Targeted Perfusion Therapy in Spinal Cord Trauma.

We review state-of-the-art monitoring techniques for acute, severe traumatic spinal cord injury (TSCI) to facilitate targeted perfusion of the injured cord rather than applying universal mean arterial pressure targets. Key concepts are discussed such as intraspinal pressure and spinal cord perfusion pressure (SCPP) at the injury site, respectively, analogous to intracranial pressure and cerebral perfusion pressure for traumatic brain injury. The concept of spinal cord autoregulation is introduced and quantified using spinal pressure reactivity index (sPRx), which is analogous to pressure reactivity index for traumatic brain injury. The U-shaped relationship between sPRx and SCPP defines the optimum SCPP as the SCPP that minimizes sPRx (i.e., maximizes autoregulation), and suggests that not only ischemia but also hyperemia at the injury site may be detrimental. The observation that optimum SCPP varies between patients and temporally in each patient supports individualized management. We discuss multimodality monitoring, which revealed strong correlations between SCPP and injury site metabolism (tissue glucose, lactate, pyruvate, glutamate, glycerol), monitored by surface microdialysis. Evidence is presented that the dura is a major, but unappreciated, cause of spinal cord compression after TSCI; we thus propose expansion duroplasty as a novel treatment. Monitoring spinal cord blood flow at the injury site has revealed novel phenomena, e.g., 3 distinct blood flow patterns, local steal, and diastolic ischemia. We conclude that monitoring from the injured spinal cord in the intensive care unit is a safe technique that appears to enable optimized and individualized spinal cord perfusion

Agricultural machinery selection and scheduling of farm operations

The procedure of calculating annual machinery ownership costs from the discounted cash flows of the mortgaged capital cost, the repair and insurance charges and the resale income is extended to include the effect of loan rate and loan period on interest charges, the effect of capital allowances taking account of the actual balancing charges at the end of the period of ownership, and the effect of tax relief on the interest charges, repair costs and insurance premiums. The concept of marginal holding cost is applied to determine the optimum ownership period.The selection of tractor- plough combinations is based on the prediction of soil characteristics such as moisture content, strength, and workability, all of which influencing the assessment of plough draught and tractor power. A number of filters are used to select the appropriate and realistic tractor /implement combinations with different sizes of fully mounted plough depending on the draught, and the speed of each selected gear of the tractor. For each acceptable combina- tion of tractor and fully mounted plough determined, the costing routine is used to calculate the annual costs.The branch and bound algorithm is suitable for mixed integer solutions to the farm machinery selection problem. Machinery sets are selected simultaneously with the chosen cropping pattern on a given land area. Machinery sets are matched correctly to the tractor sizes. Four sizes of tractor are available (45 kW, 61 kW, 74 kW and 94 kW,. Field operations take place in discrete time periods during which available work days are predicted from soil type and weather records for the specific site. Cereal and root crops are distinguished by optimum sowing and harvesting date. Discrete time periods are defined in relation to these optimal dates and give rise to overlapping operations for different crops. The calculation of probability levels for available work days when operations are subject to different criteria is discussed. A single arbitrary value of 75% probability for available work days is adopted in the linear programming model for the main part of the study.Two stage processes are used to simulate available work days in each time period. The patterns generated converge on the relative frequency pattern laid down by the generating process. The range of experience is wider than that contained in the short series of 24 years historical data. The simulation model generates results suitable for stochastic dominance ranking.In a simulation experiment on a 250 ha arable farm cropping cereals and potatoes, alternative solutions are obtained by integer linear programming, the solutions being ranked according to gross revenue. Annual costs of operating farm machinery are derived from a separate costing algorithm based on the annual hours of use which are determined by the size of the task and not by the sequence of work days. After deducting the annual costs of machinery operation, the cumulative net revenue curves cross and second order stochastic dominance ranking is used to identify the optimum (maximum profit) solution.The current study demonstrates the viability of the analytical procedures but further work is now required to reduce the computing time involved for the complete machinery selection procedure. Meanwhile, a commercial software package is prepared on the calculation of annual machinery ownership costs

Virtual Manufacturing and Virtual Spaces

This article presents news problems linked to the increasing use of virtual spaces in the building of new types of manufacturing what is currently called Virtual Manufacturing (VM). VM has many consequences in the activity of industrial companies whatever be size, economic sector or geographical area. Particular attention is paid on virtual spaces, manufacturing and collaboration, skills matrix and manufacturability, the CAD and Virtual Prototyping case and, finally, the virtual partnerships or enterprise as a new type of organization

Acute Spinal Cord Injury: Correlations and Causal Relations Between Intraspinal Pressure, Spinal Cord Perfusion Pressure, Lactate-to-Pyruvate Ratio, and Limb Power.

BACKGROUND/OBJECTIVE: We have recently developed monitoring from the injury site in patients with acute, severe traumatic spinal cord injuries to facilitate their management in the intensive care unit. This is analogous to monitoring from the brain in patients with traumatic brain injuries. This study aims to determine whether, after traumatic spinal cord injury, fluctuations in the monitored physiological, and metabolic parameters at the injury site are causally linked to changes in limb power. METHODS: This is an observational study of a cohort of adult patients with motor-incomplete spinal cord injuries, i.e., grade C American spinal injuries association Impairment Scale. A pressure probe and a microdialysis catheter were placed intradurally at the injury site. For up to a week after surgery, we monitored limb power, intraspinal pressure, spinal cord perfusion pressure, and tissue lactate-to-pyruvate ratio. We established correlations between these variables and performed Granger causality analysis. RESULTS: Nineteen patients, aged 22-70 years, were recruited. Motor score versus intraspinal pressure had exponential decay relation (intraspinal pressure rise to 20 mmHg was associated with drop of 11 motor points, but little drop in motor points as intraspinal pressure rose further, R2 = 0.98). Motor score versus spinal cord perfusion pressure (up to 110 mmHg) had linear relation (1.4 motor point rise/10 mmHg rise in spinal cord perfusion pressure, R2 = 0.96). Motor score versus lactate-to-pyruvate ratio (greater than 20) also had linear relation (0.8 motor score drop/10-point rise in lactate-to-pyruvate ratio, R2 = 0.92). Increased intraspinal pressure Granger-caused increase in lactate-to-pyruvate ratio, decrease in spinal cord perfusion, and decrease in motor score. Increased spinal cord perfusion Granger-caused decrease in lactate-to-pyruvate ratio and increase in motor score. Increased lactate-to-pyruvate ratio Granger-caused increase in intraspinal pressure, decrease in spinal cord perfusion, and decrease in motor score. Causality analysis also revealed multiple vicious cycles that amplify insults to the cord thus exacerbating cord damage. CONCLUSION: Monitoring intraspinal pressure, spinal cord perfusion pressure, lactate-to-pyruvate ratio, and intervening to normalize these parameters are likely to improve limb power

Impact of Oil Spills on Marine Life

Petroleum contamination is a growing environmental concern that harms both terrestrial and aquatic ecosystems. However, the public and regulatory and scientific communities have given more attention to the contamination of marine habitats. This is because marine oil spills can have a serious economic impact on coastal activities, as well as on those who exploit the resources of the sea. Thus, communities that are at risk of oil disasters must anticipate the consequences and prepare for them

Public and private surgeon attitude towards informed consent

Background: Informed consent ranks as one of the most prominent issues in the recent bioethics literature due to increasing number of medico-legal cases and, the introduction of new national guidelines.Objectives: The aim of this study is to examine the attitude of surgeons working in public and private hospitals towards informed consent.Subjects and methods: This study is a cross-sectional survey that was conducted from January to June 2016 in all five governmental general hospitals, and two private hospitals in Kuwait. A selfadministered questionnaire was used to collect data from the surgeons working in the selected hospitals including six domains related to informed consent.Results: The majority of surgeons believed that informed consent routinely achieved in their current practice and that all doctors should receive formal training on informed consent, though only 35.7% of public surgeon received training compared to 76.7% of private surgeons. Although 82.7% of public surgeons believed that written information leaflets should be provided for patients, only 41.1% provide their patients with these type of leaflets. There was no significant difference between public and private surgeons regarding the purpose of informed consent except that higher proportion of private surgeons believed that informed consent improves the doctor-patient relationship. There was an agreement between public and private surgeons that junior doctors should not conduct the informed consent. Higher proportion of private than public surgeons stated that the content of informed consent was affected by patient’s age, gender, and social class whereas level of education was thought by public surgeons.Conclusion: Private surgeons differ from those in the public hospitals in that they tend to look at informed consent as not only an ethical and legal obligation, but also of benefit to patients. The introduction of formal training on informed consent in both types of hospitals are recommended.Keywords: Informed consent, Attitude, Surgeons, Public, Privat

Spinal cord injury: is monitoring from the injury site the future?

This paper challenges the current management of acute traumatic spinal cord injury based on our experience with monitoring from the injury site in the neurointensive care unit. We argue that the concept of bony decompression is inadequate. The concept of optimum spinal cord perfusion pressure, which differs between patients, is introduced. Such variability suggests individualized patient treatment. Failing to optimize spinal cord perfusion limits the entry of systemically administered drugs into the injured cord. We conclude that monitoring from the injury site helps optimize management and should be subjected to a trial to determine whether it improves outcome

Convective and radiative heat transfer in a high-swirl direct-injection diesel engine

The investigation described in this thesis is a study of instantaneous heat fluxes (total and radiative) and their variation with operating conditions in a high-swirl direct-injection diesel engine. The problem is approached experimentally and methods for prediction of convective and radiative components are suggested. Total heat fluxes were measured using a thin-film type thermocouple developed in the course of the work, while the radiant flux was measured by a pyroelectric infrared detector. The experimental observations demonstrate variations in local heat fluxes which are moderate under motored conditions but large in the fired engine. Some of the observed features of flux variation with time and with location have been shown to be qualitatively explicable in terms of probable local events during the cycle. [Continues.