TGF-beta inhibits IL-2-induced tyrosine phosphorylation and activation of Jak-1 and Stat 5 in T lymphocytes

The major yolk protein precursor in mosquito oocytes, vitellogenin (Vg), is internalized by a 205-kDa membrane-bound receptor (VgR). Recently, VgR has been isolated permitting the production of polyclonal anti-VgR antibodies. To elucidate the pathway of VgR internalization and recycling in mosquito oocytes during Vg uptake, we carried out an immunogold electron-microscopic study, labeling both Vg and VgR in ultrathin frozen sections of ovarian tissue. VgR immunolabeling demonstrated that the oocyte plasma membrane was subdivided into microdomains, with VgR being located between and at the lower portions of the oocyte microvilli. During the early stages of internalization, Vg and VgR were observed together in coated pits, coated vesicles, and early endosomes. Fusion of early endosomes created transitional yolk bodies (TYB) in which Vg and VgR became segregated. VgR label was present in the numerous tubular compartments that protruded from the TYBs. These tubular organelles extended to and fused with the plasma membrane, suggesting that they represented the vehicle for VgR recycling. Vg label was not observed in the tubular compartments. Instead, Vg accumulated in the core of the TYB, a region free of VgR label. Mature yolk bodies (MYB) were heavily labeled for Vg, but completely lacked any VgR label, indicating that MYB are storage compartments that do not participate in receptor recycling. Thus, our immunocytochemical data clearly visualize the steps in Vg/VgR internalization, dissociation, sorting, and recycling of the receptor to the plasma membrane.     

Adaptive digital access protocol: a MAC protocol for multiservicebroadband access networks

The authors describe a protocol that can adapt to the changing demands of a mix of synchronous transfer mode (STM) and asynchronous transfer mode (ATM) applications and efficiently allocate bandwidth to a variety of bursty traffic sources. In the case of a hybrid fiber-coaxial (HFC) network, the protocol resides in customer premises equipment (CPE) and a common head-end/central-office (HE/CO) controller. A medium-access control (MAC) processor provides for dividing the time domain for a given digital bitstream into successive frames, each with multiple STM and ATM time slots. Within the STM region of a frame, variable-length time slots are allocated to calls (e.g., telephony, video telephony) requiring different amounts of bandwidth. In the upstream channels, a contention access signaling time slot is also provided in the STM region for call control and setup requests. Within the ATM region, fixed-length time slots accommodate one individual ATM cell. These ATM time slots may be reserved for a user for either the duration of a call or a burst of successive ATM cells, or shared via a contention process. At least one contention time slot is available for signaling messages related to ATM call control and setup requests. The MAC-layer protocol, its relation to circuit- and ATM-amenable applications, and its performance with respect to throughput, latency, and bandwidth efficiency for several service scenarios are examined     

Melt growth of novel organic nonlinear optical material and its characterization

Ethyl P-amino benzoate (EPAB) is also known as benzocaine was recently identified as new organic non linear optical (NLO) material which is having nearly six times higher SHG efficiency than that of KDP. Hence, growth of unidirectional EPAB crystal gains importance for phase matching studies and this is the first melt growth report of EPAB single crystal. Seeding with the microtube in the present technique eliminates the need for pre-grown seed and has more probability to grow bulk single crystal. Growth direction of the μT-Cz grown EPAB single crystals was identified as <100> using X-ray powder diffraction studies. Thermal properties and optical transparency of the grown material were analyzed by TG and DTA and UV-VIS spectroscopic studies respectively. Laser damage threshold study shows nearly five times high damage threshold than KDP.     

Effect of sugars on freeze-thaw and lyophilization of liposomes

Various sugars were investigated for their ability to protect liposomes against fusion and leakage during freeze-and-thaw or lyophilization processes. Size of liposome was measured before and after the events with a light scattering technique. Leakage of the content of the sulfate, was encapsulated in the liposome which was made of egg phosphatidylcholine (EPC)/egg phosphatidylglycerol (EPG)/cholesterol (5:1:2). Addition of 1% lactose to the liposome suspension prevented the fusion between liposome but not the leakage of the content. Freeze-thawing caused more damage to the liposomes than the freeze-drying/reconstitution. After freeze-thawing, one-third of the encapsulated drug leaked out from the liposome. The freeze-drying did not cause additional leakage.     

Electrical resistivity and superconductivity in the chevrel phase compounds of the type Cu1.8Mo6S8—ySey (0 ⩽ y ⩽ 8) and Cu1.8Mo6S8—y Tey, (0 ⩽ y ⩽ 4)

The superconducting transition temperatures and normal state residual electrical resistivities of the ternary Chevrel phase compounds Cu_1.8Mo₆S_8-YSe_y (0 ?y ? 8) and Cu_1.8Mo₆S_8-y Te_y (0 ? y ?4) are reported. The data are examined for possible correlations with structural parameters of the rhombohedral unit call and the residual resistivity values. It is found that T_c decreases as the c/a ratio increases and as the rhombohedral angle approaches 90°. There is also an inverse correlation between T_c and the normal residual resistivity of the samples.     

Prolog representation of reliability networks and evaluation of system reliability

The suitabilities of Prolog to represent reliability networks are discussed in this paper. The capabilities of Prolog are illustrated by relevant examples in various reliability network configurations. The network reliability has been estimated by using the recursive nature of Prolog.     

SIMULATION OF BUBBLE BREAKUP DYNAMICS IN HOMOGENEOUS TURBULENCE

This article presents numerical simulation results for the deformation and breakup of bubbles in homogeneous turbulence under zero gravity conditions. The lattice Boltzmann method was used in the simulations. Homogeneous turbulence was generated by a random stirring force that acted on the fluid in a three-dimensional periodic box. The grid size was sufficiently small that the smallest scales of motion could be simulated for the underlying bubble-free flow. The minimum Weber number for bubble breakup was found to be about 3. Bubble breakup was stochastic, and the average time needed for breakup was much larger for small Weber numbers than for larger Weber numbers. For small Weber numbers, breakup was preceded by a long period of oscillatory behavior during which the largest linear dimension of the bubble gradually increased. For all Weber numbers, breakup was preceded by a sudden increase in the largest linear dimension of the bubble. When the Weber number exceeded the minimum value, the average surface area increased by as much as 80%.     

Evaluation and re-evaluation of genetic radiation hazards in man. III. Other relevant data and risk assessment

Some of the advances in mammalian radiation genetics, human genetics and cytogenetics that were made during the last 2-3 years and that have either a direct bearing on, or that may be potentially useful in, the evaluation of genetic radiation hazards in man have been examined. Among these are (1) the new data on the incidence of genetic diseases in man; (2) the latest results of the study of mortality rates among children born to survivors of the atomic bombings of Hiroshima and Nagasaki; (3) new data on the radiation-induction of reciprocal translocations in human spermatogonia; (4) new results from radiation studies with mice on skeletal mutations, autosomal recessive lethals, sex-chromosome losses, translocation induction and recovery etc., and (5) a re-analysis of the earlier data on dose-rate effects for the induction of specific locus mutations in mouse spermatogonia. Using the pertinent new information as a basis, quantitative estimates are presented employing both a direct method of expressing risks in terms of effects per unit dose of irradiation and the indirect doubling-dose method of expressing these as increments over the load of genetic disorders occurring spontaneously in man.     

Distributed policy processing in active‐service based infrastructures

More and more applications in the Internet are requiring an intelligent service infrastructure to provide customized services. In this paper, we present an infrastructure, which can transparently and effectively provide customized active‐services to end users and dynamically adapt to changing customized policies in large distributed heterogeneous environments. The infrastructure consists of two components: the policy agent and middleware box. Particularly, our technologies include: (1) Generic active‐service based infrastructure, where the policy agent can integrate policies requested by applications, and middleware boxes can transparently execute services and (2) Distributed policy processing in the middleware box. We study two policy partitioning schemes to achieve conflict‐free policies for distributed policy processing and guarantee the correctness of the policy execution. We conduct extensive performance evaluations on different schemes proposed. Our experimental results demonstrate that our policy partitioning schemes can effectively generate partition‐capable and conflict‐free policy sets. The evaluation results also show that distributed policy processing can achieve over 70% increase in performance/price ratio with proper assignment of the policy distribution degree compared to a purely centralized approach. Copyright © 2005 John Wiley & Sons, Ltd.