Near Field Communication

Near Field Communication (NFC) is a technology that enables a device to communicate with another at a maximum distance of around 20cm or less. Currently, mobile phone manufacturers, banking institutions and mobile network providers are attempting to apply this technology to Smartphones and other handheld devices because of the opportunity to enable the consumer to use commercial services more easily. This paper discusses the expected increase in mobile payments using Near Field Communication, possible uses and the risks associated with carrying out transactions over a wireless network. We also discuss a real world implementation of an NFC based loyalty card system for retail.DOI:http://dx.doi.org/10.11591/ijece.v2i3.23

T-cell responses during Trypanosoma brucei infections

African trypanosomiasis is caused by Trypanosoma brucei and is a disease of considerable importance causing infection in both humans and livestock. There is a degree of protection from the antibody response produced by the host but it is ineffective and infections are chronic and debilitating. This chronicity is due to antigenic variation by the trypanosomes and to immunosuppression of the host. Antigenic variation is a classic, and well studied, B-cell evasion mechanism in a number of infections and can be observed at a highly sophisticated level during African trypanosome infections. As yet, it has been little studied as a possible T-cell evasion mechanism and this is the subject of my thesis. Initially, a reliable in vitro assay system was devised in order to examine the proliferative T-cell responses of mononuclear splenocyte populations as T-cell proliferation had not been detected during trypanosome infections in previous studies. Responses against trypanosome lysates, paraformaldehyde-fixed and live trypanosomes were examined with paraformaldehyde-fixed trypanosomes being the preferred choice of antigenic stimuli. The optimal conditions for this assay were also determined as far as mitogen concentration, concentration of trypanosome antigen and incubation time were concerned. Using this reliable proliferation assay system I examined a number of trypanosome infection and immunisation regimes. Most of these analyses were conducted using splenocytes taken from mice at first peak of parasitaemia employing parasite lines in each of which 99% of the trypanosomes present express the same variant antigen type (VAT) during the first parasitaemic wave. The mononuclear splenocytes from infected mice produced a high level of proliferation in response to mitogen stimulation but also produced trypanosome antigen-driven proliferation. This antigen-driven proliferative response was mainly against the homologous VATs but there was also a degree of heterologous antigen-driven proliferation in response to some VATs but not against others. Immunosuppression is considered to be a major contributing factor in continuation of an infection by dampening down any effective immune response during African trypanosomiasis. Immunosuppression is noticeable after the first peak of parasitaemia and involves a number of components with 'suppressor' macrophages appealing to play a key role. I therefore investigated the role of nitric oxide (NO), a major product of activated macrophages, in the regulation of T-cell responses during chronic Trypanosoma brucei infection. Using transgenic mice deficient in inducible nitric oxide synthase (iNOS), the proliferative and cytokine responses were examined. Daily parasitaemias were determined, nitrate levels calculated and antibody isotyping examined using infected and uninfected mice homozygous and heterozygous for the iNOS loci. This work highlighted the key role of NO in the regulation of T-cell responses during trypanosome infections: in the absence of iNOS activity there was an upregulation in proliferation, IFNgamma production and IL-2 receptor expression causing improved clearance of trypanosomes from the systemic circulation. In conclusion, this body of work has successfully designed an in vitro assay system to examine T-cell proliferation to trypanosome VATs and, using this assay, I have successfully detected trypanosome antigen-driven T-cell proliferation during acute infections. This proliferation was observed using mononuclear splenocyte populations from infected and immunised mice and was found to be homologous antigen-driven and of T-helper 1 type. There was however heterologous antigen-driven T-cell proliferation against some trypanosome VATs but a lack of proliferation against others. A pivotal role for NO in causing immunosuppression during chronic T. brucei infections was determined and this immunosuppression influenced the cytokine production and T-cell proliferative responses but did not appear to affect the antibody production. These data suggest that VAT-specific T-cell responses are an important component of the immune response to T. brucei. (Abstract shortened by ProQuest.)

Parasitismo em serpentes

A criação cativa de serpentes tem sido cada vez mais intensificada devido ao seu uso como pet, conservação de animais selvagens, importância em pesquisas, desenvolvimento tecnológico, produção de soro antipeçonha e outros produtos. O parasitismo nestes animais é frequente, podendo atingir alta carga parasitária, a qual pode ser intensificada com o estresse de cativeiro que leva à depressão do sistema imunológico. Os parasitos não apenas influenciam na viabilidade dos animais mantidos em cativeiro, como também podem ter potencial zoonótico. Esta revisão visa auxiliar profissionais da área na manutenção adequada de serpentes em cativeiro

Laboratory and tentative interstellar detection of trans-methyl formate using the publicly available Green Bank Telescope PRIMOS survey

The rotational spectrum of the higher-energy trans conformational isomer of methyl formate has been assigned for the first time using several pulsed-jet Fourier transform microwave spectrometers in the 6-60 GHz frequency range. This species has also been sought toward the Sagittarius B2(N) molecular cloud using the publicly available PRIMOS survey from the Green Bank Telescope. We detect seven absorption features in the survey that coincide with laboratory transitions of trans-methyl formate, from which we derive a column density of 3.1 (+2.6, -1.2) \times 10^13 cm-2 and a rotational temperature of 7.6 \pm 1.5 K. This excitation temperature is significantly lower than that of the more stable cis conformer in the same source but is consistent with that of other complex molecular species recently detected in Sgr B2(N). The difference in the rotational temperatures of the two conformers suggests that they have different spatial distributions in this source. As the abundance of trans-methyl formate is far higher than would be expected if the cis and trans conformers are in thermodynamic equilibrium, processes that could preferentially form trans-methyl formate in this region are discussed. We also discuss measurements that could be performed to make this detection more certain. This manuscript demonstrates how publicly available broadband radio astronomical surveys of chemically rich molecular clouds can be used in conjunction with laboratory rotational spectroscopy to search for new molecules in the interstellar medium.Comment: 40 pages, 7 figures, 4 tables; accepted for publication in Ap

T-cell responses during Trypanosoma brucei infections in mice deficient in inducible nitric oxide synthase

We have investigated the possibility that nitric oxide (NO) synthesis may affect the course of a trypanosome infection via T-cell responses using mice deficient in inducible NO synthase (iNOS). Parasitemia levels increased at the same rate in both iNOS-deficient homozygous and control heterozygous mice, and peak parasitemia values were the same in both groups. However, the heterozygous mice maintained higher parasitemia levels after the peak of an infection than the homozygous mice due to a decrease in the rate of clearance of parasites. In iNOS-deficient mice there was an increase in the numbers of total CD41 cells and activated (interleukin- 2 receptor-expressing) CD41 cells in infected mice compared with the numbers in uninfected mice. Spleen cells from infected iNOS-deficient mice displayed increased proliferative responses and gamma interferon secretion when stimulated in vitro than those of control mice. These data suggest that NO production depresses T-helper 1-like responses generated during Trypanosoma brucei infections, thus promoting the survival of the parasite

Innate Lymphoid Cell Activation and Sustained Depletion in Blood and Tissue of Children Infected with HIV from Birth Despite Antiretroviral Therapy

Innate lymphoid cells (ILCs) are important for response to infection and for immune development in early life. HIV infection in adults depletes circulating ILCs, but the impact on children infected from birth remains unknown. We study vertically HIV-infected children from birth to adulthood and find severe and persistent depletion of all circulating ILCs that, unlike CD4+ T cells, are not restored by long-term antiretroviral therapy unless initiated at birth. Remaining ILCs upregulate genes associated with cellular activation and metabolic perturbation. Unlike HIV-infected adults, ILCs are also profoundly depleted in tonsils of vertically infected children. Transcriptional profiling of remaining ILCs reveals ongoing cell-type-specific activity despite antiretroviral therapy. Collectively, these data suggest an important and ongoing role for ILCs in lymphoid tissue of HIV-infected children from birth, where persistent depletion and sustained transcriptional activity are likely to have long-term immune consequences that merit further investigation

Risk of Early Versus Later Rebleeding From Dural Arteriovenous Fistulas With Cortical Venous Drainage

Background: Cranial dural arteriovenous fistulas with cortical venous drainage are rare lesions that can present with hemorrhage. A high rate of rebleeding in the early period following hemorrhage has been reported, but published long-term rates are much lower. No study has examined how risk of rebleeding changes over time. Our objective was to quantify the relative incidence of rebleeding in the early and later periods following hemorrhage. Methods: Patients with dural arteriovenous fistula and cortical venous drainage presenting with hemorrhage were identified from the multinational CONDOR (Consortium for Dural Fistula Outcomes Research) database. Natural history follow-up was defined as time from hemorrhage to first treatment, rebleed, or last follow-up. Rebleeding in the first 2 weeks and first year were compared using incidence rate ratio and difference. Results: Of 1077 patients, 250 met the inclusion criteria and had 95 cumulative person-years natural history follow-up. The overall annualized rebleed rate was 7.3% (95% CI, 3.2-14.5). The incidence rate of rebleeding in the first 2 weeks was 0.0011 per person-day; an early rebleed risk of 1.6% in the first 14 days (95% CI, 0.3-5.1). For the remainder of the first year, the incidence rate was 0.00015 per person-day; a rebleed rate of 5.3% (CI, 1.7-12.4) over 1 year. The incidence rate ratio was 7.3 (95% CI, 1.4-37.7; P, 0.026). Conclusions: The risk of rebleeding of a dural arteriovenous fistula with cortical venous drainage presenting with hemorrhage is increased in the first 2 weeks justifying early treatment. However, the magnitude of this increase may be considerably lower than previously thought. Treatment within 5 days was associated with a low rate of rebleeding and appears an appropriate timeframe