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Purpose This study aimed to compare the outcomes of primary radiotherapy (RT) versus surgery in early-stage human papilloma virus-positive oropharyngeal squamous cell carcinoma (hpv+OPC), and investigate the preoperative clinical factors that can predict the requirement for postoperative adjuvant treatment. Materials and Methods This multicenter study included 166 patients with American Joint Committee on Cancer 8th edition-Stages I-II hpv+OPC. Sixty (36.1%) and 106 (63.9%) patients underwent primary (concurrent chemo)radiotherapy [(CC)RT] and surgery, respectively. Seventy-eight patients (73.6%) in the surgery group received postoperative (CC)RT. Results With a median follow-up of 45.6 months for survivors, the 2-year overall survival (OS), progression-free survival (PFS), and locoregional control (LC) for RT/surgery were 97.8%/96.4%, 91.1%/92.0%, and 92.9%/93.3%, respectively. In multivariate analyses, patients with synchronous radiologic extranodal extension and conglomeration (ENEcong) of metastatic lymph nodes (LNs) showed significantly poorer OS (p=0.047), PFS (p=0.001), and LC (p=0.003). In patients undergoing primary surgery, two or more clinically positive LN metastases (odds ratio [OR], 5.15; p=0.004) and LN metastases with ENEcong (OR, 3.75; p=0.009) were predictors of postoperative chemoradiotherapy. No patient in the primary RT group demonstrated late severe toxicity whereas three (2.8%), one (0.9%), and one (0.9%) patient in the surgery group showed grade 3 dysphagia, grade 3 xerostomia, and fatal oral cavity bleeding. Conclusion We found no differences in OS, PFS, and LC between upfront RT and surgery in stage I-II hpv+OPC which warrants comparison through a prospective trial in the treatment de-escalation era. However, most early-stage hpv+OPC patients undergoing surgery received adjuvant (CC)RT. Pretreatment LN findings were prognostic and predictive for adjuvant treatment. [ABSTRACT FROM AUTHOR]

Background: It is challenging to diagnose asthma in preschool children. The asthma predictive index (API) has been used to predict asthma and decide whether to initiate treatment in preschool children. Purpose: This study aimed to investigate the association between questionnaire-based current asthma with API, pulmonary function, airway hyperreactivity (AHR), fractional expiratory nitric oxide (FeNO), and atopic sensitization in preschool children. Methods: We performed a population-based cross-sectional study in 916 preschool children aged 4–6 years. We defined current asthma as the presence of both physician-diagnosed asthma and at least one wheezing episode within the previous 12 months using a modified International Study of Asthma and Allergies in Childhood questionnaire. Clinical and laboratory parameters were compared between groups according to the presence of current asthma. Results: The prevalence of current asthma was 3.9% in the study population. Children with current asthma showed a higher rate of positive bronchodilator response and loose and stringent API scores than children without current asthma. The stringent API was associated with current asthma with 72.2% sensitivity and 82.0% specificity. The diagnostic accuracy of the stringent API for current asthma was 0.771. However, no intergroup differences in spirometry results, methacholine provocation test results, FeNO level, or atopic sensitization rate were observed. Conclusion: The questionnaire-based diagnosis of current asthma is associated with API, but not with spirometry, AHR, FeNO, or atopic sensitization in preschool children. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the prognostic value of 18F-fluorodeoxyglucose positron-emission tomography (FDG PET) with computed tomography (CT) before and during radiotherapy (RT) in patients with head and neck cancer. Methods: Twenty patients with primary head and neck squamous cell carcinoma were enrolled in this study, of whom 6 had oropharyngeal cancer, 10 had hypopharyngeal cancer, and 4 had laryngeal cancer. Fifteen patients received concurrent cisplatin and 2 received concurrent cetuximab chemotherapy. FDG PET/CT was performed before RT and in the 4th week of RT. The parameters of maximum standardized uptake value, metabolic tumor volume, and total lesion glycolysis (TLG) of the primary tumor were measured, and the prognostic significance of each was analyzed with the Cox proportional hazards model. Results: Higher TLG (>19.0) on FDG PET/CT during RT was a poor prognostic factor for overall survival (OS) (p = 0.001) and progression-free survival (PFS) (p = 0.007). In the multivariate analysis, TLG during RT as a continuous variable was significantly associated with OS and PFS rate (p = 0.023 and p = 0.016, respectively). Tumor response worse than partial remission at 1 month after RT was another independent prognostic factor for PFS (p = 0.024). Conclusions: Higher TLG of the primary tumor on FDG PET/CT during RT was a poor prognostic factor for OS and PFS in patients with head and neck cancer. [ABSTRACT FROM AUTHOR]

Background Relationship between recurrent wheeze and airway function and inflammation in preschool children is not fully known. Objective To investigate the relationship between recurrent wheeze and airway inflammation, lung function, airway hyper-reactivity (AHR) and atopy in preschool children. Design Observational study, comparing forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and midforced expiratory flow (FEF25%-75%), dose-response slope (DRS), exhaled nitric oxide (eNO) and atopic sensitisation between children with recurrent wheeze and those without. Setting Population-based, cross-sectional study in Seoul and the Gyeonggi province of Korea conducted as a government-funded programme to perform standardised measurement of the prevalence of allergic diseases, and related factors, in preschool children. Participants 900 children aged 4-6 years. Primary and secondary outcome measures eNO, FEV1/FVC, FEF25%-75%, DRS, atopic sensitisation and allergic diseases. Methods Children completed the modified International Study of Asthma and Allergies in Childhood questionnaire and underwent eNO assessments, spirometry, methacholine bronchial provocation tests and skin prick tests. Recurrent wheeze was defined as having a lifetime wheeze of more than three episodes, based on the questionnaire. The frequency of hospitalisation and emergency room visits was also obtained by means of the questionnaire. 'Current' wheeze was defined as having symptoms or treatments within the past 12 months. Results The prevalence of recurrent wheeze was 13.4%. Children with recurrent wheeze showed a higher prevalence of lifetime or current allergic rhinitis (p=0.01 and p=0.002, respectively) and lifetime atopic dermatitis (p=0.007). Children with recurrent wheeze showed lower FEV1/FVC (p=0.033) and FEF25%-75% (p=0.004), and higher eNO levels (p=0.013) than those without recurrent wheeze. However, the DRS, prevalence of atopic sensitisation and serum IgE levels were not significantly different between the two groups. Conclusions Recurrent wheeze in preschool children may be associated with airway inflammation and diminished airway function, but not with AHR or atopy. [ABSTRACT FROM AUTHOR]

The Global Initiative for Asthma (GINA) guidelines do not specify a bronchodilator range for bronchodilator response (BDR) testing and simply recommend a salbutamol dose of 200 to 400 μg. We determined the oscillometric BDR results of children given low-dose (2 puffs, 200 μg) and standard-dose (4 puffs, 400 μg) salbutamol to compare the small airway responses of healthy controls (defined using criteria based on the guidelines developed at the American Thoracic Society) and exclusion subjects (defined as any child that did not meet the inclusion criteria for healthy controls). The oscillometric reactance of small airways is significantly associated with the dose of salbutamol used for BDR testing in exclusion children. We suggest use of the standard-dose of salbutamol for oscillometric BDR testing. [ABSTRACT FROM AUTHOR]

A new hybrid automatic repeat request (HARQ) scheme for multicast service for wireless sensor networks is proposed in this study. In the proposed algorithm, the HARQ operation is combined with an autonomous retransmission method that ensure a data packet is transmitted irrespective of whether or not the packet is successfully decoded at the receivers. The optimal number of autonomous retransmissions is determined to ensure maximum spectral efficiency, and a practical method that adjusts the number of autonomous retransmissions for realistic conditions is developed. Simulation results show that the proposed method achieves higher spectral efficiency than existing HARQ techniques. [ABSTRACT FROM AUTHOR]

Background: Treatment guidelines for asthma have been established based on asthma severity; there are limitations in the identification of underlying pathophysiology and prediction of prognosis in heterogeneous phenotypes of asthma. Although the complex interactions between environmental and genetic factors affect the development and progression of asthma, studies on asthma phenotypes considering environmental factors are limited. This study aimed to identify asthma phenotypes using latent class analysis including environmental factors in school-age children.Methods: We included 235 children (6-8 years) with parent-reported, physician-diagnosed asthma from the Children's HEalth and Environmental Research (CHEER) study, which is a 4-year prospective follow-up study with 2-year intervals. At every survey, pulmonary function tests, methacholine challenge tests and blood tests with questionnaire were conducted.Results: Four asthma phenotypes were identified. Cluster 1 (22% of children) was characterized by high prevalence of atopy and mild symptoms; subjects in cluster 2 (17%) consisted of less atopy and normal lung function, but intermittent troublesome; cluster 3 (29%) experienced late-onset atopic troublesome asthma with decreased lung function in combination with low socioeconomic status; and cluster 4 was associated with early-onset and less-atopic infrequent asthma.Conclusions: Late-onset, high atopy, and low socioeconomic status are associated with troublesome persistent asthma phenotype in school-age children. Environmental factors might be implicated in the clinical heterogeneity of asthma. Asthma phenotypes considering diverse factors might be more helpful in the identification of asthma pathogenesis and its prevention. [ABSTRACT FROM AUTHOR]

Purpose: Chest radiography is often performed on patients hospitalized with typical clinical manifestations of bronchiolitis. We aimed to determine the proportion of subjects with pathologic chest radiographic findings and the clinical predictors associated with pathologic chest radiographic findings in young children admitted with the typical presentation of bronchiolitis. Methods: We obtained the following data at admission: sex, age, neonatal history, past history of hospitalization for respiratory illnesses, heart rate, respiratory rate, the presence of fever, total duration of fever, oxygen saturation, laboratory parameters (i.e., complete blood cell count, high-sensitivity C-reactive protein [hs-CRP], etc.), and chest radiography. Results: The study comprised 279 young children. Of these, 26 had a chest radiograph revealing opacity (n=24) or atelectasis (n=2). Multivariate logistic regression analysis showed that after adjustment for confounding factors, the clinical predictors associated with pathologic chest radiographic findings in young children admitted with bronchiolitis were elevated hs-CRP level (>0.3 mg/dL) and past history of hospitalization for respiratory illnesses (all P<0.05). Conclusion: The current study suggests that chest radiographs in young children with typical clinical manifestations of bronchiolitis have limited value. Nonetheless, young children with clinical factors such as high hs-CRP levels at admission or past history of hospitalization for respiratory illnesses may be more likely to have pathologic chest radiographic findings. [ABSTRACT FROM AUTHOR]

Purpose: Adherence to treatment with inhaled corticosteroids (ICS) is a critical determinant of asthma control. The objective of this study was to assess factors that determine adherence to ICS therapy in children with asthma. Methods: Fifty-eight children with asthma, aged 5 to 16 years, used ICS with or without a spacer for 3 months. Adherence rates as measured from questionnaires and canisters, asthma symptom scores, and inhalation technique scores were assessed every 30 days. The degree of supervision by caregivers was assessed at day 30. Results: Adherence rates measured using canisters were lower at day 60 than at day 30 (P =0.044) and did not change thereafter (74.4%±17.4% at day 30, 66.5%±18.4% at day 60, and 67.4%±22.2% at day 90). Adherence rates at days 60 and 90 and during the total study period were significantly different when measured by using questionnaires versus canisters (P<0.001, P =0.022, and P =0.001, respectively). In the comparison of adherence rates repeatedly measured at days 30, 60, and 90 and adherence rates during the total study period among the 3 groups, adherence rates in the high-degree supervision group were significantly higher than those in the low-degree supervision group (82.0±16.0 vs. 66.1±14.5, 75.4±14.4 vs. 56.2±18.4, 75.0±18.3 vs. 55.0±19.7 [P =0.027]; 77.9±12.2 vs. 59.1± 11.4 [P =0.021]) after adjustment for sex and age. Conclusion: The level of caregiver supervision is an important factor affecting adherence to ICS therapy in children with asthma. Therefore, a high degree of supervision may be required to increase adherence to ICS therapy in children with asthma. [ABSTRACT FROM AUTHOR]

Background: Asthma is characterized by airway inflammation, and bronchial airways are particularly susceptible to oxidant-induced tissue damage.Objective: To investigate the effect of dietary antioxidant intake and environmental tobacco smoke (ETS) on the risk of childhood asthma according to genotypes susceptible to airway diseases.Methods: This cross-sectional study included 1124 elementary school children aged 7-12 years old. Asthma symptoms and smoking history were measured using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Intake of vitamin A (including retinol and β-carotene), C, and E was measured by a semi-quantitative food frequency questionnaire (FFQ). GSTP1 polymorphisms were genotyped from peripheral blood samples.Results: ETS was significantly associated with presence of asthma symptoms (adjusted odds ratio [aOR], 2.48; 95 % confidence interval [CI], 1.29-4.76) and diagnosis (aOR, 1.91; 95 % CI, 1.19-3.06). Dietary antioxidant intake was not associated with asthma symptoms, although ETS plus low vitamin A intake showed a significant positive association with asthma diagnosis (aOR, 2.23; 95 % CI, 1.10-4.54). Children with AA at nucleotide 1695 in GSTP1 who had been exposed to ETS and a low vitamin A intake have an increased risk of asthma diagnosis (aOR, 4.44; 95 % CI,1.58-12.52) compared with children who had not been exposed to the two risk factors. However, ETS exposure and low vitamin A intake did not significantly increase odds of asthma diagnosis in children with AG or GG genotypes.Conclusion: Low vitamin A intake and ETS exposure may increase oxidative stress and thereby risk for childhood asthma. These relationships may be modified by gene susceptibility alleles of GSTP1. [ABSTRACT FROM AUTHOR]

Background: Exposure to perinatal anxiety affects disease susceptibility in offspring but studies on the association between perinatal anxiety and gene polymorphisms are lacking. This study aimed to elucidate the interaction between perinatal anxiety and polymorphisms in antioxidant defense and innate immunity genes on the development of respiratory tract infections (RTIs) during early infancy. Methods: Trait anxiety levels in 440 women were assessed by the State-Trait Anxiety Inventory during late gestation. The occurrence of RTIs, including bronchiolitis, during the first year of life was assessed by parent-reported doctor diagnosis. Polymorphisms in glutathione S-transferase P-1 (GSTP1, rs1695) and CD14 (rs2569190) were genotyped using the TaqMan assay. Copy number variations of GSTT1 were measured by real-time polymerase chain reaction. Results: Exposure to high levels of perinatal anxiety increased the risk of bronchiolitis in the first year of life (adjusted odds ratio [aOR], 1.30; 95% confidence interval [CI]: 1.00–1.80), in particular among children with the AG + GG genotype of GSTP1 or the GSTT1 null genotype (aOR 3.36 and 2.79). In infants with the TC + CC genotype of CD14, high levels of perinatal anxiety were associated with an increased risk of upper RTI, lower RTI, and bronchiolitis (aOR 2.51, 4.60, and 4.31, respectively). Conclusions: Perinatal maternal anxiety levels affect the occurrence of bronchiolitis in offspring. The effect of perinatal anxiety on the occurrence of bronchiolitis during infancy was influenced by genetic polymorphisms in antioxidant defense and innate immunity genes. [ABSTRACT FROM AUTHOR]

In this study, a decentralised ranging method for uplink orthogonal frequency division multiple access (OFDMA) systems with half-duplex (HD) amplify-and-forward (AF) relay stations (RSs) is proposed. In the OFDMA systems with HD AF RSs, twice more resources and delays are required as ranging without RS. To reduce the required resources and delays for ranging, the authors propose a two-phase ranging scheme based on the decentralised timing-offset estimation at each ranging mobile station (MS). At the first phase, RS occasionally broadcasts timing reference signal, and at the second phase RS retransmits the collected ranging signals from the MSs. Then, each ranging MSs can individually estimate its own timing offset from the received signals. In the proposed ranging method, the base station does not need to send a timing-adjustment message, and the overhead associated with ranging in the downlink resources, and computational complexity can be significantly reduced without degrading the timing-offset-estimation performance. Moreover, the delay associated with ranging can be maintained as same as ranging without RS. [ABSTRACT FROM AUTHOR]

Purpose: Previous studies suggest that the concentration of 25-hydroxyvitamin D [25(OH)D] in cord blood may show an inverse association with respiratory tract infections (RTI) during childhood. The aim of the present study was to examine the influence of 25(OH)D concentrations in cord blood on infant RTI in a Korean birth cohort. Methods: The levels of 25(OH)D in cord blood obtained from 525 Korean newborns in the prospective COhort for Childhood Origin of Asthma and allergic diseases were examined. The primary outcome variable of interest was the prevalence of RTI at 6-month follow-up, as diagnosed by pediatricians and pediatric allergy and pulmonology specialists. RTI included acute nasopharyngitis, rhinosinusitis, otitis media, croup, tracheobronchitis, bronchiolitis, and pneumonia. Results: The median concentration of 25(OH)D in cord blood was 32.0 nmol/L (interquartile range, 21.4 to 53.2). One hundred and eighty neonates (34.3%) showed 25(OH)D concentrations less than 25.0 nmol/L, 292 (55.6%) showed 25(OH)D concentrations of 25.0-74.9 nmol/L, and 53 (10.1%) showed concentrations of ⩾75.0 nmol/L. Adjusting for the season of birth, multivitamin intake during pregnancy, and exposure to passive smoking during pregnancy, 25(OH)D concentrations showed an inverse association with the risk of acquiring acute nasopharyngitis by 6 months of age (P for trend= 0.0004). Conclusion: The results show that 89.9% of healthy newborns in Korea are born with vitamin D insufficiency or deficiency (55.6% and 34.3%, respectively). Cord blood vitamin D insufficiency or deficiency in healthy neonates is associated with an increased risk of acute nasopharyngitis by 6 months of age. More time spent outdoors and more intensified vitamin D supplementation for pregnant women may be needed to prevent the onset of acute nasopharyngitis in infants. [ABSTRACT FROM AUTHOR]

metabolomics based approach has been used to study the infection of the Hwacheong rice cultivar ( Oryza sativa L. cv. Hwacheong) with compatible (KJ201) and incompatible (KJ401) strains of the rice blast fungal pathogen Magnaporthe grisea. The metabolic response of the rice plants to each strain was assessed 0, 6, 12, 24, 36, and 48 h post inoculation. Nuclear Magnetic Resonance (NMR) spectroscopy and Gas and Liquid Chromatography Tandem Mass spectrometry (GC/LC-MS/MS) were used to study both aqueous and organic phase metabolites, collectively resulting in the identification of 93 compounds. Clear metabolic profiles were observed at each time point but there were no significant differences in the metabolic response elicited by each pathogen strain until 24 h post inoculation. The largest change was found to be in alanine, which was ~30% (±9%) higher in the leaves from the compatible, compared to the resistant, plants. Together with several other metabolites (malate, glutamine, proline, cinnamate and an unknown sugar) alanine exhibited a good correlation between time of fungal penetration into the leaf and the divergence of metabolite profiles in each interaction. The results indicate both that a wide range of metabolites can be identified in rice leaves and that metabolomics has potential for the study of biochemical changes in plant-pathogen interactions. [ABSTRACT FROM AUTHOR]

Objectives/Hypothesis: Submandibular gland excision is traditionally performed by the transcervical approach. To avoid or reduce visible scarring and nerve injury, diverse innovative surgical trials have been reported. Here we report a patient who had an endoscopic submandibular gland resection via a hairline incision. Methods: A 36-year-old woman presented with a right submandibular gland tumor that was found on a routine check-up. The submandibular gland was resected under endoscopic assistance via a posterior hairline incision using an ultrasonic scalpel. Results: The resection was successful, causing no acute complications, such as neural injury, hematoma, or seroma formation. The incision scar healed with an excellent cosmetic result. Conclusions: Endoscopic submandibular gland resection via a hairline incision was feasible and resulted in an excellent surgical and cosmetic outcome. Laryngoscope, 2010 [ABSTRACT FROM AUTHOR]

Background We collected rare cases of recurrent respiratory papillomatosis (RRP) undergoing malignant transformation. We sought to identify human papillomavirus (HPV) subtypes in areas of papilloma, dysplasia, and carcinoma and investigate thve pattern of protein overexpression. Methods Three patients whose disease underwent malignant transformation from RRP to carcinoma were subjected to this study. Morphologically distinct areas in the pathology specimen of each patient were diagnosed as papilloma, dysplasia, and carcinoma. Each lesion was separately obtained by laser capture microdissection and was PCR amplified for the presence of HPV. A DNA chip was used to determine the type of HPV in each area. Immunohistochemistry for p53, Ki-67, and pRb was performed. Results HPV type 6 was present in all specimens tested positive. Expression of p53 and Ki-67 increased with increasing severity of dysplastic change. Conclusion Although HPV type 11 is most frequently associated with malignant change of RRP, HPV type 6 may also contribute to play an equally important role in RRP carcinogenesis. © 2008 Wiley Periodicals, Inc. Head Neck, 2009 [ABSTRACT FROM AUTHOR]

In this paper, a novel wideband frequency notched compact UWB antenna is designed to satisfy two licensed UWB frequency bands (3.1∼4.8 GHz, 7.1∼10.6 GHz). The notched wide bandwidth (4.8∼7.1 GHz) can be realized by inserting a pair of the inverted-L shaped slits in the fan-type arms of the coupled sectorial loop antenna(CSLA) and optimizing the positions and the length of the L-shaped slits to avoid the interferences with WLAN, GPS and so on. The performances of the designed UWB antenna are evaluated to inspect the fitness for the UWB communication services in the frequency and the time domain. [ABSTRACT FROM AUTHOR]

We report isolation and transcriptional profiling of rice ( Oryza sativa L.) mitogen-activated protein kinase (MAPK), OsSIPK (salicylic acid-induced protein kinase). OsSIPK gene is located on chromosome 6 most probably existing as a single copy in the rice genome, and encodes 398 amino acid polypeptide having the MAPK family signature and phosphorylation activation motif TEY. Steady state mRNA analyses of OsSIPK showed weak constitutive expression in leaves of 2-week-old rice seedlings. A time course (30–120 min) experiment using a variety of elicitors and stresses revealed that the OsSIPK mRNA is strongly induced by jasmonic acid (JA), salicylic acid (SA), ethephon, abscisic acid, cycloheximide (CHX), JA/SA + CHX, cantharidin, okadaic acid, hydrogen peroxide, chitosan, sodium chloride, and cold stress (12°C), but not with wounding by cut, gaseous pollutants ozone, and sulfur dioxide, high temperature, ultraviolet C irradiation, sucrose, and drought. Its transcription was also found to be tissue-specifically regulated, and followed a rhythmic dark induction in leaves. Finally, we showed that the OsSIPK protein is localized to the nucleus. From these results, OsSIPK can be implicated in diverse stimuli-responsive signaling cascades and transcription of certain genes. [ABSTRACT FROM AUTHOR]

A simple and accurate method is presented for extraction of the gate resistance components of RF MOSFETs. Both the gate electrode resistance and the channel resistance were extracted separately. Also, the gate electrode resistance was separated into an external component and an internal component. The gate electrode resistance was extracted at OFF state, and the channel resistance was extracted with at ON state. The simple extraction methodology is applied to extract parameters from the measured S-parameters of RF MOSFETs that are fabricated with 130-nm CMOS technology. [ABSTRACT FROM AUTHOR]

Heat shock proteins (Hsp) 70 are a ubiquitous family of molecular chaperones involved in many cellular processes. A yeast strain, ssa1/2, with two functionally redundant cytosolic Hsp70s (SSA1 and SSA2) deleted shows thermotolerance comparable to mildly heatshocked wild type yeast, as well as increased protein synthesis and ubiquitin-proteasome protein degradation. Since mRNA abundance does not always correlate well with protein expression levels it is essential to study proteins directly. We used a gel-based approach to identify stress-responsive proteins in the ssa1/2 mutant and identified 43 differentially expressed spots. These were trypsin-digested and analyzed by nano electrospray ionization liquid chromatography tandem mass spectrometry (nESI-LC-MS/MS). A total of 22 non-redundant proteins were identified, 11 of which were confirmed by N-terminal sequencing. Nine proteins, most of which were up-regulated (2-fold or more) in the ssa1/2 mutant, proved to be stressinducible proteins such as molecular chaperones and anti-oxidant proteins, or proteins related to carbohydrate metabolism. Interestingly, a translational factor Hyp2p up-regulated in the mutant was also found to be highly phosphorylated. These results indicate that the cytosolic Hsp70s, Ssa1p and Ssa2p, regulate an abundance of proteins mainly involved in stress responses and protein synthesis. [ABSTRACT FROM AUTHOR]

A constrained minimum mean square error (CMMSE)-RAKE receiver for multipath fading channels is developed by extending the CMMSE receiver for flat fading channels. Based on the observation that interpath interference causes a bias of the channel estimator in , a receiver that can remove such a bias is proposed, plus a closed-form expression of the bit-error rate of the receiver is derived. Computer simulation is used to demonstrate that the proposed receiver can outperform existing RAKE receivers. [ABSTRACT FROM PUBLISHER]

A technique that can suppress multiple-access interference (MAI) in space-time block-coded (STBC) multiple-input- multiple-output (MIMO) code-division multiple-access (CDMA) systems is developed. The proposed scheme, called a constrained minimum mean square error (CMMSE) receiver, is an extension of the CMMSE receiver for a single-input-single-output system to MIMO systems. It is shown that the complexity of the proposed CMMSE receiver is almost independent of the number of transmitter antennas. The advantage of the proposed receiver over the existing receivers for STEC CDMA systems is demonstrated by comparing the closed-form expressions of the signal-to-interference plus noise ratio and simulated bit error rates. The results indicate that the proposed CMMSE receiver can provide a significant performance improvement over the conventional receivers and that the gain achieved by suppressing the MAI can be larger than that from increasing the transmitter or receiver diversity. [ABSTRACT FROM AUTHOR]

A base station (BS) identification scheme for frequency-hopping (FH) orthogonal frequency division multiple access (OFDMA) is proposed. This scheme is based on the use of periodically inserted pilot tones carrying binary information. The identification process consists of two steps. First, locations of pilot tones are detected and second, the binary sequences associated with the pilots are identified. Modified maximum likelihood (ML) rules for the two steps are derived. Computer simulation results demonstrate that the proposed scheme can outperform the existing method that utilizes the slope of a pilot tone hopping sequences, yet it is considerably simpler to implement. [ABSTRACT FROM PUBLISHER]

A letter to the editor in response to an article on endoscopic resection of the submandibular gland, is presented.