Laser-Induced Graphitization of Thermosetting Polymer Substrate and its Application—A Review

Laser-induced graphene (LIG) production and application is currently receiving tremendous attention of the research community, perhaps because of its facile, clean, and sustainable nature. Thus, any critical review about the subject matter cannot be over-emphasized.  Herein, the stage-wise procedure of producing the LIG that involves preparation of polymer substrate, specification of laser machine parameters/condition, laser-induced irradiation on the prepared substrate, and characterization/confirmation of the LIG have been explained, and most importantly the various applications of the LIG in the areas of energy and power, electromagnetic interference (EMI) shielding, environmental, and sensor development have also been reviewed. It is worthy of nothing that polyimide film is predominantly employed by the different independent researches as substrate in the LIG production and applications, and fascinating findings were found. Furthermore, future perspective of LIG production and applications have been suggested. Overall, information summarized herein will no doubt provide basis for research and development in the area of LIG production and application

Improvements in Mechanical and Shape-Memory Properties of Bio-Based Composite: Effects of Adding Carbon Fiber and Graphene Nanoparticles

Shape-memory carbon fiber (CF) polymer composites reinforced with graphene nanoplatelets (GnPs) as a filler based on a bio-based V-fa/ECO copolymer were prepared at different graphene GnPs and CF mass fractions using the hand lay-up and hot-pressing methods. The obtained composite specimens were subjected to flexural, dynamic mechanical, and shape-memory analyses. The obtained results revealed that the flexural strength and modulus were improved by the addition of the GnPs and CF due to the improvement in the interfacial adhesion and fiber reinforcement with up to 3 wt.% GnPs and 60 wt.% CF. Additionally, appreciable improvements in the shape-memory performance were achieved with the addition of the GnPs, where values of up to 93% and 96% were recorded for the shape fixity and recovery, respectively. The shape-memory performance was affected by the fiber mass fraction, with the composites retaining the shape-memory effect albeit with a significant drop in performance at higher fiber mass fractions. Lastly, the specimens at 40 wt.% CF and 3 wt.% GnPs were determined to be the optimum compositions for the best performance of the bio-based SMP composite

High Prevalence of Hepatitis B Virus Pre-S Mutant in Countries Where It Is Endemic and Its Relationship with Genotype and Chronicity

It has been reported that hepatitis B virus (HBV) mutants carrying mutations in the pre-S region can be found in infected patients. In this study, we investigated the prevalence of the HBV variant with the pre-S mutant in different geographic regions, including countries with low and high levels of endemic HBV infection, and analyzed the correlation with clinical findings. We examined 387 HBV DNA-positive serum samples from individuals among 12 countries, consisting of Vietnam, Myanmar, Thailand, China, Korea, Nepal, Japan, Russia, Spain, United States, Bolivia, and Ghana. HBV pre-S mutants were detected in 71 (18.3%) of 387 serum samples tested. This mutant was the most prevalent in Vietnam (36%), followed by Nepal (27.3%), Myanmar (23.3%), China (22.4%), Korea (14.3%), Thailand (10.5%), Japan (7.7%), and Ghana (4.3%). In contrast, no case with this mutation was found in Russia, Spain, United States, and Bolivia. Among the HBV deletion mutations, 15.5% (11 of 71) occurred in the pre-S1 and 46.5% (33 of 71) in the pre-S2 regions. Eight (11.3%) cases had a mutation in both the pre-S1 and pre-S2 regions. In addition, a point mutation at the pre-S2 starting codon was observed in 19 (26.7%) cases. The detection rate of the HBV mutant in patients with hepatocellular carcinoma was significantly higher than in other patients (P < 0.05). Furthermore, these mutants were found more frequently in genotype B (25%) and genotype C (24.5%) than in the other genotypes (P < 0.05). Our results indicated that there was a high prevalence of HBV pre-S mutation in regions of endemic HBV infection in Asia. Furthermore, the pre-S mutation appeared to be correlated with hepatocellular carcinoma and HBV genotypes