Comb-shaped circularly polarised dielectric resonator antenna

A new shaped circularly polarised dielectric resonator antenna is proposed. This antenna, compared to some previous investigations, is easier to implement, free from a complicated feed network and offers wider axial ratio bandwidth. About 4% AR bandwidth (<3 dB) with S/sub 11/<-10 dB and 3.5 dBi peak gain is reported.     

Electrical and Optical Characterization of Melt-Grown Bulk InAs<Subscript>1−<Emphasis Type="Italic">y</Emphasis></Subscript>P<Subscript><Emphasis Type="Italic">y</Emphasis></Subscript> Crystals

Bulk ternary InAs_1−y P _y polycrystals with diameters up to 50 mm were grown from a pseudobinary InP-InAs melt using the vertical Bridgman technique. Electrical and optical properties were investigated as functions of alloy composition and sample temperature. As-grown undoped crystals have been found to exhibit n-type conductivity irrespective of alloy composition. Though the bulk InAs_1−y P _y substrates show high optical transmission out to long wavelengths as well as high carrier mobility, they exhibit random compositional fluctuations across the substrate area.     

Increased expression of a hemimethylated oriC binding protein, SeqA, in an aphA mutant

In Escherichia coli, the origin of DNA replication, oriC, becomes transiently hemimethylated at the GATC sequences immediately after initiation of replication and this hemimethylated state is prolonged because of its sequestration by a fraction of outer membrane. This sequestration is dependent on a hemimethylated oriC binding protein such as SeqA. We previously isolated a clone of phage lambda gt11 called hobH, producing a LacZ fusion protein which recognizes hemimethylated oriC DNA. Very recently, Thaller et al. (FEMS Microbiol. Lett. 146 (1997) 191-198) found that the same DNA segment encodes a non-specific acid phosphatase, and named the gene aphA. We show here that the interruption of the aphA reading frame by kanamycin resistance gene insertion, abolishes acid phosphatase (NAP) activity. Interestingly, in the membrane of the null mutant, the amount of SeqA protein is about six times higher than that in the parental strain, suggesting the existence of a regulatory mechanism between SeqA and NAP expression.     

Industrial fires and explosions due to electrostatic ignition

Static electricity is a frequent source of fires and explosions in industry. A variety of operations may generate static electricity leading to such fires and explosions. This requires adequate preventive and protective measures against this hazard. The present paper describes the theory and mechanism of electrostatic sparking, parameters needed to assess the respective hazard in a plant, safety measures to combat electrostatic problems, common operations where such problems exist and measures to eliminate or mitigate these problems.     

Thin film silicon solar cells grown near the edge of amorphous to microcrystalline transition

Thin films of silicon can be grown by glow-discharge decomposition of silane and hydrogen. As the hydrogen dilution increases, a transition from amorphous to microcrystalline phase takes place. The regime below and above this edge has been found to be most suitable for making high efficiency amorphous and microcrystalline solar cells. In this paper I outline the status of material research, cell performance and manufacturing of thin film silicon grown near the edge of amorphous to microcrystalline transition.     

Modification of CAPP systems for CAPP/scheduling integration

This paper presents a new approach - through the modification of an existing CAPP system, i.e. CMPP, - for achieving CAPP/scheduling integration. An operation-machine index is developed as a relative measure for selecting the best machine from all the alternates in the process planning stage to satisfy two scheduling criteria: mean flow time and number of jobs tardy.     

Signal transduction pathways and their relevance in human astrocytomas

Aberrations in a number of signal transduction pathways have been identified as playing a key role in the molecular pathogenesis of astrocytomas and their progression to high grade glioblastoma multiforme (GBM). GBMs are characterized by overexpression of the Platelet Derived Growth Factor Receptors (PDGFR) and their ligands (PDGF), as well as the Epidermal Growth Factor Receptor (EGF-R). These receptors activate the Ras pathway, a key cellular signal transduction pathway, culminating in the activation of a wide range of Ras-dependent cellular events. GBMs have also been found to either overexpression or lose expression of various Protein Kinase C (PKC) isoforms. Major strides are being made in developing pharmacological agents which specifically inhibit these growth factor receptors and intracellular signal transduction pathways. Elucidating the role of these pathways in GBMs is thus of major clinical importance, as these novel molecularly-targeted agents may prove of use in the clinical management of GBMs in the future.     

Some characteristics of ridge-trough waveguide

A single-ridged waveguide with a symmetrical longitudinal trough below the ridge, designated as a ridge-trough waveguide (RTW) has been recently proposed as a wafer probe. The authors have theoretically calculated the cutoff, bandwidth, and impedance characteristics of this modified single-ridged waveguide in two different configurations using the Ritz-Galerkin technique and different domain decompositions. The results indicate that a RTW can be a low impedance broad-band structure     

Autonomous thyroid adenoma, papillary thyroid carcinoma, and ectopic parathyroid adenoma in a patient with primary hyperparathyroidism and a nontoxic multinodular goiter

OBJECTIVE: To discuss the method for nipple-areola preserved mastectomy with one-stage breast reconstruction in cancer surgery. METHODS: Because of the merits of sufficient blood supply and plasticity of rectus abdominis musculocutaneous flap, we used one-stage breast reconstruction after modified radical mastectomy. The incision line was covered and the nipple-areola was preserved. The reconstructed breast was naturally in contour. RESULTS: 21 cases were treated from 1990 to 1995, and 18 of them received horizontal-rhombus shaped rectus abdominis musculocutaneous flaps and 3 longitudinal-rhombus flaps for breast reconstruction. Nipple-areola was preserved in 16 cases. Objective evaluation after operation showed that the excellent and satisfied rate reached to 90.5%; and subjective evaluation showed that the excellent and satisfied rate reached to 95.2%. Thirteen cases have been followed up for 3 years, and 9 for 5 years. Three-year survival rate was 100% (13/13), and 5-year 88.9% (8/9). CONCLUSION: The method is recommendable for the treatment of stage I-II breast cancer.     

Environmentally Inert Nano-Crystalline Materials

A novel process to generate environmentally-inert nano-crystalline materials is discussed here. In this process, nano-crystals of different metals such as Ni, Cu, Al, Ti etc. can be produced in a single processing step with each crystal protected by several carbon ((graphite) layers. The technology is an adaptation of the arc technique utilized to produce carbon nano-crystals (Fullerenes) and can be controlled to produce nano-crystals with a variety of coatings including graphite. These nano-crystals are in the 10-50 nm diameter range (typically 30 nm) and of uniform size distribution. These nano-crystals were chemically stable in air and inert to various acids. Further, initial (unoptimized) experiments demonstrated the feasibility of consolidating these coated nano-particles using conventional processing approaches. Novel applications of these nano-crystals such as in the magnetic recording industry are also discussed here.