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La enfermedad inflamatoria intestinal es una patología crónica en la que participa el sistema inmune, que puede acompañarse de manifestaciones extraintestinales en el hígado y vías biliares. El síndrome de Budd-Chiari se ha descrito previamente como una complicación rara de la colitis ulcerativa. Se describe el caso de una paciente joven con antecedente de colitis ulcerativa y trombosis venosa de miembro inferior, en manejo crónico con aminosalicilatos y anticoagulada durante 6 meses, quien debutó con cuadro clínico de ascitis de dos meses de evolución, con líquido ascítico de características hipertensivas, documentación imagenológica y biopsia hepática compatibles con síndrome de Budd-Chiari. Se presenta reporte de caso y revisión breve de la literatura.

Background and aim: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus responsible for the current pandemic, can have multi-organ impact. Recent studies show that liver injury could be a manifestation of the disease, and that liver disease could also be related to a worse prognosis. Our aim was to compare the characteristics of patients with severe coronavirus disease 2019 (COVID-19) due to SARS-CoV-2 who required intubation versus stable hospitalized patients to identify the early biochemical predictive factors of a severe course of COVID-19 and subsequent requirement for intubation, specifically in Mexican. Methods: This was an observational case-control study nested in a cohort study. Complete medical records of patients admitted for confirmed COVID-19 at a tertiary level center in Mexico City were reviewed. Clinical and biochemical data were collected, and the characteristics of patients who required invasive mechanical ventilation (IMV) (cases) were compared with stable hospitalized patients without ventilation (controls). Results: We evaluated 166 patients with COVID-19 due to SARS-CoV-2 infection; 114 (68.7%) were men, the mean age was 50.6 ± 13.3 years, and 27 (16.3%) required IMV. The comparative analysis between cases and controls showed (respectively) significantly lower blood oxygen saturation (SpO2) (73.5 ± 12.0% vs. 83.0 ± 6.8%, P

Introduction: Some patients with SARSCov-2 infection develop severe disease (SARS); however, the factors associated with severity are not yet fully understood. Some reports indicate that liver injury may be a poor prognostic factor. Aim: To identify the biochemical factors related to the development of SARS with mechanical ventilation (MV) requirement in patients with SARSCov-2 and COVID-19. Methods Type of study: Observational. Cohort study. Procedure: Data from COVID-19 patients were collected at admission time to a tertiary care center. Differential factors were identified between seriously ill SARS+MV patients versus stable patients without MV. Transformation to the natural logarithm of significant variables was performed and multiple linear regression was applied, then a predictive model of severity called AAD (Age-AST-D dimer) was constructed. Results: 166 patients were included, 114(68.7%) men, mean age 50.6±13.3 years-old, 27(16.3%) developed SARS+MV. In the comparative analysis between those with SARS+MV versus stable patients without MV we found significant raises of ALT (225.4±341.2 vs. 41.3±41.1; P=0.003), AST 325.3±382.4 vs. 52.8±47.1; P=0.001), LDH (764.6±401.9 vs. 461.0±185.6; P=0.001), D dimer (7765±9109 vs. 1871±4146; P=0.003), age (58.6±12.7 vs. 49.1±12.8; P=0-001). The results of the regression are shown in the Table, where model 3 was the one that best explained the development of SARS+MV; with these variables was constructed the model called AAD, where: [AAD= 3.896 + ln(age)x-0.218 + ln(AST)x-0.185 + ln(DD)x0.070], where a value ≤ 2.75 had sensitivity=0.797 and 1-specificity= 0.391, AUROC=0.74 (95%CI: 0.62-0.86; P

This study describes the association of household water system contamination with the pathogenic Free-Living Amoeba (FLA) Naegleria fowleri and a case of fatal Primary Amoebic Meningoencephalitis (PAM) in a child from the state of Monagas in Venezuela. Amoebae were initially identified by microscopy from a sample of cerebrospinal fluid (CSF) from the child. Direct DNA extraction and specific PCR/sequencing for N. fowleri was also carried out from the same CSF sample. In order to determine a possible environmental source of infection, water samples from the water tank of the child's home and also water bodies recently visited by the child and his family, were examined for the presence of N. fowleri by culture and PCR/sequencing. The results obtained from the collected water samples revealed that only the water tank of the house was positive for N. fowleri. PCR/sequencing showed that the strains isolated from the patient and the water tanks were 100 % identical. Therefore, the house water tank was confirmed as the source of infection in this case, possibly as a result of the occasional immersion of the child´s head under the water while bathing. This case highlights a novel source of thermally polluted water and another threat of N. fowleri infection.

Aim. Coronavirus disease (COVID-19) ranges from mild clinical phenotypes to life-threatening conditions like severe acute respiratory syndrome (SARS). It has been suggested that early liver injury in these patients could be a risk factor for poor outcome. We aimed to identify early biochemical predictive factors related to severe disease development with intensive care requirements in patients with COVID-19. Methods. Data from COVID-19 patients were collected at admission time to our hospital. Differential biochemical factors were identified between seriously ill patients requiring intensive care unit (ICU) admission (ICU patients) versus stable patients without the need for ICU admission (non-ICU patients). Multiple linear regression was applied, then a predictive model of severity called Age-AST-D dimer (AAD) was constructed ( n = 166 ) and validated ( n = 170 ). Results. Derivation cohort: from 166 patients included, there were 27 (16.3%) ICU patients that showed higher levels of liver injury markers ( P < 0.01 ) compared with non-ICU patients: alanine aminotrasnferase (ALT) 225.4 ± 341.2 vs. 41.3 ± 41.1 , aspartate aminotransferase (AST) 325.3 ± 382.4 vs. 52.8 ± 47.1 , lactic dehydrogenase (LDH) 764.6 ± 401.9 vs. 461.0 ± 185.6 , D-dimer (DD) 7765 ± 9109 vs. 1871 ± 4146 , and age 58.6 ± 12.7 vs. 49.1 ± 12.8 . With these finding, a model called Age-AST-DD (AAD), with a cut-point of sensitivity = 0.797 and specificity = 0.391 , c − statistic = 0.74 ; 95%IC: 0.62-0.86, P < 0.001 ), to predict the risk of need admission to ICU ( OR = 5.8 ; 95% CI: 2.2-15.4, P = 0.001 ), was constructed. Validation cohort: in 170 different patients, the AAD model < 2.75 ( c − statistic = 0.80 (95% CI: 0.70-0.91, P < 0.001 ) adequately predicted the risk ( OR = 8.8 , 95% CI: 3.4-22.6, P < 0.001 ) to be admitted in the ICU (27 patients, 15.95%). Conclusions. The elevation of AST (a possible marker of early liver injury) along with DD and age efficiently predict early (at admission time) probability of ICU admission during the clinical course of COVID-19. The AAD model can improve the comprehensive management of COVID-19 patients, and it could be useful as a triage tool to early classify patients with a high risk of developing a severe clinical course of the disease.

A nanomaterial that attracts the attention in a variety of research areas is multiwall carbon nanotubes (MWCNTs), due to their good mechanical proprieties, and high electrical and thermal conductivity. For this reason, the preparation of three-dimensional (3D) structures from them draws interest because it opens new horizons to produce materials with novel properties and useful applications. In this investigation the synthesis of 3D nanotube carbon (nanoforest type) functionalized with nanoparticles of silver, aluminum, and iron was studied. A 3D structure was produced in the form of aligned microchannels. The functionalization of carbon nanotubes with nanoparticles of silver, aluminum or iron during the synthesis process of carbon nanotubes, was carried out through spray-pyrolysis with different synthesis time and solution concentration. The results were characterized through microscopy SEM, TEM and Raman’s spectroscopy.

Background and aim: Some patients with SARSCov-2 infection develop severe disease (SARS);however, the factors associated with severity are not yet fully understood. Some reports indicate that liver injury may be a poor prognostic factor. AIM: To identify the biochemical factors related to the development of SARS with mechanical ventilation (MV) requirement in patients with SARSCov-2 and COVID-19. Methods. Type of Study: Observational. Cohort study. Procedure: Data from COVID-19 patients were collected at admission time to a tertiary care center. Differential factors were identified between seriously ill SARS + MV patients versus stable patients without MV. Transformation to the natural logarithm of significant variables was performed and multiple linear regression was applied, then a predictive model of severity called AAD (Age-AST-D dimer) was constructed. Result(s): 166 patients were included, 114(68.7%) men, mean age 50.6 +/- 13.3 years-old, 27(16.3%) developed SARS + MV. In the comparative analysis between those with SARS + MV versus stable patients without MV we found significant raises of ALT (225.4 +/- 341.2 vs. 41.3 +/- 41.1;P = 0.003), AST 325.3 +/- 382.4 vs. 52.8 +/- 47.1;P = 0.001), LDH (764.6 +/- 401.9 vs. 461.0 +/- 185.6;P = 0.001), D dimer (7765 +/- 9109 vs. 1871 +/- 4146;P = 0.003), age (58.6 +/- 12.7 vs. 49.1 +/- 12.8;P = 0-001). The results of the regression are shown in the Table, where model 3 was the one that best explained the development of SARS + MV;with these variables was constructed the model called AAD, where: [AAD = 3.896 + ln(age)x-0.218 + ln(AST)x-0.185 + ln(DD)x0.070], where a value = 2.75 had sensitivity = 0.797 and 1-specificity = 0.391, AUROC = 0.74 (95%CI: 0.62-0.86;P 0.0001), to predict the risk of developing SARS + MV (OR = 5.8, 95%CI: 2.2-15.4;P = 0.001). Conclusion(s): Elevation of AST (probable marker of liver damage) is an important predictor of progression to SARS, together with elevation of D-dimer and age early (at admission) and efficiently predict which patients will potentially require MV. Conflicts of interest: The authors have no conflicts of interest to declare. [Formula presented] [Formula presented] Copyright © 2020

Air-conditioning load and ventilation in buildings contribute more than 60% of the total energy consumption in United Arab Emirates (UAE), where the unavoidable extreme temperatures hit the region, especially during summer months. Literature survey indicates that at a depth of approximately 10 m, the soil reaches stability and it is no longer fluctuating drastically under the influence of external ambient temperatures. This relatively shallow location allows the use of soil’s practical location as a possible source for sustainable energy recovery. The aim of this investigation is to explore the feasibility of using soil as a heat sink and experimentally analyse the soil heat transfer with variations in moisture saturations and heat flux rates in a testing rig. For this purpose, an axial to radial experimental analysis on Abu Dhabi soil is carried out on a lab scale test rig. This paper provides an insight into modular design of the experimental setup using spiral and U–shape heat exchangers. Experimental validation results are presented which deliver a heat profile in the sand, measured in time and depth for various heat flux rates. Moreover, thermal conductivity of the sand is estimated from experimentation and compared with literature. The results indicate presence of considerable potential for energy savings in the region.

BMD_GV_ml1_ml2.docx. Results BMD and GV. Measured bone mineral content (DEXA) and gray scale values (X-ray) for the regions of interest 1–5 (ROI1 – ROI5) in ml1 and ml2: mean value (M) ± standard deviation (SD), coefficient of variation [CV]. (DOCX 25 kb)

ZusammenfassungGegenstand und Ziel: Die Klassifikation der kaninen Bandscheibendegeneration in der Magnetresonanztomographie ist in der Literatur beschrieben, während für die computertomographische Untersuchung kaniner Bandscheibenveränderungen bisher kein etabliertes Klassifikationssystem existiert. Da die Computertomographie ein häufig genutztes bildgebendes Verfahren in der Tiermedizin darstellt, war Ziel dieser Studie, ein derartiges Klassifikationssystems zu erstellen und zu validieren. Als vergleichende Methode stand eine T2-gewichtete magnetresonanztomographische Untersuchung zur Verfügung. Material und Methoden: Die computertomographische und magnetresonanztomographische Untersuchung von 43 Hunden ergab Bilddatensätze von 144 Bandscheiben. Diese Datensätze wurden verblindet, randomisiert und jeweils zweimal von drei Gutachtern beurteilt. Der Bewertung computertomographischer Datensätze lag das selbst entwickelte Klassifikationssystem zugrunde, während für die magnetresonanztomographischen Datensätze das Klassifikationssystem nach Pfirrmann angewendet wurde. Die Intra-und Interobserver-Übereinstimmung wurde mittels Statistical Analysis Software (SAS) bestimmt. Ergebnisse: Die Intra-und Interobserver-Übereinstimmung des Klassifikationssystems nach Pfirrmann (D-Werte 0,58–0,77) und des selbst entwickelten Klassifikationssystems (D-Werte 0,60–0,81) waren überwiegend gut. Zwischen den beiden Klassifikationssystemen ergab sich eine geringe Übereinstimmung (D = 0,26–0,29). Schlussfolgerung undklinische Relevanz: Eine zuverlässige Bewertung der Bandscheibendegeneration in der Computertomographie ist mit dem selbst entwickelten Klassifikationssystem möglich. Somit lassen sich zusätzliche Informationen für Diagnose und Prognose gewinnen. Die Computertomographie erfasst degenerative Veränderungen allerdings erst in einem fortgeschritteneren Stadium als die Magnetresonanztomographie.

In man, living environment and lifestyle influence host physiology and microbial populations, and these interactions determine the health of individuals. In particular, dietary preferences are partially triggered by genetically-mediated taste responses to specific foods and may be reflected in the metabolic phenotype. However, identification of dietary metabolic signatures in free-living populations is made difficult by the relatively low amplitude of nutritional modulations when compared to inherent intra- and inter-individual variability that results from numerous confounding factors, e.g. sampling, lifestyle, gender and ageing. The identification of dietary biomarkers lies in the application of chemometrics to recover key metabolic information from the high density and highly variable metabolic phenotypes. One preferred approach is the use of linear regression models such as Partial Least Squares – Discriminant Analysis, whose reliability depends on appropriate validation procedures. However, the high inter- and intra-individual variability in free-living populations makes difficult the direct application of consolidated validation methodologies such as n-fold cross-validation that often leads to unstable solutions. In the present manuscript, we propose a new validation strategy based on the combination of several methodologies, merging n-fold cross validation and bootstrapping procedures with the confirmation of the reliability of the model through the generation of a set of replicate models. The proposed method was employed to validate the identification of dietary specific metabolic biomarkers in 1 H NMR and UPLC TOFMS urine metabolic profiles obtained from 21 free-living subjects stratified according to their sensitivity to propylthiouracil.

Background To be effective and selective, immunotherapy ideally targets specifically tumor cells and spares normal tissues. Identification of tumor specific antigens is a prerequisite to establish an effective immunotherapy. Still very little is known about the expression of tumor-related antigens in pancreatic neoplasms. Cancer Testis antigens (CT) are antigens shared by a variety of malignant tumors, but not by normal tissues with the exception of germ cells in testis. Restricted expression in neoplastic tissues and inherent immunogenic features make CT antigens ideal for use in immunotherapy. We analyzed the expression of a selected panel of nine CT antigens that have been proven to elicit an efficient immunogenic response in other malignancies. In addition we analyzed the expression of HERV-K-MEL, an immunogenic antigen of viral origin. Methods Pancreatic adenocarcinoma tumor samples ( n = 130) were obtained intraoperatively, control tissues ( n = 23) were collected from cadaveric donor and from patients with chronic pancreatitis. Tumor-associated antigen expression of MAGE-A1, MAGE-A3, MAGE-A4, MAGE-A10, LAGE-1, NY-ESO-1, SCP-1, SSX-2, SSX-4 and HERV-K-MEL was assessed by PCR. Sequencing of PCR products were performed to assess the expression of SSX-4 in neoplastic and normal pancreatic tissues. Results Three of 10 tested antigens were expressed in over 10% of malignant pancreatic tissue samples. SSX-4 was found positive in 30% of cases, SCP-1 in 19% and HERV-K-MEL in 23% of cases. No expression of CT antigens was found in non-malignant pancreatic tissue with the exception of SSX-4 and and SSX-2. Conclusions Fifty two percentage of the analyzed tissues expressed at least one CT antigen. The concomitant expression of SSX-4 in both malignant and non-malignant pancreatic tissue is a new finding which may raise concerns for immunotherapy. However, HERV-K-MEL is expressed with a relatively high prevalence and may be a candidate for specific immunotherapy in a large subgroup of pancreatic cancer patients. This study advocates the analysis of patients with regard to their immunogenic profile before the onset of antigen-specific immunotherapy.

Although the classification of canine intervertebral disc degeneration using magnetic resonance imaging (MRI) has been described in the literature, there is no such classification using computed tomographic imaging. Because computed tomography (CT) is a frequently used diagnostic imaging tool in veterinary medicine, the aim of this study was the introduction and validation of such a scoring system. T2-weighted magnetic resonance images were available for comparative analysis.A total of 43 dogs were examined using CT and MRI. Image data records of 144 intervertebral discs were blinded, randomized and evaluated twice by three observers. CT data were analyzed using a self-developed scoring system, while MRI data sets were evaluated using the Pfirrmann scoring system. Intra- and interobserver agreement were determined using Statistical Analysis Software (SAS).Intra- and interobserver agreement were mostly substantial in the Pfirrmann (0.58-0.77) and self-developed (0.60-0.81) scoring systems. A slight agreement was found between both classification systems (κ scores 0.26-0.29).The self-developed scoring system allows a reliable assessment of canine intervertebral disc degeneration using CT imaging. Therefore, further diagnostic and prognostic information can be obtained. Degenerative changes in the intervertebral discs could be identified at an earlier stage when using MRI in comparison with CT.

The Central Solenoid Model Coil (CSMC) is a solenoid consisting of 18 concentric layers, wound with Nb/sub 3/Sn cable-in-conduit conductor, jacketed with Incoloy. The Japanese HT and USHT were in charge of the manufacturing, and the coil is being tested at JAERI, Naka (Japan). The European Home Team is involved in the testing program, which includes electromagnetic characteristics of the CSMC, and of the CS Insert. Two effects influence strongly the electromagnetic properties: (i) connections introduce a nonuniform current distribution among the strands, and (ii) the performance of the strands are dependent on the strain of the Nb/sub 3/Sn filaments. The current distribution calculated in the CS Insert takes into account magnetic field and strain applied on the conductor, the joint effect and the current transfer between strands. The model developed at CEA, uses an equivalent electric network composed of resistive joints, superconducting lengths and interstrand resistances and provides the voltage-current characteristics, which ran be directly compared to the experimental results.

MOCVD is a suitable technique for the synthesis of functional metal oxide thin films. In the present paper, injection-MOCVD was proved to be an efficient method, not only to grow single layers, but also heterostructures and superlattices of functional oxide materials. We report on the deposition of BaxSr1−xTiO3 (BST) films and BaTiO3/SrTiO3 superlattices [(BTO/STO)n] obtained by injection MOCVD. In a first step, BST films were deposited on various substrates such as LaAlO3(LAO)(012), SrTiO3:Nb(STO:Nb)(001) and Al2O3(0001), resulting in epitaxial films in the case of STO or LAO substrates and highly textured films in the case of Al2O3 substrates. The good crystallinity of the films obtained was evidenced using X-ray analysis. Concerning the dielectric properties of BST films on STO:Nb, the Tc values were found to be the same as those for bulk materials. In a next step the feasibility of (BTO/STO)n superlattices was studied. The multilayers obtained were epitaxially grown on LAO and STO:Nb substrates. XPS was used to check in detail the pattern repetition of the superlattice and proved the low interface roughness of 1 nm as well as the absence of carbon contamination in the film. The measured periodicity of these superlattices were found to be in good agreement with simulation experiments. Further superlattices have been obtained by combining ferroelectric, magnetic (CMR) and superconducting (HTS) oxides. Typical results of these superlattices will be reported.

Recent results on the study of high-TC superconductors using the e ‐ perturbed angular correlation technique are presented. The basic features of the experimental equipment and its installation at the ISOLDE facility are briefly described. Results obtained from 197m Hg implanted into high quality Y1Ba2Cu3O6+ epitaxy thin films are presented and discussed.

Superconducting YBa 2 Cu 3 O 7 thin films have been grown by Injection MOCVD on different kind of monocristalline substrates: MgO, NdGaO 3 , LaAlO 3 with critical current densities Jc(77K) over 10 6 A/cm 2 on all of these substrates and up to 7.10 6 A/cm 2 on LaAlO 3 . Heterostructures have been grown on metallic substrates with convenient YSZ buffer. Biaxially textured YBCO films have been realized with Jc(77K) = 5.10 5 A/cm 2 . Other heterostructures with an active dielectric SrTiO 3 layer have been grown for tunable microwave devices applications with promising properties. Finally Injection MOCVD has shown to be well adapted for the formation of multilayers and superlattices with a control of the layer thickness in the range of one unit cell. YBa 2 Cu 3 O 7-δ /PrBa 2 Cu 3 O 7-δ superlattices have been grown with anisotropic superconducting properties which can be tailored by changing the layer thickness of both superconducting and insulating layer.

The activation energy in several (YBCO){sub m}/(PBCO){sub n} superconducting multilayers was deduced from resistivity measurements in magnetic fields up to 16 T, as a function of the angle between the magnetic field and the ab planes. The activation energy U{sub 0}(B, {theta}) scales with a reduced field B{sub red} = B(sin{sup 2}{theta} + cos{sup 2}{theta}/I{sup 2}){sup 1/2}, with an angle dependent anisotropy parameter {Gamma}. A crossover from U{sub 0}{proportional{underscore}to}log B{sub red}, at low B{sub red}, to U{sub 0}{proportional{underscore}to}(B{sub red}){sup {alpha}} at high B{sub red}, is also observed. The implications of these results on vortex dynamics and on the coupling between the superconducting layers will be discussed.

YBaCuO/PrBaCuO multilayers have been grown by a new Pulsed Injection MO-CVD method, based on microdroplets injection of the organic precursors The x-ray rocking curves show that the FWHM is about 0.6c, comparable to the values obtained for pure YBaCuO films. The RBS results show also a good cristallinity through the whole thickness. Critical currents, irreversibility lines and pinning energies are similar to those measured in multilayers obtained by other techniques.

The possibilities of a new single source injection metalorganic chemical vapor deposition technique were demonstrated for in situ growth of YBa 2 Cu 3 O 7 films of very high crystalline and transport quality. Precisely controlled microamounts of organometallic β-diketonates dissolved in an organic solvent were injected sequentially into the evaporator by means of a computer-driven injector and the resultant vapor was transported into the deposition zone. Accuracy of microdosing (within 5%) and nonselective flash-like evaporation of the precursors were the main factors for obtaining a reproducible vapor phase composition in spite of poor stability of the Ba precursor. The influence of vapor phase composition on film properties was investigated. After the optimisation of deposition conditions, the YBa 2 Cu 3 O 7 films with very high critical current density up to (6–7)×10 6 A/cm 2 at 77 K were reproducibly grown on LaAlO 3 (0 0 1).

Epitaxial YBa 2 Cu 3 O 7 layers with 45° in-plane orientation have been grown by Injection CVD on MgO substrates polished off-axis to within 1.4–1.9° of the [100] direction. This new single-source CVD process is based on computer-controlled injection of precise microdoses of a metal–organic precursor solution into a CVD reactor. A wide range of solution compositions was tested to investigate compositional effects on phase purity, surface morphology, texturing and superconducting properties of the prepared films. The highest quality films with pure 45° texture had a smooth surface, zero resistance T c ( R =0) of 88–89 K, and critical current density J c (77 K) above 10 6 A/cm 2 .

It is well established that YBa2Cu3O7−x bulk crystals twin when crossing the tetragonal to orthorhombic transition. Much fewer investigations have been performed on thin films, but one expects a strong influence of the strain induced by the underlying substrate. An analysis of this influence has been undertaken by X-ray diffraction and transmission electron microscopy, from a set of specific samples grown by metal-organic chemical vapor deposition: YBa2Cu3O7 − x PrBa2Cu3O7 − x and YBa2Cu3O7−x-PrBa2Cu3O7−x thin films and superlattices. Results indicate that thick (> 100 nm) YBCO films on cubic SrTiO3 (001) substrates exhibit the same twinning behaviour as bulk crystals. For YBCO films grown on orthorhombic YAIO3, substrates only one twinning direction is observed. YBCO-PBCO superlattices on SrTiO3 exhibit an orthorhombic symmetry down to superperiods of 25 A. The superlattices twinning behaviour is also highly dependent on the total thickness of the stacking.

This work aims toward the development of new, objective and innovative tools and means, intended to improve the acquisition of new medical equipment process, by considering the utilization behavior of existing equipment. The capture of the relevant data is accomplished by selecting al-ready available information in the point of care, found in the patient’s nursing chart. This data is then inputted in the HL7 transport standard, processed and reported by world class developed software.

The scanning properties of shaped reflectors, both offset and circularly symmetric, are examined and compared to conic section scanning characteristics. Scanning of the pencil beam is obtained by lateral and axial translation of a single point source feed. The feed is kept pointed toward the center of the subreflector. The effects of power spillover and aperture phase error as a function beam scanning are examined for several different types of large reflector design including dual-offset, circularly symmetric large f/D, and smaller f/D dual reflector antenna system. It is shown that the Abbe-sine condition for improved scanning of an optical system cannot, inherently, be satisfied in a dual-shaped reflector system that is shaped for high gain and low feed spillover. The gain loss, with scanning, of a high-gain shaped reflector pair is demonstrated to be due to both aperture phase error loss and power spillover loss. >

The application of the theory of the synthesis of offset dual-shaped reflectors to the design of compact ranges is examined. The object of the compact range is to provide a uniform plane wave with minimum amplitude and phase ripple over as large a volume as possible for a given size reflector. Ripple can be lowered by reducing the edge diffraction from the reflector producing the plane wave. This has been done either by serrating or rolling the edge. An alternative approach is to use dual offset-shaped reflector synthesis techniques to produce a reflector aperture distribution that is uniform over most of the aperture, but with a Gaussian taper near the edge. This approach can be used together with rolling and/or serration if desirable. The amount of phase and amplitude ripple obtained with two different dual-shaped reflector designs is studied as a function of position in the plane wave zone and reflector size in wavelengths. The amount of both transverse and longitudinal (z-component) cross polarization is studied. >

In an earlier paper by V. Galindo-Israel et al. (see ibid., vol.AP-35, p.887-96, August 1987) the geometrical optics (GO) principles, constraints, and requirements of the dual- and single-offset-shaped reflector synthesis problem were collected and developed into a set of nonlinear first-order partial differential equations (PDEs). Methods of solving these PDEs numerically were illustrated, as were certain problems that may arise. An extension of the methods by which solutions to the PDEs can be obtained is presented, together with several case examples. These examples are independently analyzed by GO and physical optics diffraction methods. The starting point for the integration over each reflector can be taken on the outer rim, at the center, or at an intermediate point-the intermediate starting point being the more general case. The utility of the speed of this synthesis method is demonstrated. This makes practical the incorporation of the synthesis into a search algorithm that can optimize one or more parameters of the reflector system. As an example, the optimization of the mapping equations for low cross polarization is discussed. >

Results are presented of an investigation on improvements in a geometrical optics design of a beam-waveguide antenna for operation at multiple frequency bands. Improvements might be possible by changing the design of the lower-frequency input pattern to the beam waveguide. The effects of amplitude and phase shaping the input pattern have been studied with an aperture diffraction model. Accurate vector near-field computations were made rapidly with a spherical wave expansion of the input and scattered fields. Numerical results indicate that for aperture sizes of less than 30 wavelengths, there is insufficient control on defocusing due to amplitude and phase shaping. Design tradeoffs on spillover loss and defocusing are possible by changing the amplitude and phase distribution of the input wavefront for larger size apertures. >

Poorer than expected surface reflectivity was observed in an early Tracking and Data Relay Satellite System antenna utilizing a tricot mesh weave. This poor reflectivity was determined to be caused by inadequate electrical contact at wire crossover points. A proper mathematical and numerical approach to assess the impact of wire junctions on reflectivity performance is developed. A mathematical method is presented for computing the surface reflectivity of complex mesh configurations like those on unfurlable-type spacecraft antennas. The method is based on the Floquet mode expansion to establish an integral equation for mesh wire currents. The equation is solved using the method of moments with triangular basis functions. It is observed that it is necessary to give special attention to the junction treatment among different branches of the mesh configurations. A vector junction current approach that resulted in satisfactory solutions for the current is described. The results of numerical simulations are compared against measured data and excellent agreement is observed. >

The singular nature of the UTD (uniform geometrical theory of diffraction) subreflector scattered field at the vicinity of the main reflector edge (for a high-grain antenna design) is investigated. It is shown that the singularity in the UTD edge-diffracted and slope-diffracted fields is due to the reflection distance parameter approaching infinity in the transition functions. While the GO (geometrical optics) and UTD edge-diffracted fields exhibit singularities of the same order, the edge slope-diffracted field singularity is more significant and is substantial for greater subreflector edge tapers. The diffraction analysis of such a subreflector in the vicinity of the main reflector edge has been carried out efficiently and accurately by a stationary phase evaluation of the phi -integral, whereas the theta -integral is carried out numerically. Computational results from UTD and PO (physical optics) analysis of a 34-m ground station dual-shaped reflector confirm the analytical formulations for both circularly symmetric and offset asymmetric subreflectors. It is concluded that the proposed PO/sub theta /GO/sub phi / technique can be used to study the spillover or noise temperature characteristics of a high-grain reflector antenna efficiently and accurately. >

Pancreatic carcinoma is a very aggressive disease and little is known about its immunobiology. We here describe the presence in pancreatic cancer patients of spontaneously induced functional CD4 and CD8 memory/effector T cells reactive to autologous tumor cells or to the pancreatic cancer associated antigen, MUC-1. Such specific cells were present in the bone marrow or peripheral blood of most of the 23 tested patients. Low dose stimulation of primary cultures of pancreatic cancer cells with 500 IU/ml IFN-gamma for 72 h enhanced HLA-I expression and induced the de novo expression of HLA-II molecules. This led to a much better immune recognition by autologous HLA-I restricted and purified CD8 T cells and allowed tumor cell recognition by HLA-II restricted purified CD4 T-helper cells. Thus, interferon-gamma appears to be a useful adjuvant cytokine to enhance the immunogenicity of a patients' tumor cells and their recognition by tumor reactive immune cells.