233 research outputs found
Evaluation of therapeutic response of Keloid and Hypertrophic scars to bleomycin tatto and to cryotherapy followed by intralesional triamcinolone injection
کلوئید و اسکارهایپرتروفیک بیماری هایی هستند ناشی از پاسخ غیر طبیعی پوست بدن به صدمات وارده که به علت تولید بیش ازحد بافت های فیبروس متراکم در محل ضایعه ایجاد می شوند. از بین درمان های بسیار زیاد پیشنهاد شده برای این بیماری ها، کرایوتراپی و تزریق داخل ضایعه تریامسینولون جزء متداول ترین این درمان ها است، اما هنوز موفقیت درمانی در این بیماری کامل نیست. هدف از انجام این پژوهش بررسی پاسخ درمانی کلوئید و اسکارهایپرتروفیک به تاتوی بلئومایسین و مقایسه آن با درمان معمول کرایوتراپی و تزریق داخل ضایعه تریامسینولون می باشد. بدین منظور 45 نفر از بیماران مبتلا به کلوئید و اسکارهایپرتروفیک مراجعه کننده به درمانگاه های پوست دانشگاه علوم پزشکی اصفهان بر اساس ترتیب مراجعه به دوگروه A (23 نفر) و گروه B (22 نفر) تقسیم شدند. گروه A بوسیله تاتوی بلئومایسین و گروه B بوسیله کرایوتراپی و تزریق داخل ضایعه تریامسینولون درمان شدند. درمان ها در چهار مرحله و با فواصل یک ماهه در هر دو گروه انجام شد و بیماران تا 3 ماه پس از پایان درمان پیگیری شدند. قبل و پس از درمان اندازه (شامل ضخامت و وسعت ضایعات)، علائم کلینیکی، محل و تعداد ضایعات و دیگر اطلاعات مورد نیاز ثبت و در هر گروه مقایسه گردید. پاسخ درمانی که بر اساس کاهش اندازه ضایعات نسبت به ویزیت اول تعریف شده بود، در گروه A، 14±3/88 درصد و در گروه B، 5/22±3/67 درصد به دست آمد که تفاوت معنی داری بین دوگروه مشاهده می شود (001/0P=) ضمن آنکه 69 بیماران گروه A در مقایسه با قبل از درمان بدون علامت شده بودند در حالی که تعداد کسانی که در گروه B بدون علامت شده بودند 49 درصد بود. همچنین در گروه B هر چه اندازه ضایعه بزرگتر بود پاسخ درمانی ضعیف تری به دست می آمد ولی در گروه A اندازه ضایعات تقریباً اثری در پاسخ درمانی ایجاد نکرد. نتیجه آنکه تاتوی بلئومایسین پاسخ درمانی بالائی می تواند در این بیماری ها ایجاد کند خصوصاً آنکه در ضایعات با اندازه بزرگ نیز اثر درمانی آن حفظ می شود
Influence of monolayer contamination on electric-field-noise heating in ion traps
Electric field noise is a hinderance to the assembly of large scale quantum
computers based on entangled trapped ions. Apart from ubiquitous technical
noise sources, experimental studies of trapped ion heating have revealed
additional limiting contributions to this noise, originating from atomic
processes on the electrode surfaces. In a recent work [A. Safavi-Naini et al.,
Phys. Rev. A 84, 023412 (2011)] we described a microscopic model for this
excess electric field noise, which points a way towards a more systematic
understanding of surface adsorbates as progenitors of electric field jitter
noise. Here, we address the impact of surface monolayer contamination on
adsorbate induced noise processes. By using exact numerical calculations for H
and N atomic monolayers on an Au(111) surface representing opposite extremes of
physisorption and chemisorption, we show that an additional monolayer can
significantly affect the noise power spectrum and either enhance or suppress
the resulting heating rates.Comment: 8 pages, 5 figure
A New Look at the Refund Mechanism in the Bitcoin Payment Protocol
BIP70 is the Bitcoin payment protocol for communication between a merchant and a pseudonymous customer. McCorry et al. (FC 2016) showed that BIP70 is prone to refund attacks and proposed a fix that requires the customer to sign their refund request. They argued that this minimal change will provide resistance against refund attacks. In this paper, we point out the drawbacks of McCorry et al.’s fix and propose a new approach for protection against refund attacks using the Bitcoin multisignature mechanism. Our solution does not rely on merchants storing the refund request, and unlike the previous solution, allows updating the refund addresses through email. We discuss the security of our proposed method and compare it with the previous solution. We also propose a novel application of our refund mechanism in providing anonymity for payments between a payer and payee in which merchants act as mixing servers. We finally discuss how to combine the above two mechanisms in a single payment protocol to have an anonymous payment protocol secure against refund attacks
Saddle-point scrambling without thermalisation
Out-of-time-order correlators (OTOCs) have proven to be a useful tool for
studying thermalisation in quantum systems. In particular, the exponential
growth of OTOCS, or scrambling, is sometimes taken as an indicator of chaos in
quantum systems, despite the fact that saddle points in integrable systems can
also drive rapid growth in OTOCs. By analysing the Dicke model and a driven
Bose-Hubbard dimer, we demonstrate that the OTOC growth driven by chaos can,
nonetheless, be distinguished from that driven by saddle points through the
long-term behaviour. Besides quantitative differences in the long-term average,
the saddle point gives rise to large oscillations not observed in the chaotic
case. The differences are also highlighted by entanglement entropy, which in
the chaotic driven dimer matches a Page curve prediction. These results
illustrate additional markers that can be used to distinguish chaotic behaviour
in quantum systems, beyond the initial exponential growth in OTOCs.Comment: 7 pages, 5 figure
Electric-field noise from carbon-adatom diffusion on a Au(110) surface: first-principles calculations and experiments
The decoherence of trapped-ion quantum gates due to heating of their motional
modes is a fundamental science and engineering problem. This heating is
attributed to electric-field noise arising from the trap-electrode surfaces. In
this work, we investigate the source of this noise by focusing on the diffusion
of carbon-containing adsorbates on the surface of Au(110). We show by density
functional theory, based on detailed scanning probe microscopy, how the carbon
adatom diffusion on the gold surface changes the energy landscape, and how the
adatom dipole moment varies with the diffusive motion. A simple model for the
diffusion noise, which varies quadratically with the variation of the dipole
moment, qualitatively reproduces the measured noise spectrum, and the estimate
of the noise spectral density is in accord with measured values.Comment: 8 pages, 6 figure
Breast-Lesion Characterization using Textural Features of Quantitative Ultrasound Parametric Maps
© 2017 The Author(s). This study evaluated, for the first time, the efficacy of quantitative ultrasound (QUS) spectral parametric maps in conjunction with texture-analysis techniques to differentiate non-invasively benign versus malignant breast lesions. Ultrasound B-mode images and radiofrequency data were acquired from 78 patients with suspicious breast lesions. QUS spectral-analysis techniques were performed on radiofrequency data to generate parametric maps of mid-band fit, spectral slope, spectral intercept, spacing among scatterers, average scatterer diameter, and average acoustic concentration. Texture-analysis techniques were applied to determine imaging biomarkers consisting of mean, contrast, correlation, energy and homogeneity features of parametric maps. These biomarkers were utilized to classify benign versus malignant lesions with leave-one-patient-out cross-validation. Results were compared to histopathology findings from biopsy specimens and radiology reports on MR images to evaluate the accuracy of technique. Among the biomarkers investigated, one mean-value parameter and 14 textural features demonstrated statistically significant differences (p < 0.05) between the two lesion types. A hybrid biomarker developed using a stepwise feature selection method could classify the legions with a sensitivity of 96%, a specificity of 84%, and an AUC of 0.97. Findings from this study pave the way towards adapting novel QUS-based frameworks for breast cancer screening and rapid diagnosis in clinic
Monitoring Breast Cancer Response to Neoadjuvant Chemotherapy Using Ultrasound Strain Elastography
© 2019 The Authors Strain elastography was used to monitor response to neoadjuvant chemotherapy (NAC) in 92 patients with biopsy-proven, locally advanced breast cancer. Strain elastography data were collected before, during, and after NAC. Relative changes in tumor strain ratio (SR) were calculated over time, and responder status was classified according to tumor size changes. Statistical analyses determined the significance of changes in SR over time and between response groups. Machine learning techniques, such as a naïve Bayes classifier, were used to evaluate the performance of the SR as a marker for Miller-Payne pathological endpoints. With pathological complete response (pCR) as an endpoint, a significant difference (P < .01) in the SR was observed between response groups as early as 2 weeks into NAC. Naïve Bayes classifiers predicted pCR with a sensitivity of 84%, specificity of 85%, and area under the curve of 81% at the preoperative scan. This study demonstrates that strain elastography may be predictive of NAC response in locally advanced breast cancer as early as 2 weeks into treatment, with high sensitivity and specificity, granting it the potential to be used for active monitoring of tumor response to chemotherapy
Chemotherapy-Response Monitoring of Breast Cancer Patients Using Quantitative Ultrasound-Based Intra-Tumour Heterogeneities
© 2017 The Author(s). Anti-cancer therapies including chemotherapy aim to induce tumour cell death. Cell death introduces alterations in cell morphology and tissue micro-structures that cause measurable changes in tissue echogenicity. This study investigated the effectiveness of quantitative ultrasound (QUS) parametric imaging to characterize intra-tumour heterogeneity and monitor the pathological response of breast cancer to chemotherapy in a large cohort of patients (n = 100). Results demonstrated that QUS imaging can non-invasively monitor pathological response and outcome of breast cancer patients to chemotherapy early following treatment initiation. Specifically, QUS biomarkers quantifying spatial heterogeneities in size, concentration and spacing of acoustic scatterers could predict treatment responses of patients with cross-validated accuracies of 82 ± 0.7%, 86 ± 0.7% and 85 ± 0.9% and areas under the receiver operating characteristic (ROC) curve of 0.75 ± 0.1, 0.80 ± 0.1 and 0.89 ± 0.1 at 1, 4 and 8 weeks after the start of treatment, respectively. The patients classified as responders and non-responders using QUS biomarkers demonstrated significantly different survivals, in good agreement with clinical and pathological endpoints. The results form a basis for using early predictive information on survival-linked patient response to facilitate adapting standard anti-cancer treatments on an individual patient basis
Multiworm algorithm quantum Monte Carlo
We review the path-integral quantum Monte Carlo method and discuss its
implementation by multiworm algorithms. We analyze in details the features of
the algorithms, and focus our attention on the computation of the -body
density matrix to study N-body correlations. Finally, we demonstrate the
validity of the algorithms on a system of dipolar bosons trapped in a stack of
one-dimensional layers in the case of zero and finite inter-layer hopping.Comment: 20 pages, 10 figure
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