Energy In Joules Research Articles

Reliability of the 3-Component Model of Aerobic, Anaerobic Lactic, and Anaerobic Alactic Energy Distribution (PCr-LA-O2) for Energetic Profiling of Continuous and Intermittent Exercise.

To assess the test-retest reliability of the continuous (PCr-LA-O2) and intermittent (PCr-LA-O2int) version of the 3-component model of energy distribution in an applied setting. Sixteen male handball players (age 23 [3]y, height 185 [7]cm, weight 85 [14]kg) completed the 30-15 Intermittent Fitness Test (30-15IFT) twice. Performance was assessed by peak speed (speed of the last successfully completed stage of the 30-15IFT [VIFT], in kilometers per hour) and time to exhaustion (in seconds). Oxygen uptake (in milliliters per kilogram per minute) and blood lactate concentrations (in millimoles per liter) were obtained before, during, and until 15minutes after exercise. Total metabolic energy (in joules per kilogram), total metabolic power (in watts per kilogram), and energy shares (in joules per kilogram and percentage) of the aerobic (energy contribution of the aerobic system [WAERint]), anaerobic lactic, and anaerobic alactic (anaerobic alactic energy [WPCrint]) systems were calculated using both model versions, respectively. Test-retest reliability was very good for VIFT (limits of agreement [LoA]: -1.13 to 0.63km·h-1, coefficient of variation [CV%] 1.68), time to exhaustion (LoA: -101 to 38s, CV% 2.92), peak oxygen uptake (LoA: -2.68 to 4.04mL·min-1·kg-1, CV% 1.48), and peak heart rate (-6.9 to 7.7 beats·min-1, CV% 1.1), but moderate for change in blood lactate concentration (LoA: -3.84 to 4.07mmol·L-1, CV% 11.43). Reliability of the modeled total energy and its fractions were high for total metabolic energy (LoA: -1489 to 1177J·kg-1, CV% 2.88), total metabolic power (LoA: -2.0 to 1.9W·kg-1, CV% 3.58), contribution of aerobic (LoA: -1673 to 1283J·kg-1, CV% 3.62), WAERint (LoA: -1760 to 2160J·kg-1, CV% 6.04), and moderate for anaerobic alactic (LoA: -368 to 439J·kg-1, CV% 14.85), WPCrint (LoA: -1707 to 988J·kg-1, CV% 9.98), and energy share of anaerobic lactic concentration (LoA: -229 to 235J·kg-1, CV% 11.43). Considering the inherent fluctuations of the underlying energetics, the reliabilities of both versions of the 3-component model of energy distribution are acceptable for applied settings.

Energy Required for Fracture in Synthetic Proximal Femoral Models After Synthesis Material Removal: a Biomechanical Study Using Cannulated Screws, Dynamic Hip Screws, and Proximal Femoral Nails.

Objective The present study aims to identify the energy required for synthetic proximal femoral fracture after removal of three implant types: cannulated screws, dynamic hip screws (DHS), and proximal femoral nail (PFN). Methods Twenty-five synthetic proximal femur bones were used: 10 were kept intact as the control group (CG), 5 were submitted to the placement and removal of 3 cannulated screws in an inverted triangle configuration (CSG), 5 were submitted to the placement and removal of a dynamic compression screw (DHSG), and 5 were submitted to the placement and removal of a proximal femur nail (PFNG). All samples were biomechanically analyzed simulating a fall on the greater trochanter using a servo-hydraulic machine to determine the energy (in Joules [J]) required for fracture. Results All samples presented basicervical fractures. The energy required for fracture was 7.1 J, 6.6 J, 6 J, and 6.7 J for the CG, CSG, DHSG and PFNG, respectively. There was no statistically significant difference (considering a 95% confidence interval) in energy among the study groups ( p = 0.34). Conclusion There was no statistically significant difference in the energy required to cause a synthetic proximal femoral fracture after removing all three implant types and simulating a fall over the greater trochanter.

Incorporation and validation of clinically relevant performance metrics of simulation (CRPMS) into a novel full-immersion simulation platform for nerve-sparing robot-assisted radical prostatectomy (NS-RARP) utilizing three-dimensional printing and hydrogel casting technology.

To incorporate and validate clinically relevant performance metrics of simulation (CRPMS) into a hydrogel model for nerve-sparing robot-assisted radical prostatectomy (NS-RARP). Anatomically accurate models of the human pelvis, bladder, prostate, urethra, neurovascular bundle (NVB) and relevant adjacent structures were created from patient MRI by injecting polyvinyl alcohol (PVA) hydrogels into three-dimensionally printed injection molds. The following steps of NS-RARP were simulated: bladder neck dissection; seminal vesicle mobilization; NVB dissection; and urethrovesical anastomosis (UVA). Five experts (caseload >500) and nine novices (caseload <50) completed the simulation. Force applied to the NVB during the dissection was quantified by a novel tension wire sensor system fabricated into the NVB. Post-simulation margin status (assessed by induction of chemiluminescent reaction with fluorescent dye mixed into the prostate PVA) and UVA weathertightness (via a standard 180-mL leak test) were also assessed. Objective scoring, using Global Evaluative Assessment of Robotic Skills (GEARS) and Robotic Anastomosis Competency Evaluation (RACE), was performed by two blinded surgeons. GEARS scores were correlated with forces applied to the NVB, and RACE scores were correlated with UVA leak rates. The expert group achieved faster task-specific times for nerve-sparing (P = 0.007) and superior surgical margin results (P = 0.011). Nerve forces applied were significantly lower for the expert group with regard to maximum force (P = 0.011), average force (P = 0.011), peak frequency (P = 0.027) and total energy (P = 0.003). Higher force sensitivity (subcategory of GEARS score) and total GEARS score correlated with lower nerve forces (total energy in Joules) applied to NVB during the simulation with a correlation coefficient (r value) of -0.66 (P = 0.019) and -0.87 (P = 0.000), respectively. Both total and force sensitivity GEARS scores were significantly higher in the expert group compared to the novice group (P = 0.003). UVA leak rate highly correlated with total RACE score r value = -0.86 (P = 0.000). Mean RACE scores were also significantly different between novices and experts (P = 0.003). We present a realistic, feedback-driven, full-immersion simulation platform for the development and evaluation of surgical skills pertinent to NS-RARP. The correlation of validated objective metrics (GEARS and RACE) with our CRPMS suggests their application as a novel method for real-time assessment and feedback during robotic surgery training. Further work is required to assess the ability to predict live surgical outcomes.

Floral resource availability of Dicliptera squarrosa (Acanthaceae) and its dependence on hummingbirds for fruit formation in a forest fragment of Central Brazil

Background and aims – Hummingbirds are dependent and specialized on nectar-feeding, and many plants depend upon them for pollination. However, the degree of plant-pollinator interdependence varies greatly among species; thus, information on plant mating systems and availability of resources may help to clarify the dependence of interacting organisms. The goals of this study were to (1) quantify the floral resource available during the flowering of Dicliptera squarrosa Nees for comparison with other co-flowering ornithophilous species, and to (2) determine the importance of floral visitors for the reproductive success of this plant.Methods – Data collection was performed in a forest fragment within the urban perimeter of Catalão, Goiás, from September 2012 to August 2013. We investigated the flowering phenology, floral biology, nectar characteristics, flower visitors and mating systems of D. squarrosa. Additionally, we evaluated the amount of floral resource offered (number of flowers and energy in joules) by co-flowering ornithophilous species within an area of 6000 m2 for comparison with D. squarrosa.Key results – Dicliptera squarrosa presents flowers adapted to pollination by hummingbirds, which act as the sole pollinator group for flowers of this species. Flowering occurs from June to September and is synchronous with five other co-flowering species. During the months between July and September, D. squarrosa is the main food source for hummingbirds in the area, offering more floral resources than all of the other five ornithophilous species together. Plants of this species are self-compatible, but they depend on hummingbirds to transfer pollen; levels of autonomous autogamy were low.Conclusions – We suggest that D. squarrosa is an important species for maintaining hummingbirds in the forest fragment due to its high production of nectar resources. In addition, data on floral biology, flower visitors, and mating systems showed the importance of hummingbirds for reproduction of D. squarrosa, suggesting a mutualistic interaction between plant and hummingbirds.

Енергетична ефективність технологій вирощування пшениці озимої у сівозмінах південного степу України

The results of the researches got in the protracted and temporal field researches during 2007–2017 are represented in the article. The aim of researches was determination of power efficiency of technologies of growing of wheat winter-annual for different predecessors, systems of till of soil, terms of sowing, bringing of mineral fertilizers, microfertilizers and biologics in short term crop rotations. Researches executed on the experienced field of the Odesa state agricultural experimental station of the National academy of agrarian sciences of Ukraine. It is set that a decision of problem of increase of production of high-quality grain-growing goods with diminishing of charges on condition of maintenance of the ecological state of environment and increase of level of fertility of soil was and remains a key task for agriculture of Ukraine. The important condition of increase of power efficiency of production of high-quality grain-growing goods are determination and introduction of effective technologies of growing of wheat winter-annual in the crop rotations of different ground-climatic terms of country. Certainly, that one of basic measures in relation to stopping and prevention of development of negative processes and crisis phenomena in agriculture there is the scientifically reasonable placing of wheat winter-annual after the best predecessors in crop rotations with application of rational till of soil, optimization of norms of bringing of mineral fertilizers and biologics. In particular, lands are more productively used, potential possibilities of sorts of plants will be realized better, an impurit goes down, influence of wreckers and illnesses diminishes in sowing of agricultural cultures. All of it positively influences on the state of environment, opens additional possibilities of increase of grain-growing products with diminishing of charges on her production. It is found out, that the tendency of increase of power charges in an agricultural production can result in negative consequences, that is why in the entire countries of the world large attention is spared the problem of energy-savings. One of important tasks that appear before modern agriculture is realization of control after the use of all types of power resources and translation of his industries on an energy keeping level. During realization of efficiency of technologies of growing of wheat winter-annual, a power analysis that considerably complements possibilities economic is applied Tom. Besides, the indexes of power analysis do not require the prices given about a change at comparison in time and does not depend on inflationary factors. Certainly, that corresponding methodologies of power and biopower analysis are worked out for today. Methodologies of power analysis principle of expression of all charges through a power index and corresponding correlation of all power charges is the basis of on the production of goods to energy, that in her is contained. On the basis of modern researches power indexes after that estimated efficiency of technologies of growing of wheat winter-annual are certain. For the calculation of the combined energy, gross products expended in a production on every technology, used power equivalents. Power equivalents are an amount of primary energy in Joules, that is needed for implementation of certain type of work. On this index compared power-hungryness of different technologies, determined the power structure of charges, different elements related to application. Account of the combined energy, grain-growing products expended in a production, carried out on the basis of flowsheets growing of cultures and charges of energy on implementation of works, and also power equivalents of the used capital goods. For the basic criterion of power efficiency of technologies took the coefficient of power efficiency, that was determined by the relation of mass of energy that is contained in the grown products, to the energy expended in her receipt. On results comparative power efficiency of technologies the rational growing of wheat winter-annual is set in the short term crop rotations of South Steppe of Ukraine. The favourable action of the system of shallow without shelves till of soil is certain in crop rotations, where as a predecessor of wheat winter-annual peas and mustard came forward white, on the receipt of the greatest indexes of power efficiency. It is found out, that at growing of wheat winter-annual after peas and mustard white the most coefficient of power efficiency was got at bringing of mineral fertilizers in combination with the variants of additional for a root signup by nitrogen and biologics of Gumatal nano and Azotofit. Certainly, that in a control variant without bringing of mineral fertilizers and biologics and additional for a root signup the coefficient of power efficiency headily went down nitric fertilizers, that unsatisfactorily had influenced on power efficiency of production of grain-growing goods.

New Insights into the Investigation of Smoke Production Using a Cone Calorimeter

Smoke release data from the cone calorimeter are often underused. They may provide additional information to better understand the fire reaction of polymers and the efficiency of flame retardants. A new method is proposed to investigate the smoke release in cone calorimeter tests and to correlate it to heat release, based on studies with pure and flame retarded polymers. Smoke release rate is plotted versus heat release rate and new parameters are pointed out. In particular, parameter A represents the smoke release per unit energy (in Joules) released. Its value increases when the carbon fraction and the aromaticity of a polymer increase. It can reach around 0.05 m2/kJ for epoxy resins but is null for well-known smoke-free polyoxymethylene (POM). HRR threshold (HRRth) represents the critical heat release rate above which smoke release is measured. Its value is close to 100 kW/m2 for polyolefins but decreases drastically for aromatic polymers. The approach developed in this study is potentially useful for assessing the smoke release of different materials for a heat release rate scenario chosen arbitrarily. The influence of two specific smoke suppressants and of two specific flame retardants on smoke release is also discussed and the proposed method allows for a better understanding of their role in smoke release.

Artificial Neural Network-Based Modeling for Impact Energy of Cast Duplex Stainless Steel

The exploitation of artificial neural network as a computational technique in predicting the impact energy of cast duplex stainless steels based on its chemical composition is reported in this research work. Two hundred and twenty melts of duplex stainless steel of different compositions were casted, heat-treated and tested for Charpy impact test. A multilayer feed forward ANN model was developed based on 75% of the available chemical compositions of duplex stainless steel as input and impact energy in joules as output. The prediction efficiency of the developed models was calculated based on mean absolute error and mean absolute percentage error; the best model thus sorted out was validated and tested. A multilayer feed forward ANN model with two hidden layers was selected which provided better linear correlation between the chemical composition and impact energy. Correlation performance of considered ANN model with network topology expressed in terms of mean absolute percent error was found to be 0.43% with a correlation coefficient value of 0.95714. Testing and evaluation of the developed model proved to be efficient enough for the development of duplex stainless steels with required impact toughness.

English

There is currently great emphasis on research regarding various aspects of energy sources but the question of optimum usage of the energy is equally important. This work seeks to produce an economic computer-aided design of a fire-clay pot based on conditions that give minimum cost per unit of usage time for the consumer. A percentage of energy loss from the fuel to the environment due to inefficiency of the heating system was incorporated as a variable in the calculations. Graphs are presented to indicate the calculated optimum economic pot thicknesses at various values of the inner radii. For a common inner radius of 6.0 cm and 75% energy loss, the optimum pot thicknesses for cooking at temperatures of 60, 80, and 100°C were found to be 9.6, 12.0, and 13.8 mm, respectively. The results show that the economic thickness increases with increase in both inner radius and cooking temperature. It has also been established that the operational cost increases with increase in temperature even at the optimum economic thickness. This work includes a study of the calorimetric value of the most commonly used types of wood and charcoal fuel, in Zambia, for clay-pot cooking. These types of fuel come from the four trees locally known as the Musamba, Mubanga, Mutondo, and Mutiti. Several wood and charcoal samples from all these trees were collected and experimentally analysed using an oxygen bomb calorimeter to determine the amount of heat energy in Joules which can be realizable per kilogram of the fuel materials. Key words: Calorific value, economic operational cost, computer-aided design.

Role of peak current in conversion of patients with ventricular fibrillation

Peak currents are the final arbiter of defibrillation in patients with ventricular fibrillation (VF). However, biphasic defibrillators continue to use energy in joules for electrical conversion in hopes that their impedance compensation properties will address transthoracic impedance (TTI), which must be overcome when a fixed amount of energy is delivered. However, optimal peak currents for conversion of VF remain unclear. We aimed to determine the role of peak current and optimal peak levels for conversion in collapsed VF patients. Adult, non-pregnant patients presenting with non-traumatic VF were included in the study. All defibrillations that occurred were included. Impedance values during defibrillation were used to calculate peak current values. The endpoint was return of spontaneous circulation (ROSC). Of the 197 patients analysed, 105 had ROSC. Characteristics of patients with and without ROSC were comparable. Short duration of collapse < 10 minutes correlated positively with ROSC. Generally, patients with average or high TTI converted at lower peak currents. 25% of patients with high TTI converted at 13.3 ± 2.3 A, 22.7% with average TTI at 18.2 ± 2.5 A and 18.6% with low TTI at 27.0 ± 4.7 A (p = 0.729). Highest peak current conversions were at < 15 A and 15-20 A. Of the 44 patients who achieved first-shock ROSC, 33 (75.0%) received < 20 A peak current vs. > 20 A for the remaining 11 (25%) patients (p = 0.002). For best effect, priming biphasic defibrillators to deliver specific peak currents should be considered.

Indications of Potassium Titanyl Phosphate Laser Therapy for Slow-Flow Vascular Malformations in Oral Region.

Indications for laser therapy for slow-flow vascular malformations in the oral and maxillofacial regions have not been clearly documented. The authors aimed to estimate the frequency of resolution of slow-flow vascular malformations and to identify risk and prognostic factors associated with resolution in potassium titanyl phosphate (KTP) laser treatment. This study was designed as a prospective cohort study. Patients who had diagnosed slow-flow vascular malformations were continuously assigned to receive KTP laser therapy. All patients had intralesional laser photocoagulation performed under local anesthesia. Administered power of the KTP laser was fixed at 2 watts throughout the procedure in all patients. The primary endpoint was to understand the frequency of resolution of slow-flow vascular malformations in KTP laser treatment. Secondary endpoints were: treatment outcomes based on lesion size; treatment outcomes based on location; treatment outcomes based on total energy in joules; types of complications. Treatment outcomes were judged by a clinical assessment as well as reduction in lesion size on magnetic resonance imaging. Data were obtained from 26 patients (9 men, 17 women) with 38 lesions. The average lesion size was 13.5 ± 7.7 mm. Treatment outcomes based on lesion size showed that cure and regression were obtained in lesions less than 30 mm in size. However, lesions larger than 30 mm showed no response. Lesions in the tongue and lips showed higher cure rates than in other areas. Treatment outcomes based on administered total energy in joules showed that 68% of lesions were treated and responded well at less than 400 joules. Complication rate was relatively high in the buccal mucosal lesions. Immediate postoperative complications such as necrosis were more common in high-energy administration than in low-energy administration. Our results indicated that KTP laser therapy was effective for slow-flow vascular malformations less than 30 mm in size without significant side effects.

Energy Efficiency Behavior in Heterogeneous Networks under Various Operating Situations of Cognitive Small Cells

Recently, several approaches were followed for the enhancement and better resource utilization in mobile networks; this is to achieve energy efficient consumption for production and delivery of an information bit. Using Cognitive Femto cells (as a member of the small base stations’ family) proves that, it is an efficient solution for achieving this goal[1]. The use of Energy Efficiency term η has become one of the major indices for measuring the performance of these systems. η is the measure of the overall system Capacity (C) in bps/Hz versus the Consumed Energy (E) in Joules [2]. In consistence with many researches, analytic models and empirical measurements, η will be investigated throughout the course of this work. Cognitive Base Stations (CBS) (as an element of the system model) which performs the traffic offloading operations is proved to enhance η performance. In this work, a combination of both analytic and simulation models are used to construct a practical system model. The obtained model is then used to illustrate the effect of different operational parameters that are involved in the η problem. On the other hand, the current paper tries to focus on the selection criteria that may be used to design the cooperative cognitive networks in order to achieve the best η indices. Both of CBSs radii as well as the inter-separation distances (between CBSs and MBS location) are examined to obtain best η index for different operation scenarios; in addition, both of capacity and energy consumption are taken into consideration based on practical operating measures. This work proposed several nonlinear equations with fixed parameters to be used by field engineers to achieve the results with minimum reduced computation complexity. So, the current work may be of importance for the regulator bodies as well as the cognitive mobile operators.

Delay and Energy Constrained Random Access Transport Capacity

In this paper, we consider a delay and energy constrained wireless ad hoc network with node density of λn, where a packet should be delivered to the destination within D(λn) seconds using at most E(λn) energy in joules while satisfying the target outage probability. The performance metric for analyzing the network is the delay and energy constrained random access transport capacity (DE-RATC), i.e., C (D(λn), E(λn)), which quantifies the maximum end-to-end distance weighted rate per unit area of a delay and energy constrained network using a random access protocol. It is shown that a slotted ALOHA protocol is order-optimal under any delay and energy constraints if equipped with additional features such as power control, multihop control, interference control, and rate control, and the delay and energy constraints can be divided into three regions according to the relation between the physical quantities due to the constraints and those due to the node density and network size. The three regions are the non-constrained (NC) region, where the DE-RATC is given by Θ( √ λn/ log λn); the delay-constrained (DC) region, where the DE-RATC depends only on the delay constraint as Θ(D(λn)); and the non-achievable (NA) region where a packet delivery under the given constraints is impossible. Also, it is shown that an arbitrary tradeoff between the rate of each source node and the number of source nodes can be achieved while keeping the optimal capacity scaling as long as λs = Ω(min( √ λn/ log λn,D(λn))).

The critical size of brittle solid materials and the measurement of their surface tension

AbstractThe relationship of the energy required to break a particle or a particulate material vs. particle size has been studied by many researchers. On the one hand, mineral processing engineers, who are interested in the specific energy (in joules per cubic meter or joules per kilogram) required for grinding, almost agree that it is inversely proportional to the particle size, although they might disagree on the type of the relationship. On the other hand, building and structural engineers, who are mainly interested in the strength of materials (in newtons per square meter or pascals), they almost agree that at the size range of the elements used, their strength depends on the quality of the material rather than its size. The present article shows that both groups of engineers are right about the size range of the bodies used by each one. However, there is a critical size that determines the fracture behavior of a brittle material. The definition of the critical size can be used to understand the practical results obtained as well as to measure the surface tension of the tested materials.

Estimation of RF energy absorbed in the brain from mobile phones in the Interphone Study

ObjectivesThe objective of this study was to develop an estimate of a radio frequency (RF) dose as the amount of mobile phone RF energy absorbed at the location of a...

Embodied energy: Soil retaining geosystems

Embodied energy is defined as the total energy in joules that can be attributed to bringing an item to its existing state. This paper attempts to quantify the amount of energy that is put into constructing geotechnical structures. In this study, several common retaining wall options are designed for (i) a hypothetical highway widening project based on a typical condition in London, (ii) basement construction of actual high rise buildings in London and (iii) embankments and cuttings as part of an actual highway road widening project. The embodied energy of each design was computed. Results show that the largest variance on embodied energy is the design solutions and within a given design the materials energy dominates over the installation energy and the transportation energy. The choice of Embodied Energy Intensity (EEI) of materials, particularly steel and concrete, is shown to have a large influence on the magnitude of embodied energy. When comparing among different designs of soil retaining structures, a recycled steel wall system generally has less embodied energy than the equivalent concrete wall system, which is more efficient than the equivalent virgin steel system. Results of the three case studies collectively indicate that minimizing materials usage is the key for reducing embodied energy in soil retention projects.

Impact of Laser Fiber Design on Outcome of Endovenous Ablation of Lower-Extremity Varicose Veins: Results from a Single Practice

The design of laser fibers used for endovenous laser ablation (EVLA) in the management of lower-extremity varicose vein disease may affect treatment success. The purpose of this investigation is to report our experience using the gold-tip NeverTouch VenaCure laser fiber (AngioDynamics, Queensbury, NY) and to compare that to our experience with standard bare-tip fibers. A retrospective chart review of 363 consecutive EVLA treatments using the gold-tip laser fiber was performed. Demographic data including patient age, sex, history of previous varicose vein stripping, vein identity, laterality, treatment length, total applied energy in joules (J), use of adjuvant sclerotherapy and ambulatory phlebectomy, treatment-related complications, and treatment failure, which was defined as recanalization of any portion of the treated vein during follow-up as assessed by duplex ultrasound examination-were entered into a spreadsheet. These data were compared with a control group of 471 EVLA treatments performed with a standard bare-tip laser fiber. Data were analyzed using independent-samples Student's t test, chi-square test, and multivariate analysis. Demographic data were similar between the two groups. Treatments with the gold-tip fiber had a failure rate of 11.1%, whereas treatment with a bare-tip fiber had a failure rate of 2.3% during a similar follow-up period. This difference was highly statistically significant (p<0.0001). Multivariate analysis showed fiber type as the most significant factor associated with treatment failure. We conclude that laser fiber design has a significant effect on treatment success in the performance of EVLA.

Viscoanaesthesia in cataract surgery: a prospective, randomized clinical trial

We aimed to compare viscoanaesthesia (VisThesia) with intracameral lidocaine in cataract surgery carried out under topical anaesthesia. In this prospective study 98 patients were randomly assigned to receive VisThesia (group 1, n = 49) or 0.5 cc of 1% unpreserved lidocaine (group 2, n = 49). All surgery was carried out by one surgeon using clear corneal technique. Pachymetry, the status of the cornea and anterior chamber, and intraocular pressure (IOP) were checked pre- and postoperatively. Mean pain scores were 0.12 (maximum: 3) in group 1 and 0.37 in group 2; the difference between the groups was not statistically significant (95% confidence interval [CI] 0.003-0.487; p = 0.05). A total of 48 patients in group 1 (98%) and 49 in group 2 (100%) reported no discomfort or only mild discomfort. No significant differences in flare and cells in the anterior chamber or IOP were found between the two study groups. There was a significantly greater frequency of corneal oedema in group 1 (p = 0.001). Postoperative central corneal thickness values were also significantly higher in group 1 (95% CI 11.64-57.24; p = 0.003). Results suggest that viscoanaesthesia provides a level of comfort during cataract surgery under topical anaesthesia similar to that facilitated by intracameral lidocaine. However, patients who are given viscoanaesthesia may have increased risk for postoperative corneal oedema.

The Effects of Age and Sex on Electroconvulsive Therapy Using Remifentanil as the Sole Anesthetic Agent

This study examines electroencephalographic (EEG) and motor seizure duration and dynamic energy according to age and sex using remifentanil anesthesia in standard electroconvulsive therapy (ECT). In an earlier study, we showed that remifentanil provides superior anesthesia for ECT in terms of providing adequate seizure duration with lower stimulus doses in patients refractory to maximal ECT settings with methohexital. Patients, refractory to maximal ECT settings with methohexital, received remifentanil as the sole anesthetic agent. Stimulus dose was determined by the dose-titration method. Electroencephalographic seizure duration, motor seizure duration, and dynamic energy in joules (j) were compared between male and female subjects and among patients aged 40 years or younger, older than 40 years but aged 65 years or younger, and older than 65 years. Seventy-two patients were included in the study. There was no significant difference in remifentanil doses between female and male subjects. There was no significant statistical difference between female and male subjects regarding motor seizure duration, EEG seizure duration, or dynamic energy (P > 0.05). There were significant statistical differences among different groups in terms of motor seizure duration, EEG seizure duration, and dynamic energy (P< 0.05). The younger age group had longer motor and EEG seizure durations and required lower dynamic energy. There is no significant effect of sex on ECT with remifentanil anesthesia regarding EEG or motor seizure durations or dynamic energy; however, statistically significant differences were observed based upon age. Younger patients had both increased motor and EEG seizure duration compared with older patients who may require higher stimulus doses than younger patients for comparable motor and EEG seizure durations.

2639

After successful treatment of malignant diseases in childhood, the problem of long-term complications came to the fore. Few studies have focused on the relationship between the radiation dose received and the risk of developing a second malignant neoplasm (SMN). Most of them estimated risk coefficients according to the radiation dose received at the site of the second cancer: thus, the estimated relative risk (RR) is the ratio between the risk of developing a cancer at a given site that received a given dose and the risk of developing a cancer at the same site in the absence of this dose of radiation. This approach does not really correspond to needs in clinical practice, where a global evaluation of the risk is required. In order to investigate the influence of radiotherapy on the overall risk of SMN after a childhood cancer in a cohort of 4401 patients treated in 8 centres in France and UK between 1947 and 1986, we used another dose distribution parameter, defined as the Integral Dose, which provides an estimate of the total energy (in joules) delivered to the patient’s body during radiotherapy. We also calculated the integral dose per kilogram (kg) by dividing each integral dose by the patient’s weight in order to obtain an average dose (in grays) delivered throughout the body. The superiority of these new parameters in the risks estimate is that they take into account the deposit of a given dose to a given volume of the body whatever the irradiated site. In our cohort, we highlighted a significant linear relationship between the integral dose and the risk of SMN. According to the linear model, after adjustment on chemotherapy (mainly alkylating and intercalating agents), the excess risk of SMN was of 0.008 per unity of the integral dose. This coefficient increased to 0.017 if a negative exponential term was taken into account. With the integral dose per kg, these coefficients became respectively 0.23 and 0.48. For 20% of the patients who received the higher dose, the risk of SMN, compared to the non-irradiated patients, was 5.43 and 4.97, respectively for the integral dose and the integral dose per kg. Nevertheless, if we focus on patients who were treated by radiotherapy, only those who had received the highest integral dose had a higher risk and indeed, among the other patients, including 80% of the variability of the integral dose, no increased risk was evidenced. One of the main reasons is probably due to the wide heterogeneity in our cohort which included patients treated for all types of solid cancers and inadequate adjustment on chemotherapy whose combinations varied considerably. Finally, the estimated risk with the integral dose, in our study, cannot be considered as a good predictor of a later risk of SMN. Modern radiotherapy techniques such as intensity modulated radiation therapy (IMRT) or tomotherapy involve a greater number of treatment beams exposing a larger volume of normal tissue to lower doses. It is therefore of paramount importance to take into account the irradiated volume when evaluating the long-term adverse effect of these radiotherapy techniques. Thus, other studies with the same study design are obviously needed to evaluate the usefulness of the integral dose as a new tool of decision-making aid for choosing between different radiation therapy plans.

Fossil energy use in agriculture: an international comparison

This paper is aimed at assessing the comparative importance of constraints in land and labour endowment for energy balance in agriculture, when assessed at the level of national crop production systems. The relation between output/input energy ratio of agriculture (output: food energy in crops; input: commercial energy embodied in technical inputs), average labour productivity (food energy (in Joules) produced per hour of labour allocated to agriculture) and land productivity (food energy (in J) produced per hectare of cropped land) has been studied on a 75-country sample using a cluster analysis procedure. A cross-section equation has been developed, explaining output/input ratio in terms of intensity of land and labour-food-energy throughputs. The results suggest that land constraints, with respect to the total population size, rather than labour constraints, tend to be associated with comparatively higher energy requirements in agricultural production. Therefore, the ‘emancipation’ of agricultural production from land shortages implies two ‘biophysical costs.’ That is, for the production of the same amount of food, a consistent increase in demographic density implies both a larger consumption of fossil energy input and a larger environmental impact.