Indoor transmission dynamics of expired SARS-CoV-2 virus in a model African hospital ward

Cough and sneeze droplets' interactions with indoor air of a typical hospital clinic that could be majorly found in developing African countries were studied to investigate the effectiveness of existing guidelines/protocols being adopted in the control of the widespread coronavirus disease (COVID-19) transmission. The influences of indoor air velocity, the type, size distribution, residence time in air, and trajectory of the droplets, were all considered while interrogating the effectiveness of physical distancing measures, the use of face covers, cautionary activities of the general public, and the plausibility of community spread of the SARS-CoV-2 virus through airborne transmission. Series of 3-D, coupled, discrete phase models (DPM) were implemented in the numerical studies. Based on DPM concentration maps as function of particle positions and particle residence times that were observed under different droplets release conditions, the virus-laden droplets could travel several meters away from the source of release (index patient), with smaller-sized particles staying longer in the air. The behavior of indoor air was also found to indicate complex dynamics as particle transports showed no linear dependence on air velocity.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s40201-020-00606-5.

Supervised Machine Learning Models for Prediction of COVID-19 Infection using Epidemiology Dataset

COVID-19 or 2019-nCoV is no longer pandemic but rather endemic, with more than 651,247 people around world having lost their lives after contracting the disease. Currently, there is no specific treatment or cure for COVID-19, and thus living with the disease and its symptoms is inevitable. This reality has placed a massive burden on limited healthcare systems worldwide especially in the developing nations. Although neither an effective, clinically proven antiviral agents' strategy nor an approved vaccine exist to eradicate the COVID-19 pandemic, there are alternatives that may reduce the huge burden on not only limited healthcare systems but also the economic sector; the most promising include harnessing non-clinical techniques such as machine learning, data mining, deep learning and other artificial intelligence. These alternatives would facilitate diagnosis and prognosis for 2019-nCoV pandemic patients. Supervised machine learning models for COVID-19 infection were developed in this work with learning algorithms which include logistic regression, decision tree, support vector machine, naive Bayes, and artificial neutral network using epidemiology labeled dataset for positive and negative COVID-19 cases of Mexico. The correlation coefficient analysis between various dependent and independent features was carried out to determine a strength relationship between each dependent feature and independent feature of the dataset prior to developing the models. The 80% of the training dataset were used for training the models while the remaining 20% were used for testing the models. The result of the performance evaluation of the models showed that decision tree model has the highest accuracy of 94.99% while the Support Vector Machine Model has the highest sensitivity of 93.34% and Naïve Bayes Model has the highest specificity of 94.30%.

Selected Heavy Metals Removal From Electroplating Wastewater by Purified and Polyhydroxylbutyrate Functionalized Carbon Nanotubes Adsorbents

This research investigated the removal of heavy metals (As, Pb, Cr, Cd, Ni, Cu, Fe, and Zn) via batch adsorption process from industrial electroplating wastewater using two different nano-adsorbents; purified carbon nanotubes (P-CNTs) and polyhydroxylbutyrate functionalized carbon nanotubes (PHB-CNTs), both produced through catalytic chemical vapour deposition (CCVD) method. HRSEM, HRTEM, XRD, DLS, BET, FTIR, XPS, TGA, pH drift and Raman spectroscopy were used to characterize the developed nano-adsorbents. In the batch adsorption process, the effects of contact time, dosage, temperature and pH were studied. Both nano-adsorbents gave optimum contact time, equilibrium time, optimum dosage, and pH of 10 minutes, 70 minutes, 20 mg, and 5.63–5.65 respectively. The heavy metals removal efficiencies by the nano-adsorbents followed the order of PHB-CNTs > P-CNTs based on ion exchange and electrostatic forces mechanism. For P-CNTs and PHB-CNTs, the equilibrium sorption isotherm suits temkin model, kinetic data fitted to pseudo-second order based on the linear regression correlation coefficient, and the thermodynamic study established spontaneity and endothermic nature of the adsorption process. The findings in this research conclude that both nano-adsorbents have exceptional capacity to remove heavy metals from the adsorbate, with PHB-CNTs possessing better quality. The treated adsorbate meets the standard for industrial or irrigation re-use.

CALCINOSIS CUTIS - A SERIES OF 59 CONSECUTIVE CASES CONFINED AMONG WOMEN

BACKGROUND

Calcinosis cutis is the cutaneous deposition of calcium salts. Tumoral Calcinosis is a condition consisting of massive subcutaneous deposits of calcium salts often overlying large joints in otherwise healthy patients.

OBJECTIVE

To describe the characteristics of a series of patients with Tumoral Calcinosis in the Gurage Zone of Central Ethiopia.

METHODOLOGY

Data was collected from 59 patients who presented with clinical diagnosis of calcinosis cutis around hip region between January 2005 and January 2009.

RESULTS

All cases were females, with a mean (standard deviation) age at diagnosis of 50.7(10.8). The duration of illness ranged from one to eighteen years. The cases were distributed in the different villages of Gurage Zone without any sign of clustering of cases. The lesions were localized around hip region on both sides. The patients did not have any related co-morbidity or any history of similar illness among close family members. None of the patients gave history of evident trauma to the site of the lesions. Significant proportion of the patients (53.4%) confirmed to carry water container and/or other goods on their side. Serum Phosphate and Calcium levels in selected patients were with in normal limit. Histo-pathological examinations of five cases revealed Calcium deposits in collagenous connective tissue.

CONCLUSION

The lesion was found to be relatively common in the study area and specifically confined to females. The probable factor associated with the cases is carrying objects on their side (hip area). Further research with in-depth clinical and laboratory evaluation is of paramount importance.

Utilization of cytokeratins 7 and 20 does not differentiate between Barrett's esophagus and gastric cardiac intestinal metaplasia

Long segment Barrett's esophagus (LSBE) is a recognized risk factor for the development of esophageal dysplasia and carcinoma. However, the risk of dysplasia arising within intestinal metaplasia below a normal-appearing Z-line (i.e., in native cardiac mucosa) is unknown. Regular endoscopic surveillance is required in patients with LSBE and is frequently performed in short segment BE (SSBE), but the need for surveillance in cardiac intestinal metaplasia (CIM) is unknown. Unfortunately IM arising in SSBE and immediately below a normal Z-line can be indistinguishable histologically on H&E stains. Previous reports suggest that the appearance of superficial CK20 immunohistochemical staining accompanied by intermediate and deep CK7 positivity is characteristic of BE, whereas CIM specimens show superficial and deep CK20 positivity and weak to absent CK7 staining. We hypothesized that CK7/20 immunostaining of metaplastic biopsies from the esophagus and stomach would allow complete differentiation of these two entities when correlated with the endoscopic appearance. We undertook an evaluation of gastric and esophageal specimens to determine whether these characteristics were valid. Cases of both BE (long and short segment) and CIM, as well as cases of gastric cardiac biopsies lacking IM, were evaluated for CK7 and CK20 and correlated with the endoscopic appearance. We observed that, although the "Barrett's" pattern of CK7/20 was maintained for many cases of BE, the sensitivity and specificity were only moderate (65% and 56%, respectively). The pattern of staining for the CIM was variable, i.e., some cases showed a CK7/20 Barrett's pattern despite a normal appearance at endoscopy. The differences between this and previous studies may be due to inaccurate visualization of SSBE on endoscopy, the development of very early SSBE cases, inter-observer variability, fixation differences, or antibody differences. Whatever the cause of the differences, if results between laboratories are not comparable, CK7/20 immunostaining cannot be used to differentiate reliably between IM present in biopsy specimens taken from above versus below the Z-line. However, further studies should be performed to determine whether the presence or absence of a Barrett's pattern of CK7/20 immunostaining could predict progression to dysplasia or carcinoma.

Life-Threatening Hypercalcemia Associated With Primary Hyperparathyroidism During Pregnancy: Case Report And Review Of Literature

OBJECTIVE

To report a case of life-threatening hypercalcemia attributable to primary hyperparathyroidism in a pregnant patient and discuss the management of severe hypercalcemia during pregnancy.

METHODS

We describe a 28-year-old pregnant woman who had life-threatening hypercalcemia (serum calcium level of 25.8 mg/dL). Primary hyperparathyroidism was diagnosed. The patient's management and the published medical literature on primary hyperparathyroidism during pregnancy are reviewed.

RESULTS

Our patient had the highest reported serum calcium level that we could find attributable to primary hyperparathyroidism during pregnancy. After initial stabilization, parathyroidectomy was successfully performed during pregnancy. To our knowledge, this is the first report in which this profound degree of hypercalcemia did not result in an adverse maternal or fetal outcome.

CONCLUSION

Although uncommon, primary hyperparathyroidism during pregnancy may be associated with severe maternal and perinatal complications. Life-threatening hypercalcemia due to primary hyperparathyroidism during pregnancy can be successfully managed surgically during pregnancy, with good maternal and fetal outcome.

The Syndrome of Resistance to Thyroid Hormone, Misdiagnosed and Treated as Thyrotoxicosis

OBJECTIVE

To report two cases of resistance to thyroid hormone and to promote increased awareness of this syndrome, which is frequently misdiagnosed and incorrectly treated.

METHODS

We describe a young woman and her father, both of whom were diagnosed at a younger age as having thyrotoxicosis and were treated with thyroidectomy and radioactive iodine. Both patients later proved to have resistance to thyroid hormone and required supraphysiologic doses of levothyroxine to normalize the thyroid-stimulating hormone (TSH) while remaining euthyroid.

RESULTS

Laboratory evaluation revealed increased serum total thyroxine and triiodothyronine levels as well as normal to increased TSH levels. The free alpha sub-unit/TSH ratio was normal, and magnetic resonance imaging of the pituitary gland showed no tumor. Metabolic studies in the daughter, with use of graded doses of triiodothyronine, supported the diagnosis.

CONCLUSION

Both patients shown to have resistance to thyroid hormone were misdiagnosed and inappropriately treated in the past. The resultant hypothyroidism has been difficult to treat, particularly in the father who has coronary artery disease.