Study on Laser Surface Enhancement of Marine Propellers

Due to the effects of global warming reducing the extent of the sea ice, more and more merchant ships enter ice-infested waters. Ice damages on ships are frequently reported. Propeller is among the most vulnerable parts of a ship subject to ice damages. Propeller damages lead to efficiency loss, deterioration of cavitation and noise, and even malfunction of the propulsion system. Reparation of damaged propellers are costly. In this study, we aimed at enhancing a propeller’s ice strength while keeping its open-water profile. This was achieved by implementing cladding material on the bronze propeller blades through laser treatment. In this thesis work, numerical analyses of laser cladding process was carried out using finite element (FE) method to investigate if the laser cladding improves the resistance of the marine propeller materials against repeated ice impact loads. A Co-Cr alloy was cladded on two different substrate materials. The laser cladded surfaces were grounded where the effect of a grinding wheel was derived using a combination of rectangular distribution of heat source and grinding forces instead of the presence of actual grinding wheel. Repeated ice impact loads were applied on both the non-cladded substrate and the cladded substrates after grinding for a certain period of time. The efficiency of the cladding and grinding processes was estimated using the impact load simulations. It was observed that after the application of every impact load on the non-cladded substrate, the longitudinal residual stresses and the equivalent plastic strain were increased. But, after grinding the cladded substrate, there was an improvement in the equivalent plastic strain. The inference obtained after multiple simulations were that the grinding process improves the equivalent plastic strain on the cladded substrate. It thus concludes that the laser cladding and grinding processes improve the performance of the propellers against repeated ice impact loads considerably

Elective laparoscopic cholecystectomy:recurrent biliary admissions predispose to difficult cholecystectomy

INTRODUCTION: Patients undergoing elective laparoscopic cholecystectomy (ELLC) represent a heterogeneous group making it challenging to stratify risk. The aim of this paper is to identify pre-operative factors associated with adverse peri- and post-operative outcomes in patients undergoing ELLC. This knowledge will help stratify risk, guide surgical decision making and better inform the consent process. METHODS: All patients who underwent ELLC between January 2015 and December 2019 were included in the study. Pre-operative data and both peri- and post-operative outcomes were collected retrospectively from multiple databases using a deterministic records-linkage methodology. Patients were divided into groups based on clinical indication (i.e. biliary colic versus cholecystitis) and adverse outcomes were compared. Multivariate regression models were generated for each adverse outcome using pre-operative independent variables. RESULTS: Two-thousand one hundred and sixty-six ELLC were identified. Rates of peri- and post-operative adverse outcomes were significantly higher in the cholecystitis versus biliary colic group and increased with number of admissions of cholecystitis (p < 0.05). Rates of subtotal (29.5%), intra-operative complication (9.8%), post-operative complications (19.6%), prolonged post-operative stay (45.9%) and re-admission (16.4%) were significant in the group of patients with ≥ 2 admissions with cholecystitis. CONCLUSION: Our data demonstrate that patients with repeated biliary admission (particularly cholecystitis) ultimately face an increased risk of a difficult ELLC with associated complications, prolonged post-operative stay and readmissions. These data provide robust evidence that individualised risk assessment and consent are necessary before ELLC. Strategies to minimise recurrent biliary admissions prior to LC should be implemented

Evaluation of Textbook Outcome as a Composite Quality Measure of Elective Laparoscopic Cholecystectomy

IMPORTANCE: A textbook outcome (TO) is a composite quality measure that incorporates multiple perioperative events to reflect the most desirable outcome. The use of TO increases the event rate, captures more outcomes to reflect patient experience, and can be used as a benchmark for quality improvement. OBJECTIVES: To introduce the concept of TO to elective laparoscopic cholecystectomy (LC), propose the TO criteria, and identify characteristics associated with TO failure. DESIGN, SETTING, AND PARTICIPANTS: This retrospective cohort study was performed at 3 surgical units in a single health board in the United Kingdom. Participants included all patients undergoing elective LC between January 1, 2015, and January 1, 2020. Data were analyzed from January 1, 2015, to January 1, 2020. MAIN OUTCOMES AND MEASURES: The TO criteria were defined based on review of existing TO metrics in the literature for other surgical procedures. A TO was defined as an unremarkable elective LC without conversion to open cholecystectomy, subtotal cholecystectomy, intraoperative complication, postoperative complications (Clavien-Dindo classification ≥2), postoperative imaging, postoperative intervention, prolonged length of stay (>2 days), readmission within 100 days, or mortality. The rate of TOs was reported. Reasons for TO failure were reported, and preoperative characteristics were compared between TO and TO failure groups using both univariate analysis and multivariable logistic regressions. RESULTS: A total of 2166 patients underwent elective LC (median age, 54 [range, 13-92] years; 1579 [72.9%] female). One thousand eight hundred fifty-one patients (85.5%) achieved a TO with an unremarkable perioperative course. Reasons for TO failure (315 patients [14.5%]) included conversion to open procedure (25 [7.9%]), subtotal cholecystectomy (59 [18.7%]), intraoperative complications (40 [12.7%]), postoperative complications (Clavien-Dindo classification ≥2; 92 [29.2%]), postoperative imaging (182 [57.8%]), postoperative intervention (57 [18.1%]), prolonged length of stay (>2 days; 142 [45.1%]), readmission (130 [41.3%]), and mortality (1 [0.3%]). Variables associated with TO failure included increasing American Society of Anesthesiologists score (odds ratio [OR], 2.55 [95 CI, 1.69-3.85]; P < .001), increasing number of prior biliary-related admissions (OR, 2.68 [95% CI, 1.36-5.27]; P = .004), acute cholecystitis (OR, 1.42 [95% CI, 1.08-1.85]; P = .01), preoperative endoscopic retrograde cholangiopancreatography (OR, 2.07 [95% CI, 1.46-2.92]; P < .001), and preoperative cholecystostomy (OR, 3.22 [95% CI, 1.54-6.76]; P = .002). CONCLUSIONS AND RELEVANCE: These findings suggest that applying the concept of TO to elective LC provides a benchmark to identify suboptimal patterns of care and enables institutions to identify strategies for quality improvement

CLINICAL COMPARATIVE STUDY IN THE MANAGEMENT OF KASHTARTAVA W.S.R. PRIMARY DYSMENORRHOEA WITH RUTUKARI VATI AND KUMARYASAVA

Adolescence is the rapid growing period when mainly the physical changes are important. 95% girls attain menarche at the age group of 10 to 16 yrs, the peak being 13yrs. Among them, not less than 50% of female are said to experience some discomfort or pain in relation to menstruation. Kashtartava is a symptom mentioned in various Yoni vyapads, Vata being the main causative factor for this condition, which is commonly compared with dysmenorrhoea by cotemporary science. Conventional treatment of primary dysmenorrhoea consists of non-steroidal and anti-inflammatory drugs, hormonal therapy which causes unwanted side effects. Hence Rutukari Vati which is mentioned in Bheshaja Samhita for Kashtartava having the properties like, Vedanashamaka, Arthavajanana have been selected for the planned study. Design of Study: A Single blind comparative clinical study of two groups, trial and control, consisting of 15 subjects in each with pre-test and post-test design. Group A was given Rutukarivati and Group B was given Kumaryasava 25ml twice daily after food. Result: Rutukarivati contains most of the drugs with Tiktha and Katu rasa, Usnaveerya property and Vatakaphahara property; it is effective in controlling pain and regularizing the cycle. On comparison of overall effect of both groups has more significant result but percentage wise group A is more effective than group B. Mild increase in amount of bleeding was noted in patients in group A. It may be because of most of the ingredients in Rutukarivati are Artavajanana and Apanavatashaman. &nbsp

Economic dependence of forest fringe communities on threatened and near-threatened medicinal trees of Madhya Pradesh - the largest forest cover state of central India

People have a free access to the Non timber forest produce (NTFP) in the State of Madhya Pradesh, India barring only a few NTFP which are monopolized by the state for collection and trade. Because of such free access tenure, people and the policy makers have little appreciation for the provisional ecosystem services emanating from the state’s forests. Hence, a research study was conducted in Madhya Pradesh state of India during 2014-2015.This paper evaluates the dependence of the forest fringe communities on the already Threatened and Near-threatened Medicinal Tree resources (TNMTs) in the forests of the state for their health and livelihood requirements.This study was conducted in all the six eco-regions of the state after selecting the most forested divisions and purposely selected forest compartments and socio-economic surveys were conducted in the villages adjoining these forest compartments. The TNMTs of these compartments were fully enumerated in the selected compartments and their physical conditions were recorded. Focus group discussions and household surveys were conducted to study the dependence of forest fringe communities on TNMTs in the adjoining forests. The results show that contribution of direct forest income to the total annual household income was found to vary from 29.35% to 69.48% in forest divisions located in all the six eco-regions of the state. In all the six eco-regions, the percentage of households found to be dependent on forests for some or the other benefits ranged from 96% to 100%.  Almost all the TNMTs encountered during this survey were found facing threat of local extinction due to poor regeneration and many other factors at most of the forest sites. The authors have suggested some corrective measures for sustainable management of forest resources for the benefit of forest fringe community in the article

A uracil nitroso amine based colorimetric sensor for the detection of Cu²⁺ ions from aqueous environment and its practical applications

A simple uracil nitroso amine based colorimetric chemosensor (UNA-1) has been synthesized and screened for its cation recognition ability. Sensor UNA-1 exhibited a high sensitivity and selectivity towards Cu²⁺ ions in aqueous medium in the presence of a wide range of other competing cations (Ag⁺, Al³⁺, Ba²⁺+, Ca²⁺, Cd²⁺, Co²⁺, Cr³⁺, Cs⁺, Fe²⁺, Fe³⁺, Li⁺, Mg²⁺, Mn²⁺, Na⁺, Ni²⁺, Pb²⁺, Zn²⁺, Hg²⁺ and Sr²⁺). With Cu²⁺, the sensor UNA-1 gave a distinct color change from colorless to dark yellow by forming a complex of 1:1 stoichiometry. Furthermore, sensor UNA-1 was successfully utilized in the preparation of test strips and supported silica for the detection of Cu²⁺ ions from aqueous environment

Energy-Efficient Time-Based Encoders and Digital Signal Processors in Continuous Time

Continuous-time (CT) data conversion and continuous-time digital signal processing (DSP) are an interesting alternative to conventional methods of signal conversion and processing. This alternative proposes time-based encoding that may not suffer from aliasing; shows superior spectral properties (e.g. no quantization noise floor); and enables time-based, event-driven, flexible signal processing using digital circuits, thus scaling well with technology. Despite these interesting features, this approach has so far been limited by the CT encoder, due to both its relatively poor energy efficiency and the constraints it imposes on the subsequent CT DSP. In this thesis, we present three principles that address these limitations and help improve the CT ADC/DSP system. First, an adaptive-resolution encoding scheme that achieves first-order reconstruction with simple circuitry is proposed. It is shown that for certain signals, the scheme can significantly reduce the number of samples generated per unit of time for a given accuracy compared to schemes based on zero-order-hold reconstruction, thus promising to lead to low dynamic power dissipation at the system level. Presented next is a novel time-based CT ADC architecture, and associated encoding scheme, that allows a compact, energy-efficient circuit implementation, and achieves first-order quantization error spectral shaping. The design of a test chip, implemented in a 0.65-V 28-nm FDSOI process, that includes this CT ADC and a 10-tap programmable FIR CT DSP to process its output is described. The system achieves 32 dB – 42 dB SNDR over a 10 MHz – 50 MHz bandwidth, occupies 0.093 mm2, and dissipates 15 µW–163 µW as the input amplitude goes from zero to full scale. Finally, an investigation into the possibility of CT encoding using voltage-controlled oscillators is undertaken, and it leads to a CT ADC/DSP system architecture composed primarily of asynchronous digital delays. The latter makes the system highly digital and technology-scaling-friendly and, hence, is particularly attractive from the point of view of technology migration. The design of a test chip, where this delay-based CT ADC/DSP system architecture is used to implement a 16-tap programmable FIR filter, in a 1.2-V 28-nm FDSOI process, is described. Simulations show that the system will achieve a 33 dB – 40 dB SNDR over a 600 MHz bandwidth, while dissipating 4 mW

Samoemulzirajući pripravci za peroralnu primjenu simvastatina: Ispitivanja in vitro i in vivo

The objective of the present work was to formulate a self-emulsifying drug delivery system (SEDDS) for simvastatin, which is widely used in the treatment of hypercholesterolemia and dyslipidemia as an adjunct to diet. Simvastatin SEDDS were formulated using a 1:1 (V/V) mixture of diesters of caprylic/capric acids and polyglycolyzed glycerides with varying concentrations of polyoxy 35 castor oil and C8/C10 mono-/diglycerides. The developed SEDDS were evaluated for turbidimetry, droplet size analysis, drug content and in vitro diffusion profiles. In vivo performance of the optimized formulation was evaluated in rats using pharmacodynamic marker parameters like plasma total cholesterol (CH), triglycerides (TG) and high-density lipoprotein (HDL-CH) for 21 days. SEDDS containing 9.1% (m/m) simvastatin and 23%, (m/m) of each excipient showed minimum mean droplet size (124 nm) and optimal drug diffusion. This test formulation showed significant reduction in plasma CH and TG (around 5-fold and 4-fold, respectively), while HDL-CH concentration was markedly higher (2-fold) compared a reference simvastatin suspension formulation after oral administration for 21 days of study. Test formulation has shown enhanced pharmacodynamic performance compared to reference formulation in rats. The study illustrated the potential of simvastatin SEDDS for oral administration and its biopharmaceutic performance.Cilj rada bio je pripraviti samoemulzirajući sustav za isporuku lijeka (SEDDS) za simvastatin, hipolipemik koji se uz dijetu upotrebljava u terapiji hiperkolesterolemije i dislipidemije. Simvastatin SEDDS su pripravljene koristeći smjesu 1:1 (V/V) diestera kaprilne i kaprinske kiseline i poliglikoliziranih glicerida s različitim koncentracijama polioksil 35 kastorovog ulja i C8/C10 mono-/diglicerida. Pripravcima su ispitana turbidimetrijska svojstva, veličina čestica, udio lijeka i in vitro difuzijski profil. U pokusima in vivo na štakorima praćeni su parametri farmakodinamičkih markera kao što su ukupni kolesterol u plazmi (CH), trigliceridi (TG) i lipoproteini velike gustoće (HDL-CH) tijekom 21 dana. Pripravci koji sadrže 9,1% (m/m) simvastatina i 23% (m/m) svake od pomoćnih tvari imaju najmanju prosječnu veličinu čestica (124 nm) i iz njih je difuzija lijeka optimalna. Ispitivani pripravci značajno snizuju CH i TG u plazmi (5, odnosno 4 puta), dok je koncentracija HDL-CH ostaje izrazito visoka, 2 puta viša u usporedbi s referentnom suspenzijom simvastatina poslije peroralne primjene tijekom 21 dan. Ispitivani pripravci imaju bolji farmakodinamički profil u odnosu na referentni pripravak pa imaju veliki potencijal za peroralnu primjenu simvastatina

Morbidity following emergency and elective cholecystectomy:a retrospective comparative cohort study

INTRODUCTION: An emergency laparoscopic cholecystectomy (EMLC) is commonly performed for all biliary pathology, yet EMLC can be challenging due to acute inflammation. Understanding the risks of EMLC is necessary before patients can make an informed decision regarding operative management. The aim of the present study was to compare rates of operative and post-operative outcomes between EMLC and elective LC (ELLC) using a large contemporary cohort, to inform the consent process and influence surgical decision making. METHODS: All patients who underwent EMLC and ELLC in one UK health board between January 2015 and December 2019 were considered for inclusion. Data were collected retrospectively from multiple regional databases using a deterministic records-linkage methodology. Patients were followed up for 100 days post-operatively for adverse outcomes and outcomes were compared between groups using both univariate and multivariate analysis adjusting for pre-operative factors. RESULTS: A total of 2768 LCs were performed [age (range), 52(13–92); M:F, 1:2.7]. In both the univariate and multivariate analysis, EMLC was positively associated with subtotal cholecystectomy (RR 2.0; p < 0.001), post-operative complication (RR 2.8; p < 0.001), post-operative imaging (RR 2.0; p < 0.001), post-operative intervention (RR 2.3; p < 0.001), prolonged post-operative hospitalisation (RR 3.8; p < 0.001) and readmission (RR 2.2; p < 0.001). EMLC had higher rates of post-operative mortality in univariate analysis (RR 10.8; p = 0.01). DISCUSSION: EMLC is positively associated with adverse outcomes versus ELLC. Of course this study does not focus on a specific biliary pathology; nevertheless, it illustrates the additional risk associated with EMLC. This should be clearly outlined during the consent process but should be balanced with the risk of further biliary attacks. Further studies are required to identify particular patient groups who benefit from elective surgery

Conceptual study of Dooshivisha (Cumulative toxicity) w.r.t. Ancient classics and Modern science

Ayurveda describes the vast turnover of beauty aid products. More and more new synthetic substances are introduced every day. Many of these are not adequately tested for safety, in particular for routes other than oral or parenteral. Increased incidence of skin conditions like eczema and contact dermatitis after using newer cosmetics suggest that this may be due to local toxic effects or toxic effects manifested on this phenomenon as Dooshivisha. They are relevant to the current way of life considering the prevalence of pollution, occupational hazards and extent of exposure to toxins in food and other articles used in daily life. Present generation is much more likely to consume junk foods-cold drinks, to have unhealthy travelling habits, working late nights, working with computers in A.C rooms. This is referred to by terms like Hetusatatya, Vegavarodha, Diwaswapa, Viparit Chesta, Virudhannasevana which in turn hamper the normal physiology of human body. Same thing is mentioned in Ayurvedic texts also under the topic of Pradnyaparadh which is the basic cause for all diseases. This Pradnyaparadha is responsible to disturb the daily routine life and person has to face with the complaints of ill-health