Observation of high-energy neutrinos from the Galactic plane

The origin of high-energy cosmic rays, atomic nuclei that continuously impact Earth's atmosphere, is unknown. Because of deflection by interstellar magnetic fields, cosmic rays produced within the Milky Way arrive at Earth from random directions. However, cosmic rays interact with matter near their sources and during propagation, which produces high-energy neutrinos. We searched for neutrino emission using machine learning techniques applied to 10 years of data from the IceCube Neutrino Observatory. By comparing diffuse emission models to a background-only hypothesis, we identified neutrino emission from the Galactic plane at the 4.5σ level of significance. The signal is consistent with diffuse emission of neutrinos from the Milky Way but could also arise from a population of unresolved point sources.

Evidence for neutrino emission from the nearby active galaxy NGC 1068

A supermassive black hole, obscured by cosmic dust, powers the nearby active galaxy NGC 1068. Neutrinos, which rarely interact with matter, could provide information on the galaxy’s active core. We searched for neutrino emission from astrophysical objects using data recorded with the IceCube neutrino detector between 2011 and 2020. The positions of 110 known gamma-ray sources were individually searched for neutrino detections above atmospheric and cosmic backgrounds. We found that NGC 1068 has an excess of 79 − 20 + 22 neutrinos at tera–electron volt energies, with a global significance of 4.2σ, which we interpret as associated with the active galaxy. The flux of high-energy neutrinos that we measured from NGC 1068 is more than an order of magnitude higher than the upper limit on emissions of tera–electron volt gamma rays from this source.

Search for Unstable Sterile Neutrinos with the IceCube Neutrino Observatory

We present a search for an unstable sterile neutrino by looking for a resonant signal in eight years of atmospheric ν_{μ} data collected from 2011 to 2019 at the IceCube Neutrino Observatory. Both the (stable) three-neutrino and the 3+1 sterile neutrino models are disfavored relative to the unstable sterile neutrino model, though with p values of 2.8% and 0.81%, respectively, we do not observe evidence for 3+1 neutrinos with neutrino decay. The best-fit parameters for the sterile neutrino with decay model from this study are Δm_{41}^{2}=6.7_{-2.5}^{+3.9}  eV^{2}, sin^{2}2θ_{24}=0.33_{-0.17}^{+0.20}, and g^{2}=2.5π±1.5π, where g is the decay-mediating coupling. The preferred regions of the 3+1+decay model from short-baseline oscillation searches are excluded at 90% C.L.

Strong Constraints on Neutrino Nonstandard Interactions from TeV-Scale ν_{μ} Disappearance at IceCube

We report a search for nonstandard neutrino interactions (NSI) using eight years of TeV-scale atmospheric muon neutrino data from the IceCube Neutrino Observatory. By reconstructing incident energies and zenith angles for atmospheric neutrino events, this analysis presents unified confidence intervals for the NSI parameter ε_{μτ}. The best-fit value is consistent with no NSI at a p value of 25.2%. With a 90% confidence interval of -0.0041≤ε_{μτ}≤0.0031 along the real axis and similar strength in the complex plane, this result is the strongest constraint on any NSI parameter from any oscillation channel to date.

Search for Relativistic Magnetic Monopoles with Eight Years of IceCube Data

We present an all-sky 90% confidence level upper limit on the cosmic flux of relativistic magnetic monopoles using 2886 days of IceCube data. The analysis was optimized for monopole speeds between 0.750c and 0.995c, without any explicit restriction on the monopole mass. We constrain the flux of relativistic cosmic magnetic monopoles to a level below 2.0×10^{-19}  cm^{-2} s^{-1} sr^{-1} over the majority of the targeted speed range. This result constitutes the most strict upper limit to date for magnetic monopoles with β≳0.8 and up to β∼0.995 and fills the gap between existing limits on the cosmic flux of nonrelativistic and ultrarelativistic magnetic monopoles.

eV-Scale Sterile Neutrino Search Using Eight Years of Atmospheric Muon Neutrino Data from the IceCube Neutrino Observatory

The results of a 3+1 sterile neutrino search using eight years of data from the IceCube Neutrino Observatory are presented. A total of 305 735 muon neutrino events are analyzed in reconstructed energy-zenith space to test for signatures of a matter-enhanced oscillation that would occur given a sterile neutrino state with a mass-squared differences between 0.01 and 100  eV^{2}. The best-fit point is found to be at sin^{2}(2θ_{24})=0.10 and Δm_{41}^{2}=4.5  eV^{2}, which is consistent with the no sterile neutrino hypothesis with a p value of 8.0%.

Characteristics of the Diffuse Astrophysical Electron and Tau Neutrino Flux with Six Years of IceCube High Energy Cascade Data

We report on the first measurement of the astrophysical neutrino flux using particle showers (cascades) in IceCube data from 2010-2015. Assuming standard oscillations, the astrophysical neutrinos in this dedicated cascade sample are dominated (∼90%) by electron and tau flavors. The flux, observed in the sensitive energy range from 16 TeV to 2.6 PeV, is consistent with a single power-law model as expected from Fermi-type acceleration of high energy particles at astrophysical sources. We find the flux spectral index to be γ=2.53±0.07 and a flux normalization for each neutrino flavor of ϕ_{astro}=1.66_{-0.27}^{+0.25} at E_{0}=100  TeV, in agreement with IceCube's complementary muon neutrino results and with all-neutrino flavor fit results. In the measured energy range we reject spectral indices γ≤2.28 at ≥3σ significance level. Because of high neutrino energy resolution and low atmospheric neutrino backgrounds, this analysis provides the most detailed characterization of the neutrino flux at energies below ∼100  TeV compared to previous IceCube results. Results from fits assuming more complex neutrino flux models suggest a flux softening at high energies and a flux hardening at low energies (p value ≥0.06). The sizable and smooth flux measured below ∼100  TeV remains a puzzle. In order to not violate the isotropic diffuse gamma-ray background as measured by the Fermi Large Area Telescope, it suggests the existence of astrophysical neutrino sources characterized by dense environments which are opaque to gamma rays.

High prevalence of geriatric syndromes in older adults

INTRODUCTION

The geriatric syndromes of frailty, sarcopenia, weight loss, and dementia are highly prevalent in elderly individuals across all care continuums. Despite their deleterious impact on quality of life, disability, and mortality in older adults, they are frequently under-recognized. At Saint Louis University, the Rapid Geriatric Assessment (RGA) was developed as a brief screening tool to identify these four geriatric syndromes.

MATERIALS AND METHODS

From 2015-2019, the RGA, comprised of the FRAIL, SARC-F, Simplified Nutritional Appetite Questionnaire (SNAQ), and Rapid Cognitive Screen (RCS) tools and a question on Advance Directives, was administered to 11,344 individuals ≥ 65 years of age across Missouri in community, office-based, hospital, Programs of All-Inclusive Care for the Elderly (PACE), and nursing home care settings. Standard statistical methods were used to calculate the prevalence of frailty, sarcopenia, weight loss, and dementia across the sample.

RESULTS

Among the 11,344 individuals screened by the RGA, 41.0% and 30.4% met the screening criteria for pre-frailty and frailty respectively, 42.9% met the screening criteria for sarcopenia, 29.3% were anorectic and at risk for weight loss, and 28.1% screened positive for dementia. The prevalence of frailty, risk for weight loss, sarcopenia, and dementia increased with age and decreased when hospitalized patients and those in the PACE program or nursing home were excluded.

CONCLUSIONS

Using the RGA as a valid screening tool, the prevalence of one or more of the geriatric syndromes of frailty, sarcopenia, weight loss, and dementia in older adults across all care continuums is quite high. Management approaches exist for each of these syndromes that can improve outcomes. It is suggested that the brief RGA screening tool be administered to persons 65 and older yearly as part of the Medicare Annual Wellness Visit.

Time-Integrated Neutrino Source Searches with 10 Years of IceCube Data

This Letter presents the results from pointlike neutrino source searches using ten years of IceCube data collected between April 6, 2008 and July 10, 2018. We evaluate the significance of an astrophysical signal from a pointlike source looking for an excess of clustered neutrino events with energies typically above ∼1  TeV among the background of atmospheric muons and neutrinos. We perform a full-sky scan, a search within a selected source catalog, a catalog population study, and three stacked Galactic catalog searches. The most significant point in the northern hemisphere from scanning the sky is coincident with the Seyfert II galaxy NGC 1068, which was included in the source catalog search. The excess at the coordinates of NGC 1068 is inconsistent with background expectations at the level of 2.9σ after accounting for statistical trials from the entire catalog. The combination of this result along with excesses observed at the coordinates of three other sources, including TXS 0506+056, suggests that, collectively, correlations with sources in the northern catalog are inconsistent with background at 3.3σ significance. The southern catalog is consistent with background. These results, all based on searches for a cumulative neutrino signal integrated over the 10 years of available data, motivate further study of these and similar sources, including time-dependent analyses, multimessenger correlations, and the possibility of stronger evidence with coming upgrades to the detector.

Constraints on Minute-Scale Transient Astrophysical Neutrino Sources

High-energy neutrino emission has been predicted for several short-lived astrophysical transients including gamma-ray bursts (GRBs), core-collapse supernovae with choked jets, and neutron star mergers. IceCube's optical and x-ray follow-up program searches for such transient sources by looking for two or more muon neutrino candidates in directional coincidence and arriving within 100 s. The measured rate of neutrino alerts is consistent with the expected rate of chance coincidences of atmospheric background events and no likely electromagnetic counterparts have been identified in Swift follow-up observations. Here, we calculate generic bounds on the neutrino flux of short-lived transient sources. Assuming an E^{-2.5} neutrino spectrum, we find that the neutrino flux of rare sources, like long gamma-ray bursts, is constrained to <5% of the detected astrophysical flux and the energy released in neutrinos (100 GeV to 10 PeV) by a median bright GRB-like source is <10^{52.5}  erg. For a harder E^{-2.13} neutrino spectrum up to 30% of the flux could be produced by GRBs and the allowed median source energy is <10^{52}  erg. A hypothetical population of transient sources has to be more common than 10^{-5}  Mpc^{-3}  yr^{-1} (5×10^{-8}  Mpc^{-3}  yr^{-1} for the E^{-2.13} spectrum) to account for the complete astrophysical neutrino flux.

Search for neutrinos from decaying dark matter with IceCube: IceCube Collaboration

With the observation of high-energy astrophysical neutrinos by the IceCube Neutrino Observatory, interest has risen in models of PeV-mass decaying dark matter particles to explain the observed flux. We present two dedicated experimental analyses to test this hypothesis. One analysis uses 6 years of IceCube data focusing on muon neutrino 'track' events from the Northern Hemisphere, while the second analysis uses 2 years of 'cascade' events from the full sky. Known background components and the hypothetical flux from unstable dark matter are fitted to the experimental data. Since no significant excess is observed in either analysis, lower limits on the lifetime of dark matter particles are derived: we obtain the strongest constraint to date, excluding lifetimes shorter than10 28 s at 90% CL for dark matter masses above 10 TeV .

The Irish approach to postaccident preparedness

Ireland does not have any nuclear installations, but a nuclear accident at a site elsewhere, particularly in Europe, could result in widespread but low-level contamination of the Irish environment. Ireland's National Emergency Plan for Nuclear Accidents was established, following the Chernobyl accident, for the national response to a nuclear accident abroad affecting Ireland. It has since been extended to also cover domestic radiological emergencies for which a national-level input is required to support the local response. This paper describes the approach taken to developing and maintaining arrangements for a nuclear accident abroad. The use of hazard assessments to prioritise resource use and planned protective actions, and the specifics of Ireland's situation in terms of location, governance, economy, and available resources have heavily influenced the preparedness arrangements. In particular, the importance of the ingestion pathway to projected doses, together with the significance of agricultural exports to the Irish economy, has had a key influence on the arrangements in place.

Improving the safety and tolerability of local anaesthetic outpatient transperineal prostate biopsies: A pilot study of the CAMbridge PROstate Biopsy (CAMPROBE) method

OBJECTIVES

The aim of this study was to pilot the use of a bespoke device (CAMPROBE, the CAMbridge PROstate Biopsy) to enable routine outpatient free-hand local anaesthetic (LA) transperineal prostate biopsies.

MATERIALS AND METHODS

The CAMPROBE prototype was designed and built in our institution. Men on active surveillance due prostate resampling were invited to have a CAMPROBE biopsy as an alternative to repeat transrectal ultrasound-guided prostate biopsies (TRUSBx) as part of an approved trial (NCT02375035). Biopsies were performed using LA infiltration only, without sedation or additional analgesia. Patient-reported outcomes were recorded at day 0 and 7 using validated questionnaires and visual analogue scales (VAS). Complications were recorded prospectively.

RESULTS

Thirty men underwent biopsies with a median of 11 cores taken per procedure (interquartile range 10-12). There were no infections, sepsis or retention episodes. Haematuria and haematospermia occurred in 67% and 62% of patients, which are similar to rates reported for TRUSBx. Mean VAS for pain (0-10 scale) was less than 3 for every part of the procedure. All 30 men described the procedure as tolerable under LA. In total, 26/30 (86.7%) men expressed a preference for a CAMPROBE procedure over TRUSBx and a further 3 (10.0%) would have either.

CONCLUSIONS

In this small pilot study, the CAMPROBE device and method appears to be a safe, simple and well-tolerated out-patient transperineal replacement for TRUSBx. A major new National Institute for Health Research grant will allow its further development from a prototype to a single use, low-cost disposable device ready for multi-centre testing.

LEVEL OF EVIDENCE

1b: individual cohort study.

The IUR Forum: Worldwide Harmonisation of Networks to Support Integration of Scientific Knowledge and Consensus Development in Radioecology

During the past decades, many specialised networks have formed to meet specific radioecological objectives, whether regional or sectorial (purpose-oriented). Regional networks deal with an array of radioecological issues related to their territories. Examples include the South Pacific network of radioecologists, and the European network of excellence in radioecology. The latter is now part of the European platform for radiation protection. Sectorial networks are more problem-oriented, often with wider international representativeness, but restricted to one specific issue, (e.g. radioactive waste, low-level atmospheric contamination, modelling). All such networks, while often working in relative isolation, contribute to a flow of scientific information which, through United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR's) efforts of synthesis, feeds into the radiation protection frameworks of protecting humans and the environment. The IUR has therefore prompted a co-construction process aimed at improving worldwide harmonisation of radioecology networks. An initiative based on an initial set of 15 networks, now called the IUR FORUM, was launched in June 2014. The IUR Forum agreed to build a framework for improved coordination of scientific knowledge, integration and consensus development relative to environmental radioactivity. Three objectives have been collectively assigned to the IUR FORUM: (1) coordination, (2) global integration and construction of consensus and (3) maintenance of expertise. One particular achievement of the FORUM was an improved description and common understanding of the respective roles and functions of the various networks within the overall scene of radioecology R&D. It clarifies how the various networks assembled within the IUR FORUM interface with UNSCEAR and other international regulatory bodies (IAEA, ICRP), and how consensus on the assessment of risk is constructed. All these agencies interact with regional networks covering different geographical areas, and with other networks which address specific topics within radiation protection. After holding its first Consensus Symposium in 2015, examining the possible ecological impact of radiation from environmental contamination, the IUR FORUM continues its work towards improved radiation protection of humans and the environment. We welcome new members.

Oncology nursing in Cuba: report of the delegation

In December 2011, the first delegation of oncology nurses from the United States visited Havana, Cuba. The delegation included oncology nurses, educators, and leaders from across America and provided opportunities to learn about the healthcare system, cancer, and oncology nursing in Cuba. Delegation members attended lectures, toured facilities, and enjoyed Cuban culture. This exchange highlighted the similarities in cancer care and oncology nursing between countries and opened doors for future collaborations.

Growth Evolution of (Zn,Cd)Se Quantum Dots Deduced from Spatially Resolved Structural and Optical Characterization

The growth mode of CdSe layers grown by migration enhanced epitaxy between ZnSe barriers has been investigated. In situ reflection high-energy electron diffraction shows a gradual transition to a three-dimensional growth mode which, however, is not accompanied by a change of the surface lattice constant. High-resolution transmission electron micrographs reveal a strong Cd diffusion, leading to ternary ZnCdSe quantum wells. Furthermore. composition fluctuations perpendicular to the growth direction on a nanometer scale are found already prior to the beginning of the growth mode transition. In the case of heterostructures containing a CdSe layer that has undergone the growth mode transition, micrographs show Cd-rich quantum dots with diameters of around 8 nm and heights of around 1.5 nm within a ternary quantum well. By spatially resolved photoluminescence the emission from single quantum dots could be observed. The polarization dependence of the emission from single dots indicates an asymmetric shape of the dots with certain preferential orientations along the [110] and [110] directions.

Amphipols: polymeric surfactants for membrane biology research

Membrane proteins classically are handled in aqueous solutions as complexes with detergents. The dissociating character of detergents, combined with the need to maintain an excess of them, frequently results in more or less rapid inactivation of the protein under study. Over the past few years, we have endeavored to develop a novel family of surfactants, dubbed amphipols (APs). APs are amphiphilic polymers that bind to the transmembrane surface of the protein in a noncovalent but, in the absence of a competing surfactant, quasi-irreversible manner. Membrane proteins complexed by APs are in their native state, stable, and they remain water-soluble in the absence of detergent or free APs. An update is presented of the current knowledge about these compounds and their demonstrated or putative uses in membrane biology.

Crystallization and preliminary X-ray analysis of Drosophila glutathione S-transferase-2

The sigma-class glutathione S-transferase-2 (GST-2) from Drosophila melanogaster is predominantly found within the indirect flight muscles (IFMs), where it is bound to the 'heavy' subunit of the IFM thin filament troponin complex (Tn-H). An N-terminal extension found in GST-2 is unique within the sigma GST class and may be involved in its interaction with Tn-H or modulate its enzymatic function. The recombinant protein has been crystallized at room temperature using ammonium sulfate as precipitant. Synchrotron radiation was used to measure a complete native data set to 1.75 A resolution from flash-cooled crystals. The crystals belong to one of the trigonal space groups P3(1)21 or P3(2)21, with unit-cell parameters a = b = 89.7, c = 131.8 A. The self-rotation function is consistent with a GST-2 dimer in the asymmetric unit.

Links in the chain: the contribution of kettin to the elasticity of insect muscles

Asynchronous flight muscle fibers are activated by periodic stretches and need to be stiff for strain to be transmitted to the contractile system. Kettin associated with thin filaments and projectin with thick filaments contribute to fiber stiffness. Kettin extends along thin filaments with the N-terminus in the Z-disc and the C-terminus outside. C filaments connecting thick filaments to the Z-disc contain projectin but not kettin. Insect flight myofibrils have a titin PEVK epitope which is only exposed on stretch, suggesting it is short and inaccessible. It is concluded that kettin stiffens thin filaments near the Z-disc and projectin and titin provide elasticity to C filaments.

Gas chromatography-mass spectrometry determination of phosphine residues in stored products and processed foods

A gas chromatography-mass spectrometry (GC-MS) method was used for the quantitative confirmation of phosphine residues in stored products and processed foods. An established extraction technique was utilized for the preparation of headspace samples, which were analyzed by GC-MS and gas chromatography-nitrogen-phosphorus detection (GC-NPD). Wheat, oats, maize, white rice, brown rice, cornflakes, tortilla cornchips, groundnuts, and raisins were validated, showing excellent agreement between detectors when spiked at levels equivalent to 0.001 and 0.01 mg/kg phosphine and for samples containing incurred residues. The GC-MS method was reproducible and accurate when compared to the GC-NPD method and allowed five samples to be quantified in a working day. Subambient GC-MS oven temperatures were most suitable for phosphine residues ranging from 0.001 to 0.005 mg/kg, and a GC oven temperature of 100 degrees C was appropriate for residues >0.005 mg/kg. The method was sufficiently robust to be evaluated for other similar commodities as the need arises.

Sequence and expression of the kettin gene in Drosophila melanogaster and Caenorhabditis elegans

Kettin is a large modular protein associated with thin filaments in the Z-disc region of insect muscles. The sequence of a 21.3 kb contig of the Drosophila gene has been determined. The corresponding protein sequence has 35 immunoglobulin-like (Ig) domains which are separated by shorter linker sequences, except near the N and C termini of the molecule where linker sequences are short or missing. This confirms a model in which each Ig domain binds to an actin protomer. The Drosophila kettin gene is at 62C 1-3 on the third chromosome. Two P-element insertions, l(3)j1D7 and l(3)rL182 are in the kettin gene, and complementation tests showed that existing l(3)dre8 mutations are in the same gene. The RNA was detected in wild-type Drosophila embryos at stage 11, first in the gut invagination region of the mesoderm, and by stage 13 in both visceral and somatic mesoderm. Somatic mesoderm expression became segmental at stage 13. RNA expression was greatly reduced in embryos of P-element homozygotes but normal in heterozygotes. The structure of the flight muscle in all the heterozygous mutants was normal, including the myofibril-cuticle connections, and they were able to fly. Kettin sequence homologous to the Drosophila protein, was identified in the Caenorhabditis elegans genome database. The RNA was detected in pharyngeal, body wall and anal depressor muscles of larvae and adult worms, as well as in the male gonad. Antibody to insect kettin labelled the pharyngeal, body wall, anal depressor and proximal gonadal muscles in adult worms. Body wall muscles were labelled in an obliquely striated pattern consistent with the Z-disc localisation in insect muscle. The relationship of kettin to D-titin, which has been assigned to the same chromosomal locus in Drosophila, is discussed.

Information systems for healthcare: why haven't more success. The top 15 reasons

Over the last number of years, I have often been asked: "Why haven't we had more success in implementing Information Technology (IT) in Healthcare?" Unfortunately, there is no simple answer to this question. The answer is usually heavily dependent on several factors that "define" the specific implementation in question--consequently, the answer is one comprised of a number of interrelated factors or components. In order to facilitate this answer process, this paper attempts to identify these individual answer components. At the very least, this will help simplify the process of answering future questions by referring to the components outlined herein. At most, in addition to providing a reference compendium for others, it will assist in increasing the solution implementation success rate by exploring the problem definition in detail: The first step in solving a problem is to have it fully articulated.

Association of kettin with actin in the Z-disc of insect flight muscle

The Z-discs of insect muscle contain kettin, a modular protein of 500-700 kDa. The Drosophila protein is made up of a chain of immunoglobulin (Ig) domains separated by linker sequences. Kettin differs from other modular muscle proteins of the Ig superfamily in binding to thin filaments rather than thick filaments. Kettin isolated from Lethocerus (waterbug) muscle is an elongated molecule 180 nm long, which binds to F-actin with high affinity (Kd=1.2 nM) and a stoichiometry of one Ig domain per actin protomer. Competition between kettin and tropomyosin for binding to actin excludes tropomyosin from the Z-disc. In contrast, kettin and alpha-actinin bind simultaneously to actin, which would reinforce the Z-disc lattice. In vitro, kettin promotes the antiparallel association of actin filaments, and a similar process may occur in the developing sarcomere: actin filaments interdigitate in an antiparallel fashion in the Z-disc with the N terminus of kettin within the Z-disc, and the C terminus some way outside. We propose a model for the association of kettin with actin in which the molecule follows the genetic helix of actin and Ig domains, separated by linker sequences, bind to each actin protomer.

Structure of the insect troponin complex

Isolated troponin-tropomyosin complex from Lethocerus indicus asynchronous flight muscle forms paracrystals on a positively charged lipid monolayer. Single particle analysis was carried out on individual complexes selected from electron micrographs of negatively stained paracrystals. By a combination of correlation and classification techniques, different average projections of the object were obtained. An initial three-dimensional model was calculated by determining the Euler angles for the different views using a common line approach. This starting model was then used as a reference for the further three-dimensional refinement of the model using the original data set. The refined model of the troponin complex has a diameter of approximately 90 A and a volume corresponding with a molecular mass of about 120 kDa for the globular domain. The resolution of the reconstruction was determined to be 32 A using the differential phase residual method and 26 A using the Fourier shell correlation criterion.

The glutamine-rich domain of the Drosophila GAGA factor is necessary for amyloid fibre formation in vitro, but not for chromatin remodelling

The Drosophila GAGA factor binds specifically to the sequence GAGAG, and synergises with nucleosome remodelling factor to remodel chromatin in vitro. It consists of an N-terminal domain (POZ/BTB) which mediates protein-protein interactions, a central region which contains the DNA-binding domain, and a C-terminal glutamine-rich region. It is shown that the glutamine-rich region is responsible for the formation of fibres in vitro which, on the basis of their tinctorial properties and CD spectra, may be classified as amyloid fibres. A large structural change, probably resulting in beta-sheet structure, is observed upon fibre formation. Mutants containing the central region, either alone or together with the glutamine-rich region, are largely lacking in secondary structure but they bind specifically to the cognate DNA and are able to remodel chromatin in vitro. Consequently, neither the N-terminal domain nor the C-terminal glutamine-rich regions of the GAGA factor are necessary for chromatin remodelling in vitro.

A comparison of forensic and nonforensic malingerers: a prototypical analysis of explanatory models

Explanatory models of malingering strive to understand the primary motivation underlying attempts to feign. Rogers, Sewell, and Goldstein (1994) provided empirical support for the conceptualization of pathogenic, criminological, and adaptational models. In the current study, a prototypical analysis of 221 forensic experts results in a slightly refined formulation: the adaptational models was decomposed into its two broad dimensions (cost-benefit analysis and adversarial setting). An important findings is that the factor structure for the explanatory models remained stable when applied to both forensic and nonforensic cases. As a first investigation, significant differences were observed in prototypical cases of malingering by the category of referral (forensic or nonforensic) and by type of feigning (mental disorders, cognitive impairment, and medical syndromes). Surprisingly, the feigning of medical syndromes appeared to play a relatively prominent role in both forensic and nonforensic cases and to be influenced by the apparent adversarial context of the assessment. Finally, important gender differences were observed, especially with nonforensic prototypical cases of malingering.

Designing health care information systems for integrated delivery systems: where we are and where we need to be

A critical step in evolving an integrated delivery system (IDS) is planning, designing, and technologically realizing an efficient, appropriate, and effective infrastructure for developing an integrated network of information systems. The key to meeting this objective philosophically, logically, and physically in the face of rapid advances in computing technology and communication trends is often poorly understood by health providers and managers. The article discusses the concept of a total quality management information system model and illustrates how this sort of thinking can be applied to guide the critical steps that must be undertaken to plan, design, and develop a networked infrastructure of health care information systems that can facilitate information exchange and sharing among multiple health care providers within an IDS.

Redox components and structure of the respiratory NADH:ubiquinone oxidoreductase (complex I)

The proton-pumping NADH:ubiquinone oxidoreductase is the first complex in the respiratory chains of many purple bacteria and of mitochondria of most eucaryotes. The bacterial complex consists of 14 different subunits. The mitochondrial complex contains at least 29 additional proteins that do not directly participate in electron transfer and proton translocation. We analysed electron micrographs of isolated and negatively stained complex I particles from Escherichia coli and Neurospora crassa and obtained three-dimensional models of both complexes at medium resolution. Both have the same L-shaped overall structure with a peripheral arm protruding into the aqueous phase and a membrane arm extending into the membrane. The two arms of the bacterial complex are only slightly shorter than those of the mitochondrial complex although the protein mass of the former is only half of that of the latter. The presence of a novel redox group in the membrane arm of the complex is discussed. This group has been detected in the N. crassa complex by means of UV-visible spectroscopy. After reduction with an excess of NADH and reoxidation by the lactate dehydrogenase reaction, a reduced-minus-oxidized difference spectrum was obtained that cannot be attributed to the known cofactors flavin mononucleotide (FMN) and the FeS clusters N1, N2, N3 and N4. Due to its positive midpoint potential the novel group is believed to transfer electrons from the FeS clusters to ubiquinone. Its role in proton translocation is discussed.

Consistent structure between bacterial and mitochondrial NADH:ubiquinone oxidoreductase (complex I)

Respiratory chains of bacteria and mitochondria contain closely related forms of the proton-pumping NADH:ubiquinone oxidoreductase (complex I). In bacteria the complex has a molecular mass of approximately 530 kDa and consists of 14 different subunits. The homologues of these 14 subunits together with some 27 additional subunits make up the mitochondrial complex, adding up to a molecular mass of approximately 1 MDa. We calculated three-dimensional models at medium resolution of isolated and negatively stained complex I particles from Eschericha coli and Neurospora crassa by electron microscopy using the random conical tilt reconstruction technique. Both the bacterial and the mitochondrial complexes are L-shaped molecules with an intrinsic membrane arm extending into the lipid bilayer and a peripheral arm protruding from the membrane. It is discussed whether the consistent length of the arms of both complexes has an implication for their function. The additional protein mass of the mitochondrial complex is distributed along both arms, but especially around the junction between the two arms and around the membrane arm. It appears that the structural framework of procaryotic complex I is stabilized in eucaryotes by this additional mass. A discrete location of additional protein in the peripheral arm of the mitochondrial complex is interpreted as being the possible position of two subunits with a specialized role in the biosynthesis of a yet unknown cofactor of complex I.

TEM moiré patterns explain STM images of bacteriophage T5 tails

A subtle combination of constant current and constant height modes in scanning tunnelling microscopy allowed the imaging of a non-flat uncoated biological specimen, namely the tail of the bacteriophage T5. In parallel, a reference three-dimensional structure of the T5 tail was calculated from cryo-transmission electron microscopy images, based on its helical symmetry. This three dimensional reconstruction was compared with scanning tunnelling microscopy data. The images of the tail obtained by transmission electron microscopy, as well as projections of the reconstructed model, show similar moiré patterns. Here we show that scanning tunnelling microscopy performed in an aqueous environment provides direct images which are remarkably similar to the projection of the three dimensional model obtained by transmission electron microscopy. We deduce that our scanning tunnelling microscopy images are the result of a transmission of electrons through the gap between the scanning tip and the conductive support across the biological specimen.

Multimerization of the adenovirus DNA-binding protein is the driving force for ATP-independent DNA unwinding during strand displacement synthesis

In contrast to other replication systems, adenovirus DNA replication does not require a DNA helicase to unwind the double-stranded template. Elongation is dependent on the adenovirus DNA-binding protein (DBP) which has helix-destabilizing properties. DBP binds cooperatively to single-stranded DNA (ssDNA) in a non-sequence-specific manner. The crystal structure of DBP shows that the protein has a C-terminal extension that hooks on to an adjacent monomer which results in the formation of long protein chains. We show that deletion of this C-terminal arm results in a monomeric protein. The mutant binds with a greatly reduced affinity to ssDNA. The deletion mutant still stimulates initiation of DNA replication like the intact DBP. This shows that a high affinity of DBP for ssDNA is not required for initiation. On a single-stranded template, elongation is also observed in the absence of DBP. Addition of DBP or the deletion mutant has no effect on elongation, although both proteins stimulate initiation on this template. Strand displacement synthesis on a double-stranded template is only observed in the presence of DBP. The mutant, however, does not support elongation on a double-stranded template. The unwinding activity of the mutant is highly reduced compared with intact DBP. These data suggest that protein chain formation by DBP and high affinity binding to the displaced strand drive the ATP-independent unwinding of the template during adenovirus DNA replication.

Electron microscopic distribution of mu opioid receptors on noradrenergic neurons of the locus coeruleus

The distribution of mu opioid receptors was examined by light and electron microscopic autoradiography in the locus coeruleus of the rat following in vitro labelling with the iodinated agonist [125I]FK-33824. At the light microscopic level, specific mu opioid binding sites were concentrated over the perikarya and dendrites of neurons that were tyrosine hydroxylase-immunopositive in adjacent sections. Accordingly, both the number of tyrosine hydroxylase-immunoreactive neurons and the density of labelled mu receptors decreased markedly throughout the rostrocaudal extent of the nucleus following treatment with the catecholaminergic neurotoxin 6-hydroxydopamine. By electron microscopy, specifically labelled receptors were detected both inside and on the surface of locus coeruleus neurons. Intracellular sites were found by resolution circle analysis to be highly concentrated within the endoplasmic reticulum and Golgi apparatus, suggesting that the ligand recognizes both glycosylated and preglycosylated forms of receptor. The remainder were found mainly over the cytoplasmic matrix or intracytoplasmic vesicles, and were attributed to newly synthesized or recycled receptors in transit. Cell surface receptors were present over both dendritic and perikaryal membranes of noradrenergic cells. These were most highly concentrated opposite abutting axon terminals, suggesting the existence of receptor 'hot spots' at sites of putative endogenous ligand release. However, only a small proportion of these sites was associated with synaptic specializations. Furthermore, an important contingent was detected opposite non-axonal elements, such as dendrites and glial cells, suggesting that mu opioid ligands act mainly parasynaptically on locus coeruleus neurons. Finally, approximately 5% of labelled receptors were associated with axoglial interfaces, indicating that a minor action of mu opioids in the locus may be presynaptic and/or glial.

Drosophilaprojectin: relatedness to titin and twitchin and correlation withlethal (4) 102 CDaandbent-Dominantmutants

We have investigated projectin, a large protein of insect muscles, in Drosophila melanogaster. The 5.3 kilobases of coding sequence reported here contains Class I and Class II motifs characteristic of titin and twitchin, arranged in a three domain ... [II-I-I] [II-I-I] ... pattern. Two mutants mapped to the location of the projectin gene in the 102C subdivision of chromosome 4, lethal(4) 102 CDa and bent-Dominant, have DNA rearrangements within their projectin gene. The lethal(4) 102 CDa mutant has a 141 nucleotide insertion containing stop codons in all three reading frames within an exon sequence, showing that it cannot synthesize normal projectin. Both bent-Dominant and lethal(4) 102 CDa homozygotes die at the completion of embryogenesis because they are unable to escape the egg vitelline membrane. We propose that this hatching failure is due to muscle weakness caused by projectin defects.