Modelling of pastes as viscous soils – Lubricated squeeze flow

Highly filled suspensions (or pastes) present complex rheological behaviour and squeeze flow testing is used frequently for rheological characterisation. The extent to which liquid phase migration (LPM) occurs in such tests, and the influence of material extruded from between the plates, was investigated in experiments supported by detailed modelling based on soil mechanics approaches. Lubricated squeeze flow (LSF) tests were conducted on a model saturated ballotini paste prepared with a viscous Newtonian binder, at plate speeds spanning two decades. The tests were simulated using a two-dimensional (2 D) axisymmetric finite element model with adaptive remeshing to circumvent mesh distortion. The paste was modelled as a viscoplastic soil (Drucker-Prager) to capture both rate-dependent effects at high shear rates and LPM at low shear rates. Capillary pressure was applied at the evolving free surface and the plate surfaces were modelled as frictionless for simplicity. Reasonable agreement was obtained between the measured and predicted squeezing pressure profiles at the highest solids volume fraction tested (ϕs = 60%). Agreement was poor at the lowest ϕs (52.5%), which was due to this paste formulation behaving as a suspension/slurry without a distinct yield stress. For the first time, the predicted squeezing pressure was resolved into components using an energy analysis. The squeezing pressure was dominated by the work required to deform the paste in the gap. This result is specific to highly viscoplastic pastes and persisted to small plate separations when most of the sample lay outside the plates. Characterisation of the yield stress from the ‘shoulder’ in the squeezing pressure profile was reasonably accurate at h/h0 ≥ 96% (9% estimated error). LPM was neither observed nor predicted at the plate speeds tested, despite the favourable pore pressure driving force, due to the high binder viscosity and the zero dilation angle in the simulations. The flow field was characterised using a novel flow mode parameter derived from the shear rate tensor. The paste was predicted to undergo pure biaxial extension between the smooth plates, and for the first time was predicted to undergo pure uniaxial extension external to the plates and (briefly) pure shear at the boundary

Marine prasinoviruses and their tiny plankton hosts: A review

This is the final version. Available on open access from MDPI via the DOI in this recordViruses play a crucial role in the marine environment, promoting nutrient recycling and biogeochemical cycling and driving evolutionary processes. Tiny marine phytoplankton called prasinophytes are ubiquitous and significant contributors to global primary production and biomass. A number of viruses (known as prasinoviruses) that infect these important primary producers have been isolated and characterised over the past decade. Here we review the current body of knowledge about prasinoviruses and their interactions with their algal hosts. Several genes, including those encoding for glycosyltransferases, methyltransferases and amino acid synthesis enzymes, which have never been identified in viruses of eukaryotes previously, have been detected in prasinovirus genomes. The host organisms are also intriguing; most recently, an immunity chromosome used by a prasinophyte in response to viral infection was discovered. In light of such recent, novel discoveries, we discuss why the cellular simplicity of prasinophytes makes for appealing model host organism–virus systems to facilitate focused and detailed investigations into the dynamics of marine viruses and their intimate associations with host species. We encourage the adoption of the prasinophyte Ostreococcus and its associated viruses as a model host–virus system for examination of cellular and molecular processes in the marine environment

UNDERSTANDING THE ACTION OF VAITARANABASTI IN GRDHRASI – A CASE STUDY

In the context of Vata Vyadhi Acharyas explain about a painful condition afflicting the lower limbs called ‘Grdhrasi’, Where in the pain from low back gradually radiating towards the regions of the posterior aspect of Kati, Uru, Jaanu, Jangha and Pada is the opinion of Acharya Caraka, but Acharya Sushruta and Acharya Vagbata opines that there are two Kandara in the leg that gets afflicted (Tendons of the feet getting vitiated) by Vata which causes pain radiating towards the ankles or toes is called as Grdhrasi. These two Kandara when gets afflicted with the Vata Dosha limits the extension of the leg. This condition is similar with sciatica which refers to the Radiating pain from low back to lower limb as the typical characteristic feature of this illness. A case report with the presenting complaints of shooting type of pain from low back pain radiating to both the lower limbs posteriorly till the toes (more towards the right lower limb) since six months. As a treatment measure, Vaitarana Basti was selected which showed good result and helped to relieve the impairment of the patient in her daily activities. This article explains about the action of Vaitarana Basti in Grdhrasi

UNDERSTANDING UNMADA W.S.R TO SCHIZOPHRENIA

Manasa Vikara are considered as an abnormal mental condition characterised by impairment of mental functions. Acharyas have elaborated the importance of Manas at various places in the classics. According to Acharya Susruta Manas is regarded as Ahankarika, whereas Caraka Acharya mentions Manas is evolved from Khadini. Acharya Susruta considers Krodha, Shoka, Bhaya etc., as the Nidana of Manasa Vikara whereas Caraka Acharya mentions attachment towards undesired objects and loss of desired objects as the Karana for Manovikara. Unmada is the most elaborately dealt Manasa Vyadhi in Ayurveda. Acharyas have included a broad spectrum of psychiatric disorders under Unmada. Alpa Satwa individuals are considered to be more prone for such disorders. Even the definition of “Health†by WHO suggest mental well-being along with physical and social well-being. Once any disturbance occurs it in turn disturbs the normalcy which may affect the personality of an individual, a characteristic distortion of thinking, disturbed perception etc. Schizophrenia is such a disease characterised by disturbances in thought, verbal behaviour, perception, affect, motor behaviour and relationship to the external world

AN ANALYTICAL REVIEW OF AMLAPITTA ACCORDING TO CARAKA SAMHITA

Today’s lifestyle is completely changed by all means. Our diet pattern, lifestyle and behavioural patterns are changed and are not suitable for our normal physiology of digestion of the body. For a long time, infectious diseases were the biggest killer diseases globally. But now, the trend is changing toward increased prevalence of chronic diseases with causative factors mostly related to diet and lifestyle. Ayurveda has given utmost importance to optimal dietary regimen and its variation as per the season, Agni, Prakruti, wherein Acharyas explains about the concept of Ahara Vidhi Vidhana and Ahara Visheayadhanas to be followed for being Swastha. When these are not followed, leads to imbalance in Doshas in turn leading to the manifestation of disease. Amlapitta is such a clinical entity manifesting in the Annavaha Srotas. This is one among the commonest disorders prevalent in the society nowadays due to indulgence in causative factors like improper diets and habits, stress, spicy irritant food, oily foods, bakery products, etc., It is estimated that about 25-30% people are suffering from dyspepsia in India alone. Kashyapa Samhita, Madhava Nidana and later authors have described this disease in detail as a separate chapter wherein Bruhatrayi we get scattered references related to this disease. In Caraka Samhita, though a separate chapter has not been mentioned for Amlapitta, Acharya throughout the Samhita by his various references when complied and analysed the clear picture of the disease Amlapitta with its Nidana Panchaka can be clearly understood

UNDERSTANDING THE CHIKITSA SUTRA VIVECHANA OF NAVAJWARA

Jwara is a disease which affects the body, mind, senses simultaneously. It diminishes the intelligence, strength, complexion and enthusiasm of the sufferer and produces exhaustion, exertion and aversion to food. It should be treated considering its Avastha, causative factors and involved Dosha. Factors which are responsible for the manifestation of Jwara are the three Sareerika Doshas and two Manasika Doshas. Without the involvement of these Doshas, living beings do not get afflicted with Jwara. Abnormal functioning of Jataragni gives rise to Ama which vitiates Rasa dhatvagni. This produces Samavastha and vitiates Rasavaha Srotas. In Jwara, Swedavaha Srotas also gets affected as the vitiated Dosha along with Ama, blocks the Srotas giving rise to raised body temperature. Such an important disease should be understood clearly as the guidelines laid down in the context of Jwara to diagnose different pathological states are employed elsewhere and guides the physician to select the best line of management. Here the Chikitsa sutra Vivechana of Nava Jwara has been elaborated in detail through which Jwaragna, Deepana, lightness of body, alleviation of the aggravated Dosas, appearance of Kshut and such benefits are all achieved

CONCEPTUAL UNDERSTANDING OF AMLAPITTA (GASTRITIS)

Ayurveda has given utmost importance to optimal dietary regimen and its variation as per the season, Agni, Prakruti. When these are not followed, leads to imbalance in Doshas in turn leading to the manifestation of disease. Other contributing factors for the change in food habits are frequent traveling and change of environment which in turn has an effect on an individuals health. So it can be clearly understood that imbalanced food habits are considered as the prime cause of the manifestation of disease in an individual. Amlapitta is such a clinical entity manifesting in the Annavaha Srotas. Amlapitta can be correlated with Acid Peptic Disorders which comprises of Gastro-Oesophageal Reflux Disease, Gastritis, Functional Dyspepsia described in modern science. According to several authors of contemporary science states that, the combination of physiological, environmental, genetic and psychological factors definitely occupy a prime role in the manifestation of the disease. Through this article an attempt is made to compare and understand the Nidana, Samprapti, Purvarupa, Rupa mentioned by various Acharyas and also to analyse through the current lifestyle modifications contributing to the manifestation of the disease Amlapitta

AYURVEDIC APPROACH TOWARDS ANKYLOSING SPONDYLITIS- A CASE STUDY

Ankylosing Spondylitis is a chronic, systemic, inflammatory disease that can cause the vertebrae to fuse in advanced stages. Ankylosing Spondylitis affects men more often than women. Signs and symptoms typically begin in early adulthood. This affects primarily the sacroiliac joints and spine. Certain peripheral joints and tendons can also be affected, and extra-articular manifestations may be present. The HLA B27 gene is commonly present, and there is a strong familial association. Due to the irregular dietary habits and Irregular activities like doing exercise soon after consuming food etc., leads to indigestion and formation of Amarasa. Through this article we are going to understand a case of Ankylosing Spondylitis in the line of Amavata through detailed history taking the course of the Samprapti is understood clearly and treated accordingly. A 37 years old male patient was presenting with the complaints of Low Back Pain associated with stiffness on low back region since 1 and 1/2 years and Neck pain associated with stiffness since 8 years. Though the Vyakta Lakshanas were at low back region, the initial Samprapti started from the Ama, Ajirna and so on. So in this case these factors are concentrated, assessed carefully and managed accordingly through various Abhyantara and Bahya Prayogas. Thereby following observations like reduction in Stiffness and pain, regularized and satisfactory bowel evacuation etc., were noted

Rising to the challenge: acute stress appraisals and selection centre performance in applicants to postgraduate specialty training in anaesthesia

AcceptedArticle in Press© 2015 Springer Science+Business Media Dordrecht The ability to work under pressure is a vital non-technical skill for doctors working in acute medical specialties. Individuals who evaluate potentially stressful situations as challenging rather than threatening may perform better under pressure and be more resilient to stress and burnout. Training programme recruitment processes provide an important opportunity to examine applicants’ reactions to acute stress. In the context of multi-station selection centres for recruitment to anaesthesia training programmes, we investigated the factors influencing candidates’ pre-station challenge/threat evaluations and the extent to which their evaluations predicted subsequent station performance. Candidates evaluated the perceived stress of upcoming stations using a measure of challenge/threat evaluation—the cognitive appraisal ratio (CAR)—and consented to release their demographic details and station scores. Using regression analyses we determined which candidate and station factors predicted variation in the CAR and whether, after accounting for these factors, the CAR predicted candidate performance in the station. The CAR was affected by the nature of the station and candidate gender, but not age, ethnicity, country of training or clinical experience. Candidates perceived stations involving work related tasks as more threatening. After controlling for candidates’ demographic and professional profiles, the CAR significantly predicted station performance: ‘challenge’ evaluations were associated with better performance, though the effect was weak. Our selection centre model can help recruit prospective anaesthetists who are able to rise to the challenge of performing in stressful situations but results do not support the direct use of challenge/threat data for recruitment decisions.Funding was granted as a pilot for selection to acute specialities from the Department of Health (England). M.J.R.’s research post was funded through this grant, as were sessional time allocations for T.C.E.G. All opinions in the manuscript are those of the authors only and recommendations or policy from the DH should not be inferred from this work

Strength of the dominant upper and lower extremities predicts skeletal muscle mass irrespective of age and gender

Background: Sarcopenia is characterised by losses in muscle mass, strength and function. It is a contributing factor to numerous non-communicable diseases and frailty. Screening for sarcopenia typically requires measurements of handgrip strength, functional performance, and skeletal muscle mass. However, available tools do not tend to measure strength of the lower extremities. The aim of this study was to investigate associations between these measures and lower extremity strength with skeletal muscle mass in healthy young and older adults. Methods: Fifty younger (mean ± SD age = 22.7 ± 5.4 years) and 50 older (age = 69.9 ± 4.3 years) individuals received the following measurements after an overnight fast: Skeletal Muscle Index (SMI) derived by dual-energy X-ray absorptiometry, gait speed, handgrip strength (HGS), and unilateral one-repetition maximum (1RM) leg extension strength. Muscle quality (MQ), was also determined as the ratio of grip strength to appendicular lean mass of the upper body. Results: One older female and one older male were pre-sarcopenic and sarcopenic. Upper extremity MQ was below established cutpoints in 21 older participants. SMI was positively associated with upper and lower extremity strength in all groups except older men, and negatively associated with upper extremity MQ in young males. By multiple regression analysis, dominant HGS and dominant leg extension 1RM strength predicted SMI in the complete sample, accounting for 70.3% of the variance (B = 0.469 and 0.421, respectively; P < 0.00001). The equation for SMI is as follows: 4.568 + 0.025 x dominant leg extension 1RM + 0.059 x dominant grip strength. Discussion: Since muscle mass is the foremost variable in determining sarcopenia, we support the inclusion of lower extremity strength testing in addition to that of handgrip strength to enable better prediction of SMI in both older and younger individuals. MQ determination is also recommended since established algorithms may fail to identify individuals with muscle weakness