A 75-81 GHz, 14.3 dBm Peak Output Power, 21 dB Peak Gain, SiGe Power-Combining Amplifier Operating from a Single 3.3 V Supply

A compact differential 4-way power combiner with 2.3 dB loss and high common-mode rejection characteristic for use in mm-wave PAs is presented. A complete circuit comprised of a power splitter, two-stage cascode PA array, and a power combiner was implemented in SiGe technology. Measured small-signal gain of at least 17 dB was obtained from 74.5 GHz to 80.5 GHz with a peak 21 dB at 79 GHz. The prototype delivered 13.2 dBm P1dB and 14.3 dBm Psat when operated from a single 3.3 V supply at 75 GHz.

Dental erosion among 12-14 year old school children in Khartoum:A pilot study

Objectives: To investigate dental erosion among 12-14 year old Sudanese school children and evaluate the associated risk factors. Basic Research Design: Cross sectional survey in secondary schools in Khartoum city, Sudan. Method and Participants: A sample of 157 school children was obtained from both private and public schools. Erosion on the labial and palatal surfaces of maxillary incisors was measured by criterion based on the Smith and Knight Tooth Wear Index. Dietary intake and other related factors were assessed using a questionnaire. Results: The overall erosion prevalence in this group was 66.9%, of which 45.2% was mild and 21.7% was moderate erosion. A strong association was found between erosion and private schooling (higher socioeconomic groups), carbonated drinks, herbal hibiscus drink and traditional acidic food consumption. Conclusion: There was a high prevalence of dental erosion among Sudanese school children which was mild to moderate in severity and was strongly associated with acidic dietary intake © BASCD 2007.

Constitutive expression of human keratin 14 gene in mouse lung induces premalignant lesions and squamous differentiation

Squamous cell carcinoma accounts for 20% of all human lung cancers and is strongly linked to cigarette smoking. It develops through premalignant changes that are characterized by high levels of keratin 14 (K14) expression in the airway epithelium and evolve through basal cell hyperplasia, squamous metaplasia and dysplasia to carcinoma in situ and invasive carcinoma. In order to explore the impact of K14 in the pulmonary epithelium that normally lacks both squamous differentiation and K14 expression, human keratin 14 gene hK14 was constitutively expressed in mouse airway progenitor cells using a mouse Clara cell specific 10 kDa protein (CC10) promoter. While the lungs of CC10-hK14 transgenic mice developed normally, we detected increased expression of K14 and the molecular markers of squamous differentiation program such as involucrin, loricrin, small proline-rich protein 1A, transglutaminase 1 and cholesterol sulfotransferase 2B1. In contrast, wild-type lungs were negative. Aging CC10-hK14 mice revealed multifocal airway cell hyperplasia, occasional squamous metaplasia and their lung tumors displayed evidence for multidirectional differentiation. We conclude that constitutive expression of hK14 initiates squamous differentiation program in the mouse lung, but fails to promote squamous maturation. Our study provides a novel model for assessing the mechanisms of premalignant lesions in vivo by modifying differentiation and proliferation of airway progenitor cells. © The Author 2008. Published by Oxford University Press. All rights reserved.

Association between the 5q31.1 gene neurogenin1 and schizophrenia

Multiple lines of evidence suggest that schizophrenia results from aberrant neurodevelopment. The neurogenin1 gene (neurog1) consists of a single 1,666 bp exon that encodes a basic helix-loop-helix (bHLH) transcription factor that causes neuronal differentiation and induces cortical and glutamatergic differentiation programs. Because of its function and its location in 5q31.1, which has been linked to schizophrenia in multiple samples, we tested it for association with the disorder. We sequenced neurog1 in 25 affected subjects from the Irish Study of High-Density Schizophrenia Families. We observed a 5'-UTR SNP at position -60, already present in databases as rs8192558, and tested it along with rs2344485, rs8192559, and rs2344484. Narrow, intermediate, and broad diagnostic definitions were used. The major alleles of rs8192558 and rs2344484 were over-transmitted to affected subjects using both Pedigree Disequilibrium Test (PDT) (0.01 <or = P <or = 0.06) and FBAT (0.02 <or = P <or = 0.07). A haplotype consisting of the major alleles of all four SNPs was significantly over-transmitted in FBAT to the broad definition (P = 0.049), with trend significance to the narrow and intermediate definitions, and with trend significance in PDT. In confirmatory tests using 657 cases and 411 controls, this haplotype was slightly but not significantly over-represented in cases (81% vs. 77%, P = 0.21). These results, along with a priori evidence for the involvement of neurog1 in neurodevelopment, suggest that variants in neurog1 might have a small effect on susceptibility to schizophrenia. This gene should be tested in additional and larger samples.

238.2T-14 Concrete Thixotropy

Fresh concrete can exhibit different rheological behavior when at rest than when flowing. This difference is due to thixotropy, which can have important consequences for formwork pressure, multi-lift casting, slip-form paving, pumping, and segregation resistance. This TechNote defines thixotropy and distinguishes it from other changes in rheological properties; discusses the origins of, test methods for measuring, and factors affecting thixotropy; and concludes with its applications.