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Transmission models for infectious diseases are typically formulated in terms of dynamics between individuals or groups with processes such as disease progression or recovery for each individual captured phenomenologically, without reference to underlying biological processes. Furthermore, the construction of these models is often monolithic: they do not allow one to readily modify the processes involved or include the new ones, or to combine models at different scales. We show how to construct a simple model of immune response to a respiratory virus and a model of transmission using an easily modifiable set of rules allowing further refining and merging the two models together. The immune response model reproduces the expected response curve of PCR testing for COVID-19 and implies a long-tailed distribution of infectiousness reflective of individual heterogeneity. This immune response model, when combined with a transmission model, reproduces the previously reported shift in the population distribution of viral loads along an epidemic trajectory. This article is part of the theme issue 'Technical challenges of modelling real-life epidemics and examples of overcoming these'. [ABSTRACT FROM AUTHOR]

Background. The rapid spread of COVID-19 worldwide has imposed the need to identify a test that quickly recognizes affected subjects, both symptomatic and asymptomatic. The most reliable option has been proven to be the RT-PCR, which allows to detect virus RNA on a specimen from a high viral load site, such as nasopharynx. Nasopharyngeal sample collection is possible by means of a nasopharyngeal swab (NPS) and is a practical and relatively non-invasive technique, but rather bothersome for the recipient. Aim. The aim of the present study is to evaluate the discomfort evoked during NPS. Materials and Methods. We surveyed 429 patients receiving NPS before hospitalization or other procedures non related to COVID-19. For each one we noted the discomfort level felt during the swab using a 11-point numeric rating scale (NRS) for pain and the total time needed for the procedure to be taken. Sex, age, smoking status and positive history of previous swab have been taken into account. Results. We found that, among the variables, sex had a statistically significant impact on the perceived discomfort of nasal swab, with females experiencing slightly more discomfort. Conclusions. NPS is largely a none-to-minimum discomfort inducing procedure. The differences in perceived discomfort could be explained based on anatomical features, and should remark the need for a tailored and anatomy-oriented approach in each patient. [ABSTRACT FROM AUTHOR]

The minority carrier lifetime (τMC) and equilibrium electron concentration (i.e., the doping level, n0) are both important values that directly determine diffusion current in infrared photodetectors utilizing n-type absorbing regions. Here, time-resolved microwave reflectance measurements are used to non-destructively measure both of these values in mid-wave infrared InAs/InAs1-xSbx type-II superlattices with varying n-type doping levels between 2 × 1014 cm-3 and 2 × 1016 cm-3. The measured data are analyzed using carrier recombination theory to determine the doping level ranges where Shockley-Read-Hall (SRH), radiative, and Auger recombination limit sMC. The optimal doping level, which minimizes dark current, is experimentally determined and corresponds to the electron density at which sMC switches from SRH limited to Auger limited behavior. A comparison of two InAs/InAs1-xSbx photodetectors of different equilibrium electron densities demonstrates a decrease in dark current for a doping level near the optimal n0τMC product. [ABSTRACT FROM AUTHOR]

Optical and electrical properties of nBn photodetectors using InAs/AlAs/AlSb/AlAs/InAs/ InAs0.61Sb0.39W-structure superlattice (W-SL) absorbers are reported. Minority carrier lifetimes of 500 ± 50 ns and 400 ± 30 ns, and Auger coefficients of 2.1 × 10-26 cm6/s and 1.6 × 10-25 cm6/s, for samples with bandgap energies of 5.3 lm (W-SL A) and 7.5 lm (W-SL B) are reported at 100 K, respectively. Shockley-Read-Hall defect states are identified at 65 meV and 45 meV above the W-SL valence band edges for W-SLs A and B, respectively. Dark currents are also reported and compared with diffusion currents calculated using the carrier lifetime data, suggesting low vertical heavy hole diffusivity. [ABSTRACT FROM AUTHOR]

Carrier lifetime and dark current measurements are reported for a mid-wavelength infrared InAs0.91Sb0.09 alloy nBn photodetector. Minority carrier lifetimes are measured using a non-contact time-resolved microwave technique on unprocessed portions of the nBn wafer and the Auger recombination Bloch function parameter is determined to be |F1F2|= 0:292. The measured lifetimes are also used to calculate the expected diffusion dark current of the nBn devices and are compared with the experimental dark current measured in processed photodetector pixels from the same wafer. Excellent agreement is found between the two, highlighting the important relationship between lifetimes and diffusion currents in nBn photodetectors. [ABSTRACT FROM AUTHOR]

Introduction and Purpose. Diffusion weighted imaging (DWI) has been proven to be valuable in the diagnosis of middle ear cholesteatoma. The aims of our study were to evaluate the advantage of multi-shot turbo spin echo (MSh TSE) DWI compared to single-shot echo-planar (SSh EPI) DWI for the diagnosis of cholesteatoma. Material and Methods. Thirty-two patients with clinical suspicion of unilateral cholesteatoma underwent preoperative MRI (1.5T) with SSh EPI and MSh TSE. Images were separately analyzed by 4 readers with different expertise to confirm the presence of cholesteatoma. Sensitivity, specificity, diagnostic accuracy, and positive (PPV) and negative predictive values (NPV) were assessed for each observer and interrater agreement was assessed using kappa statistics. Diagnosis was obtained at surgery. Results. Overall MSh TSE showed higher diagnostic accuracy and lower negative predictive value (NPV) compared to conventional SSh EPI. Interreader agreement between the observers revealed the superiority of MSh TSE compared to SSh EPI. Interrater agreement among all the four observers was higher by using MSh TSE compared to SSh EPI. Conclusion. Our findings suggest that MSh TSE DWI has higher sensitivity for detection of cholesteatoma and lower probability of misdiagnosis. MSh TSE DWI is useful in guiding less experienced observers to the diagnosis. [ABSTRACT FROM AUTHOR]

Concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) were found in tissue of marine organisms such as Mediterranean mussel, Norway lobster, red mullet, common cuttle-fish, European flying squid, European anchovy, European pilchard and Atlantic mackerel, coming from two sites along the Abruzzo coast of the Adriatic Sea. Species were selected due to their habitat, trophic level, feeding behaviour and their use in the Italian diet. Mussels, filter feeder and sedentary organisms, were used in order to test water pollution whereas Norway lobster and red mullet (benthic fish) were used in order to test sediment pollution. The concentration of ∑PCBs exceeded that of ∑OCs in the samples analysed. The highest concentrations of ∑PCBs (1415 ng/g lipid weight) and ∑OCs (507 ng/g lipid weight) were found in pilchard while the lowest concentrations of the same pollutants were found in cephalopods. Our results have shown that species such as anchovy, pilchard and mackerel, were the most polluted due to their location at the last level of the trophic chain. All samples contained different concentrations of PCBs and among these, congeners 153 and 138 were the most representative. Among the OCs, except for the cuttle-fish, the highest concentrations were found for p,p′-DDE and p,p′-DDD that are metabolite of DDT. The prevailing DDE presence, compared to DDT (high DDE/DDT ratio), suggested that the biotransformation rate of pollutants was very efficacious in fish and above all in crustaceans. Results have also been interpreted in terms of geographical distribution and organisms'' biological cycle. None of the samples analysed exceeded the tolerance limits established by the OCs Italian legislation. [Copyright &y& Elsevier]

The objective of the present investigation was to study the protection afforded by a single administration of pralidoxime against the muscle necrosis induced by the organophosphate compound metamidophos at different times after intoxication. The fiber necrosis of the diaphragm muscle was quantified by a morphometric technique, comparing the area fraction occupied by necrotic muscle fibers in animals that received pralidoxime at different times after intoxication, i.e., 0, 1, 3, 6, and 12h. Pralidoxime administration protected metamidophos-induced muscle necrosis in all groups studied except for the 12-h group. The earlier the administration of pralidoxime the greater the protection against muscle necrosis. This protection was not accompanied by complete reactivation of plasma cholinesterase activity. Results support the current opinion that pralidoxime should be administered as soon as possible after organophosphate intoxication, because in addition to reversing the muscarinic effects, early administration of pralidoxime also prevents muscle necrosis—which could impair muscular function and respiratory condition. The time difference between recovery of plasma cholinesterase activity and muscle necrosis protection indicates that this method is not completely trustworthy for patient follow-up, since some improvement may occur in spite of the low plasma cholinesterase activity. [Copyright &y& Elsevier]

Cyclic vomiting syndrome is a disorder characterized by recurrent episodes of nausea and vomiting with complete resolution of symptoms between attacks. Nitric oxide plays a critical role in regulating several components of gastrointestinal mucosal defense and injury. Interleukin-6 has a wide variety of actions in the gastrointestinal apparatus. The purpose of this study was to evaluate the synthesis and release of nitric oxide and interleukin-6 by the esophageal and gastric mucosa in 10 children with cyclic vomiting syndrome, during symptom-free periods, and in 10 controls. The nitric oxide and interleukin-6 release by esophageal mucosa cells obtained from cyclic vomiting patients was quite similar to that in controls, but the release of nitric oxide from gastric mucosa cells of patients was significantly higher than that of controls. Conversely, no interleukin-6 was detectable in gastric mucosa cell supernatants in any of the patients. Further studies are needed to evaluate the relationship between factors triggering cyclic vomiting syndrome and the release of nitric oxide and interleukin-6 by gastric mucosa. [ABSTRACT FROM AUTHOR]

We studied the possible involvement of mucosal amino acid metabolism in the pathogenesis of gastroesophageal reflux disease in children. Eighteen children with gastroesophageal reflux disease (8 with reflux esophagitis and 10 without) and 10 children with normal 24-h esophageal pH monitoring as a comparative group underwent esophagogastroduodenoscopy with biopsies. Plasma and esophageal mucosa amino acids were assayed by liquid chromatography. In children affected by gastroesophageal reflux disease we found an increase of mucosal taurine (P < 0.01) and a decrease of serine (P < 0.01). No differences were noted between patients with and without esophagitis. Significant positive correlations (P < 0.001; r = 0.626) were found between mucosal taurine content and reflux index. Plasma amino acid concentrations did not show any significant differences among groups. Our results indicate that biochemical alterations precede the histological findings of inflammation, likely reflecting the adaptive response of the esophageal mucosa to the gastric contents exposure. [ABSTRACT FROM AUTHOR]

Unlabelled: Cyclic vomiting syndrome (CVS) is characterized by repeated unpredictable, explosive and unexplained bouts of vomiting. The episodes have a rapid onset, persist over a number of hours or days, and are separated by symptom-free intervals. Despite the recent interest in this disorder, its aetiology, pathogenesis and even its target organ remain unknown. The purpose of this study is to investigate the role played by food allergy in CVS. The report concerns eight children (five male, three female), mean age 8 years (3-13 years), suffering from CVS for 2 years at least. The diagnosis of CVS was based on characteristic history, normal physical examination and negative laboratory, radiographic, neurological and endoscopic studies. Despite the absence of clinical signs typical of food allergy, skin prick tests were positive in six of the eight patients (75%). Specific IgE were present in 4/8 (50%) of the patients. Skin tests and specific IgE were positive for cow's milk proteins, egg white and soya. IgE levels were higher than the mean + 2SD in 5/8 (63%) of the patients. A double blind placebo controlled food challenge (DBPCFC) was carried out on seven of the eight patients who displayed clinical improvement after an elimination diet for cow's milk (and other foodstuffs indicated by positive skin tests). The DBPCFC was positive in all seven children. Clinical follow-up revealed a state of well-being over the 6 months of observation.Conclusion: It appears reasonable to suggest that food allergy plays a role in cyclic vomiting syndrome. [ABSTRACT FROM AUTHOR]

A study to update dibutyltin (DBT) and tributyltin (TBT) residues in farmed fish and shellfish (Mytilus edulis) was carried out 4 years after the adopting of the restricting regulation of the antifouling uses of organotins in Italy. DBT and TBT were simultaneously extracted from farmed fish and shellfish (M. edulis) and from free living specimens, used as control, purchased from retail stores or fishermen in the province of Naples (Italy), and detected using a capillary gas chromatograph equipped with a flame photometric detector (GC-FPD). Dosable amounts of DBT were found in the 10% of the farmed fish analyzed, ranging from 1 to 26 micrograms kg-1 wet wt (mean 10 micrograms kg-1) and in the 23% of the free living fish at an average level of 2 micrograms kg-1 wet wt (range 1-4 micrograms kg-1 wet wt). TBT was detected in 85% of the farmed fish, in concentrations varying from 2 to 260 micrograms kg-1 wet wt (mean 28 micrograms kg-1 wet wt) and in 46% of the free living specimens (mean 39 micrograms kg-1 wet wt; range 1-93 micrograms kg-1). All the mussel samples analyzed were polluted by both DBT and TBT. In the farmed mussels the average amounts of DBT and TBT were, respectively, 4 and 2 micrograms kg-1 wet wt; in the free living they were 4 and 5 micrograms kg-1 wet wt, respectively. The results indicate that the DBT and TBT contamination is as highly diffuse in farmed as in free living fish and mussels on sale in retail markets in Naples province even if the levels of the contamination are meanly quite low. [ABSTRACT FROM AUTHOR]

Ketoprofen, 25, 50, and 100 mg, was compared with 90 mg codeine and placebo for relief of pain due to removal of impacted third molar teeth. Treatment was self-administered as a single oral dose under double-blind conditions in five parallel groups established by a random code in healthy young adults. Based on 129 patient evaluations of pain experience and pain relief, ketoprofen was shown to have a more rapid onset and longer duration of action than codeine. In the derived variables of SPID (Sum of Pain Intensity Differences) and TOPAR (Total Pain Relief), all three doses of ketoprofen, with no dose-related differences among them, were found to provide statistically superior analgesia to codeine and placebo. All five treatments were associated with some adverse reactions. [ABSTRACT FROM AUTHOR]

A total of 152 patients were treated at a single center in a single-dose, double-blind parallel study designed to compare the safety and efficacy of 25, 50, and 100 mg ketoprofen to 90 mg codeine and placebo in patients with moderate to severe postpartum pain (i.e., postepisiotomy, uterine cramping, or cesarean section pain). The analgesic responses to all three doses of ketoprofen and 90 mg codeine were superior to placebo and were not significantly different from each other. No dose-related response was observed with ketoprofen. The number of side effects was significantly greater ( P = 0.001) among patients receiving codeine (six patients) than among those receiving ketoprofen (three patients). [ABSTRACT FROM AUTHOR]

A large kindred (64 members in four generations), affected by a form of apparently congenital pulverulent cataract, was studied for linkage of its gene locus with that of the Fy blood group. No indication of linkage was found. The involvement of the cortex distinguishes this form from the zonular pulverulent cataract (total nuclear) of Nettleship and Ogilvie, the locus of which is probably linked with Fy. A correlation between morphological and genetic heterogeneity, based on the linkage with Fy, cannot be established because of the scarcity of published data. [ABSTRACT FROM PUBLISHER]

Extended abstract of a paper presented at Microscopy and Microanalysis 2011 in Nashville, Tennessee, USA, August 7–August 11, 2011. [ABSTRACT FROM PUBLISHER]

Presents a study which measured Helicobacter pylori antibodies in the serum of pediatric patients with food allergy, atopic disease and inflammatory bowel disease. Method; Results; Conclusion.

Clinical characteristics and genotype analysis of patients with cystic fibrosis and nasal polyposis The prevalence of nasal polyps in a group of paediatric patients with cystic fibrosis was prospectively studied in comparison with a control group with cystic fibrosis but without polyps. Clinical variables, including pulmonary function tests, skin testing and mucociliary transport, were carried out in both groups, as well as genotype analysis. Endoscopic intranasal evaluation identified polyps in 29 of 89 patients (33%). Statistical analysis revealed that patients with nasal polyposis had better pulmonary function, a higher rate of Pseudomonas aeruginosa colonization, more hospitalizations, and more prevalence of allergy to Aspergillus fumigatus than did the comparison group. We found no statistically different genotype distribution between the polyposis and the control group. However, it can be emphasized that the prevalence of the compound heterozygous genotype is higher in the nasal polyposis group than in controls. Our observations suggest that other genetic and environmental factors could play an important role in the development of nasal polyposis. [ABSTRACT FROM AUTHOR]

Focuses on the diagnosis of a child with sandifer's syndrome. Role of gastric motility in the pathophysiology of gastroesophageal reflux in children with Sandifer's syndrome; Tools for assessing foregut gastric motility; Need to confirm factors affecting children with the syndrome.