Central Blockage Research Articles

High-Profile Convoy Disruptions: Exploring Socioeconomic and Environmental Ramifications of Road Closures

Congestion persists despite various demand management techniques, particularly for handling recurrent congestion. However, non-recurrent congestion from events like VIP movements poses unique challenges, especially during peak hours. This study investigates the environmental and economic impacts of road blockages due to VIP movements in developing countries, focusing on Pakistan. Considering practiced standard operating procedures associated with VIP movements, this study finds significant delays and economic burdens in debt-ridden economies. It uses discrete choice modeling and microsimulation techniques to evaluate the value of travel time and quantifies road blockage effects on fuel consumption, travel time, and carbon emissions. Data from central blockage locations in Rawalpindi and Islamabad reveal a value of travel time estimated at 1.77 USD/h, with income and gender significantly influencing mode choices during VIP movements. Moreover, road blockages exceeding two minutes substantially negatively impact the environment and economy, particularly in developing nations. Urgent action is needed for effective mitigation strategies and sustainable transportation policies to address the detrimental effects and promote alternative transportation modes. Recommendations include limiting VIP blockages to a maximum of two minutes and implementing policies to discourage private car usage. Despite limitations, the study emphasizes the critical role of sustainable transportation policies in enhancing the well-being of road users in developing nations.

Effect of Copper Particle Size on the Surface Structure and Catalytic Activity of Cu–CeO2 Nanocomposites Prepared by Mechanochemical Synthesis in the Preferential CO Oxidation in a H2-Rich Stream (CO-PROX)

An effect of Cu powder dispersion and morphology on the surface structure and the physical–chemical and catalytic properties of Cu–CeO2 catalysts prepared by mechanochemical synthesis was studied in the preferential CO oxidation in a H2-rich stream (CO-PROX). Two catalysts, produced by 30 min ball-milling from CeO2 and 8 mass% of copper powders and with particle sizes of several tens (dendrite-like Cu) and 50–200 nm (spherical Cu obtained with levitation-jet method), respectively, were characterized by X-ray diffraction and electron microscopy methods, a temperature-programmed reduction with CO and H2, and with Fourier-transform infrared spectroscopy. The catalyst synthesized from the “large-scale” dendrite-like Cu powder, whose surface consisted of CuxO (Cu+) agglomerates located directly on the surface of facetted CeO2 crystals with a CeO2(111) and CeO2(100) crystal planes exposition, was approximately two times less active at 120–160 °C than the catalyst synthesized from the fine Cu powder, whose surface consisted of CuxO (Cu2+) clusters of 4–6 nm in size located on the steps of facetted CeO2 nanocrystals. Although a large part of CO2 reacted with a ceria surface to give carbonate-like species, no blockage of CO-activating centers was observed due to the surface architecture. The surface structure formed by the use of highly dispersed Cu powder is found to be a key factor responsible for the catalytic activity.

Central blockage of sympathetic nerves inhibits the abnormal vital signs and disturbance of the gut microbiota caused by continuous light exposure

BackgroundContinuous light exposure increases sympathetic excitation in rats, leading to hypertension, left ventricular hypertrophy, and fibrosis. This study was aimed to investigate whether continuous light exposure causes destabilization of vital signs and gut microbiota (GM) in Sprague Dawley (SD) rats and whether clonidine hydrochloride (CH), a central sympathetic depressant drug, could prevent these changes. MethodsEight-week-old male SD rats were divided into three groups with different interventions for 14 weeks: control group (CG), 2-mL pure water gavaged daily while on a normal 12-h light/dark cycle; continuous illumination group (CI), 2-mL pure water gavaged daily while receiving continuous exposure to light (300 lx); and drug administration group (DA), CH (10 μg/kg) gavaged daily while receiving continuous exposure to light (300 lx). ResultsThe results showed that blood pressure, heart rate, and body weight were significantly higher in the CI group than in the CG and DA groups (P < 0.05). Moreover, the Shannon index was higher in the DA group than in the CI group (P = 0.012). The beta diversity index in the CG group was significantly higher in the CI group (P = 0.039). The pairwise comparison results of the linear discriminant analysis effect size showed that Oscillospirales were enriched in the DA group, whereas the Prevotellaceae lineage (family level) > Prevotella (genus level) > Prevotellaceae_bacterium (species level) were enriched in the CI group. The Muribaculaceae family was more abundant in the CG group than in the CI group. ConclusionSympathetic nerve inhibition restored the abnormal vital signs and GM changes under continuous light exposure.

CFD analysis of porous flow blockage in a gas-lift enhanced LBE-cooled fuel assembly

Porous blockage is likely to occur in wire-wrapped fuel assemblies and cause severe consequences such as overheating and mass flow decrease. In this study, flow behavior upstream, inside and downstream of the blockage is obtained for different porosities to analyse the overheating and pressure change. Additionally, the effect of reactivity feedback considering the void fraction and radial and axial power distributions on LBE-cooled porous blockage are given. It is concluded that flow separation upstream and recirculation downstream is the main reason for the overheat phenomenon due to poor convective heat transfer. Static pressure has a local rise both upstream with small porosities and in the flow recovery region downstream, while the gradient of pressure drops inside the blockage is large and begins forwards for small porosities because of flow resistance. The study of reactivity insertion reveals that although the effect of the void fraction on the reactivity and heat power is straightforward, the volume-averaged coolant and rod temperatures are virtually unaffected within 0.02 s. The wall and bulk temperature of central blockage C1 is generally higher than that of edge blockage E1.

Optimization of Co-Ni-Mg-Al mixed-oxides CO2 methanation catalysts with solution combustion synthesis: On the importance of Co incorporation and basicity

Hydrogenation of CO2 to methane is a promising prospect for the utilization of carbon dioxide. Ni-Mg-Al mixed oxides have been reported as a catalyst for this process. Their promotion with cobalt allows to improve Ni reducibility, enhances surface basicity, electronic and textural properties. Solution combustion synthesis was used to optimize the introduction of cobalt to the Ni-Mg-Al oxide matrix. Three synthesis strategies were applied to obtain different morphologies and study their catalytic performance. Characterization techniques (ICP-MS, XRD, low-temperature N2 sorption, H2-TPR, CO2-TPD, TEM, XAS) showed that simultaneous combustion of all the precursors (Ni, Mg, Al, and Co) led to dissociation of nickel and cobalt to the support which resulted in the reduction of catalytic activity and blockage of active centers. The separation of the synthesis into two steps increased the availability of active centers, improved surface properties, and catalytic performance. Furthermore, it led to a decrease in the coordination number of nickel, due to higher contribution of cobalt in the metal crystallites, which resulted in improved catalytic activity. Our findings showed that the addition of cobalt in the second step, in the NiCo-D catalyst, enhanced the CO2 and H2 conversions for methane production compared to the other applied synthesis strategies.

Combined femoral-obturator-sciatic nerve block has superior postoperative pain score and earlier ambulation as compared to spinal anaesthesia for arthroscopic anterior cruciate ligament reconstruction.

Peripheral nerve blocks can be a suitable alternative to central neuraxial blockage, as the sole anaesthetic agent for better early postoperative outcomes, decreased hospital stay and earlier mobilisation after anterior cruciate ligament reconstruction (ACLR) surgery. The purpose of this study was to compare consciousness during the procedure, pain during early postoperative period (< 7days), and perioperative outcomes following ACLR using combined sciatic, femoral, and obturator nerve blocks compared to the spinal anaesthesia. This was a prospective case-control study including patients between 18 and 55years of age, with anterior cruciate ligament (ACL) injury confirmed clinically and radiologically and undergoing ACLR. Patients were allocated in the two groups alternatively, group 1 included patients who received combined nerve blocks, and group 2 included patients who received spinal anaesthesia for the surgery. The sensory effect, motor effect, adequacy of anaesthesia, perioperative analgesic use, duration of stay, postoperative pain (visual analogue scale 0-10cm) and functional outcomes were noted. There were 60 patients in each group. A total of seven patients in group 1 (11%) and two patients in group 2 (3%) needed conversion to general anaesthesia (n.s.). In group 1, out of 53 patients who underwent surgery, 26 patients had no perception of surgery in the joint, 17 patients had perception of manipulation of the knee joint, 4 patients had sense of touch, and 6 patients had sensation of pain in the knee (VAS scale less than 3). In group 2, out of 58 patients, 42 patients had no perception of surgery, 12 had a perception of manipulation of the knee joint, 2 had sense of touch, and 2 had sensation of pain in the knee. Blockage of sensory effect was significantly better in group 2 (p = 0.0001). However, the motor effect was comparable between the two groups (n.s.). Group 1 had significantly better pain scores 6, 12, and 18h after the surgery. Moreover, patients in group 1 also had faster ambulation (mean difference of 5.5h, p = 0.0001) and reduced hospital stay (mean difference of 8.4h, p = 0.0001). Combined sciatic, femoral, and adductor canal block is an effective sole anaesthetic modality for ACLR. The sensory effect was inferior when compared to spinal anaesthesia but sufficient for the procedure without the need for supplementation with any other anaesthetic modality. Patients receiving this combined nerve block had lesser early postoperative pain scores, earlier ambulation, and shorter hospital stay as compared to the spinal anaesthesia. Level 3.

Non-surgical Treatment of Central Venous Occlusion in Haemodialysis Patients

Background: Central venous stenosis (CVS) is often found in patients on hemodialysis. Prior ipsilateral central venous catheterization and cardiac rhythm insertion are major risk factors, however the lack of this history may potentially lead to CVS. Chronic CVS may lead to thrombosis at the point of stenosis with partial or total blockage of the central vein. Objective: To assess in patency, complication rate and death rates the impact of the endovascular repair of central vein blockage following arteriovenous fistula formation. Methods and patients: This potential non-randomized research will be carried out at the Nasr Insurance hospitals vascular chirurgy department. The trial will involve 20 individuals with chronic renal disease and limb edoema after the development of fistula. In accordance with the inclusion criteria listed below, the Ethical Committee shall receive permission. Results: Only 11 patients had balloon angioplasty. There were no immediate difficulties. Six patients with restenosis. One in six patients with PTA with stenting had restenosis. One patient developed recurrence in the stent on diagnostic venography (stenosis). All recurring patients had repeat PTA. Conclusion: Endovascular therapy in individuals who are hemodialysed is an effective and safe approach for the treatment of CVD. Without severe morbidity or death, there is a high technical success rate. Multiple re-interventions for the treatment of restenosis are nonetheless necessary.

Learning From the Law. A Review of 21 Years of Litigation of Nerve Injury Following Central Neuraxial Blockage in Obstetrics

(Anaesthesia. 2020;75:541–548) Medicolegal claims from neurological injury following central neuraxial blockade (CNB) are the second most common claims against obstetric anesthesiologists. Data is presented on 55 cases from a personal claims database maintained by one of the authors of the cases in which he served as an expert witness between 1994 and 2015. The lessons learned from having served as an expert witness, fall into 3 broad themes: Consent, Nerve Injury, and Recognition and Management of Nerve Injury.

Delivery of the 5-HT2A Receptor Agonist, DOI, Enhances Activity of the Sphincter Muscle during the Micturition Reflex in Rats after Spinal Cord Injury.

Simple SummarySpinal cord injury often disrupts connections between the brain and spinal cord leading to a plethora of health complications, including bladder dysfunction. Spinal cord injured patients are left with symptoms such as a leaky bladder (the inability to hold their urine), frequent urinary tract infections, and potential kidney failure. However, previous studies have shown that manipulation of serotoninergic receptors can improve urinary performance following spinal cord injury. In the current study, we sought to explore how stimulation of a specific serotonergic receptor subtype can significantly enhance bladder function in spinal cord injured rats. To do so, we utilized spinal cord injured female rats that underwent various bladder performance evaluations combined with pharmacological intervention of a specific serotonergic subtype. Additionally, the primary site of action was investigated to determine effects elicited during various administration routes (e.g., directly into the cord, into the femoral vein, or into the skin). Stimulation of this receptor subtype, regardless of delivery route, improved activity of the external urethral sphincter and detrusor-sphincter coordination in spinal cord injured rats. Collectively, the results of these experiments have the potential to provide vital guidance for the development of therapeutic strategies to alleviate urinary dysfunction following spinal cord injury.Traumatic spinal cord injury (SCI) interrupts spinobulbospinal micturition reflex pathways and results in urinary dysfunction. Over time, an involuntary bladder reflex is established due to the reorganization of spinal circuitry. Previous studies show that manipulation of serotonin 2A (5-HT2A) receptors affects recovered bladder function, but it remains unclear if this receptor regulates the activity of the external urethral sphincter (EUS) following SCI. To elucidate how central and peripheral serotonergic machinery acts on the lower urinary tract (LUT) system, we employed bladder cystometry and EUS electromyography recordings combined with intravenous or intrathecal pharmacological interventions of 5-HT2A receptors in female SCI rats. Three to four weeks after a T10 spinal transection, systemic and central blockage of 5-HT2A receptors with MDL only slightly influenced the micturition reflex. However, delivery of the 5-HT2A receptor agonist, DOI, increased EUS tonic activity and elicited bursting during voiding. Additionally, subcutaneous administration of DOI verified the enhancement of continence and voiding capability during spontaneous micturition in metabolic cage assays. Although spinal 5HT2A receptors may not be actively involved in the recovered micturition reflex, stimulating this receptor subtype enhances EUS function and the synergistic activity between the detrusor and sphincter to improve the micturition reflex in rats with SCI.

Experimental study on flow structures of central blockage accidents in a rectangular channel using PIV and POD

The central blockage accidents of a rectangular channel with an aspect ratio of 16.67 (50 mm in width and 600 mm in length with 3 mm spacing) are investigated using Particle Image Velocimetry (PIV) and Proper Orthogonal Decomposition (POD). 30% and 70% blockage ratios (α) are chosen to simulate low and high blockage scenarios, respectively. The Reynolds number is calculated to be 3641 based on the channel hydraulic diameter and the inlet velocity. It is found that two counter-rotating vortices are formed in the wake after blocking and the vortex shedding is suppressed for α = 70%. Specially, POD modes expose the remarkable influence of obstructions on the variations of flow structures. And a further phase-averaged analysis convincingly demonstrated the generation and evolution of vortex.

Central blockage of nesfatin-1 has anxiolytic effects but does not prevent corticotropin-releasing factor-induced anxiety in male rats

Nesfatin-1, a pleotropic peptide, was recently implicated in the regulation of anxiety and depression-like behavior in rats. However, the underlying mechanisms remain unclear so far. Thus, this study aimed to investigate the role of endogenous nesfatin-1 in the mediation of anxiety and depression-like behavior induced by corticotropin-releasing factor (CRF). Therefore, normal weight male intracerebroventricularly (icv) cannulated Sprague Dawley rats received two consecutive icv injections of anti-nesfatin-1 antibody or IgG control antibody followed by CRF or saline, before being exposed to a behavioral test. In the elevated zero maze test, assessing anxiety and explorative behavior, blockade of nesfatin-1 using an anti-nesfatin-1 antibody under basal conditions increased the number of entries into the open arms compared to control antibody/vehicle (1.6-fold, p < 0.05) and the time in open arms compared to the other groups (p < 0.05). Control antibody/CRF-treated animals tended to spend less time in the open arms compared to control antibody/vehicle (0.7-fold, p = 0.17), an effect not altered by the nesfatin-1 antibody (control antibody/CRF-treated animals vs. nesfatin-1 antibody/CRF group, p = 1.00). In the novelty-induced hypophagia test, assessing anhedonia as part of depression-like behavior, no significant differences were observed between the four groups for the latency to the first bout, number of bouts and the amount of palatable snack eaten (p > 0.05). In summary, CRF tended to increase anxiety and explorative behavior an effect not altered by blockade of nesfatin-1, whereas no significant effect of CRF on anhedonia was observed. Blockade of endogenous nesfatin-1 significantly decreased anxiety-like behavior giving rise to a physiological role of brain nesfatin-1 in the mediation of anxiety.

Chemokine CCL7 regulates spinal phosphorylation of GluA1-containing AMPA receptor via interleukin-18 in remifentanil-induced hyperalgesia in rats

BackgroundRemifentanil-induced hyperalgesia (RIH) may be a potential component for acute confusional state and chronic pain after surgery, but specific mechanism remains elusive. Chemokines and inflammatory mediators associated neuroinflammation is involved in central nociceptive sensitization. The contribution of AMPA receptor to excitatory synaptic transmission in pathologic pain has been indicated. This study investigated whether chemokine CCL7 modulated spinal phosphorylation of AMPA receptor via interleukin (IL)-18 in a rat model of RIH. MethodsMechanical allodynia and thermal hyperalgesia after remifentanil infusion were verified by assessment of paw withdrawal threshold and paw withdrawal latency, respectively. A neutralizing antibody against CCL7, IL-18 antagonist and recombinant CCL7 were employed to identify the mechanisms. Levels of CCL7 and its receptors, expressions of IL-18 and its receptor IL-18R, and the phosphorylation of GluA1 in the spinal cord dorsal horn were evaluated. ResultsWe reported that acute exposure to remifentanil caused and maintained behavioral RIH with up-regulation of expression in CCL7/CCR2 and IL-18/IL-18R and the phosphorylation of GluA1 in the dorsal horn. Spinal inhibition of CCL7/CCR2 impaired RIH, spinal expression of IL-18/IL-18R and the phosphorylation of GluA1. Central blockage of IL-18/IL-18R reduced spinal phosphorylation of GluA1 and behavioral RIH. Also, intrathecal injection of exogenous CCL7 facilitated acute pain behaviors and spinal phosphorylation of GluA1 in naïve mice, which was suppressed by co-administration of IL-18 antagonist. ConclusionOur current findings demonstrate that spinal CCL7/CCR2 modulation of GluA1-containing AMPA receptor activation via IL-18 and IL-18R over-expression is an important pathogenesis of remifentanil-induced hyperalgesia in rats.

Central blockade of NLRP3 reduces blood pressure via regulating inflammation microenvironment and neurohormonal excitation in salt-induced prehypertensive rats

BackgroundInflammation has been implicated in the development of cardiovascular disease. We determined whether nod-like receptor with pyrin domain containing 3 (NLRP3) involved in the process of prehypertension, central blockade of NLRP3 decreased inflammation reaction, regulated neurohormonal excitation, and delayed the progression of prehypertension.MethodsPrehypertensive rats were induced by 8% salt diet. The rats on high-salt diet for 1 month were administered a specific NLRP3 blocker in the hypothalamic paraventricular nucleus (PVN) for 4 weeks. ELISA, western blotting, immunohistochemistry, and flow cytometry were used to measure NLRP3 cascade proteins, pro-inflammation cytokines (PICs), chemokine ligand 2 (CCL2), C-X-C chemokine receptor type 3 (CXCR3), vascular cell adhesion molecule 1 (VCAM-1), neurotransmitters, and leukocytes count detection, respectively.ResultsNLRP3 expression in PVN was increased significantly in prehypertensive rats, accompanied by increased number of microglia, CD4+, CD8+ T cell, and CD8+ microglia. Expressions of PICs, CCL2, CXCR3, and VCAM-1 significantly increased. The balance between 67-kDa isoform of glutamate decarboxylase (GAD67) and tyrosine hydroxylase (TH) was damaged. Plasma norepinephrine (NE) in prehypertensive rats was increased and gamma-aminobutyric acid (GABA) was reduced. NLRP3 blockade significantly decreased blood pressure, reduced PICs, CCL2, VCAM-1 expression in PVN, and restored neurotransmitters. Blood pressure and inflammatory markers were upregulated after termination of central blockage NLRP3.ConclusionsSalt-induced prehypertension is partly due to the role of NLRP3 in PVN. Blockade of brain NLRP3 attenuates prehypertensive response, possibly via downregulating the cascade reaction triggered by inflammation and restoring the balance of neurotransmitters.

Investigations on thermal hydraulic consequences of planar blockage in a prototype sodium cooled fast reactor fuel subassembly

A Computational Fluid Dynamics (CFD) based investigation has been carried out to understand the thermal hydraulic consequences of planar blockage within a 217 pin wire wrapped prototype fuel bundle. The computational domain comprising of 7 helical pitch lengths is meshed with structured hexahedral mesh. To reduce the computational time it is decomposed into 84 sub domains and each sub domain is handled by a separate processor. Detailed validation of the models used in the present analysis has been carried out with the data from an appropriate experiment, reported in open literature. Consequences of various radial extents of planar blockage located in the central pin and corner pin of the fuel subassembly are studied and compared. The contribution of pressure drop by the blockages and the associated flow reduction in the affected fuel subassembly has been quantified. Based on this, the increase in the bulk sodium outlet temperature of the subassembly and the efficiency of blockage detection by core temperature monitoring thermocouple has been assessed. Based on the parametric studies, it is found that inception of sodium boiling is likely if 3 or more rows are obstructed by a blockage located either in the center or in the corner pin of the subassembly. Even when the blockage is symmetric about the subassembly axis, large asymmetry in temperature field is observed within the blockage. This asymmetry is observed to be strongly dependent on the wire orientation in the upstream of blockage. As expected, a large reverse flow zone is observed in the downstream of the blockage. But, for similar number of blocked rows, corner blockage is found to have a larger reverse flow zone than that of central blockage. This is attributed to the fact that the presence of hexcan walls inhibits flow redistribution. Further, in accordance with size of reverse flow zone, higher sodium temperature is found in the downstream of corner blockage than a central blockage, even though the blocked cross section is less in the former case. This suggests that, sodium boiling is more likely in the case of corner blockage. Large circumferential temperature variation up to 650 °C is possible in the case of 4-row blockage and the peak variation is observed in the periphery of the blockage. Further it is found that monitoring of online bulk sodium temperature of subassembly exit cannot ensure blockage detection before inception of local sodium boiling within the subassembly. But, in the cases of both central and corner blockages, the disturbance generated in the temperature field prevails up to the outlet. This could act as a means for blockage detection.

Pre-test CFD simulations of the NACIE-UP BFPS test section

The present paper is focused on the CFD pre-test analysis and design of the new experimental facility ‘Blocked’ Fuel Pin bundle Simulator (BFPS) that will be installed into the NACIE-UP (NAtural CIrculation Experiment-UPgrade) facility located at the ENEA Brasimone Research Center (Italy).The BFPS test section will carry out suitable experiments to fully investigate different flow blockage regimes in a 19 fuel pin bundle providing experimental data in support of the development of the ALFRED (Advanced Lead-cooled Fast Reactor European Demonstrator) LFR DEMO.The geometrical domain of the fuel pin bundle simulator was designed to reproduce the geometrical features of ALFRED, e.g. the external wrapper in the active region and the spacer grids. Pre-tests calculations were carried out by applying accurate boundary conditions; the conjugate heat transfer in the clad is also considered.The blockages investigated are internal blockages of different extensions and in different locations: central sub-channel blockage, corner sub-channel blockage, edge sub-channel blockage, one sector blockage, and two-sector blockage.RANS simulations were carried out adopting the ANSYS CFX commercial code with the laminar sublayer resolved by the mesh resolution. The loci of the peak temperatures and their width as predicted by the CFD simulations are used for determining the location of the pin bundle instrumentation. The CFD pre-test analysis allowed also investigating the temperature distribution in the clad to operate the test section safely.

New treatment strategies for benign prostatic hyperplasia in the frail elderly population: a systematic review.

Life expectancy is constantly increasing and as a consequence older men, frequently with multiple comorbidities, are seeking treatment for benign prostatic hyperplasia. Given their frail health, these men need extreme attention in their management, as efficacious and safe treatment strategies in the general population may not be adequate for them. The National Library of Medicine Database was searched for relevant articles published between 2006 and 2015. Each article's title, abstract and text were reviewed for their appropriateness and their relevance. 57 articles were eligible for the review. In the elderly and frail, α1-antagonists should be used with caution given the risk of orthostatic hypotension and consequent falls, cause of significant morbidity in the elderly. 5ARIs present a good safety profile. Anticholinergics must also be prescribed with caution, given the risk of aggravating symptoms of dementia due to a central blockage of cholinergic neuronal pathways. Prostatic urethral lift is a medical device with low morbidity and valid functional results, which appear to endure over time. Prostatic artery embolization is demonstrating good results with minimal complication rates. Laser prostate vaporization or enucleation is also safe in elderly men and in those receiving anticoagulation therapy, due to its excellent hemostatic effect on prostatic tissue. Urologists should be familiar with the safety and efficacy profile of medical and surgical therapy in the elderly population, given the inevitable increase in older patients which we will observe in the near future.

Thermal hydraulic effect of porous blockage in fuel subassembly of sodium cooled fast reactor

Three-dimensional flow and temperature fields within a 19-pin wire-wrapped fuel bundle of fast reactor with internal blockage have been predicted by Computational fluid dynamic (CFD) studies. Simulations are carried out for a stream-wise length of seven helical pitches. Blockage geometry (shape and size), its radial position and blockage porosity which influence the clad temperature and hence increase the risk of sodium boiling, are systematically varied in a parametric study. Clad temperature, cross-stream sodium velocity and cross-stream temperature distributions are investigated in detail. Axial variation of clad temperature is seen to exhibit strong fluctuations due to the interaction of helical spacer wire and coolant flow through a subassembly with porous blockage. The maximum difference in the circumferential temperature of clad, which is a critical parameter for fuel pin mechanical design, is large in pins that are partially exposed to blockage. Effect of porous blockage is found to be limited to the porous zone and the peak clad temperature is proportional to the volume of the porous zone. Peak temperature in the blockage is strongly influenced by the radial extent of blockage and it is higher if the radial extent is larger. Maximum difference in the circumferential clad temperature is relatively low for a corner blockage compared to that of a central blockage. Sodium boiling is imminent in fuel pin bundle with six blocked sub-channels located at the centre when porosity value reduces below 45%.

Far-field formulation of a Cassegrain reflector using a novel illumination function and aperture field integration

In this paper, the far-field pattern of a Cassegrain reflector is formulated. A novel illumination function is used to approximate the field distribution at the aperture of the reflector. The defined illumination function takes into account the central aperture blockage created by the subreflector. Using the illumination function, a closed-form expression describing the far-field radiation pattern of the Cassegrain reflector is formulated. The radiation pattern obtained from the derived equation is compared with the results obtained from physical optics and physical theory of diffraction. The results are found to be consistent with each other. It is found that the derived results show an impressive accuracy of 99.8% over the main-lobe region. The accuracy is found to be over 91 and 84% for the first and second significant side-lobe region, respectively, which can be considered satisfactory for many applications.

Prostate cancer considered low or intermediate risk for biochemical failure according to the rtog-astro phoenix definition: Results of the use of neoadjuvant androgen deprivation before high-dose rate brachytherapy and external beam radiotherapy

16121 Background: Patients treated with radiation therapy have a significantly better outcome as the dose to the prostate is increased. Conformal high dose rate brachytherapy (HDR) is a successful method for delivering higher dose of radiation. This is a retrospective analysis of patients presenting with low (LR) or intermediate (IR) risk features, who were submitted or not to neoadjuvant androgen deprivation (NAAD). Methods: Charts of patients treated with HDR and localized 3DRT between 1997 and 2005 were reviewed. At the discretion of the referral urologist patients had NAAD (goserelin +/− flutamide or ciproteron acetate). 3 to 6 months. Results: 142 patients were eligible for study entry, 84 (59.1%) had no NAAD. Median age of the patients was 70 years (range, 53–81 years). Median follow-up was 6 years. There were 77 (54.2%) of patients into the LRG and 65 (45.8%) into IRG. The dose of EBRT ranged from 40 to 54 Gy (median 47 Gy). The HDR dose ranged from 16 to 24 Gy given in 4 fractions, BID, in two days. Median HDR dose was 20 Gy. Of the patients who had NAAD, 38 (26.8%) of the patients had central or total androgen blockage and 20 (14.1%) patients had peripheral blockage only. The crude overall survival (OS) rate at 4-year was 95.1%. The 5- and 10-year actuarial OS rates were 93.6% and 85.8%, respectively. The crude biochemical control (BC) rate at 4-year was 79.2%. Actuarial BC rates at 5- and 10-year were 91.4% and 59.6% for LRG and for IRG were 89.2% and 45.4%, respectively (p=0.308). NAAD did not influence the BC rates (p=0.477). Conclusion: dose of radiation prescribed seems to be an important factor related to BC. So far in our own experience, HDR and 3DRT are successful forms of treatment combination, but data from prospective randomized trials are still missing. We favour the use of adjuvant androgen deprivation over NAAD for patients presenting with adverse prognostic factors. No significant financial relationships to disclose.

Ketamine in post-tonsillectomy pain

There has yet been no ideal method for postoperative analgesia in children. Ketamine demonstrates a potent analgesic effect by central blockage of perception of pain with sub-anesthetic doses. Preoperative intramuscular administration of ketamine for sedation decreases the pain during swallowing after tonsillectomy, while it provides long-term analgesia when applied around the incision. The aim of this study is to compare the effectiveness of ketamine administered to the tonsillar region following tonsillectomy for postoperative pain management. After obtaining consent from the local ethics committee and the parents, 60 patients from the ASA groups I and II, between 3 and 7 years of age, planned for adenotonsillectomy as outpatients, were included in the study. Subjects were randomly assigned to two equal groups and 2ml 0.9% saline for group S, and 0.5mgkg(-1) ketamine and saline 2ml in volume for group K were administered into the tonsillar region. All subjects were monitored in a standard manner and SpO(2), systolic arterial pressure (SAP), and cardiac pulse rates were recorded in 5min intervals. The CHEOPS and Wilson sedation scale were used to evaluate pain levels and sedative condition, respectively. Nausea and vomiting scores of the subjects were also noted. The time of the first analgesic administration and the total amount of analgesics in an 8-hour period were recorded. Student-T and Chi-Square tests were used for the statistical evaluation of the data and a p value of <0.05 was accepted as significant. There were no significant differences between groups according to age, sex, weight, intermittent SAP and cardiac pulse rates. However, the CHEOPS value, the first analgesic need and the total amount of analgesic need were in favor of ketamine (p<0.05). In previous studies, no significant differences were demonstrated in pre-emptive analgesia with ketamine, magnesium, morphine, and clonidine. The dose of ketamin and the volume used in this study caused no sedation or nausea and provided a high level of analgesia. Ketamine infiltration into the tonsillar region after tonsillectomy was found to be easy and effective.