Ultrafast all-optical wavelength conversion in silicon waveguides using femtosecond pump-probe pulses

Experimental results on ultrafast all-optical wavelength conversion in silicon-on-insulator waveguides are presented. Red and blue shifts of 10nm have been observed in femtosecond pump-probe experiments. Alloptical switching and the importance of waveguide dispersion are discussed

Burn Care in the Greek and Roman Antiquity

The last century brought about more rapid new developments in the treatment of burns, which significantly lowered the mortality of burn injuries. However, burns were already treated in antiquity, where the threshold from spirituality to scientific medicine originated. The existing literature on burn treatment is very limited and there are many cross-references, some of them incorrect. The aim of this work by an interdisciplinary team of historians and physicians is to offer a more precise reproduction of the burn treatment of Greek and Roman antiquity using original texts in context and with a modern scientific background. There are many sources from ancient doctors on the subject of burn treatment, as well as the treatment of burned-out wounds and frostbite, which have not yet been mentioned. The literature research also showed an understanding of scientific contexts in ancient medicine, such as antiseptics or rheology. Interestingly, there was a change in burn medicine from everyday Greek medicine to Roman military medicine with other burn patterns. The care of patients using analgetics and the therapy of burn shock arose from the literature. The ancient world is considered to be the foundation of medicine, but it is believed to have been based mainly on shamanism rather than science. However, already more than two millennia ago, burns were correctly assessed and treated according to today’s scientific standards and scientific relationships were recognized

International Network for Capacity Building for the Control of Emerging Viral Vector-Borne Zoonotic Diseases: Arbo-Zoonet

Arboviruses are arthropod-borne viruses, which include West Nile fever virus (WNFV), a mosquito-borne virus, Rift Valley fever virus (RVFV), a mosquito-borne virus, and Crimean-Congo haemorrhagic fever virus (CCHFV), a tick-borne virus. These arthropod-borne viruses can cause disease in different domestic and wild animals and in humans, posing a threat to public health because of their epidemic and zoonotic potential. In recent decades, the geographical distribution of these diseases has expanded. Outbreaks of WNF have already occurred in Europe, especially in the Mediterranean basin. Moreover, CCHF is endemic in many European countries and serious outbreaks have occurred, particularly in the Balkans, Turkey and Southern Federal Districts of Russia. In 2000, RVF was reported for the first time outside the African continent, with cases being confirmed in Saudi Arabia and Yemen. This spread was probably caused by ruminant trade and highlights that there is a threat of expansion of the virus into other parts of Asia and Europe. In the light of global warming and globalisation of trade and travel, public interest in emerging zoonotic diseases has increased. This is especially evident regarding the geographical spread of vector-borne diseases. A multi-disciplinary approach is now imperative, and groups need to collaborate in an integrated manner that includes vector control, vaccination programmes, improved therapy strategies, diagnostic tools and surveillance, public awareness, capacity building and improvement of infrastructure in endemic regions

Recurrent Plasmodium falciparum Malaria Infections in Kenyan Children Diminish T-Cell Immunity to Epstein Barr Virus Lytic but Not Latent Antigens

Plasmodium falciparum malaria (Pf-malaria) and Epstein Barr Virus (EBV) infections coexist in children at risk for endemic Burkitt's lymphoma (eBL); yet studies have only glimpsed the cumulative effect of Pf-malaria on EBV-specific immunity. Using pooled EBV lytic and latent CD8+ T-cell epitope-peptides, IFN-γ ELISPOT responses were surveyed three times among children (10 months to 15 years) in Kenya from 2002–2004. Prevalence ratios (PR) and 95% confidence intervals (CI) were estimated in association with Pf-malaria exposure, defined at the district-level (Kisumu: holoendemic; Nandi: hypoendemic) and the individual-level. We observed a 46% decrease in positive EBV lytic antigen IFN-γ responses among 5–9 year olds residing in Kisumu compared to Nandi (PR: 0.54; 95% CI: 0.30–0.99). Individual-level analysis in Kisumu revealed further impairment of EBV lytic antigen responses among 5–9 year olds consistently infected with Pf-malaria compared to those never infected. There were no observed district- or individual-level differences between Pf-malaria exposure and EBV latent antigen IFN-γ response. The gradual decrease of EBV lytic antigen but not latent antigen IFN-γ responses after primary infection suggests a specific loss in immunological control over the lytic cycle in children residing in malaria holoendemic areas, further refining our understanding of eBL etiology

Stability of interferon-gamma and interleukin-10 responses to Plasmodium falciparum liver stage antigen-1 and thrombospondin-related adhesive protein in residents of a malaria holoendemic area

The stability of anti-malarial immunity will influence the interpretation of immunologic endpoints during malaria vaccine trials conducted in endemic areas. Therefore, we evaluated cytokine responses to Plasmodium falciparum liver stage antigen-1 (LSA-1) and thrombospondin-related adhesive protein (TRAP) by Kenyans from a holoendemic area at a 9-month interval. The proportion of adults with interferon-gamma (IFN-gamma) responses to 9-mer LSA-1 peptides was similar at both time-points, whereas responses from children decreased (P \u3c 0.05). Response to the longer, 23-mer LSA-1 peptide was variable, decreasing in adults and children over time (P \u3c 0.02 and P \u3c 0.001, respectively). The proportion of children with IFN-gamma responses to either antigen at the second time-point was significantly lower than that of adults, yet more adults responded to 9-mer TRAP peptides (P \u3c 0.02). In contrast, the proportion of interleukin-10 responses to LSA-1 and TRAP was similar at both time-points for both age groups. Most noteworthy was that even when the repeat cross-sectional frequency of cytokine responses was the same, these responses were not generated by the same individuals. This suggests that cytokine responses to LSA-1 and TRAP are transient under natural exposure conditions

Time to Reflect on Global Health Agenda in Kenya: A Tribute to our Academic and Biomedical Research Mentors

We submit this column to present a brief biography, a tribute to three departed global health mentors who were instrumental in our careers and for the growth of biomedical research in Kenya. We briefly discuss their educational backgrounds and put forth a set of qualities, values, personal supportive experiences, and achievements that nurtured our careers as scientists. The mentors are Prof. Ayub Opiyo Ofulla, Dr. John F. Kennedy Vulule, and Dr. Peter Odada Sumba. We appeal to the community of researchers in biomedical sciences, global health, and epidemiology who study a particular disease or health risk (conducting interventional and observational research) to mentor, teach, and serve as role models for upcoming scholars. There is a need for a positive and supportive attitude to create a universal environment to nurture the next generation of researchers transcending race, color, nationality, ethnicity, culture, faith, gender identities, sexual orientation, age, ability, and background

Antibodies to pre-erythrocytic Plasmodium falciparum antigens and risk of clinical malaria in Kenyan children

BACKGROUND: IgG antibodies to pre-erythrocytic antigens are involved in prevention of infection and disease in animal models of malaria but have not been associated with protection against disease in human malaria. METHODS: Levels of IgG antibodies to circumsporozoite protein (CSP), liver-stage antigen type 1 (LSA-1), and thrombospondin-related adhesive protein (TRAP) were measured in 86 children in a malaria-holoendemic area of Kenya. The children were then monitored for episodes of clinical malaria for 52 weeks. RESULTS: Children with high levels of IgG antibodies to CSP, LSA-1, and TRAP had a decreased risk of clinical malaria (adjusted hazard ratio, 0.29; 95% confidence interval 0.10-0.81; P = .02), a lower incidence of clinical malaria (P=.006), protection from clinical malaria with a parasite level of \u3e or =4000 parasites/microL (P= .03), and a higher hemoglobin level at enrollment (P= .009), compared with children with lower antibody levels. Protection against malaria morbidity was associated primarily with antibodies to CSP and LSA-1. CONCLUSIONS: Kenyan children with high levels of IgG antibodies to the pre-erythrocytic antigens CSP, LSA-1, and TRAP have a lower risk of developing clinical malaria than children without high levels of these antibodies. The decreased risk of clinical malaria may be mediated in part by prevention of high-density parasitemia

Longevity of Genotype-Specific Immune Responses to Plasmodium falciparum Merozoite Surface Protein 1 in Kenyan Children from Regions of Different Malaria Transmission Intensity

Naturally acquired immunity to Plasmodium falciparum presents a changing landscape as malaria control programs and vaccine initiatives are implemented. Determining which immunologic indicators remain surrogates of past infection, as opposed to mediators of protection, led us to compare stability of immune responses across regions with divergent malaria transmission intensities. A repeat cross-sectional study of Kenyan children from a malaria-holoendemic area and an epidemic-prone area was used to examine longitudinal antibody and interferon-gamma (IFN-gamma) responses to the 3D7 and FVO variants of merozoite surface protein 1 (MSP1). Antibodies to MSP1 were common in both study populations and did not significantly wane over a 21-month time period. IFN-gamma responses were less frequent and rapidly disappeared in children after a prolonged period of no malaria transmission. Antibody and IFN-gamma responses rarely correlated with each other; however, MSP1-specific IFN-gamma response correlated with lack of concurrent P. falciparum parasitemia of the same genotype, though only statistically significantly in the malaria-holoendemic region (odds ratio = 0.31, 95% confidence interval = 0.12-0.84). This study affirms that antimalarial antibodies are informative for evaluation of history of malaria exposure within individuals, whereas cell-mediated immunity, though short lived under natural exposure conditions, might provide an assessment of recent infection and protection from parasitemia

Correlation of high levels of antibodies to multiple pre-erythrocytic Plasmodium falciparum antigens and protection from infection

High levels of antibodies to multiple antigens may be more strongly associated with protection from infection than antibodies to a single antigen. Antibody-associated protection against Plasmodium falciparum infection was assessed in a cohort of 68 adults living in an area of holoendemic malaria in Kenya. Antibodies to the pre-erythrocytic antigens circumsporozoite protein (CSP), liver-stage antigen-1 (LSA-1), thrombospondin-related adhesive protein (TRAP), and blood-stage antigens apical membrane antigen-1 (AMA-1), erythrocyte binding antigen-175 (EBA-175), and merozoite surface protein 1 (MSP-1) were tested. Peptides were used for CSP (NANP repeat) and LSA-1 (central repeat), and recombinant antigens were used for TRAP (aa D(48)-K(394)), AMA-1 (ectodomain, non-glycosylated), EBA-175 (non-glycosylated), and MSP-1 (MSP-1(19)). Weekly microscopy testing for P. falciparum infection was performed over a 12-week period after drug-mediated clearance of P. falciparum parasitemia. Individuals with high levels of IgG antibodies (\u3e 2 arbitrary units) to CSP, LSA-1, and TRAP had a 57% decrease in the risk of infection (95% confidence interval = 20-77%, P = 0.016). This decreased risk remained significant after adjustment for age, prior parasitemia, bed net use, sickle cell trait, and village of residence. In contrast, protection against infection did not correlate with high levels of IgG antibodies to blood-stage antigens or IgM antibodies to pre-erythrocytic or blood-stage antigens. High levels of IgG antibodies to CSP, LSA-1, and TRAP may be useful immune correlates of protection against P. falciparum infection in malaria-endemic populations

Identification of a novel variant of LMP-1 of EBV in patients with endemic Burkitt lymphoma in western Kenya

BACKGROUND: Epstein Barr virus (EBV) is a gammaherpesvirus that is associated with nasopharyngeal carcinoma (NPC) and endemic Burkitt lymphoma (eBL). EBV carries several latent genes that contribute to oncogenesis including the latent membrane protein 1 (LMP-1), a known oncogene and constitutively active CD40 homolog. Variation in the C terminal region of LMP-1 has been linked to NPC pathogenesis, but little is known regarding LMP-1 variation and eBL. RESULTS: In the present study, peripheral blood samples were obtained from 38 eBL patients and 22 healthy controls in western Kenya, where the disease is endemic. The LMP-1 C-terminal region from these samples was sequenced and analyzed. The frequency of a 30 base pair deletion of LMP-1 previously linked to NPC was not associated with eBL compared to healthy controls. However a novel LMP-1 variant was identified, called K for Kenya and for the G318K mutation that characterizes it. The K variant LMP-1 was found in 40.5% of eBL sequences and 25.0% of healthy controls. All K variant sequences contained mutations in both of the previously described minimal T cell epitopes in the C terminal end of LMP-1. These mutations occurred in the anchor residue at the C-terminal binding groove of both epitopes, a pocket necessary for MHC loading. CONCLUSIONS: Overall, our results suggest that there is a novel K variant of LMP-1 in Kenya that may be associated with eBL. Further studies are necessary to determine the functional implications of the LMP-1 variant on early events in eBL genesis