New Developments and Challenges in Liver Transplantation.

Liver disease is increasing in incidence and is the third most common cause of premature death in the United Kingdom and fourth in the United States. Liver disease accounts for 2 million deaths globally each year. Three-quarters of patients with liver disease are diagnosed at a late stage, with liver transplantation as the only definitive treatment. Thomas E. Starzl performed the first human liver transplant 60 years ago. It has since become an established treatment for end-stage liver disease, both acute and chronic, including metabolic diseases and primary and, at present piloting, secondary liver cancer. Advances in surgical and anaesthetic techniques, refined indications and contra-indications to transplantation, improved donor selection, immunosuppression and prognostic scoring have allowed the outcomes of liver transplantation to improve year on year. However, there are many limitations to liver transplantation. This review describes the milestones that have occurred in the development of liver transplantation, the current limitations and the ongoing research aimed at overcoming these challenges.

Fingerprint image enhancement using multiple filters.

Biometrics is the measurement of an individual's distinctive physical and behavioral characteristics. In comparison to traditional token-based or knowledge-based forms of identification, biometrics such as fingerprints, are more reliable. Fingerprint images recorded digitally can be affected by scanner noise, incorrect finger pressure, condition of the finger's skin (wet, dry, or abraded), or physical material it is scanned from. Image enhancement algorithms applied to fingerprint images remove noise elements while retaining relevant structures (ridges, valleys) and help in the detection of fingerprint features (minutiae). Amongst the most common image enhancement filters is the Gabor filter, however, given their restricted maximum bandwidth as well as limited range of spectral information, it falls short. We put forward a novel method of fingerprint image enhancement using a combination of a diffusion-coherence filter and a 2D log-Gabor filter. The log-Gabor overcomes the limitations of the Gabor filter while Coherence Diffusion mitigates noise elements within fingerprint images. Implementation is done on the FVC image database and assessed via visual comparison with coherence diffusion used disjointedly and with the Gabor filter.

Optimization of calcium carbonate precipitation during alpha-amylase enzyme-induced calcite precipitation (EICP).

The sand production during oil and gas extraction poses a severe challenge to the oil and gas companies as it causes erosion of pipelines and valves, damages the pumps, and ultimately decreases production. There are several solutions implemented to contain sand production including chemical and mechanical means. In recent times, extensive work has been done in geotechnical engineering on the application of enzyme-induced calcite precipitation (EICP) techniques for consolidating and increasing the shear strength of sandy soil. In this technique, calcite is precipitated in the loose sand through enzymatic activity to provide stiffness and strength to the loose sand. In this research, we investigated the process of EICP using a new enzyme named alpha-amylase. Different parameters were investigated to get the maximum calcite precipitation. The investigated parameters include enzyme concentration, enzyme volume, calcium chloride (CaCl2) concentration, temperature, the synergistic impact of magnesium chloride (MgCl2) and CaCl2, Xanthan Gum, and solution pH. The generated precipitate characteristics were evaluated using a variety of methods, including Thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). It was observed that the pH, temperature, and concentrations of salts significantly impact the precipitation. The precipitation was observed to be enzyme concentration-dependent and increase with an increase in enzyme concentration as long as a high salt concentration was available. Adding more volume of enzyme brought a slight change in precipitation% due to excessive enzymes with little or no substrate available. The optimum precipitation (87%) was yielded at 12 pH and with 2.5 g/L of Xanthan Gum as a stabilizer at a temperature of 75°C. The synergistic effect of both CaCl2 and MgCl2 yielded the highest CaCO3 precipitation (32.2%) at (0.6:0.4) molar ratio. The findings of this research exhibited the significant advantages and insights of alpha-amylase enzyme in EICP, enabling further investigation of two precipitation mechanisms (calcite precipitation and dolomite precipitation).

Photocatalytic deactivation of sulphate reducing bacteria using visible light active CuO/TiO2 nanocomposite photocatalysts synthesized by ultrasonic processing.

Sulphate-reducing bacteria wreaks havoc to oil pipelines, as it is an active agent for scale formation in the oil production tubing, and plugging of reservoir rock around the oil wells, and this leads to the degradation of oil quality. In this work, we synthesized copper oxide/titanium dioxide nanocomposite photocatalysts with three different mass contents of copper oxide (10%, 20% and 30%) and used them as an effective photo-catalyst in the process of photo-catalytic deactivation of sulphate-reducing bacteria. The anchoring of copper oxide on titanium dioxide brought about the following positive attributes in copper oxide/titanium dioxide nanocomposite pertained to the photo-catalyst: (i) the material transformed to visible light active with the potential to harness the more efficient visible spectral region of the solar radiation, (ii) increased surface area on the photo-catalyst enhanced the number of active reaction sites in the material, and (iii) efficiently retarded the undesired photo-generated electron hole recombination to promote the photo-catalytic activity. Although, the photo-catalyst effective under both UV and visible light, the deactivation was found to be higher in visible radiation, particularly the nanocomposite with 20%- copper oxide on titanium dioxide showed the highest photocatalytic degradation with of Sulphate-reducing bacteria with a decay constant as high as 1.38 min -1 and the total depletion time as low as 8 min. It was confirmed that the bacterial deactivation was neither due to the bactericidal effect of the nanocomposite nor due to the light mediated deactivation.

CRISPR/Cas System Toward the Development of Next-Generation Recombinant Vaccines: Current Scenario and Future Prospects.

The initially developed vaccines were relying mostly on attenuation and inactivation of pathogens. The use of recombinant DNA technology allows the targeting of immune responses focused against a few protective antigens. The conventional recombination methods for generating vaccines are time-consuming, laborious, and less efficient. To overcome these limitations, a new precise CRISPR/Cas9 with high efficacy, specificity, and low-cost properties has solved a lot of current problems of recombinant vaccines that intrigued the inspiration for novel recombinant vaccine development. CRISPR/Cas9 system was discovered as a bacterial adaptive immune system. In the domain of virology, CRISPR/Cas9 is used to engineer the virus genome to understand the fundamentals of viral pathogenesis, gene therapy, and virus-host interactions. One step ahead CRISPR/Cass9 bypassed the vaccine to precisely engineer the B-cells to secrete the specific antibodies against deadly viral pathogens. There is a critical literature review gap especially in the use of CRISPR/Cas9 to generate recombinant vaccines against viral diseases and its prospective application to engineering the B-cells in immunocompromised people. This review heights the application of CRISPR/Cas9 compared to conventional approaches for the development of recombinant vaccine vectors, editing the genes of B-cells, and challenges that need to be overcome. The factors affecting CRISPR/Cas9-edited recombinant vaccines and prospects in the context of viral genome editing for the development of vaccines will be discussed.

A Review of Advanced Molecular Engineering Approaches to Enhance the Thermostability of Enzyme Breakers: From Prospective of Upstream Oil and Gas Industry.

During the fracture stimulation of oil and gas wells, fracturing fluids are used to create fractures and transport the proppant into the fractured reservoirs. The fracturing fluid viscosity is responsible for proppant suspension, the viscosity can be increased through the incorporation of guar polymer and cross-linkers. After the fracturing operation, the fluid viscosity is decreased by breakers for efficient oil and gas recovery. Different types of enzyme breakers have been engineered and employed to reduce the fracturing fluid's viscosity, but thermal stability remains the major constraint for the use of enzymes. The latest enzyme engineering approaches such as direct evolution and rational design, have great potential to increase the enzyme breakers' thermostability against high temperatures of reservoirs. In this review article, we have reviewed recently advanced enzyme molecular engineering technologies and how these strategies could be used to enhance the thermostability of enzyme breakers in the upstream oil and gas industry.

Extensive use of face masks during COVID-19 pandemic: (micro-)plastic pollution and potential health concerns in the Arabian Peninsula.

Face masks are primary line of defense to reduce the transmission risk of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). World Health Organization (WHO) has already updated the guidelines and advised the use of face masks in public areas essentially. This has dramatically increased the production and use of face masks in many parts of the world. Arabian Peninsula is comprised of six countries where the public perception of following WHO guidelines is high. In this study, we highlight the concerns relating to extensive use of face masks in this region, particularly in the context of (micro-)plastic pollution. We computed the number of face masks to be used in each of the countries of Arabian Peninsula for varying levels of acceptance rate and average number of daily usages. Accordingly, the amount of (micro-)plastic that could come into the terrestrial and marine environment is also reported. Saudi Arabia, being the most populated country in the region may contribute up to 32-235 thousand tons of (micro-)plastic which is nearly half of the amount in the whole Peninsula. On the other hand, an extremely high infection rate in Qatar (25.74%) may also lead to a significant increase of (micro-)plastic content due to high public acceptance rate and living standards. The high (micro-)plastic fraction is of significant concern because it ends up in the marine ecosystems. Further, it allows colonization of several pathogenic microorganisms (bacteria, viruses, fungal filaments, and spores) and might serve as carriers of disease transmission finally affecting the living organisms habituating these ecosystems. It is suggested that appropriate regulations on face masks waste should be devised to avoid any unwanted consequences in the near future.

Genomic comparison of anoxybacillus flavithermus AK1, a thermophilic bacteria, with other strains.

From ecological and industrial perspectives, Anoxybacillus flavithermus species that lives in a thermophilic environment, are extremely important bacteria due to their potential in producing highly interesting compounds and enzymes. In order to understand the genetic makeup of these thermophiles, we have performed a comparative genomics study of 12 genome-sequenced strains of Anoxybacillus flavithermus bacteria. The genome size of Anoxybacillus flavithermus strains is from 2.5Mbp to 3.7Mbp and on average containing a low percentage of G + C genomic content (˜41.9%). We show that, on the basis of the total gene-content, Anoxybacillus flavithermus strains are grouped in three different subgroups. In the future, it would be interesting to explore these strain subgroups to further understand the lifestyle of thermophilic bacteria. Focussing on the Anoxybacillus flavithermus AK1 strain, which was isolated from a Hot Spring in Saudi Arabia and closely related to A. flavithermus NBRC strain, we identified a unique list of 75 genes specific to AK1 strain, of which 63 of them have homologs in other taxonomically related species. We speculate that these AK1-specific genes might be resulted due to horizontal gene transfer from other bacteria in order to adapt to the extreme environmental conditions. Moreover, we predicted three potential secondary metabolite gene clusters in the AK1 strain that further need to be experimentally characterised. Genomic annotation, secondary metabolite gene clusters and outcomes of the strain genomic comparisons from this study would be the basis for the strain-specific mathematical model for exploiting the metabolism for the industrial and ecological applications.

Site-directed chemically-modified magnetic enzymes: fabrication, improvements, biotechnological applications and future prospects.

Numerous enzymes of biotechnological importance have been immobilized on magnetic nanoparticles (MNP) via random multipoint attachment, resulting in a heterogeneous protein population with potential reduction in activity due to restriction of substrate access to the active site. Several chemistries are now available, where the modifier can be linked to a single specific amino acid in a protein molecule away from the active-site, thus enabling free access of the substrate. However, rarely these site-selective approaches have been applied to immobilize enzymes on nanoparticles. In this review, for the first time, we illustrate how to adapt site-directed chemical modification (SDCM) methods for immobilizing enzymes on iron-based MNP. These strategies are mainly chemical but may additionally require genetic and enzymatic methods. We critically examine each method and evaluate their scope for simple, quick, efficient, mild and economical immobilization of enzymes on MNP. The improvements in the catalytic properties of few available examples of immobilized enzymes are also discussed. We conclude the review with the applications and future prospects of site-selectively modified magnetic enzymes and potential benefits of this technology in improving enzymes, including cold-adapted homologues, modular enzymes, and CO2-sequestering, as well as non-iron based nanomaterials.

Insights into Brevibacillus borstelensis AK1 through Whole Genome Sequencing: A Thermophilic Bacterium Isolated from a Hot Spring in Saudi Arabia.

Brevibacillus borstelensis AK1 is a thermophile which grows between the temperatures of 45°C and 70°C. The present study is an extended genome report of B. borstelensis AK1 along with the morphological characterization. The strain is isolated from a hot spring in Saudi Arabia (southeast of the city Gazan). It is observed that the strain AK1 is rod-shaped, motile, and strictly aerobic bacterium. The whole genome sequence resulted in 29 contigs with a total length of 5,155,092 bp. In total, 3,946 protein-coding genes and 139 RNA genes were identified. Comparison with the previously submitted strains of B. borstelensis strains illustrates that strain AK1 has a small genome size but high GC content. The strain possesses putative genes for degradation of a wide range of substrates including polyethylene (plastic) and long-chain hydrocarbons. These genomic features may be useful for future environmental/biotechnological applications.

Genome Sequence of Anoxybacillus flavithermus Strain AK1, a Thermophile Isolated from a Hot Spring in Saudi Arabia.

Anoxybacillus flavithermus strain AK1 was isolated from Al-Ain Alhara, a thermal hot spring located 50 km southeast of the city of Gazan, Saudi Arabia (16°56'N, 43°15'E). The sequenced and annotated genome is 2,630,664 bp and encodes 2,799 genes.

Fast Disinfection of Escherichia coli Bacteria Using Carbon Nanotubes Interaction with Microwave Radiation.

Water disinfection has attracted the attention of scientists worldwide due to water scarcity. The most significant challenges are determining how to achieve proper disinfection without producing harmful byproducts obtained usually using conventional chemical disinfectants and developing new point-of-use methods for the removal and inactivation of waterborne pathogens. The removal of contaminants and reuse of the treated water would provide significant reductions in cost, time, liabilities, and labour to the industry and result in improved environmental stewardship. The present study demonstrates a new approach for the removal of Escherichia coli (E. coli) from water using as-produced and modified/functionalized carbon nanotubes (CNTs) with 1-octadecanol groups (C18) under the effect of microwave irradiation. Scanning/transmission electron microscopy, thermogravimetric analysis, and FTIR spectroscopy were used to characterise the morphological/structural and thermal properties of CNTs. The 1-octadecanol (C18) functional group was attached to the surface of CNTs via Fischer esterification. The produced CNTs were tested for their efficiency in destroying the pathogenic bacteria (E. coli) in water with and without the effect of microwave radiation. A low removal rate (3-5%) of (E. coli) bacteria was obtained when CNTs alone were used, indicating that CNTs did not cause bacterial cellular death. When combined with microwave radiation, the unmodified CNTs were able to remove up to 98% of bacteria from water, while a higher removal of bacteria (up to 100%) was achieved when CNTs-C18 was used under the same conditions.

Rapid disinfection of E-Coliform contaminated water using WO3 semiconductor catalyst by laser-induced photo-catalytic process.

Laser-induced photo-catalysis process using WO(3) semiconductor catalyst was applied for the study of disinfection effectiveness of E-coliform-contaminated water. For this purpose, wastewater polluted with E-coliform bacteria was exposed to 355 nm UV radiations generated by third harmonic of Nd: YAG laser in special glass cell with and without WO(3) catalyst. E-Coliform quantification was performed by direct plating method to obtain the efficiency of each disinfection treatment. The dependence of disinfection process on laser irradiation energy, amount of catalyst and duration of laser irradiation was also investigated. The disinfection with WO(3) was quite efficient inactivating E-coliforms. For inactivation of E-coliforms, less than 8 minutes' laser irradiation was required, so that, the treated water complies with the microbial standards for drinking water. This study opens the possibility of application of this simple method in rural areas of developing countries using solar radiation.