A novel self-oscillating HEMT-HBT cascode VCO-mixer using an activetunable inductor

Here we describe a unique Ka-band self-oscillating HEMT-HBT cascode mixer design which integrates an active tunable resonator circuit. The VCO-mixer MMIC integrates GaAs HEMT's and HBT's using selective molecular beam epitaxy (MBE) technology. The HEMT-HBT cascode active mixer operates similarly to a dual-gate mixer. The HBT of the cascode is used to construct a VCO by presenting the base with an HEMT tunable active inductor. The VCO can be tuned from 28.5 to 29.3 GHz while providing ≈0 dBm of output power. Operated as an upconverter, the MMIC achieves 6-9 dB conversion loss over a 31-39 GHz output frequency band. Using these active approaches, both VCO and mixer functions were integrated into a compact 1.44×0.76 mm² chip area. The active RF integrated circuit (IC) techniques presented here have direct implications to future high complexity millimeter-wave monolithic integrated circuits (MIMICs) for ultrahigh-speed clock recovery and digital radio applications     

Extreme variation in X-linked agammaglobulinemia phenotype in a three-generation family

BACKGROUND: X-linked agammaglobulinemia is typically a severe life-threatening disease characterized by the failure of B-cell differentiation and antibody production, which manifests in infancy and early childhood. Recently, we reported a novel mutation (Cys145-->STOP) in Bruton's tyrosine kinase in a 51-year-old man who was referred for evaluation because of chronic nasal congestion, recurrent sinusitis, sporadic pneumonia, and a family history suggestive of an X-linked immunodeficiency disease. He had not been treated with gammaglobulin. OBJECTIVE: This study was performed to investigate the clinical and immunologic phenotypes of this patient's other affected male family members. METHODS: A detailed family history and comprehensive review of medical records was carried out. Genetic mutation analysis of the gene encoding Bruton's tyrosine kinase was carried out in the proband's brother and nephew. RESULTS: Clinically affected male family members exhibit marked phenotypic variation with manifestations ranging from extremely mild to severe recurrent infections. Immunologic evaluation revealed extreme variation in immunoglobulin levels, B-cell numbers, and functional antibody titers. Genetic analysis documented a novel mutation in the gene encoding Bruton's tyrosine kinase in the proband, his brother, and his nephew. CONCLUSIONS: Despite their sharing the same genetic abnormality, extreme variation was noted in the immunologic findings and phenotypic expression of affected family members. This family study is extraordinary in that clinically affected male members who did not receive aggressive medical treatment died of the disease in childhood or survived into late adulthood.     

The efficacy of epinephrine test doses during spinal anesthesia in volunteers: implications for combined spinal-epidural anesthesia

Epinephrine test doses may be administered during combined spinal-epidural anesthesia to determine intravascular placement of epidural catheters. This study was designed to determine systolic blood pressure (SBP) and heart rate (HR) responses to intravenous injection of epinephrine (15 microg) during spinal anesthesia. Twelve volunteers received three spinal anesthetics (lidocaine 100 mg, tetracaine 15 mg, and bupivacaine 15 mg) in a randomized, double blind, cross-over fashion. Epinephrine was administered prior to spinal anesthesia (control), 30 min after injection of spinal anesthesia, and at regression of sensory block to T-10. SBP was measured with a radial arterial catheter and HR with an electrocardiogram. Positive responses were defined as peak increase in SBP > or = 15 mm Hg or HR > or = 20 bpm after injection of epinephrine. Compared with control, peak SBP responses decreased by a mean of 12 mm Hg during spinal anesthesia with tetracaine and bupivacaine (P < 0.05). Peak HR responses decreased by 11 bpm during all three spinal anesthetics (P < 0.05). Incidences of detection of intravenous injection by positive SBP and HR responses ranged from 50% to 100% and were not significantly affected by spinal anesthesia. Spinal anesthesia reduces hemodynamic responses to intravenous epinephrine injection but is unlikely to reduce detection by positive SBP and HR criteria.     

Patterns of fetal perinasal fluid flow in cases of congenital diaphragmatic hernia

OBJECTIVE(S): Our purpose was to expand the previous reported series of observations of fetal perinasal fluid flow in cases of antenatally diagnosed congenital diaphragmatic hernia, characterize the timing parameters of the fetal breath cycle, and define the relationship of fetal perinasal fluid flow and the diaphragmatic component of fetal breathing movements. Our hypothesis was that characteristics of diaphragm-related and nondiaphragm-related perinasal fluid flow and other breath cycle characteristics differ in cases of congenital diaphragmatic hernia compared with controls. STUDY DESIGN: Fetal perinasal fluid flow velocity and fetal chest wall movements were studied in 24 cases of uncomplicated pregnancy, and flow was studied in 24 cases of antenatally diagnosed congenital diaphragmatic hernia at gestational ages ranging from 30 to 41 weeks. The examination of fetal perinasal fluid flow velocity was performed with use of an ultrasonography system applying color flow and spectral Doppler analysis. Breath-to-breath interval, time of inspiration, time of expiration, and peak inspiratory and expiratory velocities were determined for each type of perinasal flow. RESULTS: The study revealed that the time of expiration in cases of congenital diaphragmatic hernia at 30 to 36 and 37 to 41 weeks of gestation was significantly shorter than in cases of uncomplicated pregnancy. The ratio of time of inspiration and breath-to-breath interval in cases of diaphragmatic hernia was approximately 30% higher (p = 0.001) at 30 to 36 weeks of gestation than in cases of uncomplicated pregnancy. The study also showed that in cases of congenital diaphragmatic hernia the expiratory peak velocity ratio at 30 to 36 weeks of gestation was significantly lower than in cases of uncomplicated pregnancy. CONCLUSIONS: We conclude that by Doppler ultrasonography measurements of fetal perinasal fluid flow, in cases of congenital diaphragmatic hernia, we can evaluate the timing parameters of fetal diaphragm-related breath cycles, the relationship of intraalveolar and intraamniotic pressures, and fetal upper respiratory tract resistance. Fetuses with diaphragmatic hernia spent significantly more time with diaphragm-nonrelated perinasal flow than did fetuses in cases of uncomplicated pregnancy, which can cause the increased loss of lung liquid and consequently be associated with pulmonary insufficiency in the early neonatal period.     

The water channel gene in human uterus

The cDNA coding the water channel was isolated from a human uterus cDNA library template by a one-step polymerase chain reaction (PCR). The oligonucleotide primers corresponding to the 5' untranslated nucleotide sequence and complementary to the 3' untranslated nucleotide sequence of the cDNA coding the 28 kDa erythrocyte integral membrane protein (CHIP28) were synthesized and used to initiate the reaction. A 1340 bp cDNA coding the human uterine water channel (hUWC) was cloned and sequenced. The hUWC showed 99.8% and 99% identity with the nucleotide and amino-acid sequences of CHIP28, respectively. The deduced hUWC polypeptide is composed of 269 amino acid residues with a single amino acid variant from CHIP28 protein at position 45, where valine replaces alanine. The hUWC cDNA translated in a prokaryotic protein expression system produced a protein with an estimated Mr of 28 kDa, equivalent to the size of the human red cell CHIP28 protein. The present results suggest that the human uterus contains water channels that may play an important role in regulating water transport and imbibition in the uterus.     

Identification of protein A-binding components in Spisula oocytes

Components involved in sustaining meiosis arrest of oocytes were determined. Proteins that bind to protein A from meiosis-arrested and 5-HT-matured Spisula oocytes were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. Meiosis-arrested oocytes contained three doublets of proteins with estimated Mrs of 43 and 45, 38 and 40, and 21 and 23 kDa. In 5 HT-matured oocytes the 21 and 23 and 38 and 40 kDa proteins were retained; whereas the 43 and 45 kDa proteins were absent. The protein A-bound proteins did not interact with antibodies against the various subclasses of human, mouse, rat and rabbit IgG or human Fc fragment. The amino acid sequence of the N-terminus of the 43 kDa protein was determined to be NH2-VLRIGSGMXDT. Comparison of this sequence with existing database at Protein Identification Resource (R 32.0), GenBank (R 72.0), SWISS-PROT (R 22.0), and EMBL (R 31.0) showed no homology with any reported protein. The protein A-bound components from meiosis-arrested oocytes were incubated in vitro with [gamma-32P]ATP. Only the 68 kDa protein was radiophosphorylated. This protein was not detected in 5-HT-matured oocytes. The disappearance of the 43, 45, and 68 kDa proteins in 5-HT-matured oocytes suggests that these components may be involved in sustaining meiosis meiosis. A unique property of these proteins is that they interact with protein A and are distinctly different from immunoglobulin.     

Der Eisen-Dampf-Prozeß zur Wasserstofferzeugung

Verwendung und Gewinnung von Wasserstoff. Angaben zur periodischen Wasserstofferzeugung und Verfahrensvorschläge zur kontinuierlichen Wasserstoffproduktion nach dem Eisen-Dampf-Prozeß. Vergleich der Wasserstoffgewinnung auf Kohlebasis nach dem Eisen-Dampf-Prozeß und dem Wassergasprozeß.