-week ART conferred a reduction in the HIV RNA level of 0.44 log(10) copies per milliliter (95% CI, 0.25 to 0.64) 36 weeks after the completion of short-course therapy. There were no significant between-group differences in the incidence of the acquired immunodeficiency syndrome, death, or serious adverse events. CONCLUSIONS: A 48-week course of ART in patients with primary HIV infection delayed disease progression, although not significantly longer than the duration of the treatment. There was no evidence of adverse effects of ART interruption on the clinical outcome. (Funded by the Wellcome Trust; SPARTAC Controlled-Trials.com number, ISRCTN76742797, and EudraCT number, 2004-000446-20.).


Assuntos
Antirretrovirais/administração & dosagem , Infecções por HIV/tratamento farmacológico , Adulto , Antirretrovirais/efeitos adversos , Antirretrovirais/uso terapêutico , Contagem de Linfócito CD4 , Progressão da Doença , Esquema de Medicação , Feminino , Seguimentos , HIV/genética , HIV/isolamento & purificação , Infecções por HIV/imunologia , Humanos , Masculino , Pessoa de Meia-Idade , RNA Viral/sangue , Adulto Jovem
10.
Crit Care Med ; 43(9): 1964-77, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26154929

RESUMO

OBJECTIVES: To describe unique features of neurocritical illness that are relevant to provision of high-quality palliative care; to discuss key prognostic aids and their limitations for neurocritical illnesses; to review challenges and strategies for establishing realistic goals of care for patients in the neuro-ICU; and to describe elements of best practice concerning symptom management, limitation of life support, and organ donation for the neurocritically ill. DATA SOURCES: A search of PubMed and MEDLINE was conducted from inception through January 2015 for all English-language articles using the term "palliative care," "supportive care," "end-of-life care," "withdrawal of life-sustaining therapy," "limitation of life support," "prognosis," or "goals of care" together with "neurocritical care," "neurointensive care," "neurological," "stroke," "subarachnoid hemorrhage," "intracerebral hemorrhage," or "brain injury." DATA EXTRACTION AND SYNTHESIS: We reviewed the existing literature on delivery of palliative care in the neurointensive care unit setting, focusing on challenges and strategies for establishing realistic and appropriate goals of care, symptom management, organ donation, and other considerations related to use and limitation of life-sustaining therapies for neurocritically ill patients. Based on review of these articles and the experiences of our interdisciplinary/interprofessional expert advisory board, this report was prepared to guide critical care staff, palliative care specialists, and others who practice in this setting. CONCLUSIONS: Most neurocritically ill patients and their families face the sudden onset of devastating cognitive and functional changes that challenge clinicians to provide patient-centered palliative care within a complex and often uncertain prognostic environment. Application of palliative care principles concerning symptom relief, goal setting, and family emotional support will provide clinicians a framework to address decision making at a time of crisis that enhances patient/family autonomy and clinician professionalism.


Assuntos
Encefalopatias/terapia , Cuidados Críticos/organização & administração , Unidades de Terapia Intensiva/organização & administração , Cuidados Paliativos/organização & administração , Assistência Terminal/organização & administração , Comunicação , Tomada de Decisões , Indicadores Básicos de Saúde , Humanos , Planejamento de Assistência ao Paciente , Prognóstico , Fatores de Tempo , Obtenção de Tecidos e Órgãos/organização & administração , Suspensão de Tratamento
11.
Nano Lett ; 14(11): 6287-92, 2014 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-25259929

RESUMO

Strain-induced changes to the electronic structure of nanoscale materials provide a promising avenue for expanding the optoelectronic functionality of semiconductor nanostructures in device applications. Here we use pump-probe microscopy with femtosecond temporal resolution and submicron spatial resolution to characterize charge-carrier recombination and transport dynamics in silicon nanowires (NWs) locally strained by bending deformation. The electron-hole recombination rate increases with strain for values above a threshold of ∼1% and, in highly strained (∼5%) regions of the NW, increases 6-fold. The changes in recombination rate are independent of NW diameter and reversible upon reduction of the applied strain, indicating the effect originates from alterations to the NW bulk electronic structure rather than introduction of defects. The results highlight the strong relationship between strain, electronic structure, and charge-carrier dynamics in low-dimensional semiconductor systems, and we anticipate the results will assist the development of strain-enabled optoelectronic devices with indirect-bandgap materials such as silicon.

12.
Nano Lett ; 14(6): 3079-87, 2014 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-24867088

RESUMO

Silicon nanowires incorporating p-type/n-type (p-n) junctions have been introduced as basic building blocks for future nanoscale electronic components. Controlling charge flow through these doped nanostructures is central to their function, yet our understanding of this process is inferred from measurements that average over entire structures or integrate over long times. Here, we have used femtosecond pump-probe microscopy to directly image the dynamics of photogenerated charge carriers in silicon nanowires encoded with p-n junctions along the growth axis. Initially, motion is dictated by carrier-carrier interactions, resulting in diffusive spreading of the neutral electron-hole cloud. Charge separation occurs at longer times as the carrier distribution reaches the edges of the depletion region, leading to a persistent electron population in the n-type region. Time-resolved visualization of the carrier dynamics yields clear, direct information on fundamental drift, diffusion, and recombination processes in these systems, providing a powerful tool for understanding and improving materials for nanotechnology.

13.
Pediatr Crit Care Med ; 15(8): 762-7, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25080152

RESUMO

OBJECTIVE: This review highlights benefits that patients, families and clinicians can expect to realize when palliative care is intentionally incorporated into the PICU. DATA SOURCES: We searched the MEDLINE database from inception to January 2014 for English-language articles using the terms "palliative care" or "end of life care" or "supportive care" and "pediatric intensive care." We also hand-searched reference lists and author files and relevant tools on the Center to Advance Palliative Care website. STUDY SELECTION: Two authors (physicians with experience in pediatric intensive care and palliative care) made final selections. DATA EXTRACTION: We critically reviewed the existing data and tools to identify strategies for incorporating palliative care into the PICU. DATA SYNTHESIS: The Improving Palliative Care in the ICU Advisory Board used data and experience to address key questions relating to: pain and symptom management, enhancing quality of life, communication and decision-making, length of stay, sites of care, and grief and bereavement. CONCLUSIONS: Palliative care should begin at the time of a potentially life-limiting diagnosis and continue throughout the disease trajectory, regardless of the expected outcome. Although the PICU is often used for short term postoperative stabilization, PICU clinicians also care for many chronically ill children with complex underlying conditions and others receiving intensive care for prolonged periods. Integrating palliative care delivery into the PICU is rapidly becoming the standard for high quality care of critically ill children. Interdisciplinary ICU staff can take advantage of the growing resources for continuing education in pediatric palliative care principles and interventions.


Assuntos
Comitês Consultivos , Atenção à Saúde/organização & administração , Unidades de Terapia Intensiva Pediátrica/normas , Cuidados Paliativos/normas , Luto , Comunicação , Tomada de Decisões , Humanos , Tempo de Internação , Manejo da Dor , Qualidade de Vida
14.
Nano Lett ; 13(3): 1336-40, 2013 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-23421654

RESUMO

We have developed a pump-probe microscope capable of exciting a single semiconductor nanostructure in one location and probing it in another with both high spatial and temporal resolution. Experiments performed on Si nanowires enable a direct visualization of the charge cloud produced by photoexcitation at a localized spot as it spreads along the nanowire axis. The time-resolved images show clear evidence of rapid diffusional spreading and recombination of the free carriers, which is consistent with ambipolar diffusion and a surface recombination velocity of ∼10(4) cm/s. The free carrier dynamics are followed by trap carrier migration on slower time scales.

15.
Int J Food Microbiol ; 395: 110191, 2023 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-37019040

RESUMO

Spores of Clostridium botulinum are widely distributed in the environment, including in foods. Prevention of foodborne botulism relies on the inhibition of spore germination and subsequent growth and toxin production, or the destruction of viable spores in food and beverages. This study examined the lethality of 254 nm UV radiation (UV-C) to spores of Group I and Group II C. botulinum. Spores of C. botulinum were inactivated by UV-C, with doses required for incremental log reduction (D10) values calculated using linear regression ranging from 2.87 to 3.70 mJ/cm2 for Group I strains and 4.46 to 6.15 mJ/cm2 for Group II strains. The measured D10 value for spores of C. sporogenes ATCC 19404 was 8.27 mJ/cm2 indicating it was more resistant than the strains of C. botulinum used in this study. Calculation of dose per log using a Weibull model resulted in higher D10 values of 6.67 to 8.81 mJ/cm2 for Group I strains and 9.24 to 10.7 mJ/cm2 for Group II strains. Spores of C. sporogenes possessed a D10 value of 14.4 mJ/cm2. The higher values for the Weibull model indicate the Weibull model to be more conservative as a result as it factors in the lag prior to inactivation and the tailing observed with very low numbers of survivors. Spores of both Group I and Group II C. botulinum strains tended to form large aggregates, visible with phase contrast microscopy, that resulted in severe tailing. Disruption of aggregates by ultrasonication was necessary to obtain linear destruction curves extending beyond 5 log reduction. All strains from Group I and Group II required <55 mJ/cm2 to achieve 5 log inactivation. The strain of C. sporogenes used in this work can therefore be a conservative non-pathogenic surrogate, having higher UV-C resistance than the C. botulinum strains used in this study. Overall, this study is the first detailed study to demonstrate UV-C as an effective treatment method to inactivate C. botulinum spores in a suspending medium. In addition, the study paves the way for further studies towards the applications of this technology to inactivate C. botulinum spores in beverages or other liquids.


Assuntos
Clostridium botulinum , Raios Ultravioleta , Esporos Bacterianos , Água , Desinfecção/métodos
16.
J Am Chem Soc ; 134(41): 17036-45, 2012 Oct 17.
Artigo em Inglês | MEDLINE | ID: mdl-22764889

RESUMO

Protein kinases catalyze the phosphorylation of cellular proteins involved in the regulation of many cellular processes and have emerged as promising targets for the treatment of several diseases. Conventional assays to monitor protein kinase activity are limited because they typically rely on transfer of radioactive phosphate or phospho-specific antibodies that recognize specific substrates or sequence motifs. To overcome the limitations of conventional assays, we have developed a versatile approach based on transfer of ferrocene-phosphate that can be readily monitored using electrochemical detection or detection with antiferrocene antibodies in an immunoarray format. This assay is readily adapted to multiplex arrays and can be employed for monitoring kinase activity in complex mixtures and for kinase inhibitor profiling.


Assuntos
Técnicas Eletroquímicas , Imunoensaio , Proteínas Quinases/metabolismo , Animais , Anticorpos/metabolismo , Biocatálise , Fosforilação , Proteínas Quinases/química , Coelhos
17.
Planta ; 235(5): 1013-22, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22127737

RESUMO

Structural determinants responsible for the substrate preference of the potassium-independent (ASPGA1) and -dependent (ASPGB1) asparaginases from Arabidopsis thaliana have been investigated. Like ASPGA1, ASPGB1 was found to be catalytically active with both L: -Asn and ß-Asp-His as substrates, contrary to a previous report. However, ASPGB1 had a 45-fold higher specific activity with Asn as substrate than ASPGA1. A divergent sequence between the two enzymes forms a variable loop at the C-terminal of the alpha subunit. The results of dynamic simulations have previously implicated a movement of the C-terminus in the allosteric transduction of K(+)-binding at the surface of LjNSE1 asparaginase. In the crystal structure of Lupinus luteus asparaginase, most residues in this segment cannot be visualized due to a weak electron density. Exchanging the variable loop in ASPGA1 with that from ASPGB1 increased the affinity for Asn, with a 320-fold reduction in K (m) value. Homology modeling identified a residue specific to ASPGB1, Phe(162), preceding the variable loop, whose side chain is located in proximity to the beta-carboxylate group of the product aspartate, and to Gly(246), a residue participating in an oxyanion hole which stabilizes a negative charge forming on the side chain oxygen of asparagine during catalysis. Replacement with the corresponding leucine from ASPGA1 specifically lowered the V (max) value with Asn as substrate by 8.4-fold.


Assuntos
Arabidopsis/enzimologia , Asparaginase/metabolismo , Asparagina/metabolismo , Lupinus/enzimologia , Sequência de Aminoácidos , Asparaginase/química , Modelos Moleculares , Estrutura Molecular , Potássio/metabolismo , Isoformas de Proteínas , Relação Estrutura-Atividade , Especificidade por Substrato
18.
Environ Sci Technol ; 46(24): 13432-9, 2012 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-23186002

RESUMO

California's furniture flammability standard Technical Bulletin 117 (TB 117) is believed to be a major driver of chemical flame retardant (FR) use in residential furniture in the United States. With the phase-out of the polybrominated diphenyl ether (PBDE) FR mixture PentaBDE in 2005, alternative FRs are increasingly being used to meet TB 117; however, it was unclear which chemicals were being used and how frequently. To address this data gap, we collected and analyzed 102 samples of polyurethane foam from residential couches purchased in the United States from 1985 to 2010. Overall, we detected chemical flame retardants in 85% of the couches. In samples purchased prior to 2005 (n = 41) PBDEs associated with the PentaBDE mixture including BDEs 47, 99, and 100 (PentaBDE) were the most common FR detected (39%), followed by tris(1,3-dichloroisopropyl) phosphate (TDCPP; 24%), which is a suspected human carcinogen. In samples purchased in 2005 or later (n = 61) the most common FRs detected were TDCPP (52%) and components associated with the Firemaster550 (FM 550) mixture (18%). Since the 2005 phase-out of PentaBDE, the use of TDCPP increased significantly. In addition, a mixture of nonhalogenated organophosphate FRs that included triphenyl phosphate (TPP), tris(4-butylphenyl) phosphate (TBPP), and a mix of butylphenyl phosphate isomers were observed in 13% of the couch samples purchased in 2005 or later. Overall the prevalence of flame retardants (and PentaBDE) was higher in couches bought in California compared to elsewhere, although the difference was not quite significant (p = 0.054 for PentaBDE). The difference was greater before 2005 than after, suggesting that TB 117 is becoming a de facto standard across the U.S. We determined that the presence of a TB 117 label did predict the presence of a FR; however, lack of a label did not predict the absence of a flame retardant. Following the PentaBDE phase out, we also found an increased number of flame retardants on the market. Given these results, and the potential for human exposure to FRs, health studies should be conducted on the types of FRs identified here.


Assuntos
Monitoramento Ambiental , Retardadores de Chama/análise , Éteres Difenil Halogenados/análise , Decoração de Interiores e Mobiliário , California , Cromatografia Gasosa-Espectrometria de Massas , Poliuretanos/análise
19.
J Food Prot ; 85(11): 1625-1634, 2022 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-36075045

RESUMO

ABSTRACT: A study was undertaken to model the UV-C inactivation kinetics and determine the fluences required for the incremental inactivation of several strains of Cronobacter spp. suspended in clear phosphate-buffered saline (PBS). In total, 13 strains of Cronobacter spp. were individually suspended in PBS and treated with UV-C doses of 0, 2, 4, 6, 8, and 10 mJ cm-2 with a collimated beam device emitting UV-C at 253.7 nm. The log reduction from each treatment was identified using the plate count method and plotted against the UV-C dose and then curve fitted using several mathematical models. The UV-C dose required for incremental inactivation of each isolate was determined using both linear and nonlinear regression. For the 13 strains tested, a UV-C dose of 10 mJ cm-2 inactivated between 3.66 ± 0.101 and 5.04 ± 0.465 log CFU mL-1. The survival behavior of all strains was best fitted to the Weibull+tail model, with correlation coefficients between 97.17 and 99.71%, and was used to determine the fluences required for incremental inactivation. The UV-C fluences needed to inactivate 1 log (D10-value) of Cronobacter spp. in buffer were between 3.53 and 5.50 mJ cm-2, whereas a fluence greater than 6.57 mJ cm-2 was required to achieve a 4-log inactivation. A clear understanding of the UV-C dose-response of several strains of Cronobacter spp. lays the foundation to design effective UV-based disinfection systems.


Assuntos
Cronobacter , Cinética , Raios Ultravioleta , Desinfecção/métodos , Fosfatos
20.
Lancet HIV ; 9(12): e838-e847, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36460023

RESUMO

BACKGROUND: High levels of HIV testing in men who have sex with men remain key to reducing the incidence of HIV. We aimed to assess whether the offer of a single, free HIV self-testing kit led to increased HIV diagnoses with linkage to care. METHODS: SELPHI was an internet-based, open-label, randomised controlled trial that recruited participants via sexual and social networking sites. Eligibility criteria included being a man or trans woman (although trans women are reported separately); being resident in England or Wales, UK; being aged 16 years or older; having had anal intercourse with a man; not having a positive HIV diagnosis; and being willing to provide name, email address, date of birth, and consent to link to national HIV databases. Participants were randomly allocated (3:2) by computer-generated number sequence to receive a free HIV self-test kit (BT group) or to not receive this free kit (nBT group). Online surveys collected data at baseline, 2 weeks after enrolment (BT group only), 3 months after enrolment, and at the end of the study. The primary outcome was confirmed (linked to care) new HIV diagnosis within 3 months of enrolment, analysed by intention to treat. Those assessing the primary outcome were masked to allocation. This study is registered with the ISRCTN Clinical Trials Register, number ISRCTN20312003. FINDINGS: 10 111 participants (6049 in BT group and 4062 in nBT group) enrolled between Feb 16, 2017, and March 1, 2018. The median age of participants was 33 years (IQR 26-44 years); 9000 (89%) participants were White; 8118 (80%) participants were born in the UK; 81 (1%) participants were transgender men; 4706 (47%) participants were university educated; 1537 (15%) participants had never been tested for HIV; and 389 (4%) participants were taking pre-exposure prophylaxis. At enrolment, 7282 (72%) participants reported condomless anal sex with at least one male partner in the previous 3 months. In the BT group, of the 4511 participants for whom HIV testing information was available, 4263 (95%) reported having used the free HIV self-test kit within 3 months.Within 3 months of enrolment there were 19 confirmed new HIV diagnoses (0·31%) in 6049 participants in the BT group and 15 (0·37%) of 4062 in the nBT group (p=0·64). INTERPRETATION: The offer of a single, free HIV self-test did not lead to increased rates of new HIV diagnoses, which could reflect decreasing HIV incidence rates in the UK. Nonetheless, the offer of a free HIV self-testing kit resulted in high HIV testing rates, indicating that self-testing is an attractive testing option for a large group of men who have sex with men. FUNDING: UK National Institute for Health and Care Research.


Assuntos
Infecções por HIV , Minorias Sexuais e de Gênero , Feminino , Masculino , Humanos , Adulto , Infecções por HIV/diagnóstico , Infecções por HIV/epidemiologia , Infecções por HIV/prevenção & controle , Autoteste , País de Gales/epidemiologia , Homossexualidade Masculina , Teste de HIV , Comportamento Sexual , Internet
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