Size-resolved particulate matter inside selected fire stations and preliminary evaluation of the effectiveness of washing machines in reducing its concentrations.

The study aimed to determine and compare the mass concentration and size distribution of particulate matter (PM) at two Polish fire stations, one equipped with a washing machine intended for the decontamination of uniforms (FSN) and the other not equipped with this type of device (FSC), to assess the effectiveness of washing machines in reducing PM concentrations inside fire stations and estimate PM doses inhaled by firefighters while performing activities in truck bays and changing rooms during one work shift. The average PM concentrations at the FSN were 18.2-28.

Bidirectional light-emitting diode as a visible light source driven by alternating current.

Gallium nitride-based light-emitting diodes have revolutionized the lighting market by becoming the most energy-efficient light sources. However, the power grid, in example electricity delivery system, is built based on alternating current, which raises problems for directly driving light emitting diodes that require direct current to operate effectively. In this paper, we demonstrate a proof-of-concept device that addresses this fundamental issue - a gallium nitride-based bidirectional light-emitting diode.

Role of Metallic Adlayer in Limiting Ge Incorporation into GaN.

Atomically thin metal adlayers are used as surfactants in semiconductor crystal growth. The role of the adlayer in the incorporation of dopants in GaN is completely unexplored, probably because n-type doping of GaN with Si is relatively straightforward and can be scaled up with available Si atomic flux in a wide range of dopant concentrations. However, a surprisingly different behavior of the Ge dopant is observed, and the presence of atomically thin gallium or an indium layer dramatically affects Ge incorporation, hindering the fabrication of GaN:Ge structures with abrupt doping profiles.

Mitigating Ammonia and Greenhouse Gaseous Emission From Arable Land by Co-application of Zeolite and Biochar.

The intensive use of chemical fertilizers in arable farming dramatically increased environmental pollution through anthropogenic ammonia (NH) and greenhouse gaseous emissions. Therefore, there is a need to develop improved fertilizer management practices that can reduce these losses. An experiment was conducted to assess the mitigating effects of sole or combined application of zeolite with biochar on gaseous emissions from arable land.

Electrically pumped blue laser diodes with nanoporous bottom cladding.

We demonstrate electrically pumped III-nitride edge-emitting laser diodes (LDs) with nanoporous bottom cladding grown by plasma-assisted molecular beam epitaxy on c-plane (0001) GaN. After the epitaxy of the LD structure, highly doped 350 nm thick GaN:Si cladding layer with Si concentration of 6·10 cm was electrochemically etched to obtain porosity of 15 ± 3% with pore size of 20 ± 9 nm. The devices with nanoporous bottom cladding are compared to the reference structures.

Dependence of InGaN Quantum Well Thickness on the Nature of Optical Transitions in LEDs.

The design of the active region is one of the most crucial problems to address in light emitting devices (LEDs) based on III-nitride, due to the spatial separation of carriers by the built-in polarization. Here, we studied radiative transitions in InGaN-based LEDs with various quantum well (QW) thicknesses-2.6, 6.

Revealing inhomogeneous Si incorporation into GaN at the nanometer scale by electrochemical etching.

Typical methods of doping quantification are based on spectroscopy or conductivity measurements. The spatial dopant distribution assessment with nanometer-scale precision is limited usually to one or two dimensions. Here we demonstrate an approach to detect three-dimensional dopant homogeneity in GaN:Si layers using electrochemical etching (ECE).

Stack of two III-nitride laser diodes interconnected by a tunnel junction.

We demonstrate a stack of two III-nitride laser diodes (LDs) interconnected by a tunnel junction grown by plasma-assisted molecular beam epitaxy. Hydrogen-free growth is used to obtain as-grown p-type conductivity essential for buried tunnel junctions (TJ). We show the impact of the design of tunnel junction.

Analysis of CD44-hyaluronan interactions in an artificial membrane system: insights into the distinct binding properties of high and low molecular weight hyaluronan.

CD44 is a major cell surface receptor for the large polydisperse glycosaminoglycan hyaluronan (HA). Binding of the long and flexible HA chains is thought to be stabilized by the multivalent nature of the sugar molecule. In addition, high and low molecular weight forms of HA provoke distinct proinflammatory and anti-inflammatory effects upon binding to CD44 and can deliver either proliferative or antiproliferative signals in appropriate cell types.

On the adsorption behavior of biotin-binding proteins on gold and silica.

Streptavidin (SAv), avidin (Av), and neutravidin (NAv) have become widely used molecular tools in biotechnology thanks to their remarkable affinity for biotin. Their tetravalency renders these molecules particularly interesting for the functionalization of solid-liquid interfaces. Using the quartz crystal microbalance with dissipation monitoring, we systematically investigate the deposition of biotin-binding proteins to two surfaces that are popular in biotechnology: gold and silica.