bluuebunny/crossref_metadata_2025 huggingface dataset:
Transmitter with quantum cascade laser for free space optics communication system
Authors: Gutowska M. , Pierścińska D. , Nowakowski M. , Pierściński K. , Szabra D. , Mikołajczyk J. , Wojtas J. , Bielecki Z.
Published: March 2012

Transmitter with quantum cascade laser for free space optics communication system

The paper presents results of experimental tests of the quantum cascade laser from Alpes Lasers company in terms of its application in the optic communication system in an open space. The measurements involved the current - voltage characteristics while measuring also the average power of emitted radiation, and spectral characteristics for different temperatures and different laser pulse durations. The duration of laser pulses was matched to parameters used in telecommunication interfaces. The construction of the transmitter module which uses the tested laser is also presented.
Solution growth of ZnO sub-micro rods enhanced by electric field
Authors: Pisarkiewicz T. , Kenig T. , Rydosz A. , Maziarz W.
Published: March 2012

Solution growth of ZnO sub-micro rods enhanced by electric field

Recently the one-dimensional ZnO nanostructures have attracted much attention in gas sensor applications owing to their increased role of the surface. The authors have obtained ZnO rods of sub-micron size using the solution growth method with the growth temperature below 100°C. Investigations indicate that the rods have a well-defined hexagonal morphology and a wurtzite structure. The best uniformity and alignment of the sub-micron crystals was however obtained when electrodeposition from aqueous solution was developed. Sizes of these rods depend on the growth parameters. Moreover electrodeposition leads to a faster growth rate of ZnO sub-micron rods (2 hrs) as compared to the growth from solution (8 hrs). After electrodeposition the rods can be easily reoriented in external electric fields by using substrates with electrodes of appropriate geometry and configuration (dielectrophoretic effect). This enables the preparation of samples which can be used in gas sensor technology.
Noninvasive acoustic blood volume measurement system for the POLVAD prosthesis
Authors: Opilski Z. , Konieczny G. , Pustelny T. , Gacek A. , Kustosz R. , Gawlikowski M.
Published: March 2012

Noninvasive acoustic blood volume measurement system for the POLVAD prosthesis

The following paper presents researches concerning a noninvasive real-time blood volume measurement system applied in POLVAD prosthesis. The system is based on the acoustic Helmholtz resonator principle. The basis of the measurement method, followed by the preliminary tests of the possibility of incorporating the Helmholtz resonance idea into the POLVAD prosthesis is shown. The paper includes the actual measurement system construction and test results, both static and dynamic obtained at the Foundation for Cardiac Surgery Development in Zabrze, Poland. Conclusions and future plans are presented too.
Intravascular low-power laser illumination through special fiber diffusers
Authors: Beres-Pawlik E. , Derkacz A.
Published: March 2012

Intravascular low-power laser illumination through special fiber diffusers

This paper presents the method of intravascular endothelial cell illumination with low-power laser radiation. Some special instruments were prepared, including designed fiber diffusers. The technical parameters of the set-up and the results of arterial system treatment with illumination instruments are presented.
Detection of illicit chemicals by portable Raman spectrometer
Authors: Smulko J. , Kwiatkowski A. , Gnyba M.
Published: March 2012

Detection of illicit chemicals by portable Raman spectrometer

The Raman spectrometers can be built as the portable devices and can be used in various places to detect illicit chemicals. This method has become popular due to deficiency of other fast methods that could be applied against terrorist attacks or could help police at their work. The Conception of a portable Raman spectrometer has been presented. The Description enclosures the presentation of the prepared device and its possible applications by presenting exemplary detection results.
Properties of the power conditioning system with a five-level cascaded converter and supercapacitor energy storage
Authors: Zygmanowski M. , Grzesik B. , Michalak J.
Published: March 2012

Properties of the power conditioning system with a five-level cascaded converter and supercapacitor energy storage

The paper presents the power conditioning system (PCS) with a five-level cascaded H-bridge converter and supercapacitor energy storage. The paper focuses on such properties of a power electronic converter as its operation, power losses, start-up as well as the DC-link voltage balancing method and controller. A laboratory model of the PCS and its test results have been presented.
Three-phase soft-switching inverter with coupled inductors, experimental results
Authors: Karyś S.
Published: March 2012

Three-phase soft-switching inverter with coupled inductors, experimental results

This paper presents experimental results of the three-phase soft-switching inverter with coupled inductors that verify the control method influence on efficiency improvement. Different kinds of control methods were tested on the 6 kW experimental inverter. A short discussion on a few design methods of the resonant tank elements was made. Experimental results confirm that the advanced control algorithm and the proposed new design method of the resonant tank elements significantly increase the efficiency of this resonant inverter.
Efficiency improvement due to direct torque and flux three levels three areas control method applied to small hydroelectric power plant
Authors: Kulikowski K. , Sikorski A.
Published: March 2012

Efficiency improvement due to direct torque and flux three levels three areas control method applied to small hydroelectric power plant

The paper presents a description of a new DTFC3L3A (direct torque and flux control three levels three areas) control method of induction machine as well as its comparison with the DTC method. The basis for the comparison is the switching frequency of described methods. The proposed method is optimized to reduce number of switchings (which is proportional to switching power losses) in static state, as well as it takes into account the δ angle which makes it possible to obtain a sinusoidal shape of flux within range of low angular frequencies of an asynchronous machine. The paper includes the results of experiments performed on a three level DC/AC inverter for both control methods.
The Management of Injuries to the Medial Side of the Knee
Authors: Laprade Robert F. , Wijdicks Coen A.
Published: March 2012

Synopsis

Injuries to the medial side of the knee are the most common knee ligament injuries. The majority of injuries occur in young athletes during sporting events, with the usual mechanism involving a valgus contact, tibial external rotation, or a combined valgus and external rotation force delivered to the knee. Although most complete grade III medial knee injuries heal, some do not, which can lead to continued instability. For these patients, a thorough understanding of the presenting history and a physical examination are important because these injuries can often be confused with posterolateral corner injuries. The main anatomic structures of the medial side of the knee are the superficial medial collateral ligament, deep medial collateral ligament, and posterior oblique ligament. In addition, accurately locating 3 bony prominences over the medial aspect of the knee—the adductor tubercle, gastrocnemius tubercle, and medial epicondyle—is important to conduct a proper physical examination and for surgical repairs and reconstructions. Clinical diagnosis of medial knee injuries is primarily performed via the application of a valgus stress in full extension and at 30° of knee flexion. In addition, an examination of the amount of anteromedial tibial rotation is performed at 90° of flexion, while the dial test, performed at 30° and 90° of flexion, is important because it evaluates for rotational abnormalities. Valgus stress radiographs are useful to objectively determine the amount of medial compartment gapping and to discern whether there is medial or lateral compartment gapping when a medial or posterolateral corner knee injury cannot be differentiated, especially with a chronic injury. The majority of acute grade III medial knee injuries will heal after a nonoperative rehabilitation program. In most instances when there is a knee dislocation or multiligament injury, a primary repair with sutures may be indicated. In severe midsubstance injuries or chronic medial knee injuries, an anatomic medial knee reconstruction with grafts may be indicated. Rehabilitation principles for acute medial knee injuries involve controlling edema, regaining range of motion, and avoiding any significant stress on the healing ligaments. A well-guided rehabilitation program can result in excellent functional outcomes in the majority of patients. J Orthop Sports Phys Ther 2012;42(3):221–233. doi:10.2519/jospt.2012.3624
Recent Advances in the Rehabilitation of Anterior Cruciate Ligament Injuries
Authors: Wilk Kevin E. , Macrina Leonard C. , Cain E. Lyle , Dugas Jeffrey R. , Andrews James R.
Published: March 2012

Synopsis

Rehabilitation following anterior cruciate ligament surgery continues to change, with the current emphasis being on immediate weight bearing and range of motion, and progressive muscular strengthening, proprioception, dynamic stability, and neuromuscular control drills. The rehabilitation program should be based on scientific and clinical research and focus on specific drills and exercises designed to return the patient to the desired functional goals. The goal is to return the patient's knee to homeostasis and the patient to his or her sport or activity as safely as possible. Unique rehabilitation techniques and special considerations for the female athlete will also be discussed. The purpose of this article is to provide the reader with a thorough scientific basis for anterior cruciate ligament rehabilitation based on graft selection, patient population, and concomitant injuries. J Orthop Sports Phys Ther 2012;42(3):153–171. doi:10.2519/jospt.2012.3741
Neonatal posthemorrhagic hydrocephalus from prematurity: pathophysiology and current treatment concepts
Authors: Robinson Shenandoah
Published: March 2012

Object

Preterm infants are at risk for perinatal complications, including germinal matrix–intraventricular hemorrhage (IVH) and subsequent posthemorrhagic hydrocephalus (PHH). This review summarizes the current understanding of the epidemiology, pathophysiology, management, and outcomes of IVH and PHH in preterm infants.

Methods

The MEDLINE database was systematically searched using terms related to IVH, PHH, and relevant neurosurgical procedures to identify publications in the English medical literature. To complement information from the systematic search, pertinent articles were selected from the references of articles identified in the initial search.

Results

This review summarizes the current knowledge regarding the epidemiology and pathophysiology of IVH and PHH, primarily using evidence-based studies. Advances in obstetrics and neonatology over the past few decades have contributed to a marked improvement in the survival of preterm infants, and neurological morbidity is also starting to decrease. The incidence of IVH is declining, and the incidence of PHH will likely follow. Currently, approximately 15% of preterm infants who suffer severe IVH will require permanent CSF diversion. The clinical presentation and surgical management of symptomatic PHH with temporary ventricular reservoirs (ventricular access devices) and ventriculosubgaleal shunts and permanent ventriculoperitoneal shunts are discussed. Preterm infants who develop PHH that requires surgical treatment remain at high risk for other related neurological problems, including cerebral palsy, epilepsy, and cognitive and behavioral delay. This review highlights numerous opportunities for further study to improve the care of these children.

Conclusions

A better grasp of the pathophysiology of IVH is beginning to impact the incidence of IVH and PHH. Neonatologists conduct rigorous Class I and II studies to advance the outcomes of preterm infants. The need for well-designed multicenter trials is essential because of the declining incidence of IVH and PHH, variations in referral patterns, and neonatal ICU and neurosurgical management. Well-designed multicenter trials will eventually produce evidence to enable neurosurgeons to provide their smallest, most vulnerable patients with the best practices to minimize perioperative complications and permanent shunt dependence, and most importantly, optimize long-term neurodevelopmental outcomes.
Surgical treatment of focal inhibitory motor seizures
Authors: Shi Yanfang , Zuo Huancong
Published: March 2012

The authors describe a rare case of a pediatric patient with focal inhibitory motor seizures (ictal paralysis) with the seizure focus in the primary motor cortex. Seizures were characterized by ictal paralysis of the contralateral limbs without loss of consciousness. The seizure focus and progression were examined using long-term video electroencephalography (EEG) monitoring and MR imaging. Invasive recordings of the ictal EEG revealed spike rhythms arising from the primary motor cortex, suggesting that seizures associated with paralysis can arise from hyperactivity in either positive or negative motor areas. Resection of the cortical area related to ictal onset resulted in a seizure-free status for the last 3 years.
Establishing successful cerebrospinal fluid flow for radioimmunotherapy
Authors: Kramer Kim , McCrea Heather J. , Fischer Cheryl , Greenfield Jeffrey P.
Published: March 2012

Successful delivery of intraventricular radioimmunotherapy is contingent on adequate CSF flow. The authors present a patient with medulloblastoma in whom obstructed CSF flow was causing hydrocephalus, which was initially corrected by implantation of a programmable shunting device. While managing the hydrocephalus, an endoscopic third ventriculostomy (ETV) needed to be performed in a collapsed ventricular system to ensure adequate radioimmunotherapy distribution.

This 18-month-old patient with medulloblastoma involving leptomeningeal dissemination presented for intraventricular radioimmunotherapy. A CSF 111In-DTPA scintigraphy study obtained through the existing programmable ventriculoperitoneal shunt demonstrated activity in the lateral and third ventricles, but no activity over the cerebral convexities or spinal canal, consistent with obstruction at the level of the cerebral aqueduct. By maximization of ventricular size in a controlled setting, the patient was able to undergo a trial of ETV through very small ventricles. A postoperative CINE MR imaging study confirmed patent ETV. The pressure settings on the shunt were kept at the highest opening pressure (200 mm H2O) to maximize flow through the stoma and improve the distribution of CSF throughout the subarachnoid space. The CSF flow scintigraphy study was again performed, this time with tracer activity demonstrated down the thecal sac at 3 hours, and symmetrically over the cerebral convexities at 24 hours. The patient began weekly intraventricular administration of 131I-3F8 therapy.

Successful rerouting of CSF flow for the purpose of therapeutic radioisotope administration is possible. Endoscopic third ventriculostomy can be considered in patients with programmable shunting devices; normal or slit ventricles do not preclude successful ETV.
Surgical techniques for investigating the role of the insula in epilepsy: a review
Authors: Desai Atman , Bekelis Kimon , Darcey Terrance M. , Roberts David W.
Published: March 2012

Intracranial electroencephalography monitoring of the insula is an important tool in the investigation of the insula in medically intractable epilepsy and has been shown to be safe and reliable. Several methods of placing electrodes for insular coverage have been reported and include open craniotomy as well as stereotactic orthogonal and stereotactic anterior and posterior oblique trajectories. The authors review each of these techniques with respect to current concepts in insular epilepsy.
Comparison of seizure control outcomes and the safety of vagus nerve, thalamic deep brain, and responsive neurostimulation: evidence from randomized controlled trials
Authors: Rolston John D. , Englot Dario J. , Wang Doris D. , Shih Tina , Chang Edward F.
Published: March 2012

Epilepsy is a devastating disease, often refractory to medication and not amenable to resective surgery. For patients whose seizures continue despite the best medical and surgical therapy, 3 stimulation-based therapies have demonstrated positive results in prospective randomized trials: vagus nerve stimulation, deep brain stimulation of the thalamic anterior nucleus, and responsive neurostimulation. All 3 neuromodulatory therapies offer significant reductions in seizure frequency for patients with partial epilepsy. A direct comparison of trial results, however, reveals important differences among outcomes and surgical risk between devices. The authors review published results from these pivotal trials and highlight important differences between the trials and devices and their application in clinical use.
Prediction of neuropsychological outcome after resection of temporal and extratemporal seizure foci
Authors: Dulay Mario F. , Busch Robyn M.
Published: March 2012

Resection of seizure foci is an effective treatment for the control of medically intractable epilepsy. However, cognitive morbidity can occur as a result of surgical intervention. This morbidity is dependent on several factors, including location and extent of resection, disease characteristics, patient demographic characteristics, and functional status of the tissue to be resected. In this review article, the authors provide a summary of the neurocognitive outcomes of epilepsy surgery with an emphasis on presurgical predictors of postsurgical cognitive decline.
Analyse rétrospective de l'adaptation à la sécheresse chez le douglas
Authors: Rozenberg Philippe , Sergent Anne-Sophie , Dalla-Salda Guillermina , Martinez-Meier Alejandro , Marin Sara , Ruiz-Diaz Manuela , Bastien Jean-Charles , Sanchez Leopoldo , Bréda Nathalie
Published: March 2012

Retrospective analysis of the adaptation of the Douglas-fir to drought

For a number of years in certain regions of France the Douglas-fir trees (Pseudotsuga menziesii [Mirb.] Franco) have presented symptoms of withering which have been attributed to drought. Our results show that the hydraulic function of the wood plays a part in the resistance of the Douglas-fir to dry conditions. Narrower cellular conduits, and therefore a greater wood density, contribute to the survival of trees confronted with a period of a marked water deficit. This idea is confirmed by the existence of significant relationships between wood density and hydraulic properties of wood in which the raw sap circulates, and also by the relationships found between the ecological preferences of specimens in their area of origin and the density of their wood in regions of France where they have been introduced. Those coming from dry regions have a tendency to develop wood with characteristics similar to that of trees which have survived drought. While the relationship between wood density and survival has been demonstrated, the differences in the nature of this relationship between different sites show that the mechanisms involved are complex and to a large extent still not understood.
The Mathematical Structure of Information Bottleneck Methods
Authors: Gedeon Tomáš , Parker Albert E. , Dimitrov Alexander G.
Published: March 2012

Information Bottleneck-based methods use mutual information as a distortion function in order to extract relevant details about the structure of a complex system by compression. One of the approaches used to generate optimal compressed representations is by annealing a parameter. In this manuscript we present a common framework for the study of annealing in information distortion problems. We identify features that should be common to any annealing optimization problem. The main mathematical tools that we use come from the analysis of dynamical systems in the presence of symmetry (equivariant bifurcation theory). Through the compression problem, we make connections to the world of combinatorial optimization and pattern recognition. The two approaches use very different vocabularies and consider different problems to be “interesting”. We provide an initial link, through the Normalized Cut Problem, where the two disciplines can exchange tools and ideas.
Sulfur-Functionalized N-Heterocyclic Carbene Complexes of Pd(II): Syntheses, Structures and Catalytic Activities
Authors: Yuan Dan , Huynh Han Vinh
Published: March 2012

N-heterocyclic carbenes (NHCs) can be easily modified by introducing functional groups at the nitrogen atoms, which leads to versatile coordination chemistry as well as diverse catalytic applications of the resulting complexes. This article summarizes our contributions to the field of NHCs bearing different types of sulfur functions, i.e., thioether, sulfoxide, thiophene, and thiolato. The experimental evidence for the truly hemilabile coordination behavior of a Pd(II) thioether-NHC complex has been reported as well. In addition, complexes bearing rigid CSC-pincer ligands have been synthesized and the reasons for pincer versus pseudo-pincer formation investigated. Incorporation of the electron-rich thiolato function resulted in the isolation of structurally diverse complexes. The catalytic activities of selected complexes have been tested in Suzuki-Miyaura, Mizoroki-Heck and hydroamination reactions.
The Performance Analysis Based on SAR Sample Covariance Matrix
Authors: Erten Esra
Published: March 2012

Multi-channel systems appear in several fields of application in science. In the Synthetic Aperture Radar (SAR) context, multi-channel systems may refer to different domains, as multi-polarization, multi-interferometric or multi-temporal data, or even a combination of them. Due to the inherent speckle phenomenon present in SAR images, the statistical description of the data is almost mandatory for its utilization. The complex images acquired over natural media present in general zero-mean circular Gaussian characteristics. In this case, second order statistics as the multi-channel covariance matrix fully describe the data. For practical situations however, the covariance matrix has to be estimated using a limited number of samples, and this sample covariance matrix follow the complex Wishart distribution. In this context, the eigendecomposition of the multi-channel covariance matrix has been shown in different areas of high relevance regarding the physical properties of the imaged scene. Specifically, the maximum eigenvalue of the covariance matrix has been frequently used in different applications as target or change detection, estimation of the dominant scattering mechanism in polarimetric data, moving target indication, etc. In this paper, the statistical behavior of the maximum eigenvalue derived from the eigendecomposition of the sample multi-channel covariance matrix in terms of multi-channel SAR images is simplified for SAR community. Validation is performed against simulated data and examples of estimation and detection problems using the analytical expressions are as well given.
Dual Mode NOx Sensor: Measuring Both the Accumulated Amount and Instantaneous Level at Low Concentrations
Authors: Groß Andrea , Beulertz Gregor , Marr Isabella , Kubinski David J. , Visser Jaco H. , Moos Ralf
Published: March 2012

The accumulating-type (or integrating-type) NOx sensor principle offers two operation modes to measure low levels of NOx: The direct signal gives the total amount dosed over a time interval and its derivative the instantaneous concentration. With a linear sensor response, no baseline drift, and both response times and recovery times in the range of the gas exchange time of the test bench (5 to 7 s), the integrating sensor is well suited to reliably detect low levels of NOx. Experimental results are presented demonstrating the sensor’s integrating properties for the total amount detection and its sensitivity to both NO and to NO2. We also show the correlation between the derivative of the sensor signal and the known gas concentration. The long-term detection of NOx in the sub-ppm range (e.g., for air quality measurements) is discussed. Additionally, a self-adaption of the measurement range taking advantage of the temperature dependency of the sensitivity is addressed.
Detection, Characterization, and Biological Effect of Quorum-Sensing Signaling Molecules in Peanut-Nodulating Bradyrhizobia
Authors: Nievas Fiorela , Bogino Pablo , Sorroche Fernando , Giordano Walter
Published: March 2012

Bacteria of the genus Bradyrhizobium are able to establish a symbiotic relationship with peanut (Arachis hypogaea) root cells and to fix atmospheric nitrogen by converting it to nitrogenous compounds. Quorum sensing (QS) is a cell-cell communication mechanism employed by a variety of bacterial species to coordinate behavior at a community level through regulation of gene expression. The QS process depends on bacterial production of various signaling molecules, among which the N-acylhomoserine lactones (AHLs) are most commonly used by Gram-negative bacteria. Some previous reports have shown the production of QS signaling molecules by various rhizobia, but little is known regarding mechanisms of communication among peanut-nodulating strains. The aims of this study were to identify and characterize QS signals produced by peanut-nodulating bradyrhizobial strains and to evaluate their effects on processes related to cell interaction. Detection of AHLs in 53 rhizobial strains was performed using the biosensor strains Agrobacterium tumefaciens NTL4 (pZLR4) and Chromobacterium violaceum CV026 for AHLs with long and short acyl chains, respectively. None of the strains screened were found to produce AHLs with short acyl chains, but 14 strains produced AHLs with long acyl chains. These 14 AHL-producing strains were further studied by quantification of β-galactosidase activity levels (AHL-like inducer activity) in NTL4 (pZLR4). Strains displaying moderate to high levels of AHL-like inducer activity were subjected to chemical identification of signaling molecules by high-performance liquid chromatography coupled to mass spectrometry (LC-MS/MS). For each AHL-producing strain, we found at least four different AHLs, corresponding to N-hexanoyl-DL-homoserine lactone (C6), N-(3-oxodecanoyl)-L-homoserine lactone (3OC10), N-(3-oxododecanoyl)-L-homoserine lactone (3OC12), and N-(3-oxotetradecanoyl)-L-homoserine lactone (3OC14). Biological roles of 3OC10, 3OC12, and 3OC14 AHLs were evaluated in both AHL-producing and -non-producing peanut-nodulating strains. Bacterial processes related to survival and nodulation, including motility, biofilm formation, and cell aggregation, were affected or modified by the exogenous addition of increasing concentrations of synthetic AHLs. Our results clearly demonstrate the existence of cell communication mechanisms among bradyrhizobial strains symbiotic of peanut. AHLs with long acyl chains appear to be signaling molecules regulating important QS physiological processes in these bacteria.
THE POSSIBILITIES OF USING SAPROPEL FOR BRIQUETTE PRODUCTION / SAPROPELIO PANAUDOJIMO GALIMYBĖS BRIKETAMS GAMINTI
Authors: Kozlovska-Kędziora Justyna , Petraitis Egidijus
Published: March 2012

This article describes the possibilities of using renewable energy fuel sources for the purpose of producing thermal energy. One of the options (alternatives) is to use sapropel (lake sediment biomass) not only as a fertilizer, feed additive, binder etc. but also as an energy fuel. One of the first steps to material extraction and preparation is fuel briquette (direct extraction of useful heat) production, technology and methodology. The article compares the author’s findings with analytical and experimental results obtained by other scientists. Santrauka Straipsnyje pateiktos atsinaujinančių energijos kuro šaltinių panaudojimo galimybės šilumos energijai gaminti. Viena iš galimybių (alternatyvų) yra sapropelį (ežerų dugno nuosėdų biomasę) naudoti ne tik kaip trąšą, pašarų priedą, rišiklį ir pan., bet ir kaip energetinį elementą. Straipsnyje pateikta: žaliavos paruošimas kuro briketams gaminti, paruoštos biomasės briketavimo technologija, pagamintų sapropelio su priedais briketų deginimas (tiesiogiai naudojamų šilumai išgauti), briketus deginant išsiskiriančių teršalų koncentracijos. Gauti rezultatai lyginami su kitų autorių analitiniais ir eksperimentiniais rezultatais.
STUDY AND ESTIMATION OF THE RATIO OF 137CS AND 40K SPECIFIC ACTIVITIES IN SANDY AND LOAM SOILS / 137CS IR 40K SAVITŲJŲ AKTYVUMŲ SANTYKIŲ TYRIMAS IR VERTINIMAS PRIESMĖLIO IR PRIEMOLIO DIRVOŽEMYJE
Authors: Mikalauskienė Renata , Butkus Donatas , Bataitienė Ingrida Pliopaitė
Published: March 2012

The present article describes changes in specific activities and fluctuations in the ratio of natural 40K and artificial 137Cs radionuclides in soil samples taken from different places of Lithuanian territory. The samples of soil have been selected from the districts polluted after the accident in Chernobyl nuclear plant performing nuclear testing operations. The study has established the main physical and chemical properties of soil samples and their impact on the concentration of 40K activities. 137Cs/40K specific activities in soil have been observed under the dry weight of the sample that varied from 0.0034 to 0.0240. The results of the study could be used for establishing and estimating 137Csand 40K transfer in the system “soil-plant”.

Santrauka

Straipsnyje nagrinėjama gamtinės (40K) ir dirbtinės (137Cs) kilmės radionuklidų savitųjų aktyvumų ir jų santykio kaita skirtinguose Lietuvos teritorijos dirvožemiuose. Dirvožemio mėginiai parinkti iš vietovių, kurios buvo labiau užterštos po Černobylio atominės elektrinės avarijos ir buvusių branduolinių bandymų. Tyrimo metu nustatytos pagrindinės fizinės cheminės dirvožemio savybės ir jų poveikis 40K aktyvumų koncentracijai. 137Csir 40K savitieji aktyvumai dirvožemyje tirti esant sausam mėginio svoriui. 137Cs savitieji aktyvumai sausame dirvožemyje svyravo nuo 1,1±1,0 iki 14,3±0,9 Bq/kg, o 40K savitieji aktyvumai – nuo 326±29 iki 740±15 Bq/kg. 137Csir 40K savitųjų aktyvumų santykis skirtingų vietovių dirvožemiuose kito nuo 0,0034 iki 0,0240 Bq/kg. Tyrimo rezultatai gali būti panaudoti, nustatant ir įvertinant 137Csir 40K pernašą sistemoje dirvožemis–augalai.
RESEARCH ON THE AERODYNAMIC RESISTANCE OF TRICKLE BIOFILTER / LAŠELINIO BIOFILTRO AERODINAMINIO PASIPRIEŠINIMO TYRIMAI
Authors: Zagorskis Alvydas , Spiečiūtė Renata
Published: March 2012

A four – section trickle biofilter was constructed for experimental research. The filter was filled with the packing material of artificial origin. The material consists of plastic balls having a large surface area. The dependence of biofilter aerodynamic resistance on supply air flow rate and the number of filter sections was determined. The aerodynamic resistance of the biofilter was measured in two cases. In the first case, the packing material of the filter was dry, whereas in the second case it was wet. The experimental research determined that an increase in the air flow rate from 0.043 m/s to 0.076 m/s causes an increase in biofilter aerodynamic resistance from 30.5 to 62.5 Pa after measuring four layers of dry packing material. In case of wet packing material, biofilter aerodynamic resistance after measuring four layers of plastic balls increases from 42.1 to 90.4 Pa.

Santrauka

Eksperimentiniams tyrimams atlikti sukonstruotas keturių sekcijų lašelinis biofiltras. Filtras užpildytas dirbtinės kilmės įkrova, sudaryta iš didelį paviršiaus plotą turinčių plastikinių rutuliukų. Naudojant įkrovą, skirtą introdukuotų mikroorganizmų asociacijoms kultivuoti, nustatytos biofiltro aerodinaminio pasipriešinimo priklausomybės nuo tiekiamo oro srauto greičio ir sekcijų skaičiaus. Biofiltro aerodinaminis pasipriešinimas matuotas dviem atvejais: esant sausai ir sudrėkintai įkrovai. Nustatyta, kad didinant tiekiamo oro srauto greitį nuo 0,043 iki 0,076 m/s, įrenginio aerodinaminis pasipriešinimas išmatavus keturis įkrovos sluoksnius padidėja nuo 30,5 iki 62,5 Pa tuo atveju, kai įkrova sausa, ir nuo 42,1 iki 90,4 Pa, – kai įkrova sudrėkinta.
ANALYSIS OF DETAILED ENERGY AUDITS AND ENERGY USE MEASURES OF UNIVERSITY BUILDINGS / UNIVERSITETO PASTATŲ DETALIŲJŲ ENERGINIŲ AUDITŲ IR ENERGIJOS TAUPYMO PRIEMONIŲ ANALIZĖ
Authors: Valančius Kęstutis , Motuzienė Violeta , Paulauskaitė Sabina , Vaičaitis Arnoldas
Published: March 2012

The paper explains the results of a detailed energy audit of the buildings of Vilnius Gediminas Technical University. Energy audits were performed with reference to the international scientific project. The article presents the methodology and results of detailed measurements of energy balance characteristics.
STUDIES ON THE THERMAL CONDUCTIVITY OF COMPOSITE MATERIALS BASED ON LOCAL RENEWABLE RESOURCES / KOMPOZICINIŲ TERMOIZOLIACINIŲ MEDŽIAGŲ IŠ VIETINIŲ ATSINAUJINANČIŲ IŠTEKLIŲ ŠILUMOS LAIDUMO TYRIMAI
Authors: Vėjelis Sigitas , Vaitkus Saulius , Balčiūnas Giedrius
Published: March 2012

Thermal insulation materials produced from local renewable resources are increasingly used for two reasons – they are environmentally friendly and their manufacture requires less amount of energy. The most renewable resources include a wide variety of crop straw – barley, rye, wheat, triticale, etc. the thermal conductivity of which depends on their orientation to the product and structure of the same straw. For specimen composition, the straw stems of bulrush, reeds, bent and triticales were used, producing composites with the mass ratio of 1:1. The paper analyses the results of thermal conductivity tests on different stem composites of herbaceous plants. Thermal conductivity was investigated considering composition specimens such as bulrush-reeds, bulrush-bent, bulrush-straw, reed-straw, reed-bent. The use of composites in all cases reduced thermal conductivity compared with the thermal conductivity of materials used alone. The greatest reduction in thermal conductivity compared with the thermal conductivity of the single straws of herbaceous plants has been observed in bulrush-straw composites. Santrauka Termoizoliacinės medžiagos iš vietinių atsinaujinančių išteklių vis plačiau naudojamos dėl dviejų priežasčių – jos yra ekologiškos ir jų gamybai reikalingi maži energijos kiekiai. Iš atsinaujinančių išteklių labiausiai paplitę įvairių kultūrinių augalų šiaudai: miežių, rugių, kviečių, kvietrugių ir kt. Šių medžiagų šilumos laidumas labiausiai priklauso nuo jų orientacijos gaminyje ir pačių stiebelių struktūros. Bandiniams komponuoti buvo naudojama švendrų, nendrių, smilgų ir kvietrugių šiaudų stiebai, iš kurių pagal masės santykį 1:1 buvo komponuojami kompozitai. Atlikta kompozitų, sudarytų iš skirtingų žolinių augalų stiebelių, šilumos laidumo tyrimai. Tirti tokių sudėčių bandinių šilumos laidumai: švendrai + nendrės, švendrai + smilgos, švendrai + šiaudai, nendrės + šiaudai, nendrės + smilgos. Naudojant kompozitus visais atvejais sumažintas šilumos laidumas lyginant su šilumos laidumu, kai naudotos pavienės medžiagos: didžiausias šilumos laidumo sumažėjimas, lyginant su pavienių augalų stiebų šilumos laidumu, gautas švendrų ir šiaudų kompozite.
Stimulation of Dopamine Receptor D5 Expressed on Dendritic Cells Potentiates Th17-Mediated Immunity
Authors: Prado Carolina , Contreras Francisco , González Hugo , Díaz Pablo , Elgueta Daniela , Barrientos Magaly , Herrada Andrés A. , Lladser Álvaro , Bernales Sebastián , Pacheco Rodrigo
Published: March 2012

Dendritic cells (DCs) are responsible for priming T cells and for promoting their differentiation from naive T cells into appropriate effector cells. Emerging evidence suggests that neurotransmitters can modulate T cell-mediated immunity. However, the involvement of specific neurotransmitters or receptors remains poorly understood. In this study, we analyzed the role of dopamine in the regulation of DC function. We found that DCs express dopamine receptors as well as the machinery necessary to synthesize, store, and degrade dopamine. Notably, the expression of D5R decreased upon LPS-induced DC maturation. Deficiency of D5R on the surface of DCs impaired LPS-induced IL-23 and IL-12 production and consequently attenuated the activation and proliferation of Ag-specific CD4+ T cells. To determine the relevance of D5R expressed on DCs in vivo, we studied the role of this receptor in the modulation of a CD4+ T cell-driven autoimmunity model. Importantly, D5R-deficient DCs prophylactically transferred into wild-type recipients were able to reduce the severity of experimental autoimmune encephalomyelitis. Furthermore, mice transferred with D5R-deficient DCs displayed a significant reduction in the percentage of Th17 cells infiltrating the CNS without differences in the percentage of Th1 cells compared with animals transferred with wild-type DCs. Our findings demonstrate that by contributing to CD4+ T cell activation and differentiation to Th17 phenotype, D5R expressed on DCs is able to modulate the development of an autoimmune response in vivo.
Transboundary geophysical mapping of geological elements and salinity distribution critical for the assessment of future sea water intrusion in response to sea level rise
Authors: Jørgensen F. , Scheer W. , Thomsen S. , Sonnenborg T. O. , Hinsby K. , Wiederhold H. , Schamper C. , Burschil T. , Roth B. , Kirsch R. , Auken E.
Published: March 2012

Abstract. Geophysical techniques are increasingly used as tools for characterising the subsurface and they are generally required to develop subsurface models that properly delineate the distribution of aquifers and aquitards, salt/freshwater interfaces and geological structures that affect groundwater flow. In a study area covering 730 km2 across the border between Germany and Denmark a combination of an airborne transient electromagnetic survey (performed with the SkyTEM system), a high-resolution seismic survey and borehole logging has been used in an integrated mapping of important geological, physical and chemical features of the subsurface. The spacing between flight lines is 200–250 m giving a total of about 3200 line km. About 38 km of seismic lines have been collected. Faults bordering a graben structure, deep and shallow buried tunnel valleys, glaciotectonic thrust complexes, marine clay units, and sand aquifers are all examples of geological elements mapped by the geophysical data that control groundwater flow and to some extent hydrochemistry. Additionally, the data provide an excellent picture of the salinity distribution in the area thus providing important information on the fresh-saltwater boundary and the chemical status of groundwater. Although, the westernmost part of the study area along the North Sea coast is saturated with saline water and the TEM data therefore is strongly influenced by the increased electrical conductivity here, buried valleys and other geological elements are still revealed. The salinity distribution indicates preferential flow paths through and along specific geological elements within the area. The effects of future sea level rise on the groundwater system and chemical status are discussed with special emphasis on the importance of knowing the existence, distribution and geometry of the mapped geological elements, and assessing their control on the groundwater salinity distribution.
Model testing on rainfall-induced landslide of loose soil in Wenchuan earthquake region
Authors: Fang H. , Cui P. , Pei L. Z. , Zhou X. J.
Published: March 2012

Abstract. This study investigates the formation process of rainfall-induced landslide for slopes composed of loose soil in the Wenchuan earthquake region. Experimental investigations have been performed on the landslide's formation and the variation of the controlling soil parameters under various artificial rainfall conditions. The landslide triggering mechanisms can be described in the following way. Firstly, the large porosity of the loose soil facilitated the infiltration of water, which increased the pore water pressure and reduced the shear strength of the soil significantly. In addition, the rainfalls probably caused the concentration of finer particles at a certain depth of the valley slopes. This concentration within the soil increased the pore water pressure significantly, and consequently reduced both the porosity ratio and permeability. Therefore, when the pore water pressure reached a critical state, the effective shear strength of the soil diminished, inducing the landslide's formation.
Intra-Cavitary ECG is an Effective Method for Correct Positioning of the Tip of Tunneled Groshong Catheters
Authors: Capozzoli Giuseppe , Accinelli Gino , Fabbro Loris , Pedrazzoli Roberta , Auricchio Franco
Published: March 2012

Background

Intra-cavitary electrocardiography (ECG) is a well-known method for correct positioning of the tip of central venous catheters (CVC). A significant increase in the P wave, as registered by the intra-cavitary electrode, signals the entrance of the catheter into the right atrium.

Methods

In this prospective observational study, 155 consecutive oncologic patients were enrolled for cannulation of the right or left internal jugular vein for insertion of a tunneled Groshong catheter. In 150 patients the tip was positioned by means of intracavitary ECG. Five patients with atrial fibrillation (N=4) or pacemaker in place (N=1) were excluded from the study. As the P-wave amplitude began to increase, the catheter was secured in that position and the insertion depth was registered.

Results

Intra-cavitary ECG was always apt to detect the increase in the P wave. On the post-operative chest x-ray all Groshong catheters except two were in the correct position.

Conclusions

The need for chest x-ray or fluoroscopy may be virtually eliminated by using the ECG technique.
Alice in the Real World
Authors: Parker Tom
Published: March 2012

A computer application promotes programming knowledge and allows students to create their own worlds through mathematical problem solving.
Students' Strategies Can Take Us Off Guard
Authors: Keiser Jane M.
Published: March 2012

These students produced incorrect answers, but their teacher helped them ultimately become more proficient with computation by skillfully leveraging their prior understanding.
Trans fat, aspirin, and ischemic stroke in postmenopausal women
Authors: Yaemsiri Sirin , Sen Souvik , Tinker Lesley , Rosamond Wayne , Wassertheil‐Smoller Sylvia , He Ka
Published: March 2012

Objective:

To examine the associations between dietary fat intake and ischemic stroke among postmenopausal women.

Methods:

We conducted a prospective cohort study of 87,025 generally healthy postmenopausal women (age, 50–79 years) enrolled in the Women's Health Initiative Observational Study. Repeated and validated dietary assessments were done using a self‐administered food frequency questionnaire. We used Cox proportional hazards models to estimate hazard ratios (HRs) of ischemic stroke based on quintiles of the cumulative average of fat intake.

Results:

We documented 1,049 incident cases of ischemic stroke over 663,041 person‐years of follow‐up. Women in the highest quintile of trans fat intake had a significantly higher incidence of ischemic stroke (HR, 1.39; 95% confidence interval [CI], 1.08–1.79; p‐trend = 0.048) compared with women in the lowest quintile, while controlling for multiple covariates. The observed association was modified by aspirin use (p‐interaction = 0.02). The HR was 1.66 (95% CI, 1.21–2.36; p‐trend < 0.01) among baseline non‐aspirin users (n = 67,288) and 0.95 (95% CI, 0.60‐1.48; p‐trend = 0.43) among aspirin users (n = 19,736). No significant associations were found between intakes of saturated, monounsaturated, or polyunsaturated fat and ischemic stroke or any ischemic stroke subtypes.

Interpretation:

In this large cohort of postmenopausal women, higher intake of trans fat was associated with incident ischemic stroke independent of major lifestyle/dietary factors. Aspirin use may attenuate the potential adverse effect of trans fat intake on ischemic stroke. ANN NEUROL 2012;72:704–715
The Diaryl(oxy)methyl Group: More than an Innocent Bystander in Chiral Auxiliaries, Catalysts, and Dopants
Authors: Braun Manfred
Published: March 2012

Either as the free alcohol or deprotonated, a carbinol residue bearing gemial, identical aryl residues can at first sight be recognized as an achiral structural unit. When incorporated, however, into a chiral molecule, the two aryl groups become diastereotopic. Thus, they might contribute to an enhancement in stereoselectivity and do so in a variety of reactions. This Minireview highlights developments in stereochemistry when the diaryl(oxy)methyl group is involved, with emphasis given to the beneficial effect of this moiety. Of particular focus are auxiliaries, the stoichiometric use of metal complexes, metal and organocatalysts, and finally chiral dopants for liquid crystals, all featuring the diaryl(oxy)methyl group.
Selection and transformation of input variables for RVM based on MI–PCA–MI and 4‐CBA concentration model
Authors: Chen Chao , Yan Xuefeng
Published: March 2012

Considering that chemical process is a high nonlinear system with high‐dimensional and complex variables, relevance vector machine (RVM) with the novel selection and transformation of the candidate input variables, which combines principal component analysis (PCA) with mutual information (MI), is proposed and named as MI–PCA–MI–RVM. First, to omit the irrelevant input variables, the selected input variables are determined according to their correlation degree with output variable via MI. Second, to eliminate the multicollinearity among the selected input variables, PCA is applied for them to be principal components (PCs). Third, the PCs are reordered according to their correlation degree with output variable via MI and denoted as MI–PCs, and the optimal MI–PCs are determined as the input variables for RVM according to the predicting performance. Further, MI–PCA–MI–RVM is employed to develop the 4‐carboxybenzaldehyde concentration model. The result shows that MI–PCA–MI–RVM model has better predicting and robust performance than PCA–RVM and RVM models. © 2012 Curtin University of Technology and John Wiley & Sons, Ltd.