Carbon nanostructure-reinforced SiCw/Si3N4 composite with enhanced thermal conductivity and mechanical properties

Carbon nanostructures (CNS) as a kind of reinforcement material can remarkably enhance the mechanical and thermal properties of ceramics. This research presents an analysis of the influence of CNS on the thermal conductivity and mechanical properties of SiC_w/Si₃N₄ composites. The SiC_w/Si₃N₄ composites containing various types of CNS e.g. carbon nanofibers (CNF), multi-walled carbon nanotubes (MWCNT) and graphene nano-platelets (GNP) were fabricated by hot-press sintering. XRD analysis confirmed a complete transformation of α-Si₃N₄ to β-Si₃N₄ and microstructural analysis shows a uniform distribution, as well as a pullout and bridging mechanism of CNS. The results revealed that the thermal conductivity and mechanical properties of SiC_w/Si₃N₄ composites increased with the addition of CNS. Maximum values of fracture toughness (9.70 ± 0.8 MPa m^1/2) and flexural strength (765 ± 58 MPa) have been achieved for the MWCNT-containing SiC_w/Si₃N₄ composite, whereas the maximum values of Young''s modulus (250 ± 3.8 GPa) and hardness (27.2 ± 0.9 GPa) have been achieved for the CNF-containing SiC_w/Si₃N₄ composite. Moreover, thermal conductivity also improved with the addition of CNS and reached a maximum value of 110.6 W m⁻¹ K⁻¹ for the CNF-containing SiC_w/Si₃N₄ composite. This work provides a useful approach for the fabrication of high-performance multifunctional composites for emerging engineering applications.

Carbon nanostructures (CNS) as a kind of reinforcement material can remarkably enhance the mechanical and thermal properties of ceramics.     

New developments in steroid-resistant nephrotic syndrome

Nephrotic syndrome is a disorder of the glomerular filtration barrier, a highly specialised tri-layer structure with unique functional properties. Recent advances emanating from the field of molecular genetics have revealed the podocyte as probably the central player in the control of glomerular filtration. More specifically, the cell–cell junction between adjacent podocyte foot processes, namely, the slit diaphragm, has been revealed to be made up of a sophisticated multi-protein complex which dynamically controls foot process architecture via signalling to the actin cytoskeleton. Key genes that have been identified from the study of inherited nephrotic syndromes include those encoding nephrin, podocin, TRPC6 (transient receptor potential canonical channel-6) and α-actinin-4, and more remain to be found. It is now possible to identify genetic causes underlying a proportion of nephrotic syndromes presenting at any age. The next big challenge for clinicians and researchers is to translate the molecular information learnt into the understanding of acquired, non-inherited forms of the disease and to guide therapeutic options. In this regard several exciting advances have been made, both in understanding the molecular mechanisms of current therapies and in revealing circulating plasma factors and the molecular pathways they trigger in the podocyte, that could be targeted by novel therapies.     

Effect of statin on semen quality characteristics

Statins are lipid-lowering medications widely used to reduce the risk of cardiovascular diseases. Biochemically, they act by decreasing synthesis of cholesterol via inhibiting 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase. Since 1992, various research studies have investigated the effect of statins on semen quality characteristics; however, to date, there is no collective summary to such effect. Here, we have systematically discussed and abridged all research studies published in Scopus, PubMed and Web of Science databases that are directly linking statin to semen fertility characteristics using the keywords “statin” versus “sperm” and “semen”. In summary, considering the animal studies, statins, in general, were found to ameliorate semen quality characteristics in reproductive detrimental conditions, while, in human males or in in vivo systems with normal reproductive conditions, in general, statins showed negative to blunt effects against semen quality characteristics, mainly sperm motility. However, further research studies, in particular human studies, in this specific research setting is still needed to approve these effects.     

Planning of Plastic Surgery Practice to Say Sayonara

Having seen the retired life of our professors both in general and plastic surgery and how lonely and isolated they were toward the end of their lives prompted me to discuss the retirement plans. The retirement from active surgical practice is indeed difficult and more so in plastic surgery. I feel that it needs meticulous planning for setting up a successful practice and when to say sayonara , just like treatment planning of any surgical procedure for perfect execution! At the end of M.Ch training, one should analyze oneself about the goal of the professional life and commit oneself to either a solo/group practice as an independent institutional practice or in a corporate set-up or choose a state/central government set-up with some academic position. A successful plastic surgical practice is every plastic surgeon’s dream and it comprises professional and financial successes with a sense of personal achievement. The factors involved in the selection of practice are family obligations—if parents or spouse are in medical profession with an existing establishment—individual talent, willingness to learn newer techniques, and acceptance of help from the other professional colleagues. At the same time, life needs to be balanced between the professional and family commitments without ignoring either of them with a deep social and community responsibility. But what is the correct time to say sayonara ? The timing of retirement is difficult to get right, but the basic additional principle that guides one is “ Primum non-nocere ”—do no harm—to the receiver.     

Congenital massive hiatus hernia type IV; initial experience with laparoscopic repair in young infant

Congenital massive hiatus hernia (CMHH) is an uncommon disorder during childhood. It can be associated with grave complications especially if presented in the highest grade; type IV, when the hernia contains other intra-peritoneal organ beside the stomach through a large hiatus defect. The insidious form of clinical presentation can be deceptive in diagnosis and may mimic congenital diaphragmatic hernia or other chest pathologies. The basic principle of surgical repair is to reduce the herniated organs, excise the hernia sac, and repair the crural defect and to add anti-reflux procedure with or without gastropexy. Traditionally, this has been done by open approach. Nowadays, the minimally invasive approach is the preferred method of treatment. A sixteen-month-old boy with history of recurrent respiratory symptoms was diagnosed with CMHH type IV for which laparoscopic repair was performed. Few reports in using minimally invasive technique in the management of CMHH in the pediatric age group are present in the literature, to the best of our knowledge type IV had never been described in young infants. We present a new case repaired by laparoscope in a young infant with CMHH type IV from the Middle East.     

Interactions of antagonists with subtypes of inositol 1,4,5-trisphosphate (IP3) receptor

BACKGROUND AND PURPOSE

Inositol 1,4,5-trisphosphate receptors (IP₃Rs) are intracellular Ca²⁺ channels. Interactions of the commonly used antagonists of IP₃Rs with IP₃R subtypes are poorly understood.

EXPERIMENTAL APPROACH

IP₃-evoked Ca²⁺ release from permeabilized DT40 cells stably expressing single subtypes of mammalian IP₃R was measured using a luminal Ca²⁺ indicator. The effects of commonly used antagonists on IP₃-evoked Ca²⁺ release and ³H-IP₃ binding were characterized.

KEY RESULTS

Functional analyses showed that heparin was a competitive antagonist of all IP₃R subtypes with different affinities for each (IP₃R3 > IP₃R1 ≥ IP₃R2). This sequence did not match the affinities for heparin binding to the isolated N-terminal from each IP₃R subtype. 2-aminoethoxydiphenyl borate (2-APB) and high concentrations of caffeine selectively inhibited IP₃R1 without affecting IP₃ binding. Neither Xestospongin C nor Xestospongin D effectively inhibited IP₃-evoked Ca²⁺ release via any IP₃R subtype.

CONCLUSIONS AND IMPLICATIONS

Heparin competes with IP₃, but its access to the IP₃-binding core is substantially hindered by additional IP₃R residues. These interactions may contribute to its modest selectivity for IP₃R3. Practicable concentrations of caffeine and 2-APB inhibit only IP₃R1. Xestospongins do not appear to be effective antagonists of IP₃Rs.     

Assessment of Circulating Biochemical Markers in Mice Receiving Cinnamon and Glycyrrhizin Under Carbon Tetrachloride Induced Hepatic Injury

The study evaluated the hepatoprotective activity of plant extracts of cinnamon and glycyrrhizin in distinct dosage ways to minimize the oxidative stress induced by carbon tetrachloride (CCl₄) in BALB/cJ inbred albino mice. Fifteen albino mice were divided into five groups, each group containing three mice. Group A was referred as positive control while group B, C, D and E were injected intraperitoneally with 1 mL/kg body weight of CCl₄ twice a week for 1 month. Group C and D were treated orally with isolated extracts of cinnamon @50 mg/kg and glycyrrhizin @50 mg/kg respectively on daily basis for 1 month. However, group E was treated orally with combination dose of cinnamon @50 mg/kg + glycyrrhizin @50 mg/kg body weight. The increase in the levels of alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP), triglyceride (TG), malondialdehyde (MDA) and glucose were recorded in CCl₄ induced liver injury in mice while there is decrease in the levels of total protein (TP), reduced glutathione (GSH), Superoxide dismutase (SOD) and catalase (CAT) in CCL₄ intoxicated mice. Isolated therapy of plant extracts of cinnamon and glycyrrhizin decreased the levels of ALT, AST, ALP, MDA, TG and glucose whereas increase in TP, GSH, SOD and CAT was observed in plant extracts treated mice. The best restoration of all the above said parameters near to control was observed in group of mice treated with combination dose of cinnamon and glycyrrhizin @50 mg/kg. Therefore, the present study declared the antioxidative, anti-inflammatory and hepatoprotective activity of standardized extracts of cinnamon and glycyrrhizin and their potent defensive property.