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1.
PLoS One ; 19(3): e0297155, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38507357

RESUMO

OBJECTIVES: Many people with chronic pain cannot work, while working despite chronic pain is linked to absenteeism and presenteeism and a host of other deleterious effects. This disproportionately affects older adults, who are closer to retirement, while the exact relationship between pain and work cessation as well as retirement among older adults is not known. We explore longitudinally the relationship between chronic pain and the risk of ceasing work and entering retirement. METHODS: Data from 1156 individuals 50 years or older living in England taking part in the English Longitudinal Study of Ageing were used in this study. Cox proportional hazards regression analyses were used to examine the nature of the relationship between musculoskeletal pain and work cessation as well as retirement longitudinally over the course of fourteen years. RESULTS: Suffering from frequent musculoskeletal pain was associated with an increased risk of ceasing work and retiring at an earlier age, as did work dissatisfaction, higher perceived social status, female gender, and not receiving the recognition they felt they deserved in their job. Severity of depressive symptoms, psychosocial job demands, decision authority, and social support did not influence the age at which participants reported work cessation or retirement. CONCLUSIONS: Frequent musculoskeletal pain may increase the risk of earlier work exit and earlier retirement. Further research should establish the mechanisms and decision making involved in leaving the workforce in people with frequent musculoskeletal pain.


Assuntos
Dor Crônica , Dor Musculoesquelética , Humanos , Feminino , Idoso , Aposentadoria/psicologia , Estudos Longitudinais , Dor Musculoesquelética/epidemiologia , Dor Crônica/epidemiologia , Envelhecimento
2.
Pain ; 2024 Feb 20.
Artigo em Inglês | MEDLINE | ID: mdl-38381946

RESUMO

ABSTRACT: Chronic pain affects individuals' work participation. The impact of chronic pain on work has historically been measured through sickness absence, though it is now appreciated that the impacts on work are far wider. This mixed-methods review aimed to identify the full range of impacts of pain on work in addition to impacts that are currently measured quantitatively to inform the development of a new questionnaire assessing the wider impacts of chronic pain on work. MEDLINE, Embase, PsychINFO, and CINAHL were searched for studies that included quantitative measures of the impact of chronic pain on work and for qualitative studies where individuals described impacts of their chronic pain on work. Quantitative measures, and text from qualitative studies, were analysed thematically. A thematic framework was developed for establishing the types of impacts measured or described in the literature. Forty-four quantitative and 16 qualitative papers were identified. The literature described impacts within 5 areas: changes at work and to working status; aspects of the workplace and work relationships; pain and related symptoms at work; psychological factors; and factors and impacts outside the work environment related to work. Quantitative measures mainly assessed impacts related to the quantity and quality of work (29 of 42 measures). Seventeen aspects were only discussed within the qualitative literature. This study identifies a discrepancy between the impacts that have been the focus of quantitative measures and the range that individuals working with chronic pain experience and highlights the need for a new measure assessing a wider range of issues.

3.
Opt Express ; 32(1): 151-166, 2024 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-38175045

RESUMO

The wavelength dependence of atmospheric absorption creates range cues in hyperspectral measurements that can be exploited for passive ranging using only thermal emissions. In this work, we present fundamental limits on absorption-based ranging under a model of known air temperature and wavelength-dependent attenuation coefficient, with object temperature and emissivity unknown; reflected solar and environmental radiance is omitted from our analysis. Fisher information computations illustrate how performance limits depend on atmospheric conditions such as air temperature and humidity; temperature contrast in the scene; spectral resolution of measurement; and distance. These results should prove valuable in sensor system design.

4.
Scand J Work Environ Health ; 49(1): 53-63, 2023 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-36228192

RESUMO

OBJECTIVES: Physically-demanding occupations may increase rotator cuff disease (RCD) risk and need for surgery. We linked a job-exposure matrix (JEM) to the UK Biobank cohort study to measure physical occupational exposures and estimate associations with RCD surgery. METHODS: Jobs and UK Standard Occupational Classification (SOC) codes were recorded during the UK Biobank verbal interview. Lifetime job histories were captured through a web-based survey. UK SOC codes were linked to a JEM based on the US O*NET database. O*NET-based scores [static strength, dynamic strength, general physical activities, handling/moving objects (range=1-7), time spent using hands, whole body vibration, and cramped/awkward positions (range=1-5)] were assigned to jobs. RCD surgeries were identified through linked national hospital inpatient records. Multivariable Cox regression was used to calculate hazard ratios (HR) as estimates of associations with RCD surgery. Among those with lifetime job histories, associations were estimated for duration of time with greatest exposure (top quartile of exposure). RESULTS: Of 277 808 people reporting jobs, 1997 (0.7%) had an inpatient RCD surgery. After adjusting for age, sex, race, education, area deprivation, and body mass index, all O*NET variables considered were associated with RCD surgery (HR per point increase range=1.10-1.45, all P<0.005). A total of 100 929 people reported lifetime job histories, in which greater exposures were significantly associated with RCD surgery after >10 years of work (eg, HR for 11-20 versus 0 years with static strength score ≥4 = 2.06, 95% confidence interval 1.39-3.04). CONCLUSIONS: Workplace physical demands are an important risk factor for RCD surgery, particularly for workers with more than a decade of exposure.


Assuntos
Bancos de Espécimes Biológicos , Exposição Ocupacional , Humanos , Estudos de Coortes , Manguito Rotador/cirurgia , Ocupações , Reino Unido
5.
J Phys Chem Lett ; 13(6): 1489-1493, 2022 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-35129354

RESUMO

It has been proposed that entangled two-photon absorption (E2PA) can be observed with up to 1010 lower photon flux than its classical counterpart, therefore enabling ultralow-power two-photon fluorescence microscopy. However, there is a significant controversy regarding the magnitude of this quantum enhancement in excitation efficiency. We investigated the fluorescence signals from Rhodamine 6G and LDS798 excited with a CW laser or an entangled photon pair source at ∼1060 nm. We observed a signal that originates from hot-band absorption (HBA), which is one-photon absorption from thermally populated vibrational levels of the ground electronic state. This mechanism, which has not been previously discussed in the context of E2PA, produces a signal with a linear power dependence, as would be expected for E2PA. For the typical conditions under which E2PA measurements are performed, contributions from the HBA process could lead to a several orders of magnitude overestimate of the quantum advantage.

6.
BMC Public Health ; 22(1): 116, 2022 01 17.
Artigo em Inglês | MEDLINE | ID: mdl-35039031

RESUMO

BACKGROUND: Lower birth rates and increasing longevity have resulted in ageing populations in European countries. These demographic changes place challenges on pension provision as numbers of those who are economically inactive and retired increase relative to those in paid work. Therefore, governments need workers to postpone retirement and work to older ages. Whilst health and wealth are important in retirement decision-making, considerably less is known about the effects of workplace factors. The aim of this study was to explore the views of recent UK retirees about the role that work-related factors played in their decision to retire. METHODS: This qualitative study was nested within the Health and Employment After Fifty (HEAF) cohort. People who had retired 3-6 years previously (not for health reasons) were purposively sampled to obtain the views of men and women from a range of socio-economic backgrounds and jobs. Semi-structured interviews were carried out by telephone using a pre-defined topic guide. Interviews were audio-recorded, transcribed and analysed thematically. RESULTS: Seventeen interviews were conducted. Thematic analysis showed that retirement decisions were complex and multi-factorial but that work-related factors contributed to decision-making in two main ways. First, some work factors pushed participants towards retirement. These were perceptions that: workplace change had affected the way they were valued or increased pressure on them; work demands, including commuting, had intruded excessively on personal time, effects that were exacerbated by modern technology; work was draining, isolating or under-appreciated; and /or that work was causing physical strain or discomfort relative to their perception of their capacity. In contrast, work factors could also cause participants to pull back towards work, particularly: autonomy; supportive work colleagues; a sense of being appreciated; and perceived job flexibility. CONCLUSIONS: Recent retirees explained that their decision to retire was multi-factorial but work-related factors contributed importantly. Potentially, employers could: review workers' perceptions about their work; their capacity in relation to job demands; increase flexibility; and facilitate a supportive work community to encourage longer working lives.


Assuntos
Emprego , Aposentadoria , Feminino , Humanos , Masculino , Ocupações , Pensões , Reino Unido
7.
Biomed Opt Express ; 12(6): 3658-3670, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34221686

RESUMO

We demonstrate the preservation of the time-energy entanglement of near-IR photons through thick biological media (≤1.55 mm) and tissue (≤ 235 µm) at room temperature. Using a Franson-type interferometer, we demonstrate interferometric contrast of over 0.9 in skim milk, 2% milk, and chicken tissue. This work supports the many proposed opportunities for nonclassical light in biological imaging and analyses from sub-shot noise measurements to entanglement-enhanced fluorescence imaging, clearly indicating that the entanglement characteristics of photons can be maintained even after propagation through thick, turbid biological samples.

8.
Phys Rev Lett ; 124(1): 010505, 2020 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-31976704

RESUMO

Applications of randomness such as private key generation and public randomness beacons require small blocks of certified random bits on demand. Device-independent quantum random number generators can produce such random bits, but existing quantum-proof protocols and loophole-free implementations suffer from high latency, requiring many hours to produce any random bits. We demonstrate device-independent quantum randomness generation from a loophole-free Bell test with a more efficient quantum-proof protocol, obtaining multiple blocks of 512 random bits with an average experiment time of less than 5 min per block and with a certified error bounded by 2^{-64}≈5.42×10^{-20}.

9.
Opt Express ; 26(12): 14859-14868, 2018 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-30114791

RESUMO

We evaluate the performance of a mid-infrared emission spectrometer operating at wavelengths between 1.5 and 6 µm based on an amorphous tungsten silicide (a-WSi) superconducting nanowire single-photon detector (SNSPD). We performed laser induced fluorescence spectroscopy of surface adsorbates with sub-monolayer sensitivity and sub-nanosecond temporal resolution. We discuss possible future improvements of the SNSPD-based infrared emission spectrometer and its potential applications in molecular science.

10.
Nature ; 556(7700): 223-226, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29643486

RESUMO

From dice to modern electronic circuits, there have been many attempts to build better devices to generate random numbers. Randomness is fundamental to security and cryptographic systems and to safeguarding privacy. A key challenge with random-number generators is that it is hard to ensure that their outputs are unpredictable1-3. For a random-number generator based on a physical process, such as a noisy classical system or an elementary quantum measurement, a detailed model that describes the underlying physics is necessary to assert unpredictability. Imperfections in the model compromise the integrity of the device. However, it is possible to exploit the phenomenon of quantum non-locality with a loophole-free Bell test to build a random-number generator that can produce output that is unpredictable to any adversary that is limited only by general physical principles, such as special relativity1-11. With recent technological developments, it is now possible to carry out such a loophole-free Bell test12-14,22. Here we present certified randomness obtained from a photonic Bell experiment and extract 1,024 random bits that are uniformly distributed to within 10-12. These random bits could not have been predicted according to any physical theory that prohibits faster-than-light (superluminal) signalling and that allows independent measurement choices. To certify and quantify the randomness, we describe a protocol that is optimized for devices that are characterized by a low per-trial violation of Bell inequalities. Future random-number generators based on loophole-free Bell tests may have a role in increasing the security and trust of our cryptographic systems and infrastructure.

11.
Acc Chem Res ; 50(6): 1400-1409, 2017 06 20.
Artigo em Inglês | MEDLINE | ID: mdl-28573866

RESUMO

In contrast to UV photomultiplier tubes that are widely used in physical chemistry, mid-infrared detectors are notorious for poor sensitivity and slow time response. This helps explain why, despite the importance of infrared spectroscopy in molecular science, mid-infrared fluorescence is not more widely used. In recent years, several new technologies have been developed that open new experimental possibilities for research in the mid-infrared. In this Account, we present one of the more promising technologies, superconducting nanowire single photon detectors (SNSPDs) by sharing our experience with its use in a typical experiment carried out by physical chemists (laser-induced fluorescence) and comparing the SNSPD to a detector commonly used by physical chemists (InSb at LN Temperature). SNSPDs are fabricated from a thin film of superconducting metal, patterned into a meandering nanowire. The nanowire is cooled below its superconducting temperature, Tc, and held in a constant current circuit below the critical current necessary to destroy superconductivity, Ic. Upon absorption of a photon, the resulting heat is sufficient to destroy superconductivity across the entire width of the nanowire, an event that can be detected as a voltage pulse. In contrast to semiconductor-based detectors, which have a long wavelength cutoff determined by the band gap, the SNSPD exhibits single-photon sensitivity across the entire mid-IR spectrum. As these devices have not been used extensively outside the field of light detection technology research, one important goal of this Account is to provide practical details for the implementation of these devices in a physical chemistry laboratory. We provide extensive Supporting Information describing what is needed. This includes information on a liquid nitrogen cooled monochromator, the optical collection system including mid-infrared fibers, as well as a closed-cycle cryogenic cooler that reaches 0.3 K. We demonstrate the advantages of these detectors in a time-resolved laser-induced infrared fluorescence experiment on the energy pooling in crystalline CO overlayers formed on a NaCl(100) surface. We present dispersed fluorescence spectra recorded from 1.9 to 7.0 µm obtained by single-photon counting. We also estimate the sensitivity of this WSi-based detection system at 3 µm; the system's noise equivalent power (NEP) value is ∼10-3 of a conventional InSb photovoltaic device. Straightforward modifications are expected to provide another 100 000-fold improvement. We demonstrate that the temporal resolution of the experiment is limited only by the pulse duration of the laser used in this work (fwhm = 3.7 ns). The use of SNSPDs enables dramatically improved observations of energy pooling in cryogenic molecular crystals.

12.
Appl Phys Lett ; 111(14)2017.
Artigo em Inglês | MEDLINE | ID: mdl-36452265

RESUMO

We demonstrate cryogenic, electrically injected, waveguide-coupled Si light-emitting diodes (LEDs) operating at 1.22 µm. The active region of the LED consists of W centers implanted in the intrinsic region of a p-i-n diode. The LEDs are integrated on waveguides with superconducting nanowire single-photon detectors (SNSPDs). We demonstrate the scalability of this platform with an LED coupled to eleven SNSPDs in a single integrated photonic device.

13.
Phys Rev Lett ; 115(25): 250402, 2015 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-26722906

RESUMO

We present a loophole-free violation of local realism using entangled photon pairs. We ensure that all relevant events in our Bell test are spacelike separated by placing the parties far enough apart and by using fast random number generators and high-speed polarization measurements. A high-quality polarization-entangled source of photons, combined with high-efficiency, low-noise, single-photon detectors, allows us to make measurements without requiring any fair-sampling assumptions. Using a hypothesis test, we compute p values as small as 5.9×10^{-9} for our Bell violation while maintaining the spacelike separation of our events. We estimate the degree to which a local realistic system could predict our measurement choices. Accounting for this predictability, our smallest adjusted p value is 2.3×10^{-7}. We therefore reject the hypothesis that local realism governs our experiment.

14.
Diabetologia ; 57(6): 1249-56, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24623102

RESUMO

AIMS/HYPOTHESIS: The aim of this work was to assess the impact of cardiac autonomic neuropathy (CAN) on the development and progression of chronic kidney disease (CKD) in patients with type 2 diabetes. METHODS: We conducted a cohort study in adults with type 2 diabetes. Patients with end-stage renal disease were excluded. CKD was defined as the presence of albuminuria (albumin/creatinine ratio GFR > 3.4 mg/mmol) or an estimated (eGFR) < 60 ml min(-1) 1.73 m(-2). CKD progression was based on repeated eGFR measurements and/or the development of albuminuria. CAN was assessed using heart rate variability. RESULTS: Two hundred and four patients were included in the analysis. At baseline, the prevalence of CKD and CAN was 40% and 42%, respectively. Patients with CAN had lower eGFR and higher prevalence of albuminuria and CKD. Spectral analysis variables were independently associated with eGFR, albuminuria and CKD at baseline. After a follow-up of 2.5 years, eGFR declined to a greater extent in patients with CAN than in those without CAN (-9.0 ± 17.8% vs -3.3 ± 10.3%, p = 0.009). After adjustment for baseline eGFR and baseline differences, CAN remained an independent predictor of eGFR decline over the follow-up period (ß = -3.5, p = 0.03). Spectral analysis variables were also independent predictors of eGFR decline. CONCLUSIONS/INTERPRETATION: CAN was independently associated with CKD, albuminuria and eGFR in patients with type 2 diabetes. In addition, CAN was an independent predictor of the decline in eGFR over the follow-up period. CAN could be used to identify patients with type 2 diabetes who are at increased risk of rapid decline in eGFR, so that preventative therapies might be intensified.


Assuntos
Diabetes Mellitus Tipo 2/complicações , Neuropatias Diabéticas/complicações , Insuficiência Renal Crônica/etiologia , Adulto , Idoso , Feminino , Taxa de Filtração Glomerular/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos
15.
Opt Express ; 22(3): 3244-60, 2014 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-24663616

RESUMO

We measure second- and third-order temporal coherences, g((2))(τ) and g((3))(τ1,τ2), of an optically excited single-photon source: an InGaAs quantum dot in a microcavity pedestal. Increasing the optical excitation power leads to an increase in the measured count rate, and also an increase in multi-photon emission probability. We show that standard measurements of g((2)) provide limited information about this multi-photon probability, and that more information can be gained by simultaneously measuring g((3)). Experimental results are compared with a simple theoretical model to show that the observed antibunchings are consistent with an incoherent addition of two sources: 1) an ideal single-photon source that never emits multiple photons and 2) a background cavity emission having Poissonian photon number statistics. Spectrally resolved cross-correlation measurements between quantum-dot and cavity modes show that photons from these two sources are largely uncorrelated, further supporting the model. We also analyze the Hanbury Brown-Twiss interferometer implemented with two or three "click" detectors, and explore the conditions under which it can be used to accurately measure g((2))(τ) and g((3))(τ1,τ2).

16.
World J Diabetes ; 5(1): 17-39, 2014 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-24567799

RESUMO

Cardiac autonomic neuropathy (CAN) is an often overlooked and common complication of diabetes mellitus. CAN is associated with increased cardiovascular morbidity and mortality. The pathogenesis of CAN is complex and involves a cascade of pathways activated by hyperglycaemia resulting in neuronal ischaemia and cellular death. In addition, autoimmune and genetic factors are involved in the development of CAN. CAN might be subclinical for several years until the patient develops resting tachycardia, exercise intolerance, postural hypotension, cardiac dysfunction and diabetic cardiomyopathy. During its sub-clinical phase, heart rate variability that is influenced by the balance between parasympathetic and sympathetic tones can help in detecting CAN before the disease is symptomatic. Newer imaging techniques (such as scintigraphy) have allowed earlier detection of CAN in the pre-clinical phase and allowed better assessment of the sympathetic nervous system. One of the main difficulties in CAN research is the lack of a universally accepted definition of CAN; however, the Toronto Consensus Panel on Diabetic Neuropathy has recently issued guidance for the diagnosis and staging of CAN, and also proposed screening for CAN in patients with diabetes mellitus. A major challenge, however, is the lack of specific treatment to slow the progression or prevent the development of CAN. Lifestyle changes, improved metabolic control might prevent or slow the progression of CAN. Reversal will require combination of these treatments with new targeted therapeutic approaches. The aim of this article is to review the latest evidence regarding the epidemiology, pathogenesis, manifestations, diagnosis and treatment for CAN.

17.
Diabetes Care ; 36(11): 3718-25, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24062320

RESUMO

OBJECTIVE: Diabetic nephropathy (DN) is a leading cause of end-stage renal disease (ESRD). Obstructive sleep apnea (OSA) is common in type 2 diabetes and increases oxidative stress. Hence, OSA could promote the development and progression of DN. RESEARCH DESIGN AND METHODS: This was a cohort study in adults with type 2 diabetes. Patients with known OSA or ESRD were excluded. DN was defined as the presence of albuminuria or an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2. DN progression was based on eGFR measurements. OSA was defined as apnea hypopnea index (AHI) ≥5 events/h. Serum nitrotyrosine abundance (a marker of nitrosative stress) was measured by ELISA. RESULTS: A total of 224 patients were included. OSA and DN prevalence was 64.3 and 40.2, respectively. DN prevalence was higher in patients with OSA (OSA+) compared with those without OSA (OSA-) (49.3% vs. 23.8%, P < 0.001). After adjustment, OSA (odds ratio 2.64 [95% CI 1.13-6.16], P = 0.02) remained independently associated with DN. After an average follow-up of 2.5 (0.7) years, eGFR decline was greater in OSA+ compared with OSA- patients (median -6.8% [interquartile range -16.1 to 2.2] vs. -1.6% [-7.7 to 5.3%], P = 0.002). After adjusting, both baseline OSA (B = -3.8, P = 0.044) and AHI (B = -4.6, P = 0.02) remained independent predictors of study-end eGFR. Baseline serum nitrotyrosine abundance (B = -0.24, P = 0.015) was an independent predictor of study-end eGFR after adjustment. CONCLUSIONS: OSA is independently associated with DN in type 2 diabetes. eGFR declined faster in patients with OSA. Nitrosative stress may provide a pathogenetic link between OSA and DN. Interventional studies assessing the impact of OSA treatment on DN are needed.


Assuntos
Diabetes Mellitus Tipo 2/embriologia , Nefropatias Diabéticas/epidemiologia , Apneia Obstrutiva do Sono/epidemiologia , Adulto , Idoso , Albuminúria/sangue , Albuminúria/epidemiologia , Albuminúria/etiologia , Biomarcadores/sangue , Estudos de Coortes , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Feminino , Humanos , Falência Renal Crônica/complicações , Masculino , Pessoa de Meia-Idade , Prevalência , Insuficiência Renal Crônica/complicações
18.
Curr Opin Pulm Med ; 19(6): 631-8, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-24048079

RESUMO

PURPOSE OF REVIEW: The relationship between obstructive sleep apnoea (OSA) and dysglycaemia is well established. However, uncertainty remains as to the extent that obesity mediates this relationship. The impact of OSA treatment on glucose metabolism and the consequences of having OSA in patients with diabetes is unclear. This review aims to summarize the latest evidence regarding the links between OSA and dysglycaemia. RECENT FINDINGS: OSA is associated with insulin resistance in lean individuals and predicts insulin resistance worsening longitudinally. Continuous positive airway pressure (CPAP) lowers insulin resistance in CPAP-compliant patients. OSA is associated with impaired ß-cell function. In patients with type 2 diabetes (T2D), the association between OSA and glycosylated haemoglobin (HbA1c) is related to nocturnal hypoxaemia. Apnoea hypopnoea index (AHI) during rapid eye movement (REM) (not non-REM) sleep is associated with HbA1c. In-laboratory, supervised CPAP improves glycaemia. OSA is associated with and predicts the progression of some diabetic vascular complications. Intensive lifestyle intervention in patients with T2D improves OSA independent of weight loss. SUMMARY: OSA is associated with insulin resistance and ß-cell dysfunction independent of obesity. OSA is associated with HbA1c and vascular complications in patients with T2D. CPAP might improve insulin resistance and glycaemic measures. Lifestyle intervention has a significant impact on AHI in patients with T2D.


Assuntos
Pressão Positiva Contínua nas Vias Aéreas , Complicações do Diabetes/fisiopatologia , Diabetes Mellitus Tipo 2/fisiopatologia , Resistência à Insulina , Apneia Obstrutiva do Sono/fisiopatologia , Glicemia/metabolismo , Complicações do Diabetes/sangue , Complicações do Diabetes/tratamento farmacológico , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/complicações , Diabetes Mellitus Tipo 2/tratamento farmacológico , Feminino , Hemoglobinas Glicadas/metabolismo , Humanos , Masculino , Obesidade/sangue , Prognóstico , Fatores de Risco , Comportamento de Redução do Risco , Apneia Obstrutiva do Sono/sangue , Apneia Obstrutiva do Sono/complicações , Apneia Obstrutiva do Sono/terapia , Sono REM , Resultado do Tratamento
19.
ACS Nano ; 6(11): 9532-40, 2012 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-23020520

RESUMO

Carrier multiplication (CM) is the process in which absorption of a single photon produces multiple electron-hole pairs. Here, we evaluate the effect of particle shape on CM efficiency by conducting a comparative study of spherical nanocrystal quantum dots (NQDs) and elongated nanorods (NRs) of PbSe using a time-resolved technique that is based on photon counting in the infrared using a superconducting nanowire single-photon photodetector (SNSPD). Due to its high sensitivity and low noise levels, this technique allows for accurate determination of CM yields, even with the small excitation intensities required for quantitative measurements, and the fairly low emission quantum yields of elongated NR samples. Our measurements indicate an up to ∼60% increase in multiexciton yields in NRs versus NQDs, which is attributed primarily to a decrease in the electron-hole pair creation energy. These findings suggest that shape control is a promising approach for enhancing the CM process. Further, our work demonstrates the effectiveness of the SNSPD technique for the rapid screening of CM performance in infrared nanomaterials.


Assuntos
Condutometria/instrumentação , Nanotecnologia/instrumentação , Nanotubos/química , Fotometria/instrumentação , Pontos Quânticos , Coloides/química , Condutividade Elétrica , Desenho de Equipamento , Análise de Falha de Equipamento , Raios Infravermelhos , Nanotubos/efeitos da radiação
20.
Diabetes Care ; 35(9): 1913-8, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22751961

RESUMO

OBJECTIVE: Impairment of skin quality may contribute to diabetic foot ulceration (DFU). Our goal was to determine whether high-risk patients exhibited specific skin structural and metabolic deficits that could predispose to foot complications. RESEARCH DESIGN AND METHODS: A total of 46 patients comprising 9 diabetic control subjects, 16 with diabetic peripheral neuropathy (DPN) alone, and 21 with recurrent DFUs (including 9 with Charcot neuroarthropathy [CNA]) were recruited and compared with 14 nondiabetic control (NDC) subjects. DPN was assessed using the Michigan Neuropathy Screening Instrument (MNSI). Skin punch biopsies (3 mm) were performed on upper and lower leg skin for measurements of intraepidermal nerve fiber density (IENFD), structural analysis, type 1 procollagen abundance, tissue degrading matrix metalloproteinases (MMPs), and poly(ADP-ribose) (PAR) immunoreactivity. RESULTS: MNSI scores were comparable across DPN groups. IENFD was decreased by diabetes and DPN but did not differ between neuropathic groups. Skin structural deficit scores were elevated in all neuropathic subjects, particularly in the DFU group. Type 1 procollagen abundance was reduced in DFU subjects 387 ± 256 units (mean ± 1 SD) compared with NDC subjects (715 ± 100, P < 0.001). MMP-1 and MMP-2 were activated by diabetes. PAR immunoreactivity was increased in DFU (particularly in the CNA group; P < 0.01) compared with other DPN subjects. CONCLUSIONS: Increased PAR, reduced type 1 procollagen abundance, and impaired skin structure are associated with foot complications in diabetes. The potential of therapies that improve skin quality to reduce DFU needs to be investigated.


Assuntos
Pé Diabético/fisiopatologia , Pele/patologia , Pele/fisiopatologia , Adulto , Idoso , Pé Diabético/metabolismo , Pé Diabético/patologia , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Técnicas de Cultura de Órgãos , Pró-Colágeno/metabolismo , Pele/metabolismo
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