A novel non-linear recursive filter design for extracting high rate pulse features in nuclear medicine imaging and spectroscopy

Applications in imaging and spectroscopy rely on pulse processing methods for appropriate data generation. Often, the particular method utilized does not highly impact data quality, whereas in some scenarios, such as in the presence of high count rates or high frequency pulses, this issue merits extra consideration. In the present study, a new approach for pulse processing in nuclear medicine imaging and spectroscopy is introduced and evaluated. The new non-linear recursive filter (NLRF) performs nonlinear processing of the input signal and extracts the main pulse characteristics, having the powerful ability to recover pulses that would ordinarily result in pulse pile-up. The filter design defines sampling frequencies lower than the Nyquist frequency.In the literature, for systems involving NaI(Tl) detectors and photomultiplier tubes (PMTs), with a signal bandwidth considered as 15 MHz, the sampling frequency should be at least 30 MHz (the Nyquist rate), whereas in the present work, a sampling rate of 3.3 MHz was shown to yield very promising results. This was obtained by exploiting the known shape feature instead of utilizing a general sampling algorithm. The simulation and experimental results show that the proposed filter enhances count rates in spectroscopy. With this filter, the system behaves almost identically as a general pulse detection system with a dead time considerably reduced to the new sampling time (300 ns). Furthermore, because of its unique feature for determining exact event times, the method could prove very useful in time-of-flight PET imaging.     

A 4-year study of the epidemiology of Vibrio cholerae in four rural areas of Bangladesh

How Vibrio cholerae spreads around the world and what determines its seasonal peaks in endemic areas are not known. These features of cholera have been hypothesized to be primarily the result of environmental factors associated with aquatic habitats that can now be identified. Since 1997, fortnightly surveillance in 4 widely separated geographic locations in Bangladesh has been performed to identify patients with cholera and to collect environmental data. A total of 5670 patients (53% <5 years of age) have been studied; 14.3% had cholera (10.4% due to V. cholerae O1 El Tor, 3.8% due to O139). Both serogroups were found in all locations; outbreaks were seasonal and often occurred simultaneously. Water-use patterns showed that bathing and washing clothes in tube-well water was significantly protective in two of the sites. These data will be correlated with environmental factors, to develop a model for prediction of cholera outbreaks.     

Acute vestibular neuritis: A rare complication after the adenoviral vector-based COVID-19 vaccine

Journal of NeuroVirology - Vestibular neuritis was first reported in 1952 by Dix and Hallpike, and 30% of patients reporting a flu-like symptom before acquiring the disorder. The most common causes...     

Clinical value of ambulatory blood pressure: Is it time to recommend for all patients with hypertension?

Hypertension is a very common disease, and office measurements of blood pressure are frequently inaccurate. Ambulatory Blood Pressure Monitoring (ABPM) offers a more accurate diagnosis, more detailed readings of average blood pressures, better blood pressure measurement during sleep, fewer false positives by detecting more white-coat hypertension, and fewer false negatives by detecting more masked hypertension. ABPM offers better management of clinical outcomes. For example, based on more accurate measurements of blood pressure variability, ABPM demonstrates that taking antihypertensive medication at night leads to better controlled nocturnal blood pressure, which translates into less end organ damage and fewer clinical complications of hypertension. For these reasons, albeit some shortcomings which were discussed, ABPM should be considered as a first-line tool for diagnosing and managing hypertension.     

Proposal for the existence of a nasogastric reflex in humans, as a potential cause of upper gastrointestinal symptoms

The nose is a gateway of air from the environment to the body and with its rich innervation from the olfactory and trigeminal nerves plays a critical role as a sensor in both human beings and primitive animals. Irritation of the nasal or paranasal mucosa may initiate a severe bradycardia, apnea, and vasoconstriction and increase the pulmonary airflow resistance. However, the interaction between nasal mucosa and the upper gastrointestinal tract is more often than not neglected in the clinical literature. We propose that a nasogastric reflex might exist with its afferent and efferent loops being the trigeminal and vagus nerves, respectively. The central connection of these loops is located at the pontomedullary level. The sensory inputs from the nasal mucosa to the general somatic afferent component of the brainstem including the pontine and medullary trigeminal nucleuses may induce the neighboring nucleus of the solitary tract and dorsal motor nucleus of the vagus. This initiates, via the efferent fibers of the vagus nerve, the manifestations of the vagal stimulation. The presence of a nasogastric reflex may warrant considerations as diseases of nose and paranasal sinuses may be the cause upper gastrointestinal symptmatology.     

Triad of bilateral duplicated permanent teeth, persistent open apex, and tooth malformation: a case report

AIM: The aim of this article is to report a case of bilateral multiple impacted supernumerary teeth. A discussion of possible mechanisms of development is also presented along with a concise review of the literature. BACKGROUND: Supernumerary teeth occur in the context of various scenarios in the primary and the permanent dentition. Multiple supernumerary teeth are a rare finding especially in the absence of associated syndrome or disease. REPORT: A case of bilateral multiple impacted supernumerary teeth localized to the mandibular premolar region is reported. Some of the supernumerary teeth as well as the erupted premolars had persistent open apices. Coronal malformation of the right maxillary first premolar was another interesting finding. There was an absence of any concomitant disease. SUMMARY: The aforementioned combination of findings has not been reported previously. The anatomical, geometrical, and spatial relationships of supernumerary teeth with their erupted equivalents may shed light on some controversial aspects of the etiology.     

Synthesis and biological evaluation of pyrrole-2-carboxamide derivatives: oroidin analogues

The reaction of pyrrole or dibromopyrrole-2-trichloroacetone with various amines results in the series of novel pyrrole-2-carboxamide bearing aromatic heterocycle or aryl or alkyl groups. Synthesized molecules were evaluated for their in vitro antibacterial activities. Most of the compounds exhibited potent activity against both Gram-positive and negative pathogens.