Effect of a vehicle's mobility on SNR and SINR in vehicular optical camera communication systems.

The widespread use of light-emitting diodes (LEDs) and cameras in vehicular environments provides an excellent opportunity for optical camera communication (OCC) in intelligent transport systems. OCC is a promising candidate for the Internet of Vehicles (IoV), and it uses LEDs as the transmitter and cameras as the receiver. However, the mobility of vehicles has a significant detrimental impact on the OCC system's performance in vehicular environments. In this paper, a traffic light that uses multiple-input multiple-output (MIMO) technology serves as the transmitter, and the receiver is a camera mounted on a moving vehicle. The impact of vehicle mobility on the vehicular MIMO-OCC system in the transportation environment is then examined using precise point spread function (PSF) analysis. The experimental results are used to evaluate the proposed PSF. A good agreement between the laboratory's recorded videos and this PSF model's simulations is observed. Moreover, the signal-to-noise ratio (SNR) and signal-to-interference-plus-noise ratio (SINR) values are evaluated. It is shown that they are greatly influenced by the vehicle's speed, direction of motion, and position of the camera. However, since the angular velocity in a typical transportation environment is low, it does not have a significant impact on the performance of the vehicular OCC systems.

Reflector-aided underwater optical channel modeling.

Underwater visible light communication (UVLC) has been proposed as a high-speed alternative to acoustic signaling. While most UVLC systems are configured to work in line-of-sight (LOS) conditions, it is also possible to exploit reflected signals for performance enhancements. In this Letter, we propose a closed-form expression for the underwater path loss assuming non-LOS (NLOS) transmission through the water surface and man-made reflector (e.g., mirror) in addition to the LOS link. Utilizing the derived expression, we quantify the achievable NLOS gain defined as the ratio between the maximum achievable channel coefficient from reflection and the overall channel coefficient. We validate our findings experimentally by utilizing the water surface and the mirror as the reflecting surfaces in an aquarium. Our results reveal that achievable gains up to around 3 dB can be observed due to reflections.

Comprehensive study on UAV-based FSO links for high-speed train backhauling.

In this paper, we introduce the idea of using unmanned aerial vehicle (UAV)-based free-space optical communication systems to backhaul high-speed trains. We introduce a composite channel model that includes effects of both atmospheric turbulence and pointing errors due to position/orientation deviation. Based on the derived fading model, we present an approximation expression for the outage probability. The performances of the proposed air-relay and traditional ground-relay systems are compared under fair conditions. Pointing-acquisition-tracking (PAT) complexity and coverage distance under different weather conditions and different fading levels are considered as comparison metrics. Furthermore, we investigate the effect of several parameters such as beam divergence angle, displacement deviation variance, and UAV operation altitude on system performance. Our results reveal that air relay helps in mitigating the fog effect, can achieve longer coverage distance, and relaxes PAT system design.

Ursodeoxycholic acid protects neonatal rats from necrotizing enterocolitis: a biochemical, histopathological, and immunohistochemical study.

BACKGROUND: The pathophysiology of necrotizing enterocolitis (NEC) includes the massive production of endogenous cytokines with exaggerated activation of inflammatory pathways. Ursodeoxycholic acid (UDCA) has been used as an anti-inflammatory, antioxidant, and anti-apoptotic agent. We investigated the possible protective effects of UDCA in a neonatal rat pup model of NEC. METHODS: We randomly divided rat pups into three groups: a control group, a non-treated NEC group, and a UDCA-treated NEC group. We induced NEC by feeding formula enterally and via hypoxia/reoxygenation. Intestinal samples were collected for histopathological and immunohistochemical evaluation. Blood samples were taken for biochemical analyses. RESULTS: UDCA significantly reduced the extents of terminal ileal and jejunal injuries compared to the NEC group (p < .01), reduced Bax and caspase-3 immunoreactivities (both p < .01), and lowered serum levels of platelet-activating factor and intestinal fatty acid-binding protein (p < .01, p = .023, respectively). CONCLUSIONS: In a rat model of NEC, UDCA protects against adverse intestinal histological, immunohistochemical, and biochemical changes. UDCA significantly reduces the effects of NEC on the rat pup intestine.

Utilization of an OLED-Based VLC System in Office, Corridor, and Semi-Open Corridor Environments.

Organic light emitting diodes (OLEDs) have recently received growing interest for their merits as soft light and large panels at a low cost for the use in public places such as airports, shopping centers, offices, and train or bus stations. Moreover, the flexible substrate-based OLEDs provide an attractive feature of having curved or rolled lighting sources for the use in wearable devices and display panels. This technology can be implemented in visible light communications (VLC) for several applications such as visual display, data communications, and indoor localization. This article aims to investigate the use of flexible OLED-based VLC in indoor environments (i.e., office, corridor and semi-open corridor in shopping malls). We derive a two-term power series model to be match with the root-mean-square delay spread and optical path loss (OPL). We show that, for OLED positioned on outer-wall of shops, the channel gain is enhanced in contrast to them being positioned on the inner-wall. Moreover, the channel gain in empty environments is higher compare with the furnished rooms. We show that, the OPL for a 10 m link span are lower by 4.4 and 6.1 dB for the empty and semi-open corridors compared with the furnished rooms, when OLED is positioned on outer-wall of shops. Moreover, the channel gain in the corridor is higher compared with the semi-open corridor. We also show that, in furnished and semi-open corridors the OPL values are 55.6 and 57.2 dB at the center of corridor increasing to 87.6 and 90.7 dB at 20 m, respectively, when OLED is positioned on outer-wall of shops.

Experimental investigation on the effect of wavelength on aperture averaging in FSO communications.

Atmospheric turbulence is a major impairment in free-space optical (FSO) communication systems. Based on the fact that the size of receiver aperture is much larger than operation wavelength, aperture averaging extracts inherent receiver diversity gains and can be used as an effective fading mitigation technique. In this Letter, we consider the three most common wavelengths used in telecommunications, namely 1550, 1310, and 850 nm, and present a comparative performance evaluation of aperture averaging under the same emulated atmospheric conditions. Our emulator is in the form of an atmospheric chamber equipped with adjustable heaters, coolers, and fans to create the desired level of turbulence. Our results demonstrate that by changing the wavelength and/or aperture size, a strong turbulence condition with Gamma-Gamma statistics can turn into a weak turbulence condition with log-normal statistics. Such a phenomenon can be observed even for relatively small aperture sizes if the wavelength is sufficiently high.

Coverage of a shopping mall with flexible OLED-based visible light communications.

Visible light communications (VLC) can utilize light-emitting diodes (LEDs) to provide illumination and a safe and low-cost broadcasting network simultaneously. In the past decade, there has been a growing interest in using organic LEDs (OLEDs) for soft lighting and display applications in public places. Organic electronics can be mechanically flexible, thus the potential of curved OLED panels/displays devices. This paper provides unique characteristics of a flexible OLED-based VLC link in a shopping mall. We show that, for curved OLED the radiation pattern displays a symmetry, which is wider than Lambertian. A number of scenarios of VLC system with flexible OLED are analyzed. Numerical models for the delay spread and optical path loss are derived, which followed a 2-term power series model for both empty and furnished rooms. We show that using a full-circular OLED for both empty and furnished rooms offers a uniform distribution of emitted power for the same transmission link spans. The link performance using full and half-circular OLED in an empty room shows that the average optical path losses are lower by 5 and 4 dB, compared with the furnished room.

Channel modelling for indoor visible light communications.

Visible light communication (VLC) allows the dual use of light-emitting diodes (LEDs) for wireless communication purposes in addition to their primary purpose of illumination. As in any other communication system, realistic channel modelling is a key for VLC system design, analysis and testing. In this paper, we present a comprehensive survey of indoor VLC channel models. In order to set the background, we start with an overview of infrared (IR) channel modelling, which has received much attention in the past, and highlight the differences between visible and IR optical bands. In the light of these, we present a comparative discussion of existing VLC channel modelling studies and point out the relevant advantages and disadvantages. Then, we provide a detailed description of a site-specific channel modelling approach based on non-sequential ray tracing that precisely captures the optical propagation characteristics of a given indoor environment. We further present channel models for representative deployment scenarios developed through this approach that were adopted by the Institute of Electrical and Electronics Engineering (IEEE) as reference channel models. Finally, we consider mobile VLC scenarios and investigate the effect of receiver location and rotation for a mobile indoor user. This article is part of the theme issue 'Optical wireless communication'.

Evaluation of different intraarticular injection volumes to assess optimum efficient amount; an experimental study in rat knee joints.

INTRODUCTION: The injection amount of solutions differs in wide ranges, from 20 to 200 µL in intraarticular injections experiments that was carried out with rats. The 10-fold difference between applied volumes is not acceptable since injection errors might affect the outcomes of the studies significantly. The excessive amount of solution that was injected into the knee joint of rats might end up with leakage of the solution from injection aperture, and damage the articular structures etc. In our preliminary experiments, we mentioned problems during the injection of excessive amount of solution into the rat knee joint. The main purpose of the present study, which was performed with rat knee joints, was to evaluate the applicability of different amounts of solutions used in experiments and to determine the optimal volume for intraarticular injection in rats. METHODS: The volume of 100 µL water-based stain was administered into knee joints of non-living rats. The legs were dissected to evaluate the possible presence of injected solution outside the knee joint. Then, the decreasing volumes (100 µL, 50 µL, 40 µL and 30 µL) of X-ray contrast solution (lobitridol) were applied into the knees of living rats to investigate whether systemic circulation acts on the leakage outside the joint. The X-ray images of all these joints were also taken to confirm the results. RESULTS: In nonliving rats, the place where water-based strain overflow from the knee joint was pointed out. The place of leakage is where the tendo musculi extensor digitorum longus leaves outside the joint. In living rats, by using contrast solution, an overflow was noticed in the subdermal place with the intraarticular injection volumes of 100 µL, 50 µL, and 40 µL. No overflow was observed with the intraarticular injection volumes of 30 µL X-ray contrast solution. DISCUSSION: In conclusion, the injection volume for the knee joints of rats should not exceed the 30 µL for optimum efficiency.

The Protective Effects of Pulsed Magnetic Field and Melatonin on Testis Torsion and Detorsion Induced Rats Indicated by Scintigraphy, Positron Emission Tomography/Computed Tomography and Histopathological Methods.

PURPOSE: The aim of the present study was to show the protective effect of pulsed magnetic field (PMF) application and melatonin administration on damage in testis in a one-sided torsion detorsion induced rat model using testicular scintigraphy with 99mTc pertechnetate, PET/CT with 18F-FDG and histopathological methods. MATERIALS AND METHODS: Sixty male rats were used in the study; 30 rats were randomly divided into five groups for one day applications of sham control, torsion, melatonin, pulsed magnetic field (PMF) and melatonin plus PMF. Similarly, for one week group, the other 30 rats were divided into the same five group (n=6), but the animals were sacrificed after one week. Rats were exposed to 50 Hz, 1 mT PMF for two hours. PET/CT with 37 MBq 18F-FDG and testicular scintigraphy with and 37 MBq 99mTc pertechnetate examinations were carried out, and testicular tissue was examined using histopathological methods.  Results: In one day treatment, melatonin administration significantly increased perfusion and glucose metabolism compared to torsion group (p<0.01). Perfusion and glucose metabolism was also higher in the PMF and melatonin plus PMF groups than torsion group (p<0.01). In one week treatment, melatonin administration resulted in a significant higher perfusion rate and glucose metabolism rate compared to torsion group (p<0.01 and p<0.001, respectively). In addition, perfusion and glucose metabolism significantly increased in PMF and melatonin plus PMF groups compared to torsion group (p<0.01 and p<0.001, respectively). Furthermore, caspase-3 immunoreactivity and pathological changes increased in the torsion group (p<0.05). Melatonin and melatonin plus PMF treatment reduced the rate of immunoreactivity and pathological findings compared to the torsion group (p<0.05). CONCLUSION: According to these results it can be concluded that PMF application had a therapeutic benefit as effective as melatonin administering. In addition, it was indicated that PET/CT with 18F-FDG and testicular scintigraphy with 99mTc pertechnetate could be efficiently used in determining the treatment efficiency in testicular torsion.

In vivo effects of intravenous lipid emulsion on lung tissue in an experimental model of acute malathion intoxication.

Malathion can be ingested, inhaled, or absorbed through the skin, but acute toxicity is maximized when administered orally. Intravenous lipid emulsion (ILE) treatment is used as a new therapeutic method in cases of systemic toxicity caused by some lipid soluble agents. This study aimed to examine the potential treatment effect of ILE on rat lung tissue in a toxicokinetic model of malathion exposure. Twenty-one adult Wistar albino rats were randomly divided into three equal groups. The groups were organized as group I (control), group II (malathion), and group III (malathion + ILE treatment). Malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) were evaluated in lung tissues. Immunohistochemical and Western blot analyses were performed to determine the bax, bcl-2, and caspase-3 expression levels. Tissue GSH-Px and SOD activities were decreased and MDA levels were increased in the malathion group. ILE administration increased GSH-Px and SOD activity and decreased MDA levels compared to the malathion group. Furthermore, expression of bax, bcl-2, and caspase-3 significantly increased in the malathion group, and ILE infusion reduced these expression levels. The present study revealed that acute oral malathion administration increased oxidative stress and apoptosis in the lung tissue of rats. ILE infusion prevented oxidative stress and decreased the deleterious effects of malathion. Taken together, the findings of our study suggest that lipid emulsion infusion has treatment efficacy on malathion-induced lung toxicity.

Effect of eddy diffusivity ratio on underwater optical scintillation index.

The performance of underwater optical wireless communication systems is severely affected by the turbulence that occurs due to the fluctuations in the index of refraction. Most previous studies assume a simplifying, yet inaccurate, assumption in the turbulence spectrum model that the eddy diffusivity ratio is equal to unity. It is, however, well known that the eddy diffusivities of temperature and salt are different from each other in most underwater environments. In this paper, we obtain a simplified spatial power spectrum model of turbulent fluctuations of the seawater refraction index as an explicit function of eddy diffusivity ratio. Using the derived model, we obtain the scintillation index of optical plane and spherical waves and investigate the effect of the eddy diffusivity ratio.

Caecum location in laboratory rats and mice: an anatomical and radiological study.

Intraperitoneal (i.p.) injection is the most frequently used method for implementing parenteral therapies in rats and mice. Whether the caecum is located in the right caudal quadrant or left caudal quadrant in the abdominal cavity is not clear. For that reason, we have developed a method for identifying the location of the caecum in rats and mice and thus revealed the most reliable location for i.p. injection in these animals. Two hundred Wistar albino rats and 100 BALB/c mice were used. The location of the caecum was determined by revealing the intra-abdominal organs immediately following euthanasia, photographing the organs, and archiving the images. Both digital photographic images and computed tomographic (CT) sections were analysed in terms of caecum morphology and location. In both rats and mice, the caecum was most commonly located on the animal's left side. It was less frequently located on the right side or in the centre. The caecum was typically comma-shaped, but it was round or S-shaped in some animals. The direction of rotation of the caecum from the basis to the apex was mostly counterclockwise. Additionally, the apex showed a tendency to be evenly centred. This study demonstrated that the caecum was mostly located on the animal's left side; and for that reason, the most suitable location for i.p. injection in these animals was understood to be the right caudal quadrant. Furthermore, when we compared the CT images and autopsy findings, the caecum did not change location in the abdominal cavity postmortem.

Investigation of the effects of aging on the expression of aquaporin 1 and aquaporin 4 protein in heart tissue.

OBJECTIVE: Aquaporin (AQP) 1 and AQP 4 are expressed in human heart and several studies have been focused on these two aquaporins. For this purpose, the present study is aimed to research the effects of aging on AQP 1 and AQP 4 in heart tissue. METHODS: In this study, 14 Balb/C type white mice were used. Animals were divided into two equal groups. Group I consisted of 2-month-old young animals (n=7), and group II consisted of 18-month-old animals (n=7). To determine the AQP1 and AQP4 expression in the myocardium, the heart tissue was removed to perform western blotting and immunohistochemical and histopathological evaluations. RESULTS: Muscle fibers of the heart in aged animals were more irregular and loosely organized in hematoxylin-eosin (H-E) stained sections. Hscore analysis revealed that AQP1 and AQP4 immunoreactivity significantly increased in heart tissues of old mice compared with those of young mice (p<0.001). In addition, AQP1 and AQP4 protein expressions in the tissues of old animals were increased significantly according to western blot analysis (p=0.018 and p<0.001 for AQP1 and AQP4, respectively). CONCLUSION: Increased AQP1 and AQP4 levels in the heart tissue may be correlated with the maintenance of water and electrolytes balance, which decreases with aging. In this context, it might be the result of a compensatory response to decreased AQP4 functions. In addition, this increase with aging as demonstrated in our study might be one of the factors that increases the tendency of ischemia in elder people.

Investigating the effect of rose essential oil in patients with primary dysmenorrhea.

OBJECTIVE: This study aimed to evaluate the effects of rose essential oil on primary dysmenorrhea. METHODS: One hundred patients were randomly divided into two groups; Group D received diclofenac sodium (75 mg/im) and Group A administered diclofenac sodium with aromatherapy (2% rose essential oil). The visual analog scale (VAS) scores in all subjects at baseline, 10th min, and 30th min were recorded. RESULTS: When the two groups were compared before and after the treatment, there were significant decreases in VAS values at the 10 min and 30 min compared to baseline values in both groups (p < 0.001). However, the 30th min mean VAS value in Group D was higher than in Group A (p = 0.019). CONCLUSION: The present study suggests that aromatherapy with rose essential oil, which is a nonpharmacologic treatment method, as an adjuvant to conventional treatment methods may be beneficial for pain relief in individuals with primary dysmenorrhea.

Aperture averaging in multiple-input single-output free-space optical systems using partially coherent radial array beams.

Multiple-input single-output (MISO) techniques are employed in free-space optical (FSO) links to mitigate the degrading effects of atmospheric turbulence. In this paper, for the MISO FSO system, a partially coherent radial array and a finite-sized receiver aperture are used at the transmitter and the receiver, respectively. Using the extended Huygens-Fresnel principle, we formulate the average power and the power correlation at the finite-sized slow detector in weak atmospheric turbulence. System performance indicators such as the power scintillation index and the aperture averaging factor are determined. Effects of the source size, ring radius, receiver aperture radius, link distance, and structure constant and the degree of source coherence are analyzed on the performance of the MISO FSO system. In the limiting cases, the numerical results are found to be the same when compared to the existing coherent and partially coherent Gaussian beam scintillation indices.

Effects of carvedilol on an ischemia/reperfusion model: Biochemical, histopathological and immunohistochemical evaluation.

AIM: The aim of this study was to investigate the effects of carvedilol (CVD) on experimentally induced ovarian ischemia/reperfusion (I/R) injury in rats. METHODS: An ovarian I/R model was applied to rats, classified into three groups: 1 (n = 7), sham operated (control); 2 (n = 7), 3 h ischemia + 3 h reperfusion (I/R); 3 (n = 7), 3 h ischemia + CVD + 3 h reperfusion (I/R + CVD). Malondialdehyde (MDA) levels and glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities in ovarian tissues and serum were measured. Tissue damage was examined histopathologically; Bax and caspase-3 expression was determined immunhistochemically. Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay was performed to show apoptotic cell death. RESULTS: MDA levels in ovarian tissues were significantly increased in the I/R group compared with the control. CVD administration significantly decreased tissue MDA levels in the I/R + CVD in comparison with the I/R group. GSH-Px activities in serum were higher in the I/R + CVD than in the I/R group. SOD activities in tissue and serum were significantly decreased in the I/R compared with the control group. Histological examination showed a significant improvement in ovarian morphology in the I/R + CVD compared with the I/R group. Bax and caspase-3 protein was more strongly expressed in the I/R group compared with the control and I/R + CVD groups. Apoptotic index detected by TUNEL assay was significantly increased in the I/R and decreased in the I/R + CVD group. CONCLUSION: Our results suggest that CVD reduces the deleterious effects of oxidative damage on ovaries in a rat I/R model.

Investigation of age-related changes in the expression of aquaporin-1 and aquaporin-5 in the salivary glands of mice.

CONCLUSION: The increased AQP5 expression associated with ageing in glands, which mainly secreted a serous solution, suggests a compensation for the decreased amount of saliva secretion associated with age progression. OBJECTIVE: To investigate the change in aquaporin-1 (AQP1) and aquaporin-5 (AQP5) expression in the salivary glands in young and elder mice. MATERIALS AND METHOD: Twelve female mice from the Balb/C genus (30-50 g) were used. The mice were separated into two groups: Group I had 2-month-old mice and Group II had 18-month-old mice. Salivary glands (glandula parotidea, glandula sublungualis, glandula submaxillaris) were excised and examined immunohistochemically and histopathologically. AQP1 and AQP5 expression of young and elder mice was evaluated using the H-score. A p-value less than 0.05 was considered statistically significant. RESULTS: Upon histopathological examination, the acini of glands were found to be atrophic in elder mice. The number and diameter of intercalated ducts were increased. Indeed, the amount of adipose tissue in the gland was increased. Upon immunohistochemical examination, both AQP1 and AQP5 levels in sublingual glands of elder mice were increased (p < 0.01 and p < 0.001, respectively). However, only AQP5 levels were increased in the parotid gland of elder mice (p < 0.01).

The peroneus brevis tendon at its insertion site on fifth metatarsal bone.

BACKGROUND: The differences at the attachment site of peroneus brevis (PB) to the fifth metatarsal bone is important in terms of the forces exerted on the bone and hence the mechanism of fractures involving this structure. In this study, we investigated the anatomical properties of PB at the insertion site to the base of fifth metatarsal bone, its possible intertendinous connections with peroneus tertius (PT) and their possible effects on the fracture occurrence at the bony attachment site. METHODS: The length and the width of PB tendons at their mid- and end-points were measured and classified according to the insertion types. Besides, the length and the width of the base of fifth metatarsal bone were assessed. The slips extending from the PB tendons and their relationship with PT were also evaluated. The data was compared statistically with each other and between the right and left sides. RESULTS: The length of PB tendon was measured 79.57±15.40mm on the right side; 81.48±14.31mm on the left. The width of PB tendon at the mid-point was 4.46±0.80mm on the right side; 4.42±0.94mm on the left. The width of the tendon at its insertion point was measured 14.85±3.40mm and 15.16±3.42mm on the right and left sides respectively. PB was divided into three types according to its attachment to base of fifth metatarsal bone (5thMB). Type I, Type II and Type III were observed at the rates of 59.5%, 28.6% and 11.5% respectively. It was observed that the slips to the bone were extending more commonly from PB than from PT and that the large majority of them were single having their insertions on the base of the proximal phalanx of the fifth toe. CONCLUSIONS: Knowing the width and insertional types of PB aids in understanding the mechanism of fractures at the site of bony attachment. The existence of slips may help the surgeon in the procedures involving PB or the lateral side of the forefoot.

Protective effects of thymoquinone and melatonin on intestinal ischemia-reperfusion injury.

BACKGROUND/AIM: In the present study, we aimed to compare the potential protective effects of thymoquinone and melatonin by using equivalent dose, on oxidative stress-induced ischemia-reperfusion (IR) injury in the intestinal tissue of rats. MATERIALS AND METHODS: The study was performed using 32 male Wistar-Albino rats (weighing 180-200 g) randomly divided into four groups: Group I, sham group; Group II, IR group; Group III, IR with melatonin group; and Group IV, IR with thymoquinone group. After laparotomy, ischemia and reperfusion were performed for 60 and 120 min, respectively, on all the groups. Intestinal tissue sections were stained using routine histological methods and examined under the light microscope. In addition, the sections were immunohistochemically stained using the TUNEL method for determination of apoptosis. Superoxide dismutase (SOD) activity, glutathione peroxidase (GSH-Px) activity, and malondialdehyde (MDA) levels in the intestinal tissue were also measured. RESULTS: The IR group had significantly elevated tissue SOD activity, GSH-Px activity, and MDA levels compared with the sham group. Administration of thymoquinone and melatonin efficiently reduced these increases. Statistically significant number of apoptotic cells was observed in the intestinal tissue of IR group rats compared with the sham group. Treatment with thymoquinone and melatonin markedly reduced the number of apoptotic cells. CONCLUSION: The effects of melatonin and thymoquinone on IR-induced oxidative stress in rat intestines were similar. Our findings suggest that melatonin and thymoquinone protect against IR-induced injury to intestinal tissues.