Modulation of testicular macrophage activity by collagenase

Testicular macrophages (TMs) are located in the interstitial tissue of male gonad. These phagocytic cells take part in forming the organ-specific functional blood-testis barrier and participate in the regulation of the local hormonal balance. In the present study, we isolated TMs from testicular tissues using previously described methods - mechanical (M-TMs) or enzymatic, by treatment with collagenase (E-TMs) and then we studied production by these cells of several cytokines and reactive oxygen intermediates (ROI’s). Similarly treated oil-induced peritoneal macrophages (PMs) were used as control cells. PMs had a higher baseline level of production of TNF-α, IL-6, IL-10 and IL-12 than M-TMs and collagenase treatment increased the production of these cytokines (except IL-12) by both cell populations. This effect was significantly more expressed in TMs. In contrast to PMs, TMs produced little ROI’s when stimulated by zymosan. We conclude that in the case of local inflammation in the testis, ROI-negative TMs do not contribute to the tissue damage and instead may direct the local immune response into humoral pathway

Compact thermal models of semiconductor devices – a review

In the paper the problem of modelling thermal properties of semiconductor devices with the use of compact models is presented. This class of models is defined and their development over the past dozens of years is described. Possibilities of modelling thermal phenomena both in discrete semiconductor devices, monolithic integrated circuits, power modules and selected electronic circuits are presented. The problem of the usefulness range of compact thermal models in the analysis of electronic elements and circuits is discussed on the basis of investigations performed in Gdynia Maritime University

Microstructure Influence of SACX0307-TiO2 Composite Solder Joints on Thermal Properties of Power LED Assemblies

The effect of the microstructure of solder joints on the thermal properties of power LEDs was investigated. Solder joints were prepared with different solder pastes, namely 99Sn0.3Ag0.7Cu (as reference solder) and reinforced 99Sn0.3Ag0.7Cu-TiO2 (composite solder). TiO2 ceramic was used at 1 wt% and with two different primary particle sizes, which were 20nm (nano) and 200nm (submicron). The thermal resistance, the electric thermal resistance, and the luminous efficiency of the power LED assemblies were measured. Furthermore, the microstructure of the different solder joints was analyzed on the basis of cross-sections using scanning electron and optical microscopy. It was found that the addition of submicron TiO2 decreased the thermal and electric thermal resistances of the light sources by 20% and 16%, respectively, and it slightly increased the luminous efficiency. Microstructural evaluations showed that the TiO2 particles were incorporated at the Sn grain boundaries and at the interface of the intermetallic layer and the solder bulk. This caused considerable refinement of the Sn grain structure. The precipitated TiO2 particles at the bottom of the solder joint changed the thermodynamics of Cu6Sn5 formation and enhanced the spalling of intermetallic grain to solder bulk, which resulted in a general decrease in the thickness of the intermetallic layer. These phenomena improved the heat paths in the composite solder joints, and resulted in better thermal and electrical properties of power LED assemblies. However, the TiO2 nanoparticles could also cause considerable local IMC growth, which could inhibit thermal and electrical improvements

Orally administered exosomes suppress mouse delayed-type hypersensitivity by delivering miRNA-150 to antigen-primed macrophage APC targeted by exosome-surface anti-peptide antibody light chains

We previously discovered suppressor T cell-derived, antigen (Ag)-specific exosomes inhibiting mouse hapten-induced contact sensitivity effector T cells by targeting antigen-presenting cells (APCs). These suppressive exosomes acted Ag-specifically due to a coating of antibody free light chains (FLC) from Ag-activated B1a cells. Current studies are aimed at determining if similar immune tolerance could be induced in cutaneous delayed-type hypersensitivity (DTH) to the protein Ag (ovalbumin, OVA). Intravenous administration of a high dose of OVA-coupled, syngeneic erythrocytes similarly induced CD3+CD8+ suppressor T cells producing suppressive, miRNA-150-carrying exosomes, also coated with B1a cell-derived, OVA-specific FLC. Simultaneously, OVA-immunized B1a cells produced an exosome subpopulation, originally coated with Ag-specific FLC, that could be rendered suppressive by in vitro association with miRNA-150. Importantly, miRNA-150-carrying exosomes from both suppressor T cells and B1a cells efficiently induced prolonged DTH suppression after single systemic administration into actively immunized mice, with the strongest effect observed after oral treatment. Current studies also showed that OVA-specific FLC on suppressive exosomes bind OVA peptides suggesting that exosome-coating FLC target APCs by binding to peptide-Ag-major histocompatibility complexes. This renders APCs capable of inhibiting DTH effector T cells. Thus, our studies describe a novel immune tolerance mechanism mediated by FLC-coated, Ag-specific, miRNA-150-carrying exosomes that act on the APC and are particularly effective after oral administration

The influence of SACX0307-ZnO nano-composite solder alloys on the optical and thermal properties of power LEDs

Purpose This paper aims to present the results of investigations that show the influence of ZnO composite soldering paste on the optical and thermal parameters of power LEDs. Design/methodology/approach ZnO nano-composite solder alloys were produced via the ball milling process from the solder paste SACX0307 (Sn99Ag0.3Cu0.7) and 1.0 wt.% of ZnO nanoparticle reinforcements with different primary particle sizes (200 nm, 100 nm, and 50 nm). Power LEDs were soldered onto a metal core printed circuit board (MCPCB). A self-designed LED test system was used to measure the thermal and optical characteristics of the LEDs. Findings The influence of the soldering paste on the thermal and optical parameters of LEDs was observed. In all solder alloys, ZnO ceramic reinforcement increased the thermal parameters of LEDs and decreases their luminous efficiency. Thermal resistance values were10% higher, and junction temperature change over ambient temperature was 20% higher for the samples soldered with composite solder pastes, as compared to the reference sample. At the same time, luminous efficiency dropped by 32%. Originality/value The results prove that ZnO ceramic reinforcement of solder paste influences the thermal properties of solder joints. As it was proven, the quality of the solder joints influences the whole assembly