低压载波集抄的技术突破方向探讨

分析了目前低压载波集抄系统存在的抄收覆盖率低与"孤岛"效应问题,指出其产生的原因是载波通信环境恶劣,尤其是受信道衰减和干扰随机动态变化的影响,文章针对此问题提出了解决的方案。

Pollution Characteristics and Ecological Risk Assessment of Polycyclic Aromatic Hydrocarbons in Agricultural Soils of Hohhot,China

[Objective] This study was conducted to provide a scientific theoretical ba- sis for pollution forewarning and agricultural planning. [Method] 15 PAHs were stud- ied for pollution characteristics, source analysis and ecological risk assessment at 60 sites in Hohhot farmland. [Result] The results showed that the total contents of 15 PAHs （：EPAHs） in 60 sampling points of Hohhot farmland were in the range of 114-948 ~g/kg, with an average content of 338 pg/kg. According to soil PAH as- sessment standards, more than 70% of soil in Hohhot City was lightly polluted, and there were no heavily-polluted points. The soil of the area was mainly polluted by PAHs with high molecular weights, which accounted for 74% of the total content. The soil in suburban farmland of Hohhot suffered from the heaviest pollution. Quan- titative analysis showed that PAH pollution in Hohhot farmland was mainly from combustion of coal, coke and timber and automotive exhaust emission. [Conclusion] Ecological effect interval method and method of equivalents equivalent to benzo （a） pyrene toxicity benzo [a] pyrene both proved that there is certain potential ecological risk for soil of Hohhot farmland, and PAHs with high molecular weights such as benzo （a） pyrene and dibenzo [a, h] anthracene are main potential pollutants with ecological risk.

Clinical outcomes in patients with ICU-related pancreatitis

AIM:To identify risk factors predictive of intensive care unit(ICU) mortality in patients with ventilator-related pancreatitis.The clinical outcomes of patients with ventilator-related pancreatitis were compared with those of patients with pancreatitis-related respiratory failure as well as controls.METHODS:One hundred and forty-eight patients with respiratory failure requiring mechanical ventilation and concomitant acute pancreatitis were identified from a prospectively collected dataset of 9108 consecutive patients admitted with respiratory failure over a period of five years.Sixty patients met the criteria for ventilator-related pancreatitis,and 88(control patients),for pancreatitis-related respiratory failure.RESULTS:Mortality rate in ventilator-related pancreatitis was comparable to that in ICU patients without pancreatitis by case-control methodology(P=0.544).Multivariate logistic regression analysis identified low PaO2/FiO2(OR:1.032,95% CI:1.006-1.059,P=0.016) as an independent risk factor for mortality in patients with ventilator-related pancreatitis.The mortality rate in patients with ventilator-related pancreatitis was lower than that in patients with acute pancreatitis-related respiratory failure(P<0.001).CONCLUSION:We found that low PaO2/FiO2 was an independent clinical parameter predictive of ICU mortality in patients with ventilator-related pancreatitis.

L-arginine administration ameliorates serum and pulmonary cytokine response after gut ischemia-reperfusion in immature rats

AIM: Small intestinal ischemia-reperfusion (IR) has been demonstrated to result in both local mucosal injury and systemic injuries. The exact role of nitric oxide (NO) in intestinal IR is unclear. We propose that NO and some other cytokines change in the reperfusion period and these changes are associated with lung injury. The aim of this study was to determine the effect of supplementing NO substrate, L-arginine (L-arg), on serum and pulmonary cytokine production during small intestinal IR in immature rats. METHODS: Immature rats underwent 60 min. of superior mesenteric artery occlusion followed by 90 min of reperfusion. L-arg (250 mg/kg) was given intravenously to the experimental group (IR+L-arg) which received L-arg after 45 min of intestinal ischemia. Serum and lung endothelin-1 (ET-1), NO, malondialdehyde (MDA), and tumor necrosis factor a (TNFα) were measured. Sham operation (SHAM) and intestinal IR (IR) groups were performed as control. The lavage fluid of the lung was collected by bronchoalveolar lavage (BAL) and white blood cells and polymorphonuclear cells (PMNs) were immediately counted to identify lung damage. RESULTS: When L-arg was given during small intestinal IR, serum NO concentration increased significantly in IR+L-arg group (162.17±42.93 μmol/L) when compared with IR group (87.57±23.17 μmol/L, t=3.190, P= 0.008 <0.01). Serum MDA reduced significantly in IR+L-arg group (8.93±1.50 nmol/L) when compared with SHAM (23.78±7.81 nmol/L, t= 3.243, P= 0.007<0.01) and IR (25.54±9.32 nmol/L, t= 3.421, P= 0.006<0.01). ET-1 level in lung tissues was significantly lower in IR+L-arg group (13.81±7.84 pg/mL) than that in SHAM (35.52±10.82 pg/mL, t= 2,571, P= 0,03<0.05) and IR (50.83±22.05 pg/mL, t= 3.025, P= 0.009<0.01) groups. MDA contents in lung tissues were significantly lower in IR+L-arg group (10.73±1.99 nmol/L) than in SHAM (16.62±2.28 nmol/L, t= 3.280, P = 0.007<0.01) and IR (21.90±4.82 nmol/L, t= 3.322, P= 0.007<0.01) groups. Serum and lung TNFα concentrations were not significantly different in three groups. NO contents in lung homogenates and white blood cell counts in BAL had no significant difference in three groups; but the percentage of PMNs in BAL was 13.50±8.92, 33.20±16.59, and 22.50±6.09 in SHAM, IR, and IR+L-arg groups, respectively. CONCLUSION: Small intestinal IR induced increases of pulmonary neutrophil infiltration in immature rats. Neutrophil infiltration in lung tissues was reduced by L-arg administration but remained higher than in SHAM group. L-arg administration during intestinal IR enhances serum NO production, reduces serum MDA and lung ET-1 and MDA levels, resulting in the improvement of systemic endothelial function. L-arg supplementation before reperfusion may act as a useful clinical adjunct in the management of intestinal IR, thus preventing the development of adult respiratory distress syndrome, even multiple organ dysfunction syndrome (MODS).

NOVEL MULTIMEDIA TRAFFIC MODELING BASED CAC SCHEME FOR CDMA COMMUNICATION SYSTEMS

As the radio spectrum is a very scarce resource,the Call Admission Control (CAC) is one of the most important parts in radio resource management. The Code Division Multiple Access (CDMA) based next generation wireless communications systems will support the transmission of multimedia traffic,such as voice,video and data,thus the CAC,which can support the multimedia traffic and guarantee the Quality of Service (QoS) of different traffic,has gained broad attention. In this paper,a novel multimedia traffic modeling method and a corresponding dynamic QoS based CAC are proposed. The analysis and simulation results show that the proposed CAC scheme can guarantee the QoS to different traffic demand,and improve the system performance significantly.

Reservation-based dynamic admission control scheme for wideband code division multiple access systems

Call admission control (CAC) and resource reservation (RR) for mobile communication are two important factors that guarantee system efficiency and quality of service (QoS) required for different services in a very scarce resource as the radio spectrum. A new scheme was proposed which extends the concepts of resource sharing and reservations for wideband code division multiple access (WCDMA) systems with a unique feature of soft capacity. Voice and data traffic were considered. The traffic is further classified into handoff and new requests. The reservation thresholds were dynamically adjusted according to the traffic pattern and mobility prediction in order to achieve the maximum channel utilization, while guaranteeing different QoS constraints. The performance of proposed scheme was evaluated using Markov models. New call blocking probability, handoff call dropping probability, and channel utilization were used as benchmarks for the proposed scheme.

Reasons for Calling Doctor： Visualizing Callers＇ Multi-unit Turns and Filming Television Call-ins as Institutional Interaction

This study describes discursive and visual features of telephone openings to a live broadcast television call-in program based on the analysis of the ＂multi-unit reason-for-the-call turn＂ （Couper-Kuhlen, 2001）. The data were based on video-recordings of the call-in program broadcast daily on Hakka channel in Taiwan, in which callers call to seek advice on health problems. The discourse analysis shows that callers＇ ＂multi-unit reason-for-the-call turns＂ can be classified into three forms including request, epistemic frame and descriptions of symptoms, and telling of lifestyle. The visual analysis demonstrates that the visual shots of ＂multi-unit reason-for-the-call turns＂ orient viewers to the studio scene in which the invited guest, usually the medical doctor, can be seen listening to callers＇ upcoming questions. Based on the analyses and an interview with the camera director of this television program, the discussion sheds light on how television production practices use callers＇ multi-unit turns as a resource for switching to the studio shot, which helps to build an image of the expert and his/her role and function in the advice-seeking program. In this sense, filming and television production practices rely on linguistic resources and the visualization of callers＇ multi-unit turns has meanings in the organization of studio interaction as ＂institutional interaction＂ （Drew ＆ Heritage, 1992）, being shaped by interactants＇ identities, roles, and tasks relevant for the specific institutional needs or purposes.

Calcific degeneration and rupture of the aortic valve and ascending aorta： from cardiac auscultation to multimodality imaging

A 76-year-old Caucasian woman was admitted to the emergency room and referred for cardiac evaluation for dyspnea and abrupt onset of cough three weeks ago. She had a history of well-controlled arterial hypertension and was on adequate oral anticoagulant therapy for permanent atrial fibrillation. Previous thoracic injuries, connective tis- sue disorders or recent infections were excluded. No chest pain or syncope was reported. mmHg in both arms, heart rate Blood pressure was 150/50 was 90 beats/min.

Platypnea orthodeoxia pathophysiology on screen

A 64-year-old lady lying in supine position because multiple sclerosis, suffered a major stroke with no other plausible reasons but a hugc right-to-left shunt confirmed by transthoracic echocardiography as a patent foramen ovale （PFO） with atrial septal aneurysm （ASA）. Further examination with transesophageal echocardiography was not possible because of hostile esophageal tract. During rehabilitation exercise protocol in upright position, the patient developed severe dyspnoea and hypoxaemia. The patient was taken into the catheterization lab and a right heart catheterization with intracardiac echocardiography and eventual closure of the interatrial communication was planned.

Respiratory Virus Multiplex RT-PCR Assay Sensitivities and Influence Factors in Hospitalized Children with Lower Respiratory Tract Infections

Multiplex RT-PCR assays have been widely used tools for detection and differentiation of a panel of respiratory viral pathogens. In this study, we evaluated the Qiagen ResPlex lI V2.0 kit and explored factors influencing its sensitivity. Nasopharyngeal swab （NPS） specimens were prospectively collected from pediatric inpatients with lower respiratory tract infections at the time of admission in the Shenzhen Children＇s Hospital from May 2009 to April 2010. Total nucleic acids were extracted using the EZ1 system （Qiagen, Germany） and 17 respiratory viruses and genotypes including influenza A virus （FluA）, FluB, parainfluenza virus 1 （PIV1）, PIV2, PIV3, PIV4, respiratory syncytial virus （RSV）, human metapneumovirus （hMPV）, rhinoviruses （RhV）, enteroviruses （EnV）, human bocaviruses （hBoV）, adenoviruses （AdV）, four coronaviruses （229E, OC43, NL63 and HKU1）, and FluA 2009 pandemic H1NI（H1NI-p） were detected and identified by the ResPlex II kit. In parallel, 16 real-time TaqMan quantitative RT-PCR assays were used to quantitatively detect each virus except for RhV. Influenza and parainfluenza viral cultures were also performed. Among the total 438 NPS specimens collected during the study period, one or more viral pathogens were detected in 274 （62.6%） and 201（45.9%） specimens by monoplex TaqMan RT-PCR and multiplex ResPlex, respectively. When results from monoplex PCR or cell culture were used as the reference standard, the multiplex PCR possessed specificities of 92.9-100.0%. The sensitivity of multiplex PCR for PIV3, hMPV, PIV1 and BoV were 73.1%, 70%, 66.7% and 55.6%, respectively, while low sensitivities （11.1%-40.0%） were observed for FluA, EnV, OC43, RSV and H1N1. Among the seven viruses/genotypes detected with higher frequencies, multiplex PCR sensitivities were correlated significantly with viral loads determined by the TaqMan RT-PCR in FluA, H 1N 1-p and RSV （p=0.011-0.000） The Qiagen ResPlex II multiplex RT-PCR kit possesses excellent specificity for simultaneous detection of 17 viral pathogens in NPS specimens in pediatric inpatients at the time of admission. The sensitivity of multiplex RT-PCR was influenced by viral loads, specimen process methods, primer and probe design and amplification condition.

Protective Effect of Rhubarb on Endotoxin-Induced Acute Lung Injury

To approach the mechanism of lipopolysaccharide (LPS) in causing acute lung injury (ALI) and the protective effect of rhubarb and dexamethasone, lung specimens were examined with macroscopy, microscopy, electron microscopy and the biological markers of ALI including lung wet/dry weight, the rate of neutrophils and protein content in the pulmonary alveolar lavage fluid, pulmonary capillary permeability and pulmonary alveolar permeability index were observed. The mechanism of the ALI is mainly due to direct injury of alveolar epithelium and pulmonary vascular endothelium. Rhubarb and dexamethasone could significantly reduce the edema of the lung tissue, decrease the red blood cell exudation, neutrophil infiltration and plasma protein exudation in the alveoli and all the biological markers in comparison with the ALI model rats, indicating they have protective action on vascular endothelium and alveolar epithelium.

A Novel Effective Bandwidth Based Call Admission Control for Multimedia CDMA Systems

A novel Call Admission Control(CAC)scheme is proposed for multimedia CDMA systems.The effectivebandwidth of real time calls is reserved in the CAC with the consideration of active factors.The admission of non-real timecalls is controlled by the system according to the residual effective bandwidth left from real time calls.Simulation resultshave shown that the novel CAC has greatly enlarged the admission region for real time calls and make the transmission de-lay of non-real time calls under an acceptable level.

Multiplicity results of breathers for the discrete nonlinear Schrodinger equations with unbounded potentials

We consider a class of discrete nonlinear Schrdinger equations with unbounded potentials. We obtain some new multiplicity results of breathers of the equations by using critical point theory. Our results greatly improve some recent results in the literature.

Antepenultimate residue at the C-terminus of NADPH oxidase RBOHD is critical for its function in the production of reactive oxygen species in Arabidopsis

Production of reactive oxygen species(ROS)is a conserved immune response primarily mediated by NADPH oxidases(NOXs),also known in plants as respiratory burst oxidase homologs(RBOHs).Most microbe-associated molecular patterns(MAMPs)trigger a very fast and transient ROS burst in plants.However,recently,we found that lipopolysaccharides(LPS),a typical bacterial MAMP,triggered a biphasic ROS burst.In this study,we isolated mutants defective in LPS-triggered biphasic ROS burst(delt)in Arabidopsis,and cloned the DELT1 gene that was shown to encode RBOHD.In the delt1-2 allele,the antepenultimate residue,glutamic acid(E919),at the C-terminus of RBOHD was mutated to lysine(K).E919 is a highly conserved residue in NADPH oxidases,and a mutation of the corresponding residue E568 in human NOX2 has been reported to be one of the causes of chronic granulomatous disease.Consistently,we found that residue E919 was indispensable for RBOHD function in the MAMP-induced ROS burst and stomatal closure.It has been suggested that the mutation of this residue in other NADPH oxidases impairs the protein’s stability and complex assembly.However,we found that the E919K mutation did not affect RBOHD protein abundance or the ability of protein association,suggesting that the residue E919 in RBOHD might have a regulatory mechanism different from that of other NOXs.Taken together,our results confirm that the antepenultimate residue E is critical for NADPH oxidases and provide a new insight into the regulatory mechanisms of RBOHD.

Radial breathing modes of multi-walled carbon nanotubes by an atomic beam-spring model

Based on molecular force fields,a new finite element model is constructed for multi-walled carbon nanotubes where the interlayer interactions and C--C bonds are simulated by the elements of piece-wise linear spring and rectangular cross section beam,respectively.For high computation efficiency and atomic reification,the radial breathing modes of multi-walled carbon nanotubes are studied systemically using this model.The results show the correspondence between carbon nanotube structures and vibrational modes,which provide unequivocal data for the experimental characterization of carbon nanotubes.An empirical relationship of radial breathing modes frequencies with the nanotube radius are also obtained for two-layer carbon nanotubes.

Soil Respiration and Litter Decomposition Increased Following Perennial Forb Invasion into an Annual Grassland

Exotic plant invasions may alter ecosystem carbon processes, especially when native plants are displaced by plants of a different functional group. Forb invasions into grasslands are common, yet little is known about how they impact carbon cycling. We conducted a field study over 2 years from April 2010 to March 2012 in China to examine changes in soil respiration （Rsoil） following invasion of exotic perennial forb species （Alternanthera philoxeroides or Solidago canadensis） into an annual grassland dominated by a native annual graminoid （Eragrostis pilosa）. Measurements of Rsoil were taken once a week in stands of the native annual graminoid or one of the forb species using static chamber-gas chromatograph method. Aboveground litterfall of each of the three focal species was collected biweekly and litter decomposition rates were measured in a 6-month litterbag experiment. The monthly average and annual cumulative Rsoil increased following invasion by either forb species. The increases in cumulative Rsoil were smaller with invasion of Solidago （36%） than Alternanthera （65%）. Both invasive forbs were associated with higher litter quantity and quality （e.g., C：N ratio） than the native annum graminoid. Compared to the native annual graminoid, the invasive forbs Altevnanthera （155%） and Solidago （361%） produced larger amounts of more rapidly decomposing litter, with the litter decay constant k being 3.8, 2.0 and 1.0 for Alternanthera, Solidago and Eragrostis, respectively. Functional groups of the invasive plants and the native plants they replaced appear to be useful predictors of directions of changes in Rsoil, but the magnitude of changes in Rsoil seems to be sensitive to variations in invader functional traits.

Influence of Sanao Tang on urine volume and expression of aquaporin 2 in rats with respiratory function impairment induced by passive smoking and lipopolysaccharide

OBJECTIVE: To investigate the effect of Sanao Tang(SAT) on urine volume and the expression of aquaporin-2(AQP2) in rats with lung dysfunction induced by passive smoking and lipopolysaccharide.METHODS: Totally 45 healthy Specific pathogen Free Wistar Rats were randomized into 3 groups:normal control group, model group and SAT group.A rat model of respiratory dysfunction induced by exposure to cigarette smoking and lipopolysaccharide(LPS). Lavage of decoction of the Chinese medicine was performed for rats in the SAT group. Anires 2005 System was used to analyze the pulmonary function. Urine of rats was collected through metabolism cage method. Enzyme-linked immunosorbent assay(ELISA) was used to determine content of antidiuretic hormone(ADH), angiotensin Ⅱ(AngⅡ), atrial natriuretic factor(ANP), endothelin 1(ET-1), nitric oxide(NO) and prostaglandin E2(PGE2) in serum, lung and kidney. The expression of AQP2 in rat renal tissue was determined with real-time fluorescence quantitative PCR(RT-PCR).RESULTS:(a) In comparison with the normal control, It was found that enforced vital capacity(FVC),1-second forced expiratory volume/forced vital capacity%(FEV1/FVC%), 24 h urine volume content of NO and PGE2 were decreased, while AQP2 m RNA level and content of ADH, Agn Ⅱ, ANP and ET-1were increased in the model group with statistical significance(P < 0.05).(b) In comparison with the model group, It was found that FVC, FEV1, FEV1/FVC%, 24 h urine volume, content of PGE2 and NO decreased, while AQP2 m RNA level, content of ANP,ADH and AngⅡ decreased in the SAT group with statistical significance(P < 0.05).CONCLUSION: SAT might effectively regulate the urine volume in the modeled rats; ADH, Ang Ⅱ,ANP, ET-1, NO and PGE2 might play an important role in the regulation on urine volume by lungs.This might be the mechanisms underpinning the function of lung governing water passage in terms of the theory of Traditional Chinese Medicine.

A breathing chiral molecular solid for enantioseparation via single-crystal-to-single-crystal transformation

Two chiral supramolecular porous solids derived from novel cluster-based structures of [Mn^Ⅲ_4Mn^Ⅱ] and [Mn_7^Ⅲ Mn_3^Ⅱ ] were synthesized. Driven by the distinct pores and host-guest interactions, they exhibited either selective gas adsorption ability for the former or the ability of enan- tioselective separation via reversible single-crystal-to-sin- gle-crystal transformation for the latter.

NLS equation wronskians Peregrine breather rogue waves

The Peregrine breather of order eleven（P_（11） breather） solution to the focusing one-dimensional nonlinear Schrdinger equation（NLS） is explicitly constructed here. Deformations of the Peregrine breather of order 11 with 20 real parameters solutions to the NLS equation are also given： when all parameters are equal to 0 we recover the famous P_（11） breather. We obtain new families of quasi-rational solutions to the NLS equation in terms of explicit quotients of polynomials of degree 132 in x and t by a product of an exponential depending on t. We study these solutions by giving patterns of their modulus in the（x; t） plane, in function of the different parameters.