Determination of aflatoxin M1 levels in 1 white cheese samples by ELISA in Gilan province, Iran

Aflatoxin M1 (AFM1) in milk and milk products is considered to pose certain hygienic risks for human health. These metabolites are not destroyed during the pasteurization and heating process. This study was undertaken to determine the presence and levels of aflatoxin M1 (AFM1) in Iranian white cheese consumed in Gilan province (Northern Iran). A total of 90 cheese samples was randomly obtained from retail outlets. ELISA technique was used to determine the presence and the level of AFM1. In 78 of the 90 cheese samples examined (86.66%), the presence of AFM1 was detected in concentrations between 7.2 - 413ng/l. The mean level of AFM1 in positive samples was 151.97 ng/l. AFM1 levels in 21 samples (23.33%) were higher than the maximum tolerance limit (250 ng/l) accepted by the European countries. Aflatoxin high concentration in milk and milk products cause widespread negative impact on public health and demonstrate considerable economic losses for producers. Therefore, it is necessary to establish strategies for reducing aflatoxin levels in animal feed and milk products. © IDOSI Publications, 2012

Rapid acoustic boundary element method for solution of 3D problems using hierarchical adaptive cross approximation GMRES approach

This paper presents a new solver for 3D acoustic problems called RABEM (Rapid Acoustic Boundary Element Method). The Adaptive Cross Approximation and a Hierarchical GMRES solver are used to generate both the system matrix and the right hand side vector by saving storage requirement, and to solve the system solution. The potential and the particle velocity values at selected internal points are evaluated using again the Adaptive Cross Approximation (ACA). A GMRES without preconditioner and with a block diagonal preconditioner are developed and tested for low and high frequency problems. Different boundary conditions (i.e. Dirichlet, Neumann and mixed Robin) are also implemented. Herein the problem of engine noise emanating from the Falcon aircraft is presented. The tests demonstrated that the new solver can achieve CPU times of almost O(N) for low frequency and O(NlogN) for high frequency problems

Dual Boundary Element Method for fatigue crack growth: implementation of the Richard\u2019s criterion

A new criterion for fatigue crack growth, whose accuracy was previously tested in the literature with the Finite Element Method, is here adopted with a Dual Boundary Element formulation. The fatigue crack growth of an elliptical inclined crack, embedded in a three dimensional cylindrical bar, is analyzed. In this way in addition to the propagation angle estimated by the Sih\u2019s criterion, it is possible to take into account a twist propagation angle. The two propagation criteria are compared in terms of shape of the propagated crack and in terms of SIFs along the crack front. The efficiency of the Dual Boundary Element Method in this study is highlighted

An analysis of the global pharmacy workforce capacity

BACKGROUND: The World Health Organization (WHO) estimates that there is a global healthcare workforce shortage of 7.2 million, which is predicted to grow to 12.9 million by 2035. Globally, people are living longer with multiple co-morbidities and require increased access and use of medicines. Pharmacists are a key component of the healthcare workforce, and in many countries, pharmacists are the most accessible healthcare profession. This paper identifies key issues and current trends affecting the global pharmacy workforce, in particular workforce distribution, country economic status, capacity, and workforce gender balance. METHODS: National professional pharmacy leadership bodies, together with other contacts for professional bodies, regulatory bodies, and universities, were approached to provide country-level data on pharmacy workforce. A descriptive and comparative analysis was conducted to assess each country's pharmacy workforce. RESULTS: A total of 89 countries and territories responded to the survey. To standardise the capacity measure, an analysis of the population density of pharmacists (per 10 000 population) was performed. The sample mean was 6 pharmacists per 10 000 population (n = 80). There is considerable variation between the surveyed countries/territories ranging from 0.02 (Somalia) to 25.07 (Malta) pharmacists per 10 000 population. African nations have significantly fewer pharmacists per capita. Pharmacist density correlates with gross national income (GNI) and health expenditure. The majority of pharmacists are employed in community settings, followed by hospital, industry-related, academia, and regulation. There is a greater proportion of females in the pharmacy workforce globally, with some WHO regions showing female representation of more than 65 % with an increasing trend trajectory. CONCLUSIONS: Pharmacy workforce capacity varies considerably between countries and regions and generally correlates with population- and country-level economic indicators. Those countries and territories with lower economic indicators tend to have fewer pharmacists and pharmacy technicians; this has implications for inequalities regarding access to medicines and medicine expertise

Design of a wireless passive sensing system for impact detection of aerospace composite structures

In this paper, the design and implementation of a novel on-board wireless passive sensing system for impact detection of composite airframe is presented for the first time. Several modules, including filtering, impact detection, local processing and wireless transmission are designed and evaluated for detecting rare, random and transitory impact events. An event-triggered mechanism with high responsiveness is adopted to reduce the system power dissipation and to maintain the detection effectiveness. This design allows the system to be adaptive, energy-efficient and highly responsive to impacts. The whole system was implemented in an experimental study, and the effectiveness was evaluated and illustrated. The system was woken up by impact events in around 12 µs, and the impact data were recorded at 200 kHz (up to 5.33 MHz). This work provides a guideline for low-power, high-responsiveness passive on-board sensing system design. This system can also be adapted to other sensing applications in aerospace engineering

Damage characterization of composite plates under low velocity impact using ultrasonic guided waves

In this work, two numerical procedures based on Finite Elements Method (FEM) have been developed in order to simulate the Lamb wave propagation in Low Velocity Impact (LVI) damaged CFRP (Carbon Fibre Reinforced Polymer) laminate. The former (softening representation), usually adopted in literature, consists of modelling LVI damages by lowering the elastic material properties which allowed investigating the Lamb wave propagation at different stages of LVI damages evolution. The latter, proposed in this paper, conversely to the first one and the most of techniques presented in literature, consists of simulating Lamb wave propagation in a plate characterized by an initial stress-strain state and the related failures carried out by a previous impact simulation involving the same model. Such technique allows a better damage modelling and, consequently, overcoming the damage modelling approximations introduced by the former strategy; the lowering of the elastic material properties leads to a bad damage modelling which does not allow reproducing accurately what happens in the reality. Such procedure allowed investigating the Lamb wave propagation at different impact energy levels. The interaction between Lamb waves and damages has been investigated under three central frequencies of the actuation signal: 150 kHz, 200 kHz and 250 kHz which resulted in interesting observations to minimize the effect of the first lamina's fibres orientation on the wave propagation velocity. It is well known that different wave propagation velocities along fibres and matrix lead to different RMSD (Root Mean Square Deviation) damage index values, even if the sensors are mounted at the same distance from the damage location, resulting in wrong or less accurate information about the identification of both damage size and location during the post-processing phase. Moreover, the relationships between the RMSD damage index values, recorded at different instants of time of the impact history, and the impactor phases has been achieved. Finally a comparison between the results achieved by the two investigated strategies has been carried out and presented here

Reliability-based design optimization of composite stiffened panels in post-buckling regime

This paper focuses on Deterministic and Reliability Based Design Optimization (DO and RBDO) of composite stiffened panels considering post-buckling regime and progressive failure analysis. The ultimate load that a post-buckled panel can hold is to be maximised by changing the stacking sequence of both skin and stringers composite layups. The RBDO problem looks for a design that collapses beyond the shortening of failure obtained in the DO phase with a target reliability while considering uncertainty in the elastic properties of the composite material. The RBDO algorithm proposed is decoupled and hence separates the Reliability Analysis (RA) from the deterministic optimization. The main code to drive both the DO and RBDO approaches is written in MATLAB and employs Genetic Algorithms (GA) to solve the DO loops because discrete design variables and highly nonlinear response functions are expected. The code is linked with Abaqus to perform parallel explicit nonlinear finite element analyses in order to obtain the structural responses at each generation. The RA is solved through an inverse Most Probable failure Point (MPP) search algorithm that benefits from a Polynomial Chaos Expansion with Latin Hypercube Sampling (PCE-LHS) metamodel when the structural responses are required. The results led to small reductions in the maximum load that the panels can bear but otherwise assure that they will collapse beyond the shortening of failure imposed with a high reliability