Design of wavelength-flattened coupler using a novel diagram

A novel diagram which describes the condition of 3 dB coupler is proposed. Using the proposed diagram, the design of a wavelength-flattened 3 dB directional coupler composed of a uniform coupled waveguide is investigated. Normalized waveguide parameters are introduced to characterize a five-layer planar waveguide. This enables us to generalize the discussion and to reduce the number of parameters required for characterizing a coupled waveguide. A broadband 3 dB coupler having 50±5% coupling ratio over a wavelength range of 1.1-1.7 μm is designed     

Electrolytic Metallic Coatings for Carbon Fibers

This paper concerns electrolytic metallic coatings for carbon fibers and the related processes. Plating bath design, electrolyte selection and other aspects were investigated. Experimental results especially in copper electroplating show that the uniformity of metallic coatings on carbon fibers can be improved by the modification of plating bath and the selection of electrolytes. Thus continuous and uniform metallic coatings can be obtained on carbon fibers, even if the cross section of carbon fibers has irregular shape. Polarization tests on different copper baths was performed. Electrodeposition of other metallic layers such as nickel, cobalt, and copper/tin duplex layer was also introduced. A process of two or more than two plating steps in which different electrolytes may be used for same metal deposition was proposed to expedite the coating procedure     

Computational study of transport processes in a single-screw extruder for non-newtonian chemically reactive materials

A numerical study of the transport phenomena arising in a single-screw extruder channel is carried out. A non-Newtonian fluid is considered, using a power law model for the variable viscosity. Chemical reaction kinetics are also included. Finite difference computations are carried out to solve the governing set of partial differential equations for the velocity, temperature and species concentration fields, over a wide range of governing parameters for the case of a tapered screw channel. The numerical treatment for this combined heat and mass transfer problem is outlined. A marching procedure in the down-channel direction is adopted and the validity of the scheme for practical problems discussed. For large viscous dissipation, the material heats up considerably due to the prevailing shear field, affecting the viscosity significantly, and results in large changes in the pressure development at the end of the channel. The rate of reaction controls the mass diffusion rate which in turn affects viscosity and the flow significantly. The dimensionless throughput,q _v , is one of the most important parameters in the numerical solution. The dimensionless pressure variation is very sensitive toq _v , and orders of magnitude changes are possible for small variations inq _v . Schemes for dealing with other important effects such as back flow, heat transfer by conduction in the barrel, and the effect of the die are also outlined. A list of symbols is given at the end of the paper This is publication No. F-10544-4-91 of the New Jersey Agricultural Experiment Station supported by State Funds and the Center for Advanced Food Technology (CAFT). The Center for Advanced Food Technology is a New Jersey Commission on Science and Technology Center. This work was also supported in part by the US Army Research Office.     

Adenophostin, a potent agonist of the inositol 1,4,5-trisphosphate receptor, is useful for fertilization of mouse oocytes injected with round spermatids leading to normal offspring

Relaxin plays a major role in promoting the growth and softening of the cervix that occurs during the second half of pregnancy in the rat. There is limited evidence that prostaglandins play a role in cervical softening in mammalian species. Accordingly, this study was conducted to determine if prostaglandins mediate relaxin's effects on the rat cervix. To attain that objective, indomethacin was used to inhibit cyclooxygenase, the key enzyme in the conversion of arachidonic acid to prostaglandins. Twenty-six nonpregnant female rats were ovariectomized when they were 78 days old (day 1 of treatment). At ovariectomy (O), each rat was fitted with silicon tubing implants containing progesterone (P) and estrogen (E) in doses that provided blood levels similar to those during late pregnancy in rats. Rats were randomly assigned to three treatment groups. Group OPE controls (n = 8 rats) received 2 ml indomethacin vehicle (0.5% methyl cellulose, 0.025 Tween 80 in water) via gavage at 0900 h on days 8 and 9 and 0.5 ml relaxin vehicle (0.9% NaCl) s.c. at 6-h intervals from 1200 h on day 8 through 0600 h on day 10. Group OPER (n = 9 rats) was treated as group OPE except that 20 microg highly purified porcine relaxin was administered. Group OPERI (n = 9 rats) was treated as group OPER except that indomethacin was administered at a dose (20 mg/kg BW) that reduced cervical PGE2 levels by more than 90%. Between 0800 h and 1000 h on day 10, the cervices were removed, trimmed of fat, weighed, and placed in ice-cold Krebs-Ringer bicarbonate buffer, pH 7.5. Cervical extensibility (degree of softening) was determined within 4 h of tissue collection. Both the mean cervical wet weight and the mean cervical extensibility in the relaxin-treated group OPER rats were markedly greater (P < 0.01) than in the group OPE controls. Treatment with indomethacin did not diminish relaxin's effects on either cervical wet weight or cervical extensibility. In conclusion, this study provides evidence that relaxin's effects on cervical growth and softening in the rat are not mediated through prostaglandins.     

Activation of thymic B cells by signals of CD40 molecules plus interleukin-10

We have previously found that thymic B cells, particularly thymic CD5+ B cells, show low responsiveness to the usual B cell stimulants such as lipopolysaccharide or anti-IgM plus interleukin (IL)-4, although they proliferate and produce antibodies after direct interaction with major histocompatibility complex class II-restricted T blasts. These findings raise the possibility that a CD40-CD40 ligand (L) interaction is involved in the activation of thymic B cells. In the present study, we therefore examine this possibility using CD40L-transfected Chinese hamster ovary (CHO) cells or anti-CD40 monoclonal antibody (mAb). When B cells in the spleen and peritoneal cavity were stimulated, they proliferated and produced immunoglobulin (Ig) in the presence of CD40L-CHO cells or anti-CD40 mAb alone. However, another signal delivered by IL-10 in addition to CD40L-CHO cells or anti-CD40 mAb was found to be necessary for thymic B cells to proliferate and secrete Ig. Other interleukins acting on B cells, such as IL-4, IL-5, and IL-6, had no effect on the activation of thymic B cells, which thus have unique characteristics not found in peripheral B cells. This report discusses the physiological significance of IL-10- and CD40-driven signals in the activation of thymic B cells.     

Embryonal metabolism

It is very difficult to have a clear and homogeneous idea of the embryo metabolism. In fact it may vary from one species to another and also according to the embryonic stage: i.e. before and after genomic activation. Basic compounds such as glucose may be toxic, but obviously, it is more the problem of the quantity introduced in the culture media and an unsuitable balance between the metabolites which may impair the embryonic development. At low concentration glucose is actively metabolised by embryos. High levels of amino acids are deleterious (due to release of ammonia), but they are necessary at low concentrations. Addition of serum or other biological fluids is generally useless. Further knowledge on embryo metabolism is necessary to avoid culture medium related delay or developmental blocks. Sequential media are at least partly the answer.     

Ectopic accumulation of 99mTc-HMDP in primary lung cancer in comparison with CT findings

Hypertension attributable to pheochromocytoma is a very attractive model for the elucidation of the pathogenesis of hypertension. Sixteen different point mutations in the RET proto-oncogene and 30 mutations in the Von Hippel-Lindau (VHL) tumor suppressor gene have been identified so far associated with expression of pheochromocytoma. Each of these mutations initiates either the syndrome of multiple endocrine neoplasia type 2 (MEN 2) (MEN 2A and MEN 2B) or the VHL disease. Certain mutations in both genes are associated with the presence of pheochromocytoma. In general, these pheochromocytomas produce catecholamines that result in hypertension. Therefore, analysis for germline mutations in these genes are of practical value, because susceptibility to these diseases can be predicted in as yet clinically unaffected relatives.     

Experimental studies of high frequency jet ventilation improved by enhancing expiratory turbulence

A 43-year-old male and a 39-year-old male presented with multiple pituitary adenomas with two distinct histological types. The first patient who had multiple endocrine neoplasia type 1 had developed acromegaly due to a growth hormone-releasing hormone (GHRH)-producing pancreatic tumor. Both plasma GHRH and growth hormone (GH) levels decreased to normal after resection of the pancreatic tumor. However, the plasma GH level gradually increased again and magnetic resonance imaging revealed pituitary adenoma formation. Histological examination revealed two different histological types of pituitary adenoma: GH cell adenoma and null cell adenoma. The second patient, with no such genetic condition, had a non-functioning pituitary adenoma. Histological examination revealed two different histological types of silent GH cell adenoma and silent gonadotroph adenoma. Careful histological examination is required to exclude the possibility of multiple pituitary adenomas.     

A 20 GHz 8 bit multiplexer IC implemented with 0.5 μm WNx/W-gate GaAs MESFET's

An ultrahigh-speed 8 bit multiplexer (MUX) has been developed for future-generation optical-fiber communication systems having a data rate of 20 Gb/s. This IC was fabricated using a 0.5 μm WN_x/W-gate GaAs MESFET process based on optical lithography, ion implantation, and furnace annealing for good reproducibility and high throughput. The WN_x/W bilayer gate has a low sheet resistance, improving the circuit high frequency performance. To attain 20 GHz operation, advanced circuit techniques for the source-coupled FET logic (SCFL) were introduced. A cross coupled source-follower (CCSF) was developed mainly for the highest speed buffers to enhance the bandwidth. The first-stage T-type flip-flop was designed with optimization techniques and operated up to 21.1 GHz