Laser rangefinder performance (i.e., maximum range) is strongly affected by environment due to visibility-dependent laser attenuation in the atmosphere and target reflectivity variations induced by surface condition changes (dry vs. wet). Both factors have their unique spectral features which means that rangefinders operating at different wavelengths are affected by specific environmental changes in a different way. Current state of the art TOF (time of flight) semiconductor laser rangefinders are based mainly on two wavelengths: 905 nm and 1550 nm, which results from atmospheric transmission windows and availability of high power pulsed sources. The paper discusses the scope of maximum range degradation of hypothetical 0.9 μm and 1.5 μm rangefinders due to selected water-related environmental effects. Atmospheric extinction spectra were adapted from Standard Atmosphere Model and reflectance fingerprints of various materials have been measured. It is not the aim of the paper to determine in general which wavelength is superior for laser range finding, since a number of criteria could be considered, but to verify their susceptibility to adverse environmental conditions.

Heparins have been shown to be beneficial for the prevention of habitual miscarriages and repeated implantation failure, independently of their function as anticoagulants. The pro-inflammatory cytokine tumor necrosis factor (TNF)-α plays a role in the pathogenesis of these early pregnancy complications. Therefore, we examined the impact of heparin on TNF-α signaling in human endometrial stromal cells (ESCs) in vitro. Human ESCs were isolated from hysterectomy specimens and either used as undifferentiated cells or after decidualization in vitro. Cells were incubated with TNF-α, unfractionated heparin and signaling- and transporter-inhibitors. Interleukin (IL)-8 and -6 were measured using ELISAs and real-time RT–PCR. Nuclear factor of transcription (NF)-κB and its inhibitor IκBα were analyzed by in-cell western assays and confocal microscopy. Activation of NF-κB was determined in nuclear extracts using a specific transcription factor assay. Cellular internalization of heparin was detected by a heparin-uptake assay. Unfractionated heparin significantly suppressed the TNF-α-induced and NF-κB-mediated secretion and expression of IL-8 and -6 as well as other molecules in decidualized and undifferentiated human ESCs. Thereby heparin had no influence on the degradation of IκBα and the phosphorylation of NF-κB, but it inhibited the activity of NF-κB in the nucleus. An active heparin-uptake into the cells was the prerequisite for these heparin-effects. Unfractionated heparin is able to inhibit TNF-α/NF-κB-mediated inflammatory effects in the human endometrium independently of its classical function as an anticoagulant. These observations further underline on a molecular level the beneficial anti-inflammatory effects of heparin in women suffering from implantation disorders even in the absence of a thrombophilia.

Widespread availability of drones is associated with many new fascinating possibilities, which were reserved in the past for few. Unfortunately, this technology also has many negative consequences related to illegal activities (surveillance, smuggling). For this reason, particularly sensitive areas should be equipped with sensors capable of detecting the presence of even miniature drones from as far away as possible. A few techniques currently exist in this field; however, all have significant drawbacks. This study addresses a novel approach for small (<5 kg) drones detection technique based on a laser scanning and a method to discriminate UAVs from birds. The latter challenge is fundamental in minimizing the false alarm rate in each drone monitoring equipment. The paper describes the developed sensor and its performance in terms of drone vs. bird discrimination. The idea is based on simple cross-polarization ratio analysis of the optical echo received as a result of laser backscattering on the detected object. The obtained experimental results show that the proposed method does not always guarantee 100 percent discrimination efficiency, but provides certain confidence level distribution. Nevertheless, due to the hardware simplicity, this approach seems to be a valuable addition to the developed anti-drone laser scanner.

The paper describes practical application of pulsed microchip laser generating at 1535-nm wavelength to a laser rangefinder. The complete prototype of a laser rangefinder was built and investigated in real environmental conditions. The measured performance of the device is discussed. To build the prototype of a laser rangefinder at a reasonable price and shape a number of basic considerations had to be done. These include the mechanical and optical design of a microchip laser and the opto-mechanical construction of the rangefinder.

The article presents methods of long range distance measurements using pulsed lasers and the Time of Flight principle. Various algorithms of laser distance measurements with digital acquisition of echo pulses (acquisition of a signal’s full waveform) are presented. The main focus of work is concentrated on the method of distance measurements developed by the authors. With this method, during laboratory trials, a total measurement error of one centimeter was achieved using a 905 nm pulsed laser diode and pulse width of 39 ns. The maximum range of measurements with such high precision is limited only by a signal to noise ratio, duration of measurements and atmospheric conditions. All algorithms were implemented in a laser rangefinder module developed by the authors. Simulations and laboratory experiments were conducted and algorithm’s accuracy and precision were tested for various SNR conditions and changing distances.