71 research outputs found

    Optimizing cooperative cognitive radio networks with opportunistic access

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    Optimal resource allocation for cooperative cognitive radio networks with opportunistic access to the licensed spectrum is studied. Resource allocation is based on minimizing the symbol error rate at the receiver. Both the cases of all-participate relaying and selective relaying are considered. The objective function is derived and the constraints are detailed for both scenarios. It is then shown that the objective functions and the constraints are nonlinear and nonconvex functions of the parameters of interest, that is, source and relay powers, symbol time, and sensing time. Therefore, it is difficult to obtain closed-form solutions for the optimal resource allocation. The optimization problem is then solved using numerical techniques. Numerical results show that the all-participate system provides better performance than its selection counterpart, at the cost of greater resources

    Clinical insights on Tolosa Hunt syndrome: a multidisciplinary approach on neurological-related symptomatology in maxillofacial region

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    Background Tolosa–Hunt syndrome (THS) related neurological symptoms are described in literature as “unilateral”, “recurrent”, “episodic”, “intense”, “severe”, “lancinating” or “stabbing” pain on the upper face and forehead and may be misdiagnosed due to the similarity of few symptoms and a significant number of common characteristics between both conditions. Aims The aim of this brief report is to indicate some important clinical insights related to Tolosa Hunt syndrome, and to give a frank account on the multidisciplinary approach on neurological-related symptomatology in maxillofacial region. Methods We analysed a selection of patients with such clinical picture. To better describe the proper management of clinical cases, we report a 50-year-old female reporting an history of two years of recurrent, severe stabbing pain around the right eye, prominence of her cheek and forehead. Her general dentist first mistakenly diagnosed toothache and, thus, it was subsequently misdiagnosed the trigeminal neuropathy (TN). Results Reported exemplificative case presented a mild ptosis, diplopia of the right eye, corneal reflex loss, paresthesia and hyperesthesia of upper part of left side of face. Magnetic resonance imaging (MRI) findings were suggestive of THS. Complete resolution of symptoms was achieved with oral Prednisolone and constant monitoring of symptoms. Conclusion THS may be added to the long list of differential diagnosis of TN and general dentist and oral surgeons should be informed about such rare causes of facial pain through continued medical education programs

    Early complications after biliary enteric anastomosis for benign diseases: A retrospective analysis

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    Background:Biliary-enteric anastomosis (BEA) is a common surgical procedure performed for the management of biliary obstruction or leakage that results from a variety of benign and malignant diseases. Complications following BEA are not rare. We aimed to determine the incidence and the factors associated with early complications occurring after BEA for benign diseases. Methods: We reviewed the medical records of all Patients who underwent BEA for benign diseases at our institution between January 1988 and December 2009. The primary outcome was early post operative complication. Logistic regression analysis was done to identify factors predicting the occurrence of complications. Results: Records of 79 Patients were reviewed. There were 34 (43%) males and 45 (57% females). Majority (53%) had choledocholithiasis with impacted stone or distal stricture, followed by traumatic injury to the biliary system (33%). Thirty-four Patients (43%) underwent a hepaticojejunostomy, 19 Patients (24%) underwent a choledochojejunostomy, and choledochoduodenostomy was performed in 26 Patients (33%). Early complications occurred in 39 (49%) Patients - 41% had local complications and 25% had systemic complications. Most frequent complications were wound infection (23%) and bile leak (10%). Four (5%) Patients died. On multivariate analysis, low serum albumin level (odds ratio = 16, 95% CI = 1.14-234.6) and higher ASA levels (odds ratio = 7, 95% CI: 1.22-33.34) were the independent factors predicting the early complications following BEA. Conclusions: Half of the Patients who underwent BEA for benign diseases had complications in our population. This high incidence may be explained by the high incidence of hypoalbuminemia and the high-risk group who underwent operation

    Modelling and analysis of the complement system signalling pathways: roles of C3, C5a and pro-inflammatory cytokines in SARS-CoV-2 infection

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    The complement system is an essential part of innate immunity. It is activated by invading pathogens causing inflammation, opsonization, and lysis via complement anaphylatoxins, complement opsonin’s and membrane attack complex (MAC), respectively. However, in SARS-CoV-2 infection overactivation of complement system is causing cytokine storm leading to multiple organs damage. In this study, the René Thomas kinetic logic approach was used for the development of biological regulatory network (BRN) to model SARS-CoV-2 mediated complement system signalling pathways. Betweenness centrality analysis in cytoscape was adopted for the selection of the most biologically plausible states in state graph. Among the model results, in strongly connected components (SCCs) pro-inflammatory cytokines (PICyts) oscillatory behaviour between recurrent generation and downregulation was found as the main feature of SARS-CoV-2 infection. Diversion of trajectories from the SCCs leading toward hyper-inflammatory response was found in agreement with in vivo studies that overactive innate immunity response caused PICyts storm during SARS-CoV-2 infection. The complex of negative regulators FI, CR1 and DAF in the inhibition of complement peptide (C5a) and PICyts was found desirable to increase immune responses. In modelling role of MAC and PICyts in lowering of SARS-CoV-2 titre was found coherent with experimental studies. Intervention in upregulation of C5a and PICyts by C3 was found helpful in back-and-forth variation of signalling pattern linked with the levels of PICyts. Moreover, intervention in upregulation of PICyts by C5a was found productive in downregulation of all activating factors in the normal SCCs. However, the computational model predictions require experimental studies to be validated by exploring the activation role of C3 and C5a which could change levels of PICyts at various phases of SARS-CoV-2 infection

    Nano-refrigerants and nano-lubricants in refrigeration : synthesis, mechanisms, applications, and challenges

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    Addressing global energy security and environmental concerns, the utilization of nano-refrigerants and nano-lubricants has emerged as an innovative path for enhancing heat transfer. This research focuses on enhancing the thermophysical properties, heat transfer efficiency, and tribological characteristics of nanofluids—nanoparticles dispersed in refrigerants or lubricants. These nanofluids have demonstrated significant potential in applications such as cooling, air conditioning systems, and heat transfer equipment including pumps and pipes. A comprehensive understanding of parameters like thermal conductivity, viscosity, pressure drop, pumping power, and energy performance is delivered, with the aim of enhancing the overall efficiency of refrigeration systems, particularly the coefficient of performance (COP). Additionally, the review covers existing research on flow and pool boiling heat transfer, nano-lubricant tribological enhancement, and nano-refrigerant condensation. The study also addresses the challenges associated with the use of nano-refrigerants and nano-lubricants and offers a prospective outlook for their usage. These novel nanofluids are anticipated to emerge as effective solutions for increasing the COP and reducing energy consumption in the industrial sector, thus extending beyond the scope of previous efforts in this field. This review could serve as a valuable resource for a broad audience interested in this novel approach to energy efficiency

    Clinical insights on Tolosa Hunt syndrome: A multidisciplinary approach on neurological-related symptomatology in maxillofacial region

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    BackgroundTolosa–Hunt syndrome (THS) related neurological symptoms are described in literature as “unilateral”, “recurrent”, “episodic”, “intense”, “severe”, “lancinating” or “stabbing” pain on the upper face and forehead and may be misdiagnosed due to the similarity of few symptoms and a significant number of common characteristics between both conditions.AimsThe aim of this brief report is to indicate some important clinical insights related to Tolosa Hunt syndrome, and to give a frank account on the multidisciplinary approach on neurological-related symptomatology in maxillofacial region.Methods We analysed a selection of patients with such clinical picture. To better describe the proper management of clinical cases, we report a 50-year-old female reporting an history of two years of recurrent, severe stabbing pain around the right eye, prominence of her cheek and forehead. Her general dentist first mistakenly diagnosed toothache and, thus, it was subsequently misdiagnosed the trigeminal neuropathy (TN). Results Reported exemplificative case presented a mild ptosis, diplopia of the right eye, corneal reflex loss, paresthesia and hyperesthesia of upper part of left side of face. Magnetic resonance imaging (MRI) findings were suggestive of THS. Complete resolution of symptoms was achieved with oral Prednisolone and constant monitoring of symptoms.ConclusionTHS may be added to the long list of differential diagnosis of TN and general dentist and oral surgeons should be informed about such rare causes of facial pain through continued medical education programs

    Management of Uncommon Secondary Trigeminal neuralgia related to a rare Arnold Chiari type I malformation

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    BackgroundTrigeminal neuralgia (TN) may sometimes present secondary to an intra-cranial cause. Arnold Chiari Malformation (ACM) is downward herniation of the cerebellar tonsils through the foramen magnum that may be a cause of TN like pain in very rare cases.AimsThe aim of this brief report is to suggest the proper management of uncommon secondary trigeminal neuralgia related to a rare Arnold Chiari type I malformation.Methods A male patient presented electric shock like stabbing pain on the right side of the face for more than ten years. The symptoms were typical of trigeminal neuralgia except that there was loss of corneal reflex on the right side and the patient also complained of gait & sleep disturbances. Complex and multilevel diagnosis was made. Results A multiplanar imaging through brain acquiring T1/T2W1 revealed ACM Type I Malformation with caudal displacement of cerebellar tonsils through foramen magnum.ConclusionDental surgeons and oral and Maxillofacial Surgeons should exclude intra-cranial causes by Magnetic Resonance Imaging(MRI) in patients of TN presenting with loss of corneal reflex, gait and sleep disturbances due to night time pain episodes

    Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

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    Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely
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