Performance of multilevel-turbo codes with blind/non-blind equalization over WSSUS multipath channels

In this paper, in order to improve error performance, we introduce a new type of turbo codes, called 'multilevel-turbo codes (ML-TC)' and we evaluate their performance over wide-sense stationary uncorrelated scattering (WSSUS) multipath channels. The basic idea of ML-TC scheme is to partition a signal set into several levels and to encode each level separately by a proper component of the turbo encoder. In the considered structure, the parallel input data sequences are encoded by our multilevel scheme and mapped to any modulation type such as MPSK, MQAM, etc. Since WSSUS channels are very severe fading environments, it is needed to pass the received noisy signals through non-blind or blind equalizers before turbo decoders. In ML-TC schemes, noisy WSSUS corrupted signal sequence is first processed in equalizer block, then fed into the first level of turbo decoder and the first sequence is estimated from this first Turbo decoder. Subsequently, the other following input sequences of the frame are computed by using the estimated input bit streams of previous levels. Here, as a ML-TC example, 4PSK 2 level-turbo codes (2L-TC) is chosen and its error performance is evaluated in WSSUS channel modelled by COST 207 (Cooperation in the field of Science & Technology, Project #207). It is shown that 2L-TC signals with equalizer blocks exhibit considerable performance gains even at lower SNR values compared to 8PSK-turbo trellis coded modulation (TTCM). The simulation results of the proposed scheme have up to 5.5dB coding gain compared to 8PSK-TTCM for all cases. It is interesting that after a constant SNR value, 2L-TC with blind equalizer has better error performance than non-blind filtered schemes. We conclude that our proposed scheme has promising results compared to classical schemes for all SNR values in WSSUS channels. Copyright (C) 2005 John Wiley & Sons, Ltd

Performance of transmit diversity-turbo trellis coded modulation (TD-TTCM) over genetically estimated WSSUS mimo channels

This paper presents the performance of Transmit Diversity-Turbo Trellis Coded Modulation (TD-TTCM) over Wide Sense Stationary Uncorrelated Scattering (WSSUS), Multiple-Input-Multiple-Output (MIMO) channels. To achieve high bandwidth efficiency and/or high power efficiency, in TD-TTCM, binary input sequence is passed through a turbo trellis encoder, mapped to 8-PSK and then fed into a new transmit diversity (TD) scheme for high data transmission over wireless fading channels. At the receiver side, the distorted multi-path signals are received by multiple receive antennas. WSSUS MIMO channel parameters and modulated signals are estimated by using Genetic Algorithm (GA) and an iterative combiner, respectively. Then they are taken as an input to Turbo trellis decoder. Here, TD-TTCM and its efficient implementations are discussed and simulation results are presented

Esophageal voice prosthesis mistaken for impacted foreign body

[No abstract available

Gastroprotective effects of CoQ10 on ethanol-induced acute gastric lesions

Introduction: Alcohol consumption is frequently associated with gastric mucosal lesions. The purpose of this study was to determine the effect of Coenzyme-Q10 (CoQ10) supplementation on the ethanol-induced gastric mucosal damage in a rat model. Material and method: Sixty-four female wistar albino rats were randomly divided into 8 groups (n = 8). Studies were performed in ethanol induced gastric ulcer model in Wistar albino rats. Famotidine at a dose of 5 mg/kg or 20 mg/kg and CoQ10 at a single dose of 10 mg/kg or 20 mg/kg and 30 mg/kg for 7 days were administered as pretreatment. All the rats in study groups received 2 ml/kg ethanol 95 % intragastrically, 30 minutes after pretreatment. Four hour after ethanol administration, all rats were sacrifi ced and their stomachs were removed under ketamin anaesthesia. Gastric protection was evaluated by measuring the ulcer index, MDA concentrations, and histopathological studies. Results and discussion: Rats pretreated either with famotidine or CoQ10 had signifi cantly diminished gastric mucosal damage which was assessed with gross and microscopic analysis (p < 0.00625). MDA levels were signifi cantly lower in famotidine 20 mg/kg and CoQ10 pretreatment for 7 days group (p < 0.00625). Conclusion: CoQ 10 affords gastroprotection against ethanol-induced gastric mucosal lesions in rats especially after repetitive administrations

Gastroprotective effects of CoQ(10) on ethanol-induced acute gastric lesions

WOS: 000349275900010PubMed: 25666963Introduction: Alcohol consumption is frequently associated with gastric mucosa! lesions. The purpose of this study was to determine the effect of Coenzyme-Q(10) (CoQ(10)) supplementation on the ethanol-induced gastric mucosal damage in a rat model. Material and method: Sixty-four female wistar albino rats were randomly divided into 8 groups (n = 8). Studies were performed in ethanol induced gastric ulcer model in Wistar albino rats. Famotidine at a dose of 5 mg/kg or 20 mg/kg and CoQ(10), at a single dose of 10 mg/kg or 20 mg/kg and 30 mg/kg for 7 days were administered as pretreatment. All the rats in study groups received 2 ml/kg ethanol 95 % intragastrically, 30 minutes after pretreatment. Four hour after ethanol administration, all rats were sacrificed and their stomachs were removed under ketamin anaesthesia. Gastric protection was evaluated by measuring the ulcer index, MDA concentrations, and histopathological studies. Results and discussion: Rats pretreated either with famotidine or CoQ(10) had significantly diminished gastric mucosal damage which was assessed with gross and microscopic analysis (p < 0.00625). MDA levels were significantly lower in famotidine 20 mg/kg and CoQ(10), pretreatment for 7 days group (p < 0.00625). Conclusion: CoQ(10) affords gastroprotection against ethanol-induced gastric mucosal lesions in rats especially after repetitive administrations (Tab. 3, Fig. 2, Ref. 35). Text in PDF www.elis.sk

The Janeway gastrostomy tube for recurrent gastric intubations: A novel and simple animal model

Access to the gastric lumen can be achieved by different methods. Orogastric tubes and tube gastrostomies are frequently used but these routes have some disadvantages when recurrent gastric intubations or infusions are concerned. The Janeway gastrostomy tube is a simple-to-perform procedure and can serve as an excellent way to reach the gastric lumen of animals. It is also possible to insert large caliber devices such as cameras to examine the gastric lumen. Plugging of the pylorus is also possible with Fogarty catheters either blind or under radiological guidance. The Janeway gastric tube seems to be useful for long-lasting gastrointestinal procedures, for example gastric cancer studies. © 2007 Springer Science+Business Media, LLC

Small-bowel obstruction secondary to wireless capsule enteroscopy: extraction of the capsule without enterotomy

WOS: 000260451400201PubMed: 1795763

Complications of total thyroidectomy performed by surgical residents versus specialist surgeons

Purpose. Surgeon inexperience has been defined as a significant predictor of deleterious outcome in thyroid surgery; however, the safety of training programs in which residents are the primary surgeons is controversial. The objective of this prospective study was to compare the complication rates of total thyroidectomy (TT) performed by residents with those of TT performed by specialist surgeons in similar patient groups. Methods. Between April 2001 and May 2007, 144 patients underwent TT at our hospital. For 75 operations, the primary surgeon was a resident under the direct supervision of the attending surgeon, and for 69 operations, the primary surgeon was the experienced attending surgeon. Pre-and postoperative vocal cord examinations and serum calcium level evaluations were carried out in all patients. Results. The rates of temporary (unilateral) recurrent laryngeal nerve (RLN) palsy were 2.66% vs 2.17% after TT performed by the residents vs the attending surgeon, respectively. There were no significant differences in the incidences of temporary hypoparathyroidism (20% vs 20.28%), permanent (unilateral) RLN palsy, hematoma, infection, seroma, and incidental parathyroidectomy between the two groups. Conclusion. The complication rates of TT performed by residents and attending surgeons were similar. Thus, residents can perform TT safely and effectively under the direct supervision of a senior surgeon. Ultimately, strict adherence to the contemporary principles of thyroid surgery is of paramount importance. © 2008 Springer

Inadvertent parathyroidectomy and temporary hypocalcemia: An adverse natural outcome or a true complication during thyroidectomy?

Objective. The aim of this study was to assess the factors that might predict patients at increased risk for inadvertent parathyroidectomy and postoperative symptomatic hypocalcemia during thyroidectomy. Methods. Demographic data as well as the data on preoperative diagnosis, preoperative ultrasonography reports, operation reports, histological findings, and postoperative symptomatic hypocalcemia were collected. A total of 273 (83 male and 190 female patients) thyroid operations were included in this study. Results. Histopathological examination identified inadvertent parathyroidectomy in 10 (3.7%) cases. Statistical analysis identified the presence of cervical lymphadenopathy as detected by preoperative ultrasonography as a risk factor for inadvertent parathyroidectomy. In 57 patients (20.9%) clinically symptomatic postoperative hypocalcemia was observed. However, the difference in the frequency of such hypocalcemia between the patients with and without inadvertent parathyroidectomy was not significant. Statistical evaluation identified total thyroidectomy as a risk factor for postoperative hypocalcemia (p<0.005). Conclusion. Due to our experience, inadvertent parathyroidectomy is not a rare entity during thyroidectomy and the presence of cervical lymphadenopathy, as observed by preoperative ultrasonography, is the only risk factor for inadvertent parathyroidectomy. In contrast, no association between inadvertent parathyroidectomy and postoperative hypocalcemia was detected. Total thyroidectomy was found to be the sole risk factor for symptomatic temporary hypocalcemia