Pauli spin blockade in CMOS double quantum dot devices

Silicon quantum dots are attractive candidates for the development of scalable, spin-based qubits. Pauli spin blockade in double quantum dots provides an efficient, temperature independent mechanism for qubit readout. Here we report on transport experiments in double gate nanowire transistors issued from a CMOS process on 300 mm silicon-on-insulator wafers. At low temperature the devices behave as two few-electron quantum dots in series. We observe signatures of Pauli spin blockade with a singlet-triplet splitting ranging from 0.3 to 1.3 meV. Magneto-transport measurements show that transitions which conserve spin are shown to be magnetic-field independent up to B = 6 T.Comment: 5 pages , 4 figure

A CMOS silicon spin qubit

Silicon, the main constituent of microprocessor chips, is emerging as a promising material for the realization of future quantum processors. Leveraging its well-established complementary metal-oxide-semiconductor (CMOS) technology would be a clear asset to the development of scalable quantum computing architectures and to their co-integration with classical control hardware. Here we report a silicon quantum bit (qubit) device made with an industry-standard fabrication process. The device consists of a two-gate, p-type transistor with an undoped channel. At low temperature, the first gate defines a quantum dot (QD) encoding a hole spin qubit, the second one a QD used for the qubit readout. All electrical, two-axis control of the spin qubit is achieved by applying a phase-tunable microwave modulation to the first gate. Our result opens a viable path to qubit up-scaling through a readily exploitable CMOS platform.Comment: 12 pages, 4 figure

A malaria outbreak in Naxalbari, Darjeeling district, West Bengal, India, 2005: weaknesses in disease control, important risk factors

An outbreak of malaria in Naxalbari, West Bengal, India, in 2005 was investigated to understand determinants and propose control measures. Malaria cases were slide-confirmed. Methods included calculation of annual blood examination rates (ABER, number of slides examined/population), collection of water specimens from potential vector-breeding sites, sorting of villages in categories depending on the number of abandoned wells within two kilometers radius and review of the DDT spray coverage. Cases were compared with matched neighbourhood controls in terms of personal protection using matched odds ratios (MOR). 7,303 cases and 17 deaths were reported between April 2005 and March 2006 with a peak during October rains (Attack rate: 50 per 1,000, case fatality: 0.2%). The attack rate increased according to the number of abandoned wells within 2 kilometres radius (P < 0.0001, Chi-square for trend). Abandoned wells were Anopheles breeding sites. Compared with controls, cases were more likely to sleep outdoors (MOR: 3.8) and less likely to use of mosquito nets and repellents (MOR: 0.3 and 0.1, respectively). DDT spray coverage and ABER were 39% and 3.5%, below the recommended 85% and 10%, respectively. Overall, this outbreak resulted from weaknesses in malaria control measures and a combination of factors, including vector breeding, low implementation of personal protection and weak case detection

Thymulin (facteur thymique sérique) and zinc contents of the thymus glands of malnourished children

Protein-energy malnutrition (PEM) leads to an immune deficiency, which is now well documented. Some investigators have suggested that the associated zinc deficiency is important in thymic involution and changes in cellular immunity. To evaluate the respective roles of nutritional deficiency, infection, and zinc in the alteration of thymic function, we measured the amounts of thymulin (facteur thymique sérique, or FTS) and of Zn in the thymus glands of 58 Senegalese children who died in various stages of malnutrition. In the severe forms (marasmus, kwashiorkor, and marasmic kwashiorkor) the thymus was tiny and contained very little thymulin. The Zn content of the thymus was high whatever the nutritional state of the subject and was related significantly only to the presence of infections. In Senegalese children thymic atrophy and depleted thymulin content are associated with severe PEM but not systemic infection or depleted thymic Zn content. (Résumé d'auteur

Persistence of Diphtheria, Hyderabad, India, 2003–2006

During 2003–2006, diphtheria rates in Hyderabad, India, were higher among persons 5–19 years of age, women, and Muslims than among other groups. Vaccine was efficacious among those who received >4 doses. The proportion of the population receiving boosters was low, especially among Muslims. We recommend increasing booster dose coverage

Additional resource needs for viral hepatitis elimination through universal health coverage : projections in 67 low-income and middle-income countries, 2016–30

Background: The World Health Assembly calls for elimination of viral hepatitis as a public health threat by 2030 (ie, −90% incidence and −65% mortality). However, WHO's 2017 cost projections to achieve health-related Sustainable Development Goals did not include the resources needed for hepatitis testing and treatment. We aimed to estimate the incremental commodity cost of adding scaled up interventions for testing and treatment of hepatitis to WHO's investment scenarios. Methods: We added modelled costs for implementing WHO recommended hepatitis testing and treatment to the 2017 WHO cost projections. We quantified additional requirements for diagnostic tests, medicines, health workers' time, and programme support across 67 low-income and middle-income countries, from 2016–30. A progress scenario scaled up interventions and a more ambitious scenario was modelled to reach elimination by 2030. We used 2018 best available prices of diagnostics and generic medicines. We estimated total costs and the additional investment needed over the projection of the 2016 baseline cost. Findings: The 67 countries considered included 230 million people living with hepatitis B virus (HBV) and 52 million people living with hepatitis C virus (HCV; 90% and 73% of the world's total, respectively). Under the progress scenario, 3250 million people (2400 million for HBV and 850 million for HCV) would be tested and 58·2 million people (24·1 million for HBV and 34·1 million for HCV) would be treated (total additional cost US$27·1 billion). Under the ambitious scenario, 11 631 million people (5502 million for HBV and 6129 million for HCV) would be tested and 93·8 million people (32·2 million for HBV and 61·6 million for HCV) would be treated (total additional cost$58·7 billion), averting 4·5 million premature deaths and leading to a gain of 51·5 million healthy life-years by 2030. However, if affordable HCV medicines remained inaccessible in 13 countries where medicine patents are protected, the additional cost of the ambitious scenario would increase to $118 billion. Hepatitis elimination would account for a 1·5% increase to the WHO ambitious health-care strengthening scenario costs, avert an additional 4·6% premature deaths, and add an additional 9·6% healthy life-years from 2016–30. Interpretation: Access to affordable medicines in all countries will be key to reach hepatitis elimination. This study suggests that elimination is feasible in the context of universal health coverage. It points to commodities as key determinants for the overall price tag and to options for cost reduction strategies. Funding: WHO, United States Centers for Disease Control and Prevention, Unitaid

Self-Reported Occupational Exposure to HIV and Factors Influencing its Management Practice: A Study of Healthcare Workers in Tumbi and Dodoma Hospitals, Tanzania.

Blood borne infectious agents such as hepatitis B virus (HBV), hepatitis C virus (HCV) and human immune deficiency virus (HIV) constitute a major occupational hazard for healthcare workers (HCWs). To some degree it is inevitable that HCWs sustain injuries from sharp objects such as needles, scalpels and splintered bone during execution of their duties. However, in Tanzania, there is little or no information on factors that influence the practice of managing occupational exposure to HIV by HCWs. This study was conducted to determine the prevalence of self-reported occupational exposure to HIV among HCWs and explore factors that influence the practice of managing occupational exposure to HIV by HCWs in Tanzania. Self-administered questionnaire was designed to gather information of healthcare workers' occupational exposures in the past 12 months and circumstances in which these injuries occurred. Practice of managing occupational exposure was assessed by the following questions: Nearly half of the HCWs had experienced at least one occupational injury in the past 12 months. Though most of the occupational exposures to HIV were experienced by female nurses, non-medical hospital staff received PEP more frequently than nurses and doctors. Doctors and nurses frequently encountered occupational injuries in surgery room and labor room respectively. HCWs with knowledge on the possibility of HIV transmission and those who knew whom to contact in event of occupational exposure to HIV were less likely to have poor practice of managing occupational exposure. Needle stick injuries and splashes are common among HCWs at Tumbi and Dodoma hospitals. Knowledge of the risk of HIV transmission due to occupational exposure and knowing whom to contact in event of exposure predicted practice of managing the exposure. Thus provision of health education on occupational exposure may strengthen healthcare workers' practices to manage occupational exposure