74 research outputs found

    Multiple-access interference-resistant acquisition for band-limited CDMA systems with random sequences

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    Ability of the National Surgical Quality Improvement Program Risk Calculator to Predict Complications Following Total Laryngectomy

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    Importance The accuracy of the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) risk calculator has been assessed in multiple surgical subspecialties; however, there have been no publications doing the same in the head and neck surgery literature. Objective To evaluate the accuracy of the calculator’s predictions in a single institution’s total laryngectomy (TL) population. Design, Setting, and Participants Total laryngectomies performed between 2013 and 2014 at a tertiary referral academic center were evaluated using the risk calculator. Predicted 30-day outcomes were compared with observed outcomes for return to operating room, surgical site infection, postoperative pneumonia, length of stay, and venous thromboembolism. Main Outcomes and Measures Comparison of the NSQIP risk calculator’s predicted postoperative complication rates and length of stay to what occurred in this patient cohort using percent error, Brier scores, area under the receiver operating characteristic curve, and Pearson correlation analysis. Results Of 49 patients undergoing TL, the mean (SD) age at operation was 59 (9.3) years, with 67% male. The risk calculator had limited efficacy predicting perioperative complications in this group of patients undergoing TL with or without free tissue reconstruction or preoperative chemoradiation or radiation therapy with a few exceptions. The calculator overestimated the occurrence of pneumonia by 165%, but underestimated surgical site infection by 7%, return to operating room by 24%, and length of stay by 13%. The calculator had good sensitivity and specificity of predicting surgical site infection for patients undergoing TL with free flap reconstruction (area under the curve, 0.83). For all other subgroups, however, the calculator had poor sensitivity and specificity for predicting complications. Conclusions and Relevance The risk calculator has limited utility for predicting perioperative complications in patients undergoing TL. This is likely due to the complexity of the treatment of patients with head and neck cancer and factors not taken into account when calculating a patient’s risk

    Sarcopenia is associated with blood transfusions in head and neck cancer free flap surgery

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    Objective: To determine if sarcopenia is a predictor of blood transfusion requirements in head and neck cancer free flap reconstruction (HNCFFR). Methods: A single-institution, retrospective review was performed of HNCFFR patients with preoperative abdominal imaging from 2014 to 2019. Demographics, comorbidities (modified Charlson Comorbidity Index [mCCI]), skeletal muscle index (cm2/m2), oncologic history, intraoperative data, and 30-day postoperative complications (Clavien-Dindo score [CD]) were collected. Binary logistic regression was performed to determine predictors of transfusion. Results: Eighty (33.5%), 66 (27.6%), and 110 (46.0%) of n = 239 total patients received an intraoperative, postoperative, or any perioperative blood transfusion, respectively. Sixty-two (25.9%) patients had sarcopenia. Patients receiving intraoperative transfusions had older age (P = .035), more frequent alcoholism (P = .028) and sarcopenia (P < .001), greater mCCI (P < .001), lower preoperative hemoglobin (P < .001), reconstruction with flaps other than forearm (P = .003), and greater operative times (P = .001), intravenous fluids (P < .001), and estimated blood loss (EBL, P < .001). Postoperative transfusions were associated with major complications (CD ≄ 3; P < .001). Multivariate regression determined sarcopenia (P = .023), mCCI (P = .013), preoperative hemoglobin (P = .002), operative time (P = .036), and EBL (P < .001) as independent predictors of intraoperative transfusion requirements. Postoperative transfusions were predicted by preoperative hemoglobin (P = .007), osseous flap (P = .036), and CD ≄ 3 (P < .001). A perioperative transfusion was predicted by sarcopenia (P = .021), preoperative hemoglobin (P < .001), operative time (P = .008), and CD ≄ 3 (P = .018). Conclusion: Sarcopenia is associated with increased blood transfusions in HNCFFR. Patients should be counseled preoperatively on the associated risks, and the increased blood product requirement should be accounted in resource-limited scenarios

    Diseases of the salivary glands in infants and adolescents

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    <p>Abstract</p> <p>Background</p> <p>Diseases of the salivary glands are rare in infants and children (with the exception of diseases such as parotitis epidemica and cytomegaly) and the therapeutic regimen differs from that in adults. It is therefore all the more important to gain exact and extensive insight into general and special aspects of pathological changes of the salivary glands in these age groups. Etiology and pathogenesis of these entities is still not yet fully known for the age group in question so that general rules for treatment, based on clinical experience, cannot be given, particularly in view of the small number of cases of the different diseases. Swellings of the salivary glands may be caused by acute and chronic inflammatory processes, by autoimmune diseases, by duct translocation due to sialolithiasis, and by tumors of varying dignity. Clinical examination and diagnosis has also to differentiate between salivary gland cysts and inflammation or tumors.</p> <p>Conclusion</p> <p>Salivary gland diseases are rare in childhood and adolescence. Their pattern of incidence differs very much from that of adults. Acute and chronic sialadenitis not responding to conservative treatment requires an appropriate surgical approach. The rareness of salivary gland tumors is particularly true for the malignant parotid tumors which are more frequent in juvenile patients, a fact that has to be considered in diagnosis and therapy.</p

    Linearized esculentin-2EM shows pH dependent antibacterial activity with an alkaline optimum

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    Here the hypothesis that linearized esculentin 2EM (E2EM-lin) from Glandirana emeljanovi possesses pH dependent activity is investigated. The peptide showed weak activity against Gram-negative bacteria (MLCs ≄ 75.0 ÎŒM) but potent efficacy towards Gram-positive bacteria (MLCs ≀ 6.25 ÎŒM). E2EM-lin adopted an α-helical structure in the presence of bacterial membranes that increased as pH was increased from 6 to 8 (↑ 15.5 to 26.9 %), while similar increases in pH enhanced the ability of the peptide to penetrate (↑ 2.3 to 5.1 mN m-1) and lyse (↑ 15.1 to 32.5%) these membranes. Theoretical analysis predicted that this membranolytic mechanism involved a tilted segment, that increased along the α-helical long axis of E2EM-lin (1-23) in the N → C direction, with - increasing overall from circa - 0.8 to - 0.3. In combination, these data showed that E2EM-lin killed bacteria via novel mechanisms that were enhanced by alkaline conditions and involved the formation of tilted and membranolytic, α-helical structure. The preference of E2EM-lin for Gram-positive bacteria over Gram-negative organisms was primarily driven by the superior ability of phosphatidylglycerol to induce α-helical structure in the peptide as compared to phosphatidylethanolamine. These data were used to generate a novel pore-forming model for the membranolytic activity of E2EM-lin, which would appear to be the first, major reported instance of pH dependent AMPs with alkaline optima using tilted structure to drive a pore-forming process. It is proposed that E2EM-lin has the potential for development to serve purposes ranging from therapeutic usage, such as chronic wound disinfection, to food preservation by killing food spoilage organisms

    Mechanisms underlying the autonomic modulation of ventricular fibrillation initiation—tentative prophylactic properties of vagus nerve stimulation on malignant arrhythmias in heart failure

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    Nonlinear Behavior of Reactor-Separator and Reactor-Distillation Networks : Influence of the Energy Balance Formulation

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    Modeling of evaporative separators with mass and energy balances, only, often leads to di erential algebraic systems (DAE) with di erential index 2. To overcome the problems which are associated with the numerical solution of index 2 DAEs either a formal index reduction can be applied or the model can be reformulated by modifying the underlying assumptions. Typical modi cations leading to index 1 problems are either the assumption of a quasistatic energy balance or the inclusion of some simple uid dynamics. In the present paper the dynamic behavior predicted by these di erent model formulations are analyzed and compared with each other. First, focus is on an isolated single stage ash process with given heat input. The well-known adiabatic ash is included as a special case. It is shown that the dynamic behavior of the di erent model formulations for a stand alone ash are rather close. In particular, in all cases a stable steady state is predicted. Second, a simple reactor-separator system with recycle is considered. The reactor is a CSTR, whereas the separator is again a constantly heated ash. In a previous paper we have shown, that the recycle in such a system can induce instability and multiplicity of steady states [1]. In the present paper it is shown, that although the stand alone ash is rather insensitive to the speci c model formulation, the dynamics of the coupled system can under certain conditions to be speci ed in this paper depend on the speci c model formulation applied. In particular, a new type of bifurcation is found where the eigenvalues have a pole with a change of sign. The analysis is based on a model with negligible transportation delay of the recycle. Furthermore, these investigations are extended to reactor-distillation column models. In such models complex bifurcation structures consisting of periodic, complex-periodic, and even deterministic chaotic oscillations have been characterized. These bifurcation structures show interesting analogies to scenarios found in isothermal autocatalytic oscillators, like the Belousov-Zhabotinsky reaction [2] or the peroxidase-oxidase reaction [3]. It is illustrated that the observed bifurcation scenario critically depends on the formulation of the energy balance equation of the distillation column. © 2007 Elsevier B.V. All rights reserved. [accessed 2013 December 4th

    CO2 Laser Division of Neo-Vallecula Improves Dysphagia in the Postlaryngectomy Patient: A Case Series and Review of the Literature

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    Objectives To review the literature on neo-vallecula diagnosis and management and to report our findings regarding 3 patients who developed neo-vallecula in the context of free-flap pharyngeal reconstruction following total laryngectomy. Methods This case series reports three patients who developed a neo-vallecula following a laryngectomy and free-flap pharyngeal reconstruction. All three patients were treated with a CO2 laser endoscopic procedure. Results Neo-vallecula formation is thought to be related to tension on the neopharyngeal closure or closure technique following total laryngectomy. Diagnosis may be obtained with swallow studies, videofluoroscopy, or endoscopy. Treatment has included external excision and endoscopic procedures such as stapling, harmonic scalpel excision, and laser removal. We utilized an endoscopic approach entailing the use of a CO2 laser to divide the neo-vallecula, and all our patients reported improvement in their dysphagia. Conclusions Treatment of an anterior neo-vallecula endoscopically using a CO2 laser is an effective way to treat dysphagia in patients following total laryngectomy with free-flap pharyngeal reconstruction

    Proliferative Activity and Aneuploidy in Pleomorphic Adenomas of the Salivary Glands

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    We used flow cytometry in a retrospective study of pleomorphic adenoma and carcinoma arising in pleomorphic adenoma, using paraffin-embedded tissue, to assess the relationship among proliferative activity, ploidy, and recurrence or malignant transformation. Twenty-four specimens obtained from 22 tumors were acceptable for analysis (co-efficient of variation, \u3c or = 7.0), including multiple samples from two tumors. Fourteen tumors (13 benign and one malignant) were diploid. Six tumors were aneuploid: four benign pleomorphic adenomas and two carcinomas arising in pleomorphic adenoma. Two tetraploid tumors were malignant recurrences from the same patient. Of the recurrent tumors (nine benign and four malignant), 54% were aneuploid. The highest S-phase fractions were observed in recurrent and malignant pleomorphic adenomas. Immunostaining with p105, a nuclear proliferation antigen, revealed increased proliferative activity in a majority of pleomorphic adenomas. Increased proliferative activity and aneuploidy occurred in benign pleomorphic adenomas
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