Electronic analog to digital converters (ADCs) are running up against the well-known bit depth versus bandwidth trade off. Towards this end, radio frequency (RF) photonic-enhanced ADCs have been the subject of interest for some time. Optical frequency comb technology has been used as a workhorse underlying many of these architectures.
View Article and Find Full Text PDFWe use the drift-diffusion equations to calculate the responsivity of a modified uni-traveling carrier (MUTC) photodetector (PD) with a frequency comb input that is generated by a series of short optical pulses. We first use experimental results for the responsivity of the MUTC PD to obtain an empirical model of bleaching in pulsed mode. We incorporate our empirical bleaching model into a drift-diffusion model to calculate the impact of nonlinearity in an MUTC PD on RF-modulated electro-optic frequency combs.
View Article and Find Full Text PDFMucormycosis is a fatal opportunistic fungal infection. Rarely it can occur in immunocompetent patients. Here, we present a case of colonic mucormycosis in immunocompetent patients.
View Article and Find Full Text PDFWe describe a procedure to calculate the impulse response and phase noise of high-current photodetectors using the drift-diffusion equations while avoiding computationally expensive Monte Carlo simulations. We apply this procedure to a modified uni-traveling-carrier (MUTC) photodetector. In our approach, we first use the full drift-diffusion equations to calculate the steady-state photodetector parameters.
View Article and Find Full Text PDFMediastinal pancreatic pseudocyst (MPP) is a rare, but known, complication of both acute and chronic pancreatitis. Most pseudocysts are associated with alcoholic pancreatitis. Recent advances in endoscopic techniques have shown promising results, with reduced chances of infection and recurrence than with percutaneous drainage, but limited availability restricts widespread use.
View Article and Find Full Text PDFWe introduce a novel technique for broadband RF disambiguation which exploits a known jitter imparted onto the sampling rate of an optical pulse source in a subsampled analog optical link. Coarse disambiguation to bandwidths equal to the sample rate is achieved using pure tones as example waveforms by comparing the amplitude of the jitter-induced sidebands relative to the measured signal within the fundamental Nyquist band (frep/2). This sampling technique allows for ultra-wideband signal recovery with a single measurement.
View Article and Find Full Text PDFWe provide the first experimental demonstration of the impact of bias-frequency on second-order distortion in sampled analog optical links. We show proper selection of bias frequency yields >48 dB improvement in second-order distortion performance. In addition, we demonstrate that measurement of the average frequency of the optical comb may be used to determine the optimum bias frequency - without the need for involved radio-frequency distortion measurements.
View Article and Find Full Text PDFClin J Gastroenterol
August 2013
Histoplasmosis is an endemic infection of the Ohio and Mississippi River valleys. Clinical presentation of infection in immunocompetent hosts ranges from asymptomatic to minor flu-like symptoms; however, disseminated infection can occur in immunocompromised patients. Esophageal involvement in the form of dysphagia secondary to mediastinal histoplasmosis is rarely reported in the literature.
View Article and Find Full Text PDFA new technique to cancel photodiode-induced even-order distortion in microwave photonic links is demonstrated. A single Mach-Zehnder modulator, biased slightly away from the quadrature point, is shown to suppress photodiode second-order intermodulation distortion in excess of 40 dB without affecting the fundamental power. The technique is theoretically described with supporting experimental results.
View Article and Find Full Text PDFColorectal cancer is one of the leading causes of cancer related deaths in western world. While most common site for metastasis for colon cancer is liver, lung, and the peritoneum, metastasis to various other organs such as brain, bones and thyroid has been reported. Metastatic lesions to the small bowel are more common than primary lesions and most common primary neoplasms that metastasize to the duodenum are lung cancer, renal cell carcinoma, breast cancer, and malignant melanoma.
View Article and Find Full Text PDFIn this proof-of-concept study, high-resolution melt curve (HRMC) analysis was investigated as a postquantification screening tool to discriminate human CSF1PO and THO1 genotypes amplified with mini-STR primers in the presence of SYBR Green or LCGreen Plus dyes. A total of 12 CSF1PO and 11 HUMTHO1 genotypes were analyzed on the LightScanner HR96 and LS-32 systems and were correctly differentiated based upon their respective melt profiles. Short STR amplicon melt curves were affected by repeat number, and single-source and mixed DNA samples were additionally differentiated by the formation of heteroduplexes.
View Article and Find Full Text PDFDespite efforts to reduce malaria morbidity and mortality, drug-resistant parasites continue to evade control strategies. Recently, emphasis has shifted away from control and toward regional elimination and global eradication of malaria. Such a campaign requires tools to monitor genetic changes in the parasite that could compromise the effectiveness of antimalarial drugs and undermine eradication programs.
View Article and Find Full Text PDFBACKGROUND: Total cholesterol was among the earliest identified risk factors for coronary heart disease (CHD). We sought to identify genetic variants in six genes associated with lipid metabolism and estimate their respective contribution to risk for CHD. METHODS: For 6 lipid-associated genes (LCAT, CETP, LIPC, LPL, SCARB1, and ApoF) we scanned exons, 5' and 3' untranslated regions, and donor and acceptor splice sites for variants using Hi-Res Melting® curve analysis (HRMCA) with confirmation by cycle sequencing.
View Article and Find Full Text PDFAnn Allergy Asthma Immunol
January 2011
Background: asthma and obesity continue to have a significant effect on public health. It is widely accepted that obesity may be an independent risk factor for asthma and affect asthma severity and quality of life (QOL).
Objective: to examine the relationship between body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]) and asthma severity, spirometry findings, health care utilization (HCU), and QOL.
Objective: The aim of this study is to discover common variants in 6 lipid metabolic genes and construct and validate a genetic risk score (GRS) based on the joint effects of genetic variants in multiple genes from lipid and other pathobiologic pathways.
Background: Explaining the genetic basis of coronary artery disease (CAD) is incomplete. Discovery and aggregation of genetic variants from multiple pathways may advance this objective.
Warfarin anticoagulation is complicated by the highly variable inter-individual response. Approximately 50% of the dose variability arises from clinical factors and variants in two genes, CYP2C9 (*2 and *3 variants) and VKORC1 -1173 C > T. We tested variants in five additional genes (EPHX1, PROC, APOE, CYP4F2, CALU and a new variant in VKORC1 in an attempt to further reduce the variability in predicted stable warfarin dose.
View Article and Find Full Text PDFWarfarin anticoagulation therapy is complicated by its narrow therapeutic index and by wide inter-individual differences in dosing requirements arising, in part, from genetic factors. The present report describes the development, validation and feasibility testing of a rapid genotyping assay that concurrently detects the CYP2C9*2 and *3 variants along with the VKORC1 C1173T polymorphism. The study employed melting curve analysis using labeled probes and compared two detection instruments (the HR-1 and the R.
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