51 research outputs found
Orbital excitation blockade and algorithmic cooling in quantum gases
Interaction blockade occurs when strong interactions in a confined few-body
system prevent a particle from occupying an otherwise accessible quantum state.
Blockade phenomena reveal the underlying granular nature of quantum systems and
allow the detection and manipulation of the constituent particles, whether they
are electrons, spins, atoms, or photons. The diverse applications range from
single-electron transistors based on electronic Coulomb blockade to quantum
logic gates in Rydberg atoms. We have observed a new kind of interaction
blockade in transferring ultracold atoms between orbitals in an optical
lattice. In this system, atoms on the same lattice site undergo coherent
collisions described by a contact interaction whose strength depends strongly
on the orbital wavefunctions of the atoms. We induce coherent orbital
excitations by modulating the lattice depth and observe a staircase-type
excitation behavior as we cross the interaction-split resonances by tuning the
modulation frequency. As an application of orbital excitation blockade (OEB),
we demonstrate a novel algorithmic route for cooling quantum gases. Our
realization of algorithmic cooling utilizes a sequence of reversible OEB-based
quantum operations that isolate the entropy in one part of the system, followed
by an irreversible step that removes the entropy from the gas. This work opens
the door to cooling quantum gases down to ultralow entropies, with implications
for developing a microscopic understanding of strongly correlated electron
systems that can be simulated in optical lattices. In addition, the close
analogy between OEB and dipole blockade in Rydberg atoms provides a roadmap for
the implementation of two-qubit gates in a quantum computing architecture with
natural scalability.Comment: 6 pages, 4 figure
Association between COX-2 rs 6681231 Genotype and Interleukin-6 in Periodontal Connective Tissue. A Pilot Study
This study was partially undertaken at the UCL Eastman Dental Institute, which received a proportion of funding from the Department of Health’s
National Institute of Health Research (NIHR) Biomedical Research Centres funding scheme
The epidemiology of sexually transmitted co-infections in HIV-positive and HIV-negative African-Caribbean women in Toronto
Hepatitis B virus infection in HIV-positive individuals in the UK collaborative HIV cohort (UK CHIC) study.
Hepatitis B virus (HBV) infection is an increasingly important cause of morbidity and mortality in HIV-infected adults. This study aimed to determine the prevalence and incidence of HBV in the UK CHIC Study, a multicentre observational cohort
IL-6 and IL-10 gene polymorphisms in patients with aggressive periodontitis: effects on GCF, serum and clinic parameters
Monitoring quality and coverage of harm reduction services for people who use drugs: a consensus study.
BACKGROUND AND AIMS: Despite advances in our knowledge of effective services for people who use drugs over the last decades globally, coverage remains poor in most countries, while quality is often unknown. This paper aims to discuss the historical development of successful epidemiological indicators and to present a framework for extending them with additional indicators of coverage and quality of harm reduction services, for monitoring and evaluation at international, national or subnational levels. The ultimate aim is to improve these services in order to reduce health and social problems among people who use drugs, such as human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infection, crime and legal problems, overdose (death) and other morbidity and mortality. METHODS AND RESULTS: The framework was developed collaboratively using consensus methods involving nominal group meetings, review of existing quality standards, repeated email commenting rounds and qualitative analysis of opinions/experiences from a broad range of professionals/experts, including members of civil society and organisations representing people who use drugs. Twelve priority candidate indicators are proposed for opioid agonist therapy (OAT), needle and syringe programmes (NSP) and generic cross-cutting aspects of harm reduction (and potentially other drug) services. Under the specific OAT indicators, priority indicators included 'coverage', 'waiting list time', 'dosage' and 'availability in prisons'. For the specific NSP indicators, the priority indicators included 'coverage', 'number of needles/syringes distributed/collected', 'provision of other drug use paraphernalia' and 'availability in prisons'. Among the generic or cross-cutting indicators the priority indicators were 'infectious diseases counselling and care', 'take away naloxone', 'information on safe use/sex' and 'condoms'. We discuss conditions for the successful development of the suggested indicators and constraints (e.g. funding, ideology). We propose conducting a pilot study to test the feasibility and applicability of the proposed indicators before their scaling up and routine implementation, to evaluate their effectiveness in comparing service coverage and quality across countries. CONCLUSIONS: The establishment of an improved set of validated and internationally agreed upon best practice indicators for monitoring harm reduction service will provide a structural basis for public health and epidemiological studies and support evidence and human rights-based health policies, services and interventions
PRIMARY EXTRAMEDULLARY PLASMACYTOMA IN THE MIDDLE-EAR - DIFFERENTIAL-DIAGNOSIS AND MANAGEMENT
Primary extramedullary plasmacytoma (PEP) is an uncommon neoplasm of
plasma cell origin which afflicts the head and neck mainly. In this
study we report a rare case of a 34-year-old man who presented with left
ear tinnitus, hearing loss, blocked feeling and headache. Exploratory
tympanotomy revealed a mass extending into the attic and the mastoid
antrum. Following canal wall-up mastoidectomy, the tumour was carefully
removed. Histological examination (including immunoperoxidase staining)
and thorough clinical, laboratory and radiological evaluation revealed
an exclusively cytoplasmic monoclonal IgG immunoglobulin PEP. The
combination of surgery (including a second-look procedure) and
radiotherapy used in this case may be an over-treatment. However, the
patient is still disease-free seven years after his first admission to
hospital
Luminescence properties of (Lu,Y)(2)SiO5 : Ce and Gd2SiO5 : Ce single crystal scintillators under X-ray excitation for use in medical imaging systems
Luminescence properties of (Lu, Y)2SiO5: Ce and Gd2SiO5: Ce single crystal scintillators under X-ray excitation for use in medical imaging systems
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