82 research outputs found
INVESTIGATION of CURRENT TRANSPORT IN ITO/CdTe/polymer/Al DEVICES USING NANO-STRUCTURED CdTe
In this thesis, photo luminescent diodes with the device structure of ITO/PEI/(CdTe/PDDA)*n/Al were fabricated using the method of layer-by-layer self assembly. The film thicknesses were varied from 150 nm to 380 nm. The films were characterized through X-ray diffraction (XRD), optical absorption and photoluminescence (PL) measurements. The XRD results on the film indicated a cubic crystalline structure (111) for the nano-CdTe particles. The band gap of the nano-particles were evaluated to be 2.1 eV in solution and 2 eV in films, which was further confirmed by the PL measurements as the solution exhibited a yellow luminescence while the film exhibited orange luminescence. The J vs. V curves revealed that the diodes exhibited rectifying behavior in both the forward and reverse biasing. Two models of current transport, one based on a Schottky mechanism and the other based on a tunneling mechanism were developed and were compared with the experimental values. The tunneling model developed could simulate the experimental currents up to four orders of magnitude. The tunneling mechanism of charge transport was further proved by the capacitance vs. voltage curves, which were identical to that of ITO/MEH-PPV/Al devices, where tunneling mechanism was the dominant method of charge transport
Improved Approximation Bounds for Minimum Weight Cycle in the CONGEST Model
Minimum Weight Cycle (MWC) is the problem of finding a simple cycle of
minimum weight in a graph . This is a fundamental graph problem with
classical sequential algorithms that run in and
time where and . In recent years this problem
has received significant attention in the context of hardness through fine
grained sequential complexity as well as in design of faster sequential
approximation algorithms.
For computing minimum weight cycle in the distributed CONGEST model,
near-linear in lower and upper bounds on round complexity are known for
directed graphs (weighted and unweighted), and for undirected weighted graphs;
these lower bounds also apply to any -approximation algorithm.
This paper focuses on round complexity bounds for approximating MWC in the
CONGEST model: For coarse approximations we show that for any constant , computing an -approximation of MWC requires rounds on weighted undirected graphs and on directed graphs, even
if unweighted. We complement these lower bounds with sublinear
-round algorithms for approximating MWC close to a factor
of 2 in these classes of graphs.
A key ingredient of our approximation algorithms is an efficient algorithm
for computing -approximate shortest paths from sources in
directed and weighted graphs, which may be of independent interest for other
CONGEST problems. We present an algorithm that runs in rounds if and rounds if , and this round
complexity smoothly interpolates between the best known upper bounds for
approximate (or exact) SSSP when and APSP when
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Diagnosis of cutaneous T-cell lymphoma by insurance type before and after the Affordable Care Act: a national database study
The Affordable Care Act (ACT) was implemented to increase health care access and reduce the uninsured in the age group between pediatric and Medicare populations (18-64). The association of the ACA with insurance type upon diagnosis (uninsured, Medicaid, non-Medicaid) has been investigated for otolaryngologic, gynecologic, and the top five non-skin malignancies. Such studies for cutaneous malignancies are lacking. We conducted a retrospective analysis of the prospective National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) cancer database to assess the impact of the ACA on new diagnoses of cutaneous T-cell lymphoma (CTCL) by insurance type. Unlike prior studies of other malignancies, we did not observe significant differences between rate of diagnosis of CTCL by insurance type before and after full implementation of the ACA in all states, expansion states, and non-expansion states. Skin cancers do not have screening guidelines and CTCL is an uncommon malignancy, both of which may contribute to these findings. However, Medicaid-expansion states were much closer to reducing the percentage of newly diagnosed uninsured patients with CTCL than non-expansion states. As such, it may be prudent to investigate intrinsic socioeconomic barriers to care in Medicaid patients to improve their access to care to decrease the uninsured population and improve outcomes
Tender Erythematous and Necrotic Papules in a Young Pregnant Woman
Patient History & Physical: A pregnant 21-year-old African American female (G5P2, 34w2d) presented with one day of painful, red bumps of her upper and lower extremities. Associated symptoms included chills, malaise, headache, photophobia, phonophobia, and edematous arthralgias (left shoulder, left ankle). Personal and family history were negative for thromboembolic phenomena, autoimmune disorders, or coagulopathies. She denied intravenous drug use, new sexual partners, blood transfusions, sick contacts, or recent travel. Physical examination demonstrated sparse, irregularly-distributed, exquisitely tender erythematous to necrotic pinpoint papules and pustules of the abdomen and distal extremities. Vital signs were notable only for mild tachycardia.
Biopsies: Punch biopsies of lesions of the left ankle and left thigh revealed large neutrophilic aggregates surrounding dermal vessels featuring sludging and engorgement within the vessels themselves. This perivascular suppurative dermatitis was suspicious for infection. Tissue culture ultimately indicated presence of Neisseria gonorrhea.
Laboratory Data: Inpatient work-up revealed: elevated ESR (122 mm/hr), elevated CRP (8.8 mg/dL), negative CSF studies (VZV/CMV/EBV/HSV/cryptococcal antigen/bacterial culture), three negative peripheral blood cultures, negative syphilis serologies, normal WBC count, and normal transthoracic echocardiogram. Neisseria gonorrhea and Chlamydia trachomatis rRNA (cervical swabs) were negative 10 days prior to presentation to the hospital. However, following the biopsy and tissue culture results, urine gonococcal and chlamydial rRNA were rechecked and found to be positive.
Diagnosis: Disseminated gonococcal infection (acute arthritis-dermatitis syndrome).
Clinical Course and Treatment: Patient was treated with one week of intravenous ceftriaxone and single-dose oral azithromycin for chlamydial co-infection. At 3-week outpatient follow-up, all symptoms and cutaneous findings had resolved.https://scholarlycommons.henryford.com/merf2020caserpt/1004/thumbnail.jp
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Does it match? Analyzing self-reported online dermatology match data to Charting Outcomes in the Match
Dermatology is arguably the most competitive residency (81.6% match rate for United States allopathic seniors) with significantly more applicants than available positions. To objectify this process, the National Residency Match Program (NRMP) has produced bi-annual Charting Outcomes in Match (COM) datasets, which aggregate data from the prior two application cycles and tabulate statistics to aid applicants. In parallel, online forums provide medical trainees with vast amounts of information, including residency application insights. Reddit medical school subforum compiles annual spreadsheets of anonymous, individualized applicant data to aid future applicants. We compared this data to NRMP data to show that although the data means are similar (e.g. Step 1), the Reddit dermatology spreadsheet collects more data and the individualized nature aids applicants in a personalized way unlike the mean aggregate data in NRMP. Under univariate analysis, Alpha Omega Alpha status, overall publications, and dermatology-specific publications are associated with interview invitation rates. Although limitations of the study include small data size and reporting bias, this is the first of its kind to our knowledge to compare these two often-used tools to aid dermatology applicants. Future endeavors should expand anonymous data reporting and use the data to carry out more extensive studies to investigate factors influencing the application process
Disseminated non-segmental vitiligo with halo nevi and grey hair
HISTORY: A 20-year-old male with history of narcolepsy presented to the dermatology clinic for 5-month history of asymptomatic light spots on his trunk and graying of his hair. He initially noted acute onset of light spots slowly enlarging around moles on his chest and abdomen. Three months later, he developed slowly enlarging light spots disassociated with moles on his back and grey hairs on the back and top of his scalp. He denied new or changing moles and had no associated symptoms. Personal and family history was negative for vitiligo, autoimmune conditions, and skin cancers.
EXAMINATION: On examination, the patient has numerous, isolated hypo- to depigmented macules and patches on the trunk and back, some are surrounding symmetric, evenly pigmented, well-demarcated 3-6-mm brown-black macules. The left upper inner arm had two small de-pigmented patches and the right inner thigh had one hypopigmented patch. The scalp is noted to have diffuse hypopigmentation with associated graying of hair. Wood’s lamp examination revealed enhancement and depigmentation of these macules and patches.
COURSE AND THERAPY: The patient was started on topical betamethasone dipropionate 0.05% ointment twice daily to the hypopigmented and de-pigmented patches, and both Gingko biloba and alpha Lipoic acid capsules daily.
DISCUSSION Halo nevi (HN, also known as Sutton\u27s nevus) are thought to be a benign finding affecting 1% of the population. The diameter of the depigmented halo may range fromcentimeters, just as the size of the nevi themselves may range from a few millimeters to centimeters. Males and females are equally affected, and the mean age of onset is 15 years. Patients with Turner’s syndrome have an increased tendency and a familial variant has been reported. While the exact pathophysiology of HN is poorly understood, melanocytes are absent under histopathology, suggesting an etiologic link to vitiligo. The inflammatory composition of halo nevi is predominantly T-lymphocytes (4:1 ratio of CD8:CD4) with scattered macrophages. Overall, an immunologic mechanism seems to be the cause of melanocyte destruction in HN, although the trigger and role of lymphocytes remains uncertain. Although usually benign, HN have two important significant associations: vitiligo and melanoma-associated leukoderma. In fact, approximately 20% of individuals with HN have vitiligo. A retrospective study of 101 patients with HN-associated vitiligo demonstrated that, under multivariate analysis, Koebner phenomenon, multiple HN, and family history of vitiligo are independent factors for HN appearance predicting vitiligo. Of these, our patient had only multiple HN. However, he also had premature hair graying (PHG). Lesional leukotrichia and family history of PHG are sometimes seen in patients with non-segmental HN-associated vitiligo. However, reports of PHG occurring concurrently in a patient with acute presentation of HN-associated vitiligo are lacking. Ezzedine and colleagues remark that PHG is an inherited trait, but an immunological factor may be implicated in a subset of cases. Nevertheless, PHG is an unusual finding in a patient with HN-associated vitiligo and should prompt all practitioners to search for melanoma. Thus, patients should be referred to dermatology for a full body skin and oral examination, ophthalmology to assess for uveal melanoma, and if appropriate, OBGYN to assess for mucosal melanoma. A thorough total body skin examination of our patient did not reveal lesions concerning for melanoma. He is pending examination by Ophthalmology. Thus, his acute clinical presentation of HN, non-segmental vitiligo, and PHG represents a rare triad.https://scholarlycommons.henryford.com/merf2020caserpt/1070/thumbnail.jp
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Corrigendum: Systemic contact dermatitis related to alcoholic beverage consumption
The original article was published on September 15, 2019 and corrected on November 15, 2019.The revised version of the article adds a missing author. This change appears in the revised online PDF copy of this article
Trimethoprim sulfamethoxazole drug resistance with co resistance to extended spectrum β-lactam antibiotics among bacterial isolates from HIV patients
Immune reconstitution inflammatory syndrome in association with HIV/AIDS and tuberculosis: Views over hidden possibilities
Gut immune components are severely compromised among persons with AIDS, which allows increased translocation of bacterial lipopolysaccharides (LPS) into the systemic circulation. These microbial LPS are reportedly increased in chronically HIV-infected individuals and findings have correlated convincingly with measures of immune activation. Immune reconstitution inflammatory syndrome (IRIS) is an adverse consequence of the restoration of pathogen-specific immune responses in a subset of HIV-infected subjects with underlying latent infections during the initial months of highly active antiretroviral treatment (HAART). Whether IRIS is the result of a response to a high antigen burden, an excessive response by the recovering immune system, exacerbated production of pro-inflammatory cytokines or a lack of immune regulation due to inability to produce regulatory cytokines remains to be determined. We theorize that those who develop IRIS have a high burden of proinflammatory cytokines produced also in response to systemic bacterial LPS that nonspecifically act on latent mycobacterial antigens. We also hypothesize that subjects that do not develop IRIS could have developed either tolerance (anergy) to persistent LPS/tubercle antigens or could have normal FOXP3+ gene and that those with defective FOXP3+ gene or those with enormous plasma LPS could be vulnerable to IRIS. The measure of microbial LPS, anti-LPS antibodies and nonspecific plasma cytokines in subjects on HAART shall predict the role of these components in IRIS
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