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A novel tellurium (Te) containing fluorophore, 1 and its nickel (2) and copper (3) containing metal organic complex (MOC) have been synthesized to exploit their structural and optical properties and to deploy these molecules as fluorescent probes for the selective and sensitive detection of picric acid (PA) over other commonly available nitro‐explosives. Furthermore, density functional theory (DFT) and single crystal X‐ray diffraction (SCXRD) techniques revealed the inclusion of "soft" Tellurium (Te) and "hard" Nitrogen (N), Oxygen (O) atoms in the molecular frameworks. Owing to the presence of electron rich "N" and "O" atoms along with "Te" in the molecular framework, 1 could efficiently and selectively sense PA with more than 80 % fluorescence quenching efficiency in organic medium and having detection limit of 4.60 μM. The selective detection of PA compared to other nitro‐explosives follows a multi‐mechanism based "turn‐off" sensing which includes photo‐induced electron transfer (PET), electrostatic (π‐π stacking and π‐anion/cation) interaction, intermolecular hydrogen bonding and inner filter effect (IFE). The test strip study also establishes the sensitivity of 1 for detection of PA. [ABSTRACT FROM AUTHOR]

The research article reports the synthesis and structural study of the optimized geometry of selenium (Se) bearing 24- and 28- membered macrocyclic Schiff bases, LaH2, LbH2 and their reactions with zinc metal ion. The reactions of the macrocyclic Schiff bases with ZnCl2 in 1:2 molar ratios result in the formation of bimetallic Zn(II) complexes having molecular composition [Se{(CH2)2N = CPh(4-CH3-C6H2O) PhC = O}2 · Zn2Cl2], (1) and [Se{(CH2)3N = CPh(4-CH3-C6H2O)PhC = O}2 · Zn2Cl2], (2). Moreover, as confirmed by various physico-chemical techniques such as elemental analysis, UV–Vis, FTIR,1H NMR, and mass spectrometry, the proligands underwent partial hydrolytic cleavage at one of the C = N positions and behave like hexadentate (N2O4) ligands binding to two Zn(II) ions via bridging through the Ophenolic atoms, which results in a square pyramidal geometry around Zn(II) with the chlorine atom occupying axial positions. Further, following density functional study, the stable optimized configuration of the Schiff bases LaH2 and LbH2 is found to adopt bowl shape geometry. Conversely, in molecular docking studies, the synthesized complex 1 exhibits a significantly stronger binding affinity (−8.7 kcal/mol) to the spike protein of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) as compared to the common coronavirus disease 2019 (COVID-19) treatment drugs such as chloroquine, hydroxychloroquine, and remdesivir with activity percentage showing more than 20% overall effectiveness than remdesivir and thus indicating its potential for COVID-19 therapeutics. [ABSTRACT FROM AUTHOR]

Surgical resection of pancreatic cancer represents the only chance of cure and long-term survival in this common disease. Unfortunately, determination of a cancer-free margin at surgery is based on one or two tiny frozen section biopsies, which is far from ideal. Not surprisingly, cancer is usually left behind and is responsible for metastatic disease. We demonstrate a method of receptor-targeted imaging using peptide ligands, lipid microbubbles, and multiphoton microscopy that could lead to a fast and accurate way of examining the entire cut surface during surgery. Using a plectin-targeted microbubble, we performed a blinded in-vitro study to demonstrate avid binding of targeted microbubbles to pancreatic cancer cells but not noncancerous cell lines. Further work should lead to a much-needed point-of-care diagnostic test for determining clean margins in oncologic surgery. [ABSTRACT FROM AUTHOR]

We have developed a compact dual-view endoscopic probe without field obscuration to address the need of simultaneously observing forward and backward fields of view (FOVs) in the colon. The objective is compact with the forward-view and rear-view optical paths sharing the same optical elements. The compact objective is new in that no FOV is blocked. The illumination for forward-view imaging is provided by the cylindrical light guide and backward illumination is achieved with a reflector. We have designed, prototyped, and tested the endoscope by comparing it to a standard clinical colonoscope. We will discuss the system concept, objective design, fabrication of the freeform lens, and test results. [ABSTRACT FROM AUTHOR]

This brief presents a continuous active phase shifter for millimeter-wave phased-array transceivers. Having an all-pass network frequency response, the proposed phase shifter provides continuous insertion phase control and nearly constant insertion loss regardless of the insertion phase variation. A complete analysis for the phase shifter is provided along with circuit measurement results. The phase shifter is fabricated in a 0.13- \mu\m commercial CMOS technology. A phase tuning range larger than 90^\circ and -7 dB of insertion loss are achieved for the phase shifter. [ABSTRACT FROM AUTHOR]

Managing the switching-noise in mixed-signal systems fabricated on a single chip is becoming increasingly challenging. This needs substantial overheads in both area and power. Existing logic families that minimize switching-noise generation, such as current-steering logic (CSL), current-balanced logic (CBL) etc. require considerably more power than traditional CMOS implementations. We present a new logic family called the current-steering CMOS (CS-CMOS) obtained by a simple modification keeping the core CMOS structure in tact to preserve its most attractive features. This family not only reduces the switching noise by a factor of ten but also delivers five times higher speed than CSL and CBL for the same power consumption. Experimental results comparing 15-stage ring-oscillators configured in the CSL and CS-CMOS families and fabricated in a 0.18 \mum process show that their energy-delay-products are 6.5 fJ*ns and 1.52 fJ*ns respectively. The usefulness of this new logic family is further demonstrated by synthesizing a cell library of CS-CMOS gates and by using it to simulate benchmark circuits, a decimation filter and a frequency divider. [ABSTRACT FROM AUTHOR]

Power-supply noise is a significant problem in mixed-signal systems on a chip. This is due to the impulse like current drawn by digital CMOS gates which couples to the sensitive analog circuits through supplies and the substrate. A noise-localization technique using on-chip active inductors is proposed. This would make the noise current generated by the digital gates to remain local in the region of the digital gates. This active inductor is designed to have minimum overhead in terms of voltage headroom and area. Simulations of benchmark digital gates, frequency dividers, and buffers demonstrate about 30-dB reduction of noise with this technique. Measured results from a test-chip carrying this design further demonstrate the functionality of this inductor. [ABSTRACT FROM PUBLISHER]

OBJECTIVES:Endoscopist fatigue potentially impacts colonoscopy. Fatigue is difficult to quantitate, but polyp detection rates between non-fatigued and fatigued time periods could represent a surrogate marker. We assessed whether timing variables impacted polyp detection rates at a busy tertiary care endoscopy suite.METHODS:Consecutive patients undergoing colonoscopy were retrospectively identified. Indications, clinical demographics, pre-procedural, and procedural variables were extracted from chart review; colonoscopy findings were determined from the procedure reports. Three separate timing variables were assessed as surrogate markers for endoscopist fatigue: morning vs. afternoon procedures, start times throughout the day, and queue position, a unique variable that takes into account the number of procedures performed before the colonoscopy of interest. Univariate and multivariate analyses were performed to determine whether timing variables and other clinical, pre-procedural, and procedural variables predicted polyp detection.RESULTS:During the 4-month study period, 1,083 outpatient colonoscopy procedures (57.5±0.5 years, 59.5% female) were identified, performed by 28 endoscopists (mean 38.7 procedures/endoscopist), with a mean polyp detection rate of 0.851/colonoscopy. At least, one adenoma was detected in 297 procedures (27.4%). A 12.4% reduction in mean detected polyps was detected between morning and afternoon procedures (0.90±0.06 vs. 0.76±0.06, P=0.15). Using start time on a continuous scale, however, each elapsed hour in the day was associated with a 4.6% reduction in polyp detection (P=0.005). When queue position was assessed, a 5.4% reduction in polyp detection was noted with each increase in queue position (P=0.016). These results remained significant when controlled for each individual endoscopist.CONCLUSIONS:Polyp detection rates decline as time passes during an endoscopist's schedule, potentially from endoscopist fatigue. Queue position may be a novel surrogate measure for operator fatigue. [ABSTRACT FROM AUTHOR]

The determination of a cancer free margin I organ is a difficult and time consuming process, with an unmet need for rapid determination of tumor margin at surgery. In this paper, we report the design, fabrication, and testing of a novel miniaturized optical sensor probe with “side-viewing” capability. Its unprecedented small size, unique “side-viewing” capability, and high optical transmission efficiency enable the agile maneuvering and efficient data collection even in the narrow cavities inside the human body. The sensor probe consists of four micromachined substrates with optical fibers for oblique light incidence and collection of spatially resolved diffuse reflectance from the contacted tissues. The optical sensor probe has been used to conduct the oblique incidence diffuse reflectance spectroscopy (OIDRS) on a human pancreatic specimen. Based on the measurement results, the margin of the malignant tumor has been successfully determined optically, which matches well with the histological results. [ABSTRACT FROM PUBLISHER]

A novel technique for mitigation of self interference in a highly integrated SoC transmitter is presented. The interference originates from the internal power amplifier (i.e., aggressor) that leads to injection pulling of the local RF oscillator (i.e., victim). The characteristic of injection pulling was found to be dependent on the AM signal applied to the power amplifier. A hypothesis describing the mechanism of injection pulling of the local oscillator is presented. A mathematical model is developed to study the characteristics of this self interference verified then by measurements. Based on this model, a digitally controlled delay circuit is proposed and implemented in a digital polar GSM/EDGE transmitter that makes the system less susceptible to injection pulling through automatic phase adjustment between the aggressor and the victim. Compliant EVM and spectrum performance is measured on SoC fabricated in 65-nm CMOS showing the effectiveness of the proposed solution. [ABSTRACT FROM AUTHOR]

We present a new analytical direct parameter-extraction methodology for obtaining the small-signal equivalent circuit of HBTs. It is applied to cryogenically operated SiGe HBTs as a means to allow circuit design of SiGe HBT low-noise amplifiers for cooled radio astronomy applications. We split the transistor into an intrinsic transistor (IT) piece modeled as a H-topology, and the quasi-intrinsic transistor (QIT), obtained from the IT after that the base resistance (Rb) has been removed. The relations between Z-Y-parameters of the IT and QIT are then established, allowing us to propose a new methodology for determining Rb. The present extraction method differs from previous studies in that each of the model elements are obtained from exact equations that do not require any approximations, numerical optimization, or post-processing. The validity of this new extraction methodology is demonstrated by applying it to third-generation SiGe HBTs operating at liquid-nitrogen temperature (77 K) across the frequency range of 2-22 GHz. [ABSTRACT FROM AUTHOR]

We present a comprehensive investigation of the cryogenic performance of third-generation silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) technology. Measurements of the current-voltage (dc), small-signal ac, and broad-band noise characteristics of a 200-GHz SiGe HBT were made at 85 K, 120 K, 150 K, 200 K, and 300 K. These devices show excellent behavior down to 85 K, maintaining reasonable dc ideality, with a peak current gain of 3800, a peak cut-off frequency (fT) of 260 GHz, a peak fmax of 310 GHz, and a minimum noise figure (NFmin) of approximately 0.30 dB at a frequency of 14 GHz, in all cases representing significant improvements over their corresponding values at 300 K. These results demonstrate that aggressively scaled SiGe HBTs are inherently well suited for cryogenic electronics applications requiring extreme levels of transistor performance. [ABSTRACT FROM AUTHOR]

There is a significant need for noninvasive methods of evaluating dysplastic and neoplastic lesions in the luminal gastrointestinal tract. We have optimized an approach based on autofluorescence to study dysplastic adenomatous polyps in Apc(min/+) mice. We made recordings from both normal intestinal mucosa and from polyps using a xenon lamp-based fiberoptic device. Seventy-eight polyps in 11 mice revealed an increase in mean autofluorescence intensity ratios of 1.29 +/- 0.04 (72 small intestinal polyps; P < 0.0001) and 1.28 +/- 0.05 (6 colon polyps; P = 0.0016). Serial measurements of autofluorescence discriminated polyps from normal mucosa with a sensitivity, verified histologically, of 95%. To understand the chemical basis for increased autofluorescence, we examined the tryptophan content of intestinal polyps and the adjacent normal mucosa in a small subset of animals. The findings revealed an increased concentration of tryptophan in polyps (990 +/- 240 ng/mg) compared to normal mucosa (720 +/- 150 ng/mg; P = 0.03). In conclusion, these findings suggest that autofluorescence intensity increases in the setting of intestinal neoplasia and can be used to detect adenomas in the mouse intestine in real time. [ABSTRACT FROM AUTHOR]

In this paper, we present a thermal analysis of AlGaN-GaN power heterojunction field-effect transistors (HFETs). We report the dc, small-signal, large-signal, and noise performances of AlGaN-GaN HFETs at high temperatures. The temperature coefficients measured for GaN HFETs are lower than that of GaAs pseudomorphic high electron-mobility transistors, confirming the potential of GaN for high-temperature applications. In addition, the impact of thermal effects on the device dc, small-signal, and large-signal characteristics is quantified using a set of pulsed and continuous wave measurement setups. Finally, a thermal model of a GaN field-effect transistor is implemented to determine design rules to optimize the heat flow and overcome self-heating. Arguments from a device, circuit, and packaging perspective are presented. Index Terms—AlGaN-GaN heterojunction field-effect transistors (HFETs); high temperature; microwave; thermal effect; thermal modeling. [ABSTRACT FROM AUTHOR]

A new empirical InGaP/GaAs heterojunction bipolar transistor (HBT) large-signal model including self-heating effects is presented. The model accounts for the inherent temperature dependence of the device characteristics due to ambient-temperature variation as well as self-heating. The model is accompanied by a simple extraction process, which requires only dc current-voltage (I-V) and multibias-point small-signal S-parameter measurements. All the current-source model parameters, including the self-heating parameters, are directly extracted from measured forward I-V data at different ambient temperatures. The distributed base-collector capacitance and base resistance are extracted from measured S-parameters using a new technique. The extraction procedure is fast, accurate, and inherently minimizes the average squared-error between measured and modeled data, thereby eliminating the need for further optimization following parameter extraction. This modeling methodology is successfully applied to predict the dc, small-signal S-parameter, and output fundamental and harmonic power characteristics of an InGaP/GaAs HBT, over a wide range of temperatures. [ABSTRACT FROM AUTHOR]

Oxygen-derived free radicals mediate tissue damage in acute and chronic pancreatitis. Low levels of natural antioxidants in pancreatitis indicate their increased utilization as scavengers of free radicals. Combination therapy with selenium, β-carotene, methionine, and vitamins C and E are known to improve symptoms of chronic and recurrent pancreatitis. This, however, requires many tablets to be taken daily, which is impractical and may reduce compliance. Three patients with chronic pancreatitis (two with a history of alcohol excess and one idiopathic) are reported. Treatment with narcotic analgesics and pancreatic enzyme supplements had failed to control their symptoms. The addition of a commercially available IH636 grape seed proanthocyanidin extract (commercially known as ActiVin) to their treatment regimen led to a reduction in the frequency and intensity of abdominal pain as well as resolution of vomiting in 1 patient.Copyright © 2001 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Duodenal somatostatinoma is a rare cause of upper gastrointestinal bleeding. We report the case of a 55-yr-old woman who presented with upper gastrointestinal hemorrhage due to a duodenal somatostatinoma. We discuss the characteristics of these tumors, and review the literature on diagnostic workup and management. [ABSTRACT FROM AUTHOR]

Patients with Crohn's disease are at increased risk for developing adenocarcinoma of the small bowel and colon. Although several cases of gastric malignancy have been reported in patients with Crohn's disease, the association remains controversial, particularly because most patients have not had gastric Crohn's involvement. We report a patient with long-standing Crohn's disease, with gastric involvement, who developed adenocarcinoma of the gastric outlet. We discuss the association and include a review of the literature. [ABSTRACT FROM AUTHOR]

Paracentesis is an important and commonly performed procedure in patients with ascites. It is a safe procedure when carried out in the midline below the umbilicus, with a complication rate of less than 1%. We report an instance in which a large midline varix was entered during paracentesis. The utility of different imaging techniques in detecting such anomalies in the portal hypertensive patient with portal hypertension and ascites is discussed. The approach and management of this complication are outlined. [ABSTRACT FROM AUTHOR]

The article discusses a case study of a 71-year-old man who underwent circumferential radiofrequency ablation (RFA) for the treatment of Barett's esophagus. The use of a self-expanding metal stent (SEMS) for an esophageal stricture following RFA is highlighted. Endoscopic images of the esophageal stricture are presented.

Cancer is a cellular process. The emission spectrum of tryptophan, which produces the strongest fluorescence in cells, was investigated in cells and tissues of a normal and malignant esophagus. Estimated fluorescence intensity per cell was about three times greater in cancerous cells than in normal cells. The fluorescence was also greater in cancerous tissue but the difference was attenuated, probably because of absorption and scattering. Cellular fluorescence from tryptophan may be useful for the detection of cancer in esophageal cells and tissues. [ABSTRACT FROM PUBLISHER]