Sonographic diagnosis of neuritis ossificans of the median nerve

We report the sonographic appearance of a rare case of neuritis ossificans of the median nerve at the wrist, which appeared as a hyperechoic lesion around the nerve. Diagnosis was confirmed with magnetic resonance imaging (MRI).     

Perinatal diagnosis and management of oropharyngeal fetus in fetu: A case report

Fetus in fetu is an extremely rare congenital anomaly. We describe the perinatal diagnosis and management of a fetus with oropharyngeal and cervical fetus in fetu. High‐resolution ultrasonography with 3‐dimensional rendering can identify increased risks of airway obstruction in utero. Early identification allows a multidisciplinary team to be assembled for a scheduled ex utero intrapartum treatment procedure.     

Permanent Bilateral Vision Loss in Eclamptic Posterior Reversible Encephalopathy Syndrome

Posterior reversible encephalopathy syndrome (PRES) classically consists of reversible vasogenic oedema in the posterior circulation territories, which is reversible both clinically and radiologically in the majority of patients after the control of hypertension. The authors describe a 27-year-old eclamptic patient with PRES in accelerated hypertension who revealed permanent vision loss associated with bilateral Purtscher retinopathy. One of the two competing theories that explain vasogenic brain oedema in PRES is excessive autoregulation leading to the dilation of cerebral arterial vessels, particularly in the occipito-parietal vasculatures. Dysfunction of endothelial cells that results in constriction of vessels has also been hypothesised as a cause of PRES. The concurrence of bilateral vaso-occlusive retinopathy and PRES supports the hypothesis that vasoconstriction is a more plausible mechanism of vasogenic oedema in PRES.     

Polybenzimidazole/Nafion hybrid membrane with improved chemical stability for vanadium redox flow battery application

In order to increase the chemical stability of polybenzimidazole (PBI) membrane against the highly oxidizing environment of a vanadium redox flow battery (VRFB), PBI/Nafion hybrid membrane was developed by spray coating a Nafion ionomer onto one surface of the PBI membrane. The acid–base interaction between the sulfonic acid of the Nafion and the benzimidazole of the PBI created a stable interfacial adhesion between the Nafion layer and the PBI layer. The hybrid membrane showed an area resistance of 0.269 Ω cm² and a very low vanadium permeability of 1.95 × 10⁻⁹ cm² min⁻¹. The Nafion layer protected the PBI from chemical degradation under accelerated oxidizing conditions of 1 M VO₂⁺/5 M H₂SO₄, and this was subsequently examined in spectroscopic analysis. In the VRFB single cell performance test, the cell with the hybrid membrane showed better energy efficiency than the Nafion cell with 92.66% at 40 mA cm⁻² and 78.1% at 100 mA cm⁻² with no delamination observed between the Nafion layer and the PBI layer after the test was completed.

Novel polybenzimidazole (PBI)/Nafion hybrid membranes for the VRFB are made by spray coating a Nafion layer to protect PBI from chemical degradation.     

First-principles analysis of a molecular piezoelectric meta-nitroaniline

The piezoelectric and elastic properties of a molecular piezoelectric meta-nitroaniline (mNA) in its single-crystal form were investigated in the framework of first-principles density functional perturbation theory (DFPT). Results support the recent experimental findings those despite being soft and flexible, mNA''s piezoelectric coefficients are an order of magnitude greater than that of ZnO and LiNbO₃. A molecular-level insight into the piezoelectric properties of mNA is provided. These results are helpful not only for better understanding mNA, but also for developing new piezoelectric materials.

The piezoelectric and elastic properties of a molecular piezoelectric meta-nitroaniline (mNA) in its single-crystal form were investigated in the framework of first-principles density functional perturbation theory (DFPT).     

Variation and heritability of Hb F and F-cells among beta-thalassemia heterozygotes in Hong Kong

Enhanced fetal hemoglobin (Hb F) production can partially compensate for the lack of adult hemoglobin (Hb A) in patients with beta-thalassemia major or intermedia, and ameliorate the clinical severity of these diseases. To further elucidate factors governing Hb F levels, we evaluated demographic, clinical, laboratory, and genetic characteristics in 241 unrelated adult beta-thalassemia carriers in Hong Kong. They had wide variations in Hb F and F-cell numbers skewing toward higher levels. Individuals who coinherited the Xmn IT-allele in the (G)gamma-globin gene promoter had higher Hb F and more F-cells compared with those lacking the Xmn I T-allele. However, both groups exhibited a similarly wide spread of Hb F and F-cells. The correlation of Hb F and F-cells corresponded well to both linear and exponential models, suggesting multiple mechanisms for Hb F augmentation. The heritabilities of Hb F and F-cells were calculated in 66 families (111 parents who were beta-thalassemia carriers and 82 asymptomatic offspring) to be 0.7 to 0.9. The Xmn I polymorphism accounted for 9% of the Hb F and 13% of the F-cell heritabilities. These results suggest that these family members are well suited for genome wide association studies that will identify genetic loci regulating Hb F production, and likely novel pharmacological targets for reactivating Hb F production in adults.     

High incidence of pulmonary tuberculosis in the non-HIV infected immunocompromised patients in Hong Kong

In areas where tuberculosis is endemic, clinicians managing immunocompromised patients (ICP) are confronted with the possibility of Mycobacterium tuberculosis as a pathogen. To determine the incidence and clinical pattern of, the diagnostic approach to, and potential therapeutic implications of pulmonary tuberculosis in this patient population, we reviewed 62 non-HIV infected ICP in Hong Kong who had bronchoscopy because of pulmonary infiltrates. Pulmonary tuberculosis was the second most common cause after bacterial infections. Clinical and radiographic presentations of 12 patients with tuberculosis were nonspecific. Flexible bronchoscopy for tuberculosis carried a diagnostic sensitivity of 91.7 percent. We conclude that for the non-HIV infected ICP from areas where tuberculosis is endemic: M tuberculosis should be suspected as the pathogen; radiographic findings are diagnostically not helpful; FB is a sensitive diagnostic test for tuberculosis and in smear-negative cases where tuberculosis is suspected, initiation of empiric anti-tuberculosis therapy should be considered while awaiting culture results.     

Echocardiography as a tool for determining the incidence of congenital heart disease in newborn babies: a pilot study in Hong Kong

We studied, with echocardiography as the main tool, the incidence of congenital heart disease in newborn babies in Hong Kong. The population examined was the 20,928 babies who were born alive in the Prince of Wales Hospital from January 1987 to December 1989. All had a thorough physical examination by a paediatrician after birth, and an estimated 95% of the babies who were discharged from hospital received another routine physical examination at one of the five local Maternal and Child Health Centres within two months of birth. All babies with either suspected congenital heart disease or multiple congenital abnormalities were referred to the paediatric cardiologists in the Prince of Wales Hospital for further cardiovascular assessment that included echocardiographic examination. In all, 492 babies had Doppler and cross-sectional echocardiographic studies. Various abnormalities of the cardiovascular system were diagnosed in 216 babies. Almost all the babies who died within two months of life underwent autopsy. This proved the presence of congenital cardiac malformations in 15 babies, of whom 10 had correct echocardiographic diagnoses during life. One had a patent arterial duct which was missed by the echocardiography. The other four babies did not have echocardiographic examination while alive, either because of early death or absence of clinical suspicion. In total, congenital cardiac malformations were confirmed in 221 babies by echocardiographic examination and autopsy. Excluding 82 premature babies with patency of the arterial duct, and 6 babies with transient tricuspid regurgitation, there were 133 cases of structural cardiac malformation in the studied population, giving an incidence of 6.35 per thousand live births.(ABSTRACT TRUNCATED AT 250 WORDS)