Cellular Underwater Wireless Optical CDMA Network: Potentials and Challenges

Underwater wireless optical communications is an emerging solution to the expanding demand for broadband links in oceans and seas. In this paper, a cellular underwater wireless optical code division multiple-access (UW-OCDMA) network is proposed to provide broadband links for commercial and military applications. The optical orthogonal codes (OOC) are employed as signature codes of underwater mobile users. Fundamental key aspects of the network such as its backhaul architecture, its potential applications and its design challenges are presented. In particular, the proposed network is used as infrastructure of centralized, decentralized and relay-assisted underwater sensor networks for high-speed real-time monitoring. Furthermore, a promising underwater localization and positioning scheme based on this cellular network is presented. Finally, probable design challenges such as cell edge coverage, blockage avoidance, power control and increasing the network capacity are addressed.Comment: 11 pages, 10 figure

Utjecaj predimpregnacije anhidridom octene kiseline i vremena zagrijavanja na mehanička i fizička svojstva drvno-plastičnih kompozita

This research aimed to assess the influence of different pre-impregnation times (PITs) (60, 180, and 300 min), heating or reaction times (H/RTs) (60, 90, and 120 min), and chemical modification of wood flour (WF) on the mechanical and physical properties of wood-plastic composites (WPCs). The study employed acetylated beech (Fagus orientalis L.) flour as the filler and polypropylene (PP) as the matrix phase producing of WPC samples through melt compounding and injection molding. The resulting composites underwent testing for their physical and mechanical properties. The findings revealed that WPCs derived from acetylated wood with PITs of 60 min and H/RTs of 60 min exhibited the highest mechanical properties, except for the bending modulus. Moreover, the lowest water absorption (WA) was observed in the PITs-H/RTs combination of 60-120 min, while the lowest thickness swelling (TS) occurred in the PITs-H/RTs combination of 300-60 min. The simultaneous utilization of pre-impregnation and reaction times demonstrated a synergistic effect on the physical and mechanical properties. Consequently, the chemical modification of wood flour and the application of suitable reaction times improved the interfacial adhesion, thereby enhancing the overall performance of the WPCs.Cilj ovog istraživanja bio je procijeniti utjecaj različitih vremena predimpregnacije (PIT) (60, 180 i 300 min), vremena zagrijavanja (H/RT) (60, 90 i 120 min) i kemijske modifikacije drvnog brašna (WF) na mehanička i fizička svojstva drvno-plastičnih kompozita (WPC). U istraživanju je za proizvodnju uzoraka WPC-a taljenjem i injekcijskim prešanjem upotrijebljeno drvno brašno acetilirane bukovine (Fagus orientalis L.) kao punilo i polipropilen (PP) kao matrica. Zatim su ispitana fizička i mehanička svojstva dobivenih kompozita. Rezultati su pokazali da drvno-plastični kompoziti dobiveni od acetiliranog drva s vremenom predimpregnacije i zagrijavanja od 60 min imaju najbolja mehanička svojstva, osim modula na savijanje. Nadalje, najmanje upijanje vode (WA) zabilježeno je za kombinaciju PIT-H/RT 60-120 min, dok je najmanje debljinsko bubrenje (TS) izmjereno za kombinaciju PIT-H/RT 300-60 min. Istodobno je primjena predimpregnacije i zagrijavanja pokazala sinergijski utjecaj na fizička i mehanička svojstva. Posljedično su kemijska modifikacija drvnog brašna i odabir odgovarajućih vremena zagrijavanja poboljšali adheziju između faza, a time i svojstva drvno-plastičnih kompozita

Prevention of Enamel Adjacent to Bracket Demineralization Following Carbon Dioxide Laser Radiation and Titanium Tetra Fluoride Solution Treatment: An In Vitro Study

 Introduction: The aim of this study was to assess the caries-preventive potential of carbon dioxide (CO2) laser application in conjunction with the use of titanium tetra fluoride solution on the enamel adjacent to bracket.Methods: Seventy-five freshly extracted bovine incisors were used. In order to attach the brackets, the area of examination was covered with adhesive tape to limit acid etching of the entire enamel surface. Metal orthodontic brackets for upper central were bonded to all the teeth following the manufacturer’s instruction. Then all the teeth were painted with 2 layers of acid-resistant nail varnish on all surfaces except the boxes area cervical to the brackets. The teeth were then randomly divided into five groups (n = 15): control group (C); laser group (L); titanium group (T); laser-titanium group (LT) and titanium-laser group (TL). The laser-titanium group was first irradiated with CO2 laser (same as the L group) then TiF4 solution was applied on the enamel (same as the T group). Samples in the TL group were first treated with TiF4 solution (same as the T group) and then irradiated with CO2 laser on the surface (same as the L group). Then, the teeth were immersed in pH-cycling solutions. After that, the amount of calcium released into the two solutions (de- and re-mineralization) was measured with an atomic absorption spectroscopy. The data were analyzed by one-way Analysis of var-iance (ANOVA) and Tukey test.Results: Calcium loss in LT, TL and T groups were significantly lower than those in the L and C groups (P < 0.05).Conclusion: The application of Titanium tetra fluoride 4% solution on enamel can inhibit as much as 87% of subsequent caries like lesion progression

Human Visceral Leishmaniasis: a Serological Survey in Rural Areas of Dashti District of Bushehr Province, Southern Iran

Background: Visceral leishmaniasis (VL) or kala-azar is a parasitic disease caused by the species of Leishmania donovani complex. Mediterranean type of the disease is endemic in some parts of Iran and more than 95% of cases were reported in children up to 12 years of age. This study was performed to determine the seroprevalence of VL in the rural areas of the Dashti district from Bushehr province.Materials and Methods: In this cross-sectional study, a randomized cluster sampling method was used for the collection of blood samples from children up to 12 years old from rural areas of Dashti district. Before sampling; a questionnaire was filled out for each case. All the collected blood samples were examined after the serum separating by Direct Agglutination Test (DAT) for detection of anti-Leishmania infantum antibodies. The cutoff titers of ≥1: 3200 with specific clinical features were supposed to be considered as VL.Results: Altogether, 24 out of 1221 (1.96%) blood samples showed titers between 1:800 and 1:1600 which considered as suspicious cases. None of the suspicious cases had a history of kala-azar. None of 1221 collected blood samples showed anti Leishmania infantum (L. infantum) at titer ≥1:3200.Conclusion: This study confirms the circulation of L. infantum in Dashti district and highlights the sporadic pattern of VL in the studied areas which necessitates the surveillance system to be monitored by health authorities

Seroprevalence Survey of Visceral Leishmaniasis among Children up to 12 Years old and Domestic Dogs in Rural Areas of Dehloran District, Ilam Province of West Part of Iran, 2014

Background: Visceral leishmaniasis (VL), caused by Leishmania infantum (L. infantum), is a life-threatening vector-borne parasitic disease is distributed in some parts of the world. The disease is endemic in some parts of Iran. This study was aimed to determine the seroprevalence of VL among children and domestic dogs (as a reservoir of the parasite) in Dehloran, west of Iran.Materials and Methods: This cross-sectional study was carried out in Dehloran County. The blood samples of 872 children up to 12 years old and 52 dogs were collected from 10 villages of Dehloran using randomly-clustered sampling method. Sera were separated from all peripheral blood samples and tested by direct agglutination test (DAT). Anti-Leishmania infantum antibodies at titers of ≥1:800 and ≥1:80 were considered as Leishmania infantum infection in human and dog, respectively.Results: In general, among 872 human samples, 1.03% of samples had anti-Leishmania antibody with 1:1600 titers and 1.26% had 1:800 titers. In addition, from 52 dog samples, 21.15% of dogs had a titer of ≥1:320 and 25% had 1:80 and 1:160 titers.Conclusion: Our findings indicate that the seropositive dogs in the studied areas are considerable and L. infantum may be circulated between human and domestic dog in the studied area. Further study of isolation and molecular identification of Leishmania spp. is recommended

The Association of Human Leucocyte Antigen (HLA) Class I and II Genes with Cutaneous and Visceral Leishmaniasis in Iranian Patients: A Preliminary Case-Control Study

Background: Leishmaniasis is currently considered a re-emerging or emerging infection based on the geographic region. The outcome of leishmaniasis vastly depends on Leishmania-host interaction. This preliminary study aimed to show the association of human leukocyte antigen (HLA) class I and II genes with healed and non-healed cutaneous leishmaniasis (CL), and symptomatic and asymptomatic visceral leishmaniasis (VL) compared with control groups in Iran. Methods: Ninety-five people, including 31 patients versus 64 individuals in the control group, were enrolled. Among them, 20 patients had confirmed CL based on amastigote observation, 10 had improved CL and 10 non-healed CL. Eleven patients were suffering from confirmed VL based on direct agglutination test (Five asymptomatic and six symptomatic VL cases). Besides, they were residents in an endemic area of VL in the northwest of Iran. To select a control group, it was ensured that they had no history of leishmaniasis. Peripheral blood samples were collected from each patient. After DNA extraction, HLA typing was conducted using polymerase chain reaction - sequence-specific priming (PCR-SSP). Subsequently, data were statistically analyzed by SPSS.   Results: There was a statistical relationship between the presence of HLA-A26 and CL, healed CL and the existence of the B38 allele, C1 allele and symptomatic VL, as well as B1.4 allele and asymptomatic VL (P˂0.05). Conclusion: This primary finding indicates that several HLA genes have a potential role in the susceptibility of Iranian people to CL and VL

A historical overview of the classification, evolution, and dispersion of Leishmania parasites and sandflies

Background The aim of this study is to describe the major evolutionary historical events among Leishmania, sandflies, and the associated animal reservoirs in detail, in accordance with the geographical evolution of the Earth, which has not been previously discussed on a large scale. Methodology and Principal Findings Leishmania and sandfly classification has always been a controversial matter, and the increasing number of species currently described further complicates this issue. Despite several hypotheses on the origin, evolution, and distribution of Leishmania and sandflies in the Old and New World, no consistent agreement exists regarding dissemination of the actors that play roles in leishmaniasis. For this purpose, we present here three centuries of research on sandflies and Leishmania descriptions, as well as a complete description of Leishmania and sandfly fossils and the emergence date of each Leishmania and sandfly group during different geographical periods, from 550 million years ago until now. We discuss critically the different approaches that were used for Leishmana and sandfly classification and their synonymies, proposing an updated classification for each species of Leishmania and sandfly. We update information on the current distribution and dispersion of different species of Leishmania (53), sandflies (more than 800 at genus or subgenus level), and animal reservoirs in each of the following geographical ecozones: Palearctic, Nearctic, Neotropic, Afrotropical, Oriental, Malagasy, and Australian. We propose an updated list of the potential and proven sandfly vectors for each Leishmania species in the Old and New World. Finally, we address a classical question about digenetic Leishmania evolution: which was the first host, a vertebrate or an invertebrate? Conclusions and Significance We propose an updated view of events that have played important roles in the geographical dispersion of sandflies, in relation to both the Leishmania species they transmit and the animal reservoirs of the parasites

Who Bites Me? A Tentative Discriminative Key to Diagnose Hematophagous Ectoparasites Biting Using Clinical Manifestations

Arthropod blood feeders are vectors of several human pathogenic agents, including viruses (e.g., yellow fever, chikungunya, dengue fever), parasites (e.g., malaria, leishmaniasis, lymphatic filariasis), or bacteria (e.g., plague). Besides their role as a vector of pathogens, their biting activities cause a nuisance to humans. Herein, we document clinical symptoms associated with the biting of ten clusters of hematophagous arthropods, including mosquitoes, biting midges and sandflies, lice, ticks, tsetse flies, blackflies, horse flies, fleas, triatomine and bed bugs. Within the framework of clinical history and entomo-epidemiological information, we propose a tentative discriminative key that can be helpful for practicing physicians in identifying hematophagous arthropods biting humans and delivering treatment for the associated clinical disorders