479 research outputs found
PT-symmetry in honeycomb photonic lattices
We apply gain/loss to honeycomb photonic lattices and show that the
dispersion relation is identical to tachyons - particles with imaginary mass
that travel faster than the speed of light. This is accompanied by PT-symmetry
breaking in this structure. We further show that the PT-symmetry can be
restored by deforming the lattice
New synthetic routes to Triazolo-benzodiazepine analogues:expanding the scope of the bump-and-hole approach for selective Bromo and Extra-Terminal (BET) bromodomain inhibition
We describe new synthetic routes developed toward a range of substituted analogues of bromo and extra-terminal (BET) bromodomain inhibitors I-BET762/JQ1 based on the triazolo-benzodiazepine scaffold. These new routes allow for the derivatization of the methoxyphenyl and chlorophenyl rings, in addition to the diazepine ternary center and the side chain methylene moiety. Substitution at the level of the side chain methylene afforded compounds targeting specifically and potently engineered BET bromodomains designed as part of a bump and hole approach. We further demonstrate that marked selectivity for the second over the first bromodomain can be achieved with an indole derivative that exploits differential interaction with an aspartate/histidine conservative substitution on the BC loop of BET bromodomains
Negative refraction in hyperbolic hetero-bicrystals
We visualized negative refraction of phonon-polaritons in hetero-bicrystals
of two hyperbolic van der Waals materials: molybdenum oxide () and
isotopically pure hexagonal boron nitride (). The polaritons -
hybrids of infrared photons and lattice vibrations - form collimated rays that
display negative refraction when passing through a planar interface between the
and crystals. At a special frequency , these rays
can circulate along closed diamond-shaped trajectories. We show that polariton
eigenmodes display regions of both positive and negative dispersion interrupted
by multiple gaps resulting from polaritonic level repulsion
Metamaterial-Enhanced Nonlinear Terahertz Spectroscopy
We demonstrate large nonlinear terahertz responses in the gaps of metamaterial split ring resonators in several materials and use nonlinear THz transmission and THz-pump/THz-probe spectroscopy to study the nonlinear responses and dynamics. We use the field enhancement in the SRR gaps to initiate high-field phenomena at lower incident fields. In vanadium dioxide, we drive the insulator-to-metal phase transition with high-field THz radiation. The film conductivity increases by over two orders of magnitude and the phase transition occurs on a several picosecond timescale. In gallium arsenide, we observe high-field transport phenomena, including mobility saturation and impact ionization. The carrier density increases by up to ten orders of magnitude at high fields. At the highest fields, we demonstrate THz-induced damage in both vanadium dioxide and gallium arsenide.United States. Dept. of Energy (DOE-BES, grant DE-FG02- 09ER46643)United States. Office of Naval Research (ONR Grant No. N00014-09-1-1103
Impact of age and comorbidities on health-related quality of life for patients with prostate cancer: evaluation before a curative treatment
<p>Abstract</p> <p>Background</p> <p>Interpretation of comparative health-related quality of life (HRQOL) studies following different prostate cancer treatments is often difficult due to differing patient ages. Furthermore, age-related changes can hardly be discriminated from therapy-related changes. The evaluation of age-and comorbidity-related changes was in focus of this study.</p> <p>Methods</p> <p>HRQOL of 528 prostate cancer patients was analysed using a validated questionnaire (Expanded Prostate Cancer Index Composite) before a curative treatment. Patients were divided into age groups ≤65, 6670, 7175 and >75 years. The impact of specific comorbidities and the Charlson Comorbidity Index (CCI) were evaluated. The questionnaire comprises 50 items concerning the urinary, bowel, sexual and hormonal domains for function and bother. For assessment of sexual and hormonal domains, only patients without prior hormonal treatment were included (n = 336).</p> <p>Results</p> <p>Urinary incontinence was observed increasingly with higher age (mean function scores of 92/88/85/87 for patients ≤65, 6670, 7175 and >75 years) complete urinary control in 78%/72%/64%/58% (p < 0.01). Sexual function scores decreased particularly (48/43/35/30), with erections sufficient for intercourse in 68%/50%/36%/32% (p < 0.01) a decrease of more than a third comparing patients ≤65 vs. 6670 (36%) and 6670 vs. 7175 years (39%). The percentage of patients with comorbidities was lowest in the youngest group (48% vs. 66%/68%/63% for ages 6670/7175/>75 years; p < 0.05). A multivariate analysis revealed an independent influence of both age and comorbidities on urinary incontinence, specifically diabetes on urinary bother, and both age and diabetes on sexual function/bother. Rectal domain scores were not significantly influenced by age or comorbidities. A CCI>5 particularly predisposed for lower urinary and sexual HRQOL scores.</p> <p>Conclusion</p> <p>Urinary continence and sexual function are the crucial HRQOL domains with age-related and independently comorbidity-related decreasing scores. The results need to be considered for the interpretation of comparative studies or longitudinal changes after a curative treatment.</p
Efficacy of acupuncture for chronic low back pain: protocol for a randomized controlled trial
<p>Abstract</p> <p>Background</p> <p>Chronic back pain is a major public health problem and the primary reason patients seek acupuncture treatment. Therefore, an objective assessment of acupuncture efficacy is critical for making informed decisions about its appropriate role for patients with this common condition. This study addresses methodological shortcomings that have plagued previous studies evaluating acupuncture for chronic low back pain.</p> <p>Methods and Design</p> <p>A total of 640 participants (160 in each of four arms) between the ages of 18 and 70 years of age who have low back pain lasting at least 3 months will be recruited from integrated health care delivery systems in Seattle and Oakland. They will be randomized to one of two forms of Traditional Chinese Medical (TCM) acupuncture needling (individualized or standardized), a "control" group (simulated acupuncture), or to continued usual medical care. Ten treatments will be provided over 7 weeks. Study participants and the "Diagnostician" acupuncturists who evaluate participants and propose individualized treatments will be masked to the acupuncture treatment actually assigned each participant. The "Therapist" acupuncturists providing the treatments will not be masked but will have limited verbal interaction with participants. The primary outcomes, standard measures of dysfunction and bothersomeness of low back pain, will be assessed at baseline, and after 8, 26, and 52 weeks by telephone interviewers masked to treatment assignment. General health status, satisfaction with back care, days of back-related disability, and use and costs of healthcare services for back pain will also be measured. The primary analysis comparing outcomes by randomized treatment assignment will be analysis of covariance adjusted for baseline value. For both primary outcome measures, this trial will have 99% power to detect the presence of a minimal clinically significant difference among all four treatment groups and over 80% power for most pairwise comparisons. Secondary analyses will compare the proportions of participants in each group that improve by a clinically meaningful amount.</p> <p>Conclusion</p> <p>Results of this trial will help clarify the value of acupuncture needling as a treatment for chronic low back pain.</p> <p>Trial registration</p> <p>Clinical Trials.gov NCT00065585.</p
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