Rheological and controlled release properties of hydrogels based on mushroom hyperbranched polysaccharide and xanthan gum

A hyperbranched polysaccharide, coded as TM3a, was extracted from the Pleurotus tuber-regium sclerotia. TM3a was hybridized with xanthan gum (XG) by chemical crosslinking using sodium trimetaphosphate (STMP) to obtain new hydrogels with self-healing and release-controlled properties. The oscillatory rheological measurements indicated that chemically crosslinking was happened immediately on mixing STMP solutions into the XG-TM3a solutions, and the crosslinked network developed slightly as time increased. The resultant hydroges were disturbed into the loose structures and regrouped the microstructure in 2 min when a large and a small amplitude oscillation were applied in turn, suggesting a self-healable property. The XG-TM3a-STMP hydrogels exhibited shear-thinning behavior with yield stress. The storage modulus of the XG5-TM3a-STMP hydrogel was 445.2 Pa at 1% strain and 243.3 Pa at 100% strain, and yield stress was 160.6 Pa, which was higher than the corresponding value of the XG5-STMP hydrogel. The morphological observation indicated the aggregates of double helical XG chains exhibited directional arrangement, and were combined with the TM3a aggregates to constitute a network of hierarchical structures. The hybrid hydrogels with enhanced mechanical properties displayed good drug loading efficiencies and sustained drug release properties.This article was made possible by the grant#21344006 by National Natural Science Foundation of China ,grant#D20161603by the Foundation of Hubei Educational Committee of China,grant#GCC-2017-005by Qatar University,and grant#NPRP9-144-3-021funded by Qatar national Research Fund(apart of Qatar Foundation)

The clinical course of SARS-CoV-2 positive neonates

The COVID-19 pneumonia was firstly reported in Wuhan, China, in December 2019. The disease had a rapid spread all over the word becoming an international public health emergency. Limited data were available on COVID-19 positive neonates. We reviewed relevant literature to understand the clinical course of disease and transmission routes in affected neonates. The aim of the study was evaluating the clinical course and prognosis of SARS-CoV-2 positive neonates. Based on current literature, the hypothesis of vertical transmission of SARS-CoV-2, though conceivable, remains unproven. A research conducted on PubMed database from December 2019 to April 27, 2020 revealed that were reported 25 neonates affected by SARS-CoV-2. Main symptoms were fever, cough, or shortness of breath but often these neonates did not show other symptoms during length stay in hospital. No deaths occurred