Allelic forms of merozoite surface protein-3 in Plasmodium falciparum isolates from southeast of Iran

Background: Genetic diversity has provided Plasmodium falciparum with the potential capacity of avoiding the immune response, and possibly supported the natural selection of drug or vaccine-resistant parasites. Merozoite surface protein-3 (MSP-3) has been used to develop vaccines and investigate the genetic diversity regarding P. falciparum malaria in Iran. Objectives: The main goal of this study was to analyze the polymorphic antigen MSP-3 genes across southeast of Iran among four different districts, to identify the differences in the allele frequency and genetic diversity. Materials and Methods: Nested polymerase chain reaction amplification was used to determine polymorphisms of N-terminal region of the MSP-3 gene. A total of 85 microscopically positive P. falciparum infected individuals from southeast of Iran were included in this study. Results: Of the 85 confirmed P. falciparum samples obtained from four different districts, 72 were successfully scored for MSP-3.The MSP-3 allele classes (K1 and 3D7 types) showed comparable prevalence in all districts. Overall frequencies of K1 and 3D7 allele classes were 94.5 % for both. Conclusions: Since no study has yet looked at the extent of P. falciparum MSP-3 in this geographic region, these data can be helpful to support development of a vaccine based on MSP-3 against malaria. There should be a comparative analysis in different seasonal peaks to indicate the allelic polymorphism of MSP-3 over a period. © 2014, Ahvaz Jundishapur University of Medical Sciences; Published by Kowsar Corp

A Self-Potential for Monitoring Self-Sustaining Treatment for Active Remediation (STAR)

Self-sustaining Treatment for Active Remediation (STAR) is a novel soil remediation approach for Non-Aqueous Phase liquids (NAPLs) embedded in a porous medium. STAR is based on liquid smoldering combustion which destroys NAPLs while simultaneously generating heat due to the exothermic oxidation reaction. The technique is currently in use in several field pilot tests and a full-scale site remediation. Propagation of the smoldering front is monitored in the field by temperature data obtained from a thermocouple network, with limited resolution. Geophysical techniques, such as Self-Potential (SP), have potential as a non-destructive means for monitoring remediation processes. The SP method measures natural currents flowing in the ground generated by thermoelectric or electrokinetic processes. The objective of this work is to evaluate the potential of the SP technique for monitoring STAR. First, a series of sandbox experiments were conducted to investigate the magnitude of thermoelectric coupling coefficient for different sand sizes, water content and non- star heat sources. Results showed that a negative voltage anomaly is expected at the surface in the presence of a subsurface heat source and the magnitude of the anomaly is sensitive to water content and grain size. Next, SP measurements were conducted during several laboratory STAR tests examining the response as a function of both space and time. A significant SP anomaly was observed during the smoldering period. Moreover, the magnitude of the SP anomaly measured on the surface was demonstrated to be a function of the separation distance between the reaction front and the SP electrode position. R-squared for a linear regression of measured SP and the distance was 0.83, indicating that the majority of voltage anomaly had contribution to distance of the electrode to the smoldering front. Overall, this research demonstrated that the SP technique has significant potential as a non-invasive monitoring tool for STAR

Studies of oxide-semiconductor and metal-semiconductor interfaces for reducing defect densities

This thesis presents experimental studies of two fundamental components of electronic devices: an oxide- and metal-semiconductor interface. The importance of these interfaces increases continuously when a device size is decreased, and energy-efficiency as well as durability of the devices are increased. It is challenging, however, to characterize the interface properties on atomic level because of their hidden nature beneath the metal or oxide film. Moreover, because the semiconductor surface interacts with oxygen and metal elements during the fabrication of these junctions, electronic defect states form at the interface, lowering device efficiency and durability. This study focuses on modification and characterization of the following Si(100) and InP(100) semiconductor interfaces: (i) nitridation of HfO2/Si(100) interfaces, (ii) native oxide modification on n- and p-InP(100), and (iii) Ni/p-InP(100) interface with magnesium surface doping. The interface properties have been studied by complementary surface-science and electrical methods: scanning tunnelling microscopy/spectroscopy, low energy electron diffraction, X-ray photoelectron spectroscopy, and photoluminescence along with electrical measurements like capacitance-voltage, current-voltage, and contact resistivity. Most interface modifications have been done in ultrahigh-vacuum (UHV) chambers in controlled environments. The experimental results show that (i) NH3 nitridation of Si(100) at low temperature reduces the interface defect density at the HfO2/Si(100) junction, (ii) a proper low temperature gas-based treatment (NH3 or O2) improves the quality of the InP native-oxides by reducing the harmful surface defects, and (iii) proper wet chemically treatment combined with UHV-based InP surface modification can reduce the contact resistivity at p-InP contacts. Oksidi-puolijohde ja metalli-puolijohde rajapintojen tutkimuksia vikatilojen vähentämiseksi Tässä väitöskirjatyössä on tutkittu kahta eri tyyppistä puolijohdekiteen rajapintaa, jotka esiintyvät useimmissa puolijohdelaitteissa. Tutkittavat rajapinnat muodostuvat, kun puolijohdekiteen pintaan liitetään eristävä oksidikalvo tai sähköäjohtava metallikalvo. Näiden laiteosien merkitys kasvaa entisestään, kun puolijohdelaitteiden koko pienenee, ja kun laitteiden energiatehokkuutta sekä kestävyyttä parannetaan. Kyseiset rajapinnat ovat laitteiden heikoimpia osia, koska puolijohdekiteen pinnat reagoivat voimakkaasti eriste- tai metallikalvon valmistusolosuhteiden kanssa aiheuttaen niin sanottuja sähköisiä vikatiloja rajapintoihin. Lisäksi rajapintojen ominaisuuksia on vaikea mitata atomitarkkuudella. Työssä on valmistettu ja mitattu seuraavia puolijohdeliitoksia: (i) HfO2/Si(100) jonka Si-pinta käsiteltiin typpikaasulla ennen HfO2-kalvon kasvatusta, (ii) InP(100)-pinnan oksidien muokkaus typpi- tai happikaasulla ja (iii) InP(100)-pinnan Mg-seostus ennen Ni-metallikalvon kasvatusta. Rajapintojen ominaisuuksia mitattiin sekä pintatieteen että sähköisten tutkimusmenetelmien avulla käyttäen pyyhkäisytunnelointimikroskopiaa, fotoelektronispektroskopiaa, fotoluminesenssia, kapasitanssi-jännitemittausta ja kontaktiresistanssin määritystä. Rajapintojen ominaisuuksia muokattiin yleensä ultrahyvän tyhjiön kammiossa käsittelemällä puolijohdekiteiden pintoja ennen eriste- tai metallikalvon kasvatusta. Päätulokset ovat: (i) Si(100)-pinnan käsittely ammoniakki (NH3) kaasulla tyhjiökammiossa matalassa lämpötilassa pienentää sähköisten vikatilojen tiheyttä ja vuotovirtaa HfO2/Si(100)-rajapinnassa, (ii) InP-puolijohdekiteen pintaoksidin ominaisuuksien muokkaus NH3- tai O2-kaasulla pienentää vikatilojen tiheyttä, (iii) InP-pinnan esikäsittely sopivassa kemiallisessa liuoksessa ja sen jälkeen ultrahyvässä tyhjiössä Mg-atomeilla pienentää Ni-kalvon ja InP kiteen kontaktiresistanssia

Adaptive Delivery in Caching Networks

The problem of content delivery in caching networks is investigated for scenarios where multiple users request identical files. Redundant user demands are likely when the file popularity distribution is highly non-uniform or the user demands are positively correlated. An adaptive method is proposed for the delivery of redundant demands in caching networks. Based on the redundancy pattern in the current demand vector, the proposed method decides between the transmission of uncoded messages or the coded messages of [1] for delivery. Moreover, a lower bound on the delivery rate of redundant requests is derived based on a cutset bound argument. The performance of the adaptive method is investigated through numerical examples of the delivery rate of several specific demand vectors as well as the average delivery rate of a caching network with correlated requests. The adaptive method is shown to considerably reduce the gap between the non-adaptive delivery rate and the lower bound. In some specific cases, using the adaptive method, this gap shrinks by almost 50% for the average rate.Comment: 8 pages,8 figures. Submitted to IEEE transaction on Communications in 2015. A short version of this article was published as an IEEE Communications Letter with DOI: 10.1109/LCOMM.2016.255814