80 research outputs found
A Review of Core Catchers for Advanced Reactors
In order to address the challenges of severe accident and to ensure safety of people and environment, a core retention device called as “core catcher” has been incorporated in the present and future reactor designs. The concept of core catcher came into existence as early as in early nineties. It is the system which is placed inside the reactor in such a manner that even in the severe accidental scenario, it will retain the corium, quench it and then sustain the coolability of the debris formed due to corium water interactions. From then various approaches to development of core catchers for advanced reactors have been proposed and studied extensively. Since these studies involve milti-component analysis and multi-phase simulations, still there are unresolved issues like Understanding of phenomenology of melt inversion and ablation behaviour Kinetics of chemical interactions of corium and sacrificial materials Model development predicting the behaviour of the sacrificial material with corium
Long range prediction of Indian summer monsoon rainfall
The search for new parameters for predicting the all India summer monsoon rainfall (AISMR) has been an important aspect of long range prediction of AISMR. In recent years NCEP/NCAR reanalysis has improved the geographical coverage and availability of the data and this can be easily updated. In this study using NCEP/NCAR reanalysis data on temperature, zonal and meridional wind at different pressure levels, few predictors are identified and a prediction scheme is developed for predicting AISMR. The regression coefficients are computed by stepwise multiple regression procedure. The final equation explained 87% of the variance with multiple correlation coefficient (MCC), 0.934. The estimated rainfall in the El-Niño year of 1997 was −1.7% as against actual of 4.4%. The estimated rainfall deficiency in both the recent deficient years of 2002 and 2004 were −19.5% and −8.5% as against observed −20.4% and −11.5% respectively
On forecasting the Indian summer monsoon: The intriguing season of 2002
This year, the rainfall over India during the first half of the summer monsoon season was 30 below normal. This has naturally led to a lot of concern and speculation about the causes. We have shown that the deficit in rainfall is a part of the natural variability. Analysis of the past data suggests that there is a 78 chance that seasonal mean rainfall this year will be 10 or more below the long-term average value. We discuss briefly how forecasts for seasonal rainfall are generated, whether this event could have been foreseen, and share our perspective on the problems and prospects of forecasting the summer monsoon rainfall over the Indian region
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The impact of monsoon intraseasonal variability on renewable power generation in India
India is increasingly investing in renewable technology to meet rising energy demands, with hydropower and other renewables comprising one-third of current installed capacity. Installed wind-power is projected to increase 5-fold by 2035 (to nearly 100GW) under the International Energy Agency’s New Policies scenario. However, renewable electricity generation is dependent upon the prevailing meteorology, which is strongly influenced by monsoon variability. Prosperity and widespread electrification are increasing the demand for air conditioning, especially during the warm summer.
This study uses multi-decadal observations and meteorological reanalysis data to assess the impact of intraseasonal monsoon variability on the balance of electricity supply from wind-power and temperature-related demand in India. Active monsoon phases are characterised by vigorous convection and heavy rainfall over central India. This results in lower temperatures giving lower cooling energy demand, while strong westerly winds yield high wind-power output. In contrast, monsoon breaks are characterised by suppressed precipitation, with higher temperatures and hence greater demand for cooling, and lower wind-power output across much of India. The opposing relationship between wind-power supply and cooling demand during active phases (low demand, high supply) and breaks (high demand, low supply) suggests that monsoon variability will tend to exacerbate fluctuations in the so-called demand-net-wind (i.e., electrical demand that must be supplied from non-wind sources).
This study may have important implications for the design of power systems and for investment decisions in conventional schedulable generation facilities (such as coal and gas) that are used to maintain the supply/demand balance. In particular, if it is assumed (as is common) that the generated wind-power operates as a price-taker (i.e., wind farm operators always wish to sell their power, irrespective of price) then investors in conventional facilities will face additional weather-volatility through the monsoonal impact on the length and frequency of production periods (i.e. their load-duration curves)
Investigation of oil palm harvesting tools design and technique on work-related musculoskeletal disorders of the upper body
The oil palm industry is one of the important sectors in Malaysia. The growth and development of this industry
shows that Malaysia is the world second-largest oil palm producers. However, in the fresh fruit bunch (FFB)
harvesting process, the harvesters are exposed to many types of work-related musculoskeletal disorders
(WMSDs). The FFB harvesters tend to develop WMSDs especially the shoulders and trunk. Hence, it is important
to identify the exposure levels, awkward postures and the reaction forces of muscle activity based on the posture
and movement of the harvesters when using pole, chisel and loading spike during the harvesting process. The
objective of this study was to investigate the effect of the design of oil palm FFB harvesting tools on WMSDs of
the upper body. Rapid Upper Limb Analysis (RULA) was used to investigate and assess the exposure level on the
harvester body during the harvesting process. The assessment showed that the shoulders and trunk have high
exposure level and undergo awkward posture. Human Musculoskeletal Model Analysis (HMMA) was used to
identify the reaction force exerted on the muscle during the FFB harvesting process. In this study, 4 muscles were
analysed including Triceps, Biceps, Erector Spinae and Psoas Major. The highest reaction force of 16.36 N was
found on the left triceps when handling a loading spike. In conclusion, it is important to address the risks by
reviewing all possible aspects that contribute to the WMSDs and interventions on the tool design, task and
working shifts may be required
Cardiorespiratory Progression Over 5 Years and Role of Corticosteroids in Duchenne Muscular Dystrophy: A Single-Site Retrospective Longitudinal Study
Background:
Duchenne muscular dystrophy (DMD) boys treated with corticosteroids (CS) have prolonged survival and respiratory function when compared to CS-naïve. /\ud
Research question:
The differential impact of frequently used corticosteroids and their regimens on long-term (>5 years) cardiorespiratory progression in DMD children is unknown. /
Study Design and Methods: Retrospective longitudinal study including DMD children followed at Dubowitz Neuromuscular Centre (Great Ormond Street Hospital London), May 2000-June 2017. Patients enrolled in any interventional clinical trials were excluded. We collected patients’ anthropometrics, respiratory (forced vital capacity, FVC% predicted and absolute FVC, non-invasive ventilation requirement, NIV) and cardiac (left ventricular shortening function, LVFS%) function. CS-naïve patients had never received CS. CS-treated took either deflazacort or prednisolone, daily or intermittently (10 days on/10 days off) for >1 month. Average longitudinal models were fitted for yearly respiratory (FVC%P) and cardiac (LVFS%) progression. A time-to-event analysis to FVC%P<50%, NIV start and cardiomyopathy (LVFS<28%) was performed in CS-treated (daily and intermittent) vs CS-naïve patients. /
Results:
There were 270 patients, mean age at baseline 6.2 (±2.3) years. Median follow-up 5.6 (± 3.5) years. At baseline, 263 were ambulant. Sixty-six were CS-daily, 182 CS-intermittent >60% treatment, 22 CS-naïve. Yearly FVC%P declined similarly from 9 years (5.9% and 6.9%/year, p=0.27) in CS-daily and CS-intermittent. CS-daily declined from a higher FVC%P than CS-intermittent (p2 years later than CS-treated. LVFS% declined by 0.53%/year in CS-treated irrespective of CS regimen, significantly slower (p<0.01) than CS-naïve progressing by 1.17%/year. Age at cardiomyopathy was 16.6 in CS-treated (p<0.05) irrespective of regimen and 13.9 years in CS-naïve. /
Interpretation:
CS irrespective of their regimen significantly improved respiratory function and delayed NIV requirement and cardiomyopathy
Clinical spectrum, treatment and outcome of children with suspected diagnosis of chronic inflammatory demyelinating polyradiculoneuropathy
Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a treatable chronic disorder of the peripheral nervous system. We retrospectively studied 30 children with a suspected diagnosis of CIDP. The diagnosis of CIDP was compared against the childhood CIDP revised diagnostic criteria 2000. Of the 30 children, five did not meet the criteria and four others met the criteria but subsequently had alternative diagnosis, leaving a total of 21 children (12 male) with CIDP as the final diagnosis. Thirteen children presented with chronic symptom-onset (>8 weeks). The majority presented with gait difficulties or pain in legs (n = 16). 12 children (57%) met the neurophysiological criteria and 18/19 (94%) met the cerebrospinal fluid criteria. Nerve biopsy was suggestive in 3/9 (33%), with magnetic resonance imaging supportive in 9/20 (45%). Twenty-one children received immuno-modulatory treatment at first presentation, of which majority (n = 19, 90%) received IVIG (immunoglobulin) monotherapy with 13 (68%) showing a good response. 8 children received second line treatment with either IVIG or steroids or plasmapharesis (PE) and 4 needed other immune-modulatory agents. During a median follow-up of 3.6 years, 9 (43%) had a monophasic course and 12 (57%) had a relapsing–remitting course. At last paediatric follow up 7 (33%) were off all treatment, 9 (43%) left with no or minimal residual disability and 6 (28%) children were walking with assistance (n = 3) or were non-ambulant (n = 3). Our review highlights challenges in the diagnosis and management of paediatric CIDP. It also confirms that certain metabolic disorders may mimic CIDP
Efficacy and safety of onasemnogene abeparvovec in children with spinal muscular atrophy type 1: real-world evidence from 6 infusion centres in the United Kingdom
Background: Real-world data on the efficacy and safety of onasemnogene abeparvovec (OA) in spinal muscular atrophy (SMA) are needed, especially to overcome uncertainties around its use in older and heavier children. This study evaluated the efficacy and safety of OA in patients with SMA type 1 in the UK, including patients ≥2 years old and weighing ≥13.5 kg. / Methods: This observational cohort study used data from patients with genetically confirmed SMA type 1 treated with OA between May 2021 and January 2023, at 6 infusion centres in the United Kingdom. Functional outcomes were assessed using age-appropriate functional scales. Safety analyses included review of liver function, platelet count, cardiac assessments, and steroid requirements. / Findings: Ninety-nine patients (45 SMA therapy-naïve) were treated with OA (median age at infusion: 10 [range, 0.6–89] months; median weight: 7.86 [range, 3.2–20.2] kg; duration of follow-up: 3–22 months). After OA infusion, mean ± SD change in CHOP-INTEND score was 11.0 ± 10.3 with increased score in 66/78 patients (84.6%); patients aged 100 U/L (95% CI, 2.3–223.7; P = 0.008) and 21.2-fold increased odds of steroid doubling, as per treatment protocol (95% CI, 2.2–209.2; P = 0.009) in patients weighing ≥13.5 kg versus <8.5 kg. Weight at infusion was positively correlated with steroid treatment duration (r = 0.43; P < 0.001). Worsening transaminitis, despite doubling of oral prednisolone, led to treatment with intravenous methylprednisolone in 5 children. Steroid-sparing immunosuppressants were used in 5 children to enable steroid weaning. Two deaths apparently unrelated to OA were reported. / Interpretation: OA led to functional improvements and was well tolerated with no persistent clinical complications, including in older and heavier patients. / Funding: Novartis Innovative Therapies AG provided a grant for independent medical writing services
MRI compared to conventional diagnostic work-up in the detection and evaluation of invasive lobular carcinoma of the breast: a review of existing literature
Item does not contain fulltextPURPOSE: The clinical diagnosis and management of invasive lobular carcinoma (ILC) of the breast presents difficulties. Magnetic resonance imaging (MRI) has been proposed as the imaging modality of choice for the evaluation of ILC. Small studies addressing different aspects of MRI in ILC have been presented but no large series to date. To address the usefulness of MRI in the work-up of ILC, we performed a review of the currently published literature. MATERIALS AND METHODS: We performed a literature search using the query "lobular AND (MRI OR MR OR MRT OR magnetic)" in the Cochrane library, PubMed and scholar.google.com, to retrieve all articles that dealt with the use of MRI in patients with ILC. We addressed sensitivity, morphologic appearance, correlation with pathology, detection of additional lesions, and impact of MRI on surgery as different endpoints. Whenever possible we performed meta-analysis of the pooled data. RESULTS: Sensitivity is 93.3% and equal to overall sensitivity of MRI for malignancy in the breast. Morphologic appearance is highly heterogeneous and probably heavily influenced by interreader variability. Correlation with pathology ranges from 0.81 to 0.97; overestimation of lesion size occurs but is rare. In 32% of patients, additional ipsilateral lesions are detected and in 7% contralateral lesions are only detected by MRI. Consequently, MRI induces change in surgical management in 28.3% of cases. CONCLUSION: This analysis indicates MRI to be valuable in the work-up of ILC. It provides additional knowledge that cannot be obtained by conventional imaging modalities which can be helpful in patient treatment
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