A Review on the Need of HVDC Transmission System

With the growing demand of electricity on a daily basis, we cannot rely on conventional electric authority systems like long-haul distributed power stations as well as complicated and heavy load / distribution networks. High voltage direct current (HVDC) transmission systems include an extremely imperative role in authority systems. Without the appropriate study of the HVDC system, it is unfeasible to obtain an accurate mathematical model of the system and in the absence of proper modeling the influence transmitted in the HVDC system cannot be considered. The power transmitted through the HVDC system depends upon the competence of the controller and the converter station.Conservatively, the PID controller was used for the polar current control of the rectifier and the excitation control on the inverter side. This paper is an indication of the HVDC system and covers the essential part of the foundation of the HVDC system. Due to enlarged demand for power at the load center and concentration to distributed power generation, a lot of high capacity long distance HVDC systems are requisite and are intended to achieve various advantages. As growth in the power electronics field advances, HVDC systems are more consistent

Ultrasonic transformation of antibiotic molecules into a selective chemotherapeutic nanodrug

Ultrasound-based engineering of carrier-free nanodrugs by supramolecular self-assembly has recently emerged as an innovative and environmentally friendly synthetic approach. By applying high-frequency sound waves (490 kHz) in aqueous solutions, the transformation of small chemotherapeutic and antibiotic drug molecules into carrier-free nanodrugs with anticancer and antimicrobial activities was recently achieved. The transformation of the antibiotic drug molecules, i.e., doxycycline, into stable nanodrugs (similar to 130 nm) with selective anticancer activity was achieved without requiring organic solvents, chemical agents, or surfactants. The obtained nanodrug exhibited reactive oxygen species (ROS)-mediated cytotoxicity on human breast cancer (MDA-MB 231 cells) but a negligible antiproliferative effect on healthy fibroblast cells. Imaging by super-resolution microscopy (STORM) provided insights into the intracellular trafficking and endosomal escape of the nanodrugs. Overall, these findings suggest that small antibiotic drugs can be transformed into chemotherapeutic nanodrugs with high selectivity against cancer cells

Synthesis of bio-functional nanoparticles from sono-responsive amino acids using high frequency ultrasound

A simple, one-pot high frequency ultrasonication (490 kHz) methodology to convert hydrophobic and amphipathic amino acids into nanostructures was investigated. The approach involved the oxidative coupling of aromatic amino acids (phenylalanine and tryptophan) in aqueous solutions to form high molecular weight dimers and oligomers. The role of cavitation bubble surface and ultrasonic power to trigger the out-of-equilibrium self-assembly of dimers and trimers to spherical and uniform nanostructures with controlled size has been discussed. The synthesized particles exhibited fluorescence in blue, green and red spectral regions and a strong antioxidant activity

Sonosynthesis of nanobiotics with antimicrobial and antioxidant properties

Transforming small-molecule antibiotics into carrier-free nanoantibiotics represents an opportunity for developing new multifunctional therapeutic agents. In this study, we demonstrate that acoustic cavitation produced by high-frequency ultrasound transforms the antibiotic doxycycline into carrier-free nanobiotics. Upon sonication for 1 h at 10-15 W cm(-3), doxycycline molecules underwent hydroxylation and dimerization processes to ulti-mately self-assemble into nanoparticles of ~100-200 nm in size. Micrometer sized particles can be also obtained by increasing the acoustic power to 20 W cm(-3). The nanodrugs exhibited antioxidant properties, along with antimicrobial activity against both Gram-positive (S. aureus) and Gram-negative (E. coli) bacterial strains. Our results highlight the feasibility of the ultrasound-based approach for engineering drug molecules into a nanosized formulation with controlled and multiple bio-functionalities

Sonocrystallization of Lactose from Whey

Whey is a by-product obtained from the cheese-making industry. This by-product is the primary source of high-value products such as whey protein concentrates and lactose. The partial removal of water from the whey is the first step in the recovery of lactose. Then, lactose in the concentrated whey is forced to crystallize through a cooling stage. This conventional process of crystallization is very slow up to 72 h accompanied by the generation of a mixture of lactose types (α, β, and amorphous) and low yield of lactose. These issues have been addressed through the seeding of lactose, the antisolvent crystallization, and more recently, by the crystallization of lactose assisted with low-frequency power ultrasound. Sonocrystallization is known to have a number of specific features that include the enhancement of the primary and secondary nucleation, as well as the development of smaller crystals with more uniform sizes and higher purity. Nowadays, there are a number of studies that provide relevant information on the effects of ultrasound on lactose crystallization, although some of these effects are still not fully understood. This book chapter discusses the current knowledge on lactose sonocrystallization and describes the basic principles of lactose crystallization and sonocrystallization

The transdermal delivery of therapeutic cannabinoids

Recently, several studies have indicated an increased interest in the scientific community regarding the application of Cannabis sativa plants, and their extracts, for medicinal purposes. This plant of enormous medicinal potential has been legalised in an increasing number of countries globally. Due to the recent changes in therapeutic and recreational legislation, cannabis and cannabinoids are now frequently permitted for use in clinical settings. However, with their highly lipophilic features and very low aqueous solubility, cannabinoids are prone to degradation, specifically in solution, as they are light-, temperature-, and auto-oxidation-sensitive. Thus, plant-derived cannabinoids have been developed for oral, nasal-inhalation, intranasal, mucosal (sublingual and buccal), transcutaneous (transdermal), local (topical), and parenteral deliveries. Among these administrations routes, topical and transdermal products usually have a higher bioavailability rate with a prolonged steady-state plasma concentration. Additionally, these administrations have the potential to eliminate the psychotropic impacts of the drug by its diffusion into a nonreactive, dead stratum corneum. This modality avoids oral administration and, thus, the first-pass metabolism, leading to constant cannabinoid plasma levels. This review article investigates the practicality of delivering therapeutic cannabinoids via skin in accordance with existing literature

Chemoenzymatic surface decoration of Nisin-shelled nanoemulsions: novel targeted drug-nanocarriers for cancer applications

Nisin, a peptide used as a natural food preservative, is employed in this work for the development of a novel nanocarrier system. Stable and uniform nisin-shelled nanoemulsions (NSNE) with a diameter of 100 ± 20 nm were successfully prepared using 20 kHz flow-through ultrasonication technique. The NSNE showed limited toxicity, high bactericidal activity and high drug loading capacity (EE 65 % w/w). In addition, the nisin shell was exploited for the site-specific attachment of a recombinantly produced cancer targeting ligand (αHER2LPETG IgG). Employing a unique two phases (bio-click) approach which involved both Sortase A mediated Azide Bioconjugation (SMAB) and Strain Promoted Azide Alkyne Cycloaddition (SPAAC) reactions, targeted NSNE (NSNEDOX-αHER2 IgG) were successfully assembled and loaded with the chemotherapeutic drug Doxorubicin (DOX). Finally, NSNEDOX-αHER2 IgG showed cancer-specific binding and augmented cytotoxicity to HER2 expressing tumour cells

An engineered nanosugar enables rapid and sustained glucose-responsive insulin delivery in diabetic mice

Glucose-responsive insulin-delivery platforms that are sensitive to dynamic glucose concentration fluctuations and provide both rapid and prolonged insulin release have great potential to control hyperglycemia and avoid hypoglycemia diabetes. Here, biodegradable and charge-switchable phytoglycogen nanoparticles capable of glucose-stimulated insulin release are engineered. The nanoparticles are "nanosugars" bearing glucose-sensitive phenylboronic acid groups and amine moieties that allow effective complexation with insulin (approximate to 95% loading capacity) to form nanocomplexes. A single subcutaneous injection of nanocomplexes shows a rapid and efficient response to a glucose challenge in two distinct diabetic mouse models, resulting in optimal blood glucose levels (below 200 mg dL(-1)) for up to 13 h. The morphology of the nanocomplexes is found to be key to controlling rapid and extended glucose-regulated insulin delivery in vivo. These studies reveal that the injected nanocomplexes enabled efficient insulin release in the mouse, with optimal bioavailability, pharmacokinetics, and safety profiles. These results highlight a promising strategy for the development of a glucose-responsive insulin delivery system based on a natural and biodegradable nanosugar

Can we <i>S</i>ave the rectum by watchful waiting or <i>T</i>rans<i>A</i>nal microsurgery following (chemo) <i>R</i>adiotherapy versus total mesorectal excision for early <i>RE</i>ctal <i>C</i>ancer (STAR-TREC study)?::protocol for a multicentre, randomised feasibility study

Introduction Total mesorectal excision (TME) is the highly effective standard treatment for rectal cancer but is associated with significant morbidity and may be overtreatment for low-risk cancers. This study is designed to determine the feasibility of international recruitment in a study comparing organ-saving approaches versus standard TME surgery. Methods and analysis STAR-TREC trial is a multicentre international randomised, three-arm parallel, phase II feasibility study in patients with biopsy-proven adenocarcinoma of the rectum. The trial is coordinated from Birmingham, UK with national hubs in Radboudumc (the Netherlands) and Odense University Hospital Svendborg UMC (Denmark). Patients with rectal cancer, staged by CT and MRI as ≤cT3b (up to 5 mm of extramural spread) N0 M0 can be included. Patients will be randomised to either standard TME surgery (control), organ-saving treatment using long-course concurrent chemoradiation or organ-saving treatment using short-course radiotherapy. For patients treated with an organ-saving strategy, clinical response to (chemo)radiotherapy determines the next treatment step. An active surveillance regime will be performed in the case of a complete clinical regression. In the case of incomplete clinical regression, patients will proceed to local excision using an optimised platform such as transanal endoscopic microsurgery or other transanal techniques (eg, transanal endoscopic operation or transanal minimally invasive surgery). The primary endpoint of this phase II study is to demonstrate sufficient international recruitment in order to sustain a phase III study incorporating pelvic failure as the primary endpoint. Success in phase II is defined as randomisation of at least four cases per month internationally in year 1, rising to at least six cases per month internationally during year 2

Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability