Search for Boosted Dark Matter in COSINE-100.

We search for energetic electron recoil signals induced by boosted dark matter (BDM) from the galactic center using the COSINE-100 array of NaI(Tl) crystal detectors at the Yangyang Underground Laboratory. The signal would be an excess of events with energies above 4 MeV over the well-understood background. Because no excess of events are observed in a 97.7 kg·yr exposure, we set limits on BDM interactions under a variety of hypotheses. Notably, we explored the dark photon parameter space, leading to competitive limits compared to direct dark photon search experiments, particularly for dark photon masses below 4 MeV and considering the invisible decay mode. Furthermore, by comparing our results with a previous BDM search conducted by the Super-Kamionkande experiment, we found that the COSINE-100 detector has advantages in searching for low-mass dark matter. This analysis demonstrates the potential of the COSINE-100 detector to search for MeV electron recoil signals produced by the dark sector particle interactions.

Detection efficiency calibration for an array of fourteen HPGe detectors.

The CUP array of germanium (CAGe) is an array of fourteen high-purity germanium (HPGe) detectors. The detection efficiency of full-energy-peak emitted from the various samples assayed on the CAGe was calculated using the Monte Carlo simulation toolkit GEANT4. If the dead layer on the surface of the crystal is treated in the simulation as a continuous part of the active crystal, then the detection efficiency will be overestimated. Thus, the detection efficiency of the CAGe was adjusted using multi-nuclide source data and Monte Carlo simulations. The gamma spectra of the known activity source were obtained for each HPGe detector of the CAGe. The detection efficiency measured by the multi-source data was smaller than that of simulation data if the simulation treated the whole volume of germanium crystals as active for gamma detection. By optimizing the dead layers' thicknesses in the simulation, the detection efficiency calculated by the simulation could be matched to that of multi-source data.

Search for a Dark Matter-Induced Annual Modulation Signal in NaI(Tl) with the COSINE-100 Experiment.

We present new constraints on the dark matter-induced annual modulation signal using 1.7 years of COSINE-100 data with a total exposure of 97.7 kg yr. The COSINE-100 experiment, consisting of 106 kg of NaI(Tl) target material, is designed to carry out a model-independent test of DAMA/LIBRA's claim of WIMP discovery by searching for the same annual modulation signal using the same NaI(Tl) target. The crystal data show a 2.7 cpd/kg/keV background rate on average in the 2-6 keV energy region of interest. Using a χ-squared minimization method we observe best fit values for modulation amplitude and phase of 0.0092±0.0067 cpd/kg/keV and 127.2±45.9 d, respectively.

First Direct Search for Inelastic Boosted Dark Matter with COSINE-100.

A search for inelastic boosted dark matter (IBDM) using the COSINE-100 detector with 59.5 days of data is presented. This relativistic dark matter is theorized to interact with the target material through inelastic scattering with electrons, creating a heavier state that subsequently produces standard model particles, such as an electron-positron pair. In this study, we search for this electron-positron pair in coincidence with the initially scattered electron as a signature for an IBDM interaction. No excess over the predicted background event rate is observed. Therefore, we present limits on IBDM interactions under various hypotheses, one of which allows us to explore an area of the dark photon parameter space that has not yet been covered by other experiments. This is the first experimental search for IBDM using a terrestrial detector.

Background model for the NaI(Tl) crystals in COSINE-100.

The COSINE-100 dark matter search experiment is an array of NaI(Tl) crystal detectors located in the Yangyang Underground Laboratory (Y2L). To understand measured backgrounds in the NaI(Tl) crystals we have performed Monte Carlo simulations using the Geant4 toolkit and developed background models for each crystal that consider contributions from both internal and external sources, including cosmogenic nuclides. The background models are based on comparisons of measurement data with Monte Carlo simulations that are guided by a campaign of material assays and are used to evaluate backgrounds and identify their sources. The average background level for the six crystals (70 kg total mass) that are studied is 3.5 counts/day/keV/kg in the (2-6) keV energy interval. The dominant contributors in this energy region are found to be 210 Pb and 3 H.

An apparatus to manipulate and identify individual Ba ions from bulk liquid Xe.

We describe a system to transport and identify barium ions produced in liquid xenon, as part of R&D towards the second phase of a double beta decay experiment, nEXO. The goal is to identify the Ba ion resulting from an extremely rare nuclear decay of the isotope (136)Xe, hence providing a confirmation of the occurrence of the decay. This is achieved through Resonance Ionization Spectroscopy (RIS). In the test setup described here, Ba ions can be produced in liquid xenon or vacuum and collected on a clean substrate. This substrate is then removed to an analysis chamber under vacuum, where laser-induced thermal desorption and RIS are used with time-of-flight mass spectroscopy for positive identification of the barium decay product.

Search for neutrinoless double-beta decay in 136Xe with EXO-200.

We report on a search for neutrinoless double-beta decay of 136Xe with EXO-200. No signal is observed for an exposure of 32.5 kg yr, with a background of ∼1.5×10(-3) kg(-1) yr(-1) keV(-1) in the ±1σ region of interest. This sets a lower limit on the half-life of the neutrinoless double-beta decay T(1/2)(0νßß)(136Xe)>1.6×10(25) yr (90% C.L.), corresponding to effective Majorana masses of less than 140-380 meV, depending on the matrix element calculation.

A simple radionuclide-driven single-ion source.

We describe a source capable of producing single barium ions through nuclear recoils in radioactive decay. The source is fabricated by electroplating (148)Gd onto a silicon α-particle detector and vapor depositing a layer of BaF(2) over it. (144)Sm recoils from the alpha decay of (148)Gd are used to dislodge Ba(+) ions from the BaF(2) layer and emit them in the surrounding environment. The simultaneous detection of an α particle in the substrate detector allows for tagging of the nuclear decay and of the Ba(+) emission. The source is simple, durable, and can be manipulated and used in different environments. We discuss the fabrication process, which can be easily adapted to emit most other chemical species, and the performance of the source.

Oesophageal achalasia: an argument for primary surgical management.

INTRODUCTION: Achalasia is a primary oesophageal motility disorder resulting from damage to the ganglion cells of the myenteric plexus. Impaired relaxation of the lower oesophageal sphincter and aperistalsis causes its cardinal symptoms of dysphagia, chest pain and reflux-type symptoms. Management is somewhat controversial, with options including systemic and local pharmacotherapy, dilatation and oesophagomyotomy. We review the presentation, investigation and management of oesophageal achalasia and make an argument for primary surgical management. METHODS: We performed a Medline search of the term 'achalasia', limiting the search to clinical trials and meta-analyses. We then selected articles based on their abstracts using four main criteria: previously unreported findings, previously unreported techniques, size of patient cohort and journal impact factor. References in selected articles were manually searched for other relevant articles. FINDINGS: Achalasia has been managed using a variety of techniques including systemic and local pharmacotherapy, forced dilatation and oesophagomyotomy. Success rates vary widely between techniques. Mechanical disruption ofthe lower oesophageal sphincter is most successful. DISCUSSION: In achalasia, mechanical disruption of the lower oesophageal sphincter using forced dilatation or surgical myotomy offers the only realistic prospect of long-term symptom relief. Recent evidence suggests that previous medical treatment or dilatation makes oesophagomyotomy more difficult and increases the risk of complications. As the morbidity associated with surgery continues to decrease with improvements in minimal access techniques, the argument for primary management of achalasia with oesophagomyotomy becomes more compelling.

Precision measurement of neutrino oscillation parameters with KamLAND.

The KamLAND experiment has determined a precise value for the neutrino oscillation parameter Deltam21(2) and stringent constraints on theta12. The exposure to nuclear reactor antineutrinos is increased almost fourfold over previous results to 2.44 x 10(32) proton yr due to longer livetime and an enlarged fiducial volume. An undistorted reactor nu[over]e energy spectrum is now rejected at >5sigma. Analysis of the reactor spectrum above the inverse beta decay energy threshold, and including geoneutrinos, gives a best fit at Deltam21(2)=7.58(-0.13)(+0.14)(stat) -0.15+0.15(syst) x 10(-5) eV2 and tan2theta12=0.56(-0.07)+0.10(stat) -0.06+0.10(syst). Local Deltachi2 minima at higher and lower Deltam21(2) are disfavored at >4sigma. Combining with solar neutrino data, we obtain Deltam21(2)=7.59(-0.21)+0.21 x 10(-5) eV2 and tan2theta12=0.47(-0.05)+0.06.

Primary endourologic realignment of complete posterior urethral disruption.

The management of posterior urethral disruption is controversial. Debate continues on whether primary realignment at results in a higher incidence of incontinence and impotence compared to delayed reconstruction. We report on our experience using early endoscopic realignment. Between 1994 and 2002 ten male patients, diagnosed with complete posterior urethral disruption, had attempted early endoscopic realignment. All patients were evaluated for incontinence, impotence and stricture formation post-operatively. Six patients had endoscopic retrograde realignment, two proceeded to endoscopic rendezvous realignment and two patients had delayed reconstruction of the urethra. At follow-up, mean 41.4 months, all patients were continent four were impotent and four patients developed strictures. Endoscopic retrograde realignment is a simple atraumatic technique for early posterior urethra realignment. If unsuccessful a rendezvous approach can be attempted at the same operation. Manipulation of the periprostatic issue is minimal thus preventing iatrogenic complications.

Search for the invisible decay of neutrons with KamLAND.

The Kamioka Liquid scintillator Anti-Neutrino Detector is used in a search for single neutron or two-neutron intranuclear disappearance that would produce holes in the -shell energy level of (12)C nuclei. Such holes could be created as a result of nucleon decay into invisible modes (inv), e.g., n--> 3v or nn--> 2v. The deexcitation of the corresponding daughter nucleus results in a sequence of space and time-correlated events observable in the liquid scintillator detector. We report on new limits for one- and two-neutron disappearance: tau(n--> inv) > 5.8 x 10(29) years and tau (nn--> inv) > 1.4 x 10(30) years at 90% C.L. These results represent an improvement of factors of approximately 3 and >10(4) and over previous experiments.

Anti-human epidermal growth factor receptor 2 monoclonal antibody therapy for breast cancer.

BACKGROUND: Advances in molecular biology and improved understanding of tumour biology have led to the development of novel treatments for cancer. Trastuzumab (Herceptin; Genentech, San Francisco, California, USA) is a monoclonal antibody directed against human epidermal growth factor receptor (HER) 2 protein, which is overexpressed in a wide variety of human cancers, including 20-30 per cent of human breast cancers. HER-2 plays an important role in oncogenic transformation, tumorigenesis and metastatic spread. Overexpression is associated with a poor prognosis and predicts a poor response to several treatment modalities. METHOD: Literature relating to the monoclonal antibody was identified by a Medline literature search and by cross-referencing from the references of seminal articles on the subject. Four major clinical trials were identified and reviewed. RESULTS AND CONCLUSION: In clinical trials approximately 15-20 per cent of patients with HER-2-overexpressing tumours benefited from treatment with trastuzumab. In sensitive patients the antibody appeared to have intrinsic anticancer activity when given as a single agent. In combination chemotherapy it appeared to act synergistically with other agents. Ongoing research is evaluating trastuzumab in combination with numerous standard chemotherapy regimens and with other novel chemotherapeutic agents. Clinical trials have also revealed several serious side-effects of monoclonal antibody therapy. Most notable is an unpredictable cardiotoxicity, especially when used in combination with anthracycline-based chemotherapy regimens.

Short-term study of allogeneic retinal pigment epithelium transplants onto debrided Bruch's membrane.

PURPOSE: To investigate the survival and behavior of retinal pigment epithelium (RPE) microaggregates transplanted onto hydraulically debrided Bruch's membrane and to compare results of using three different vehicles for cell delivery. METHODS: RPE microaggregates obtained from male cats were transplanted onto the tapetal area of female cats after native RPE was debrided. For the control, one of three vehicles was introduced into the debridements. Each transplant or control specimen was analyzed histologically and immunohistochemically. Transplanted male RPE cells were identified by in situ labeling of the cat Y chromosome. RESULTS: Histologically, significant numbers of condensed, darkly stained RPE nuclei were observed in all transplants compared with few TUNEL-positive RPE cells. Cellular retinaldehyde-binding protein was present up to day 7 in all RPE cells in transplants. In both transplant and control specimens, the antibody against the Ki-67 nuclear antigen labeled some RPE cells at day 3. TUNEL-positive outer nuclear layer nuclei were most frequently observed at day 1, but were much less frequent at 7 days in both transplant and control specimens. CONCLUSIONS: Transplanted RPE appeared to retain at least some markers of differentiation up to 7 days after surgery. Some proliferation of transplanted RPE cells was also seen. Apoptotic cell death of transplanted RPE, as judged by TUNEL staining was observed rarely. RPE transplants imposed no adverse effect on the overlying retina. RPE survival appeared to be similar with each of the three vehicles for cell delivery.

Clinicopathologic correlation of localized retinal pigment epithelium debridement.

PURPOSE: To characterize changes in the retina, retinal pigment epithelium (RPE), and choriocapillaris with fluorescein angiography (FA) and histology after hydraulic or abrasive RPE debridement in 26 domestic short-haired cats. METHODS: Hydraulic debridement was produced by injecting balanced salt solution forcefully into the subretinal space. For abrasive debridement, RPE were removed with a silicone-tipped cannula after creating a localized retinal detachment. The FAs were performed after surgery, and tissue was prepared for light microscopy (LM) and scanning electron microscopy (SEM). RESULTS: Sixty-seven blebs were examined by FA 1 hour after surgery, and RPE debridement was confirmed by SEM or LM in 15 blebs from 10 animals. Hyperfluorescence and variable central fluorescein leakage were seen 1 week after surgery in 52 of 53 blebs (which includes all 27 blebs from the 1-week timepoint and 26 of 29 blebs from the 4-week timepoint that were studied by FA 1 week after surgery). Choriocapillary filling delays were seen in no hydraulic debridements, but in 11 of 14 abrasive blebs, especially in areas showing leakage late in the angiogram. In 1 of 13 hydraulic and 12 of 14 abrasive debridements, areas of late dye leakage had no RPE with outer retinal degeneration. At the 4-week timepoint, 1 of 17 hydraulic and 10 of 12 abrasive debridements had foci of delayed or absent choriocapillary perfusion by FA, with degenerated outer retina, no RPE, and choriocapillary atrophy by histologic analysis. CONCLUSIONS: Abrasive debridement is more commonly associated with abnormal FAs and with incomplete RPE repopulation, choriocapillaris atrophy, and outer retinal degeneration than is hydraulic debridement. This clinicopathologic study may give insight into FA interpretation after choroidal neovascular membrane removal in human patients.

Control of low-density gypsy moth (Lepidoptera: Lymantriidae) populations by mating disruption with pheromone.

This four-year study demonstrated that low-density populations of the gypsy moth,Lymantria dispar (L.), were effectively suppressed by annual aerial application of 75 g of racemic disparlure per hectare formulated in plastic laminate flakes. These tests also showed that, when plots were treated with 150 g of pheromone per hectare in 1990 only and left untreated for the following three years, populations continued to be suppressed in 1991-1993 as compared with the controls. Although none of the plots were treated in 1994, population assessment continued and showed that the gypsy moth population density remained low in the plots that had been treated annually for the preceding four years. The laminate flakes released an average of 0.48 g disparlure per day per hectare from each of the two applications in 1990, and 0.72 g per day per hectare from the single application in each of the following three years (1991-1993). Only 27-40% of the applied pheromone dose was emitted during male moth flight.

Degeneration of photoreceptors in rhodopsin mutants of Drosophila.

Five different, well-characterized mutants of the R1-6 rhodopsin gene (ninaE), which corresponds to the rod opsin gene of vertebrates, have been examined morphologically as a function of age (up to 9 weeks) to determine whether or not the photoreceptors degenerate and to assess the pattern of degeneration. Structural deterioration of R1-6 photoreceptors with age has been found in all five mutants. The structural pattern of degeneration is similar in the five mutants, but the time course of degeneration is allele dependent and varies greatly among the five, with the strongest alleles causing the fastest degeneration. The degeneration appears to be independent of either the illumination cycle to which the animals are exposed or the presence of screening pigments in the eye. Although the degeneration first appears in R1-6 photoreceptors, eventually R7/8 photoreceptors, which correspond to cones of vertebrates, are also affected. In many of these mutants, striking proliferations of membrane processes have been observed in the subrhabdomeric region of R1-6 photoreceptors. It is hypothesized that (1) this accumulation of membranes may be caused by the failure of newly synthesized membranes that are inserted into the base of microvilli to be assembled into R1-6 rhabdomeres and (2) this failure may be caused by the extremely low concentration of normal R1-6 rhodopsin in the ninaE mutants.

Morphological defects in oraJK84 photoreceptors caused by mutation in R1-6 opsin gene of Drosophila.

The Drosophila mutant, oraJK84, lacks rhabdomeres in the major (R1-6) class of photoreceptors because these rhabdomeres rapidly degenerate in young flies. Genetic analysis reveals that oraJK84 actually contains two mutations (a ninaE and an ort allele) that affect the visual process. The mutation in ort appears to have no effect on photoreceptor structure. The other mutation occurs within the ninaE gene, which encodes the species of rhodopsin found in the R1-6 class of photoreceptors. Our analysis shows that this mutation is responsible for R1-6 rhabdomere degeneration in oraJK84 mutants. We also examined a ninaE mutant, denoted ninaEo117, that produces no ninaE transcript. The morphological phenotype observed in ninaEo117 is similar to that seen in oraJK84 mutants. We conclude that rhodopsin plays a vital role in maintaining photoreceptor structure in Drosophila.