First Dark Matter Search with Nuclear Recoils from the XENONnT Experiment

We report on the first search for nuclear recoils from dark matter in the form of weakly interacting massive particles (WIMPs) with the XENONnT experiment, which is based on a two-phase time projection chamber with a sensitive liquid xenon mass of 5.9 ton. During the (1.09±0.03)  ton yr exposure used for this search, the intrinsic ^{85}Kr and ^{222}Rn concentrations in the liquid target are reduced to unprecedentedly low levels, giving an electronic recoil background rate of (15.8±1.3)  events/ton yr keV in the region of interest. A blind analysis of nuclear recoil events with energies between 3.3 and 60.5 keV finds no significant excess. This leads to a minimum upper limit on the spin-independent WIMP-nucleon cross section of 2.58×10^{-47}  cm^{2} for a WIMP mass of 28  GeV/c^{2} at 90% confidence level. Limits for spin-dependent interactions are also provided. Both the limit and the sensitivity for the full range of WIMP masses analyzed here improve on previous results obtained with the XENON1T experiment for the same exposure.

Searching for Heavy Dark Matter near the Planck Mass with XENON1T

Multiple viable theoretical models predict heavy dark matter particles with a mass close to the Planck mass, a range relatively unexplored by current experimental measurements. We use 219.4 days of data collected with the XENON1T experiment to conduct a blind search for signals from multiply interacting massive particles (MIMPs). Their unique track signature allows a targeted analysis with only 0.05 expected background events from muons. Following unblinding, we observe no signal candidate events. This Letter places strong constraints on spin-independent interactions of dark matter particles with a mass between 1×10^{12} and 2×10^{17}  GeV/c^{2}. In addition, we present the first exclusion limits on spin-dependent MIMP-neutron and MIMP-proton cross sections for dark matter particles with masses close to the Planck scale.

Search for New Physics in Electronic Recoil Data from XENONnT

We report on a blinded analysis of low-energy electronic recoil data from the first science run of the XENONnT dark matter experiment. Novel subsystems and the increased 5.9 ton liquid xenon target reduced the background in the (1, 30) keV search region to (15.8±1.3)  events/(ton×year×keV), the lowest ever achieved in a dark matter detector and ∼5 times lower than in XENON1T. With an exposure of 1.16 ton-years, we observe no excess above background and set stringent new limits on solar axions, an enhanced neutrino magnetic moment, and bosonic dark matter.

Material radiopurity control in the XENONnT experiment

The selection of low-radioactive construction materials is of the utmost importance for rare-event searches and thus critical to the XENONnT experiment. Results of an extensive radioassay program are reported, in which material samples have been screened with gamma-ray spectroscopy, mass spectrometry, and \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{222}$$\end{document}222Rn emanation measurements. Furthermore, the cleanliness procedures applied to remove or mitigate surface contamination of detector materials are described. Screening results, used as inputs for a XENONnT Monte Carlo simulation, predict a reduction of materials background (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\sim $$\end{document}∼17%) with respect to its predecessor XENON1T. Through radon emanation measurements, the expected \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{222}$$\end{document}222Rn activity concentration in XENONnT is determined to be 4.2 (\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$^{+0.5}_{-0.7}$$\end{document}-0.7+0.5) \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\upmu $$\end{document}μBq/kg, a factor three lower with respect to XENON1T. This radon concentration will be further suppressed by means of the novel radon distillation system.

Meta-regression Analysis of Study Heterogeneity for Systemic Outcomes after Periodontal Therapy

INTRODUCTION

The contribution of periodontal disease to adverse systemic consequences remains controversial. This analysis examined 2 well-investigated conditions independently and combined-adverse pregnancy outcomes and glycemic control for patients with diabetes-based on shared pathogenic mechanisms of periodontal infection and inflammation. It was proposed that inconsistencies in study design significantly contribute to outcome discrepancies found between periodontal intervention studies undergoing meta-analysis.

METHODS

Meta-analyses evaluating periodontal interventions on the rate of preterm birth and changes in glycated hemoglobin A1c in type 2 diabetes populations were conducted based on a systematic review of randomized controlled trials. Meta-regression covariates for exploring heterogeneity included sample size, level of medical management, and bias risk as moderator variables in a random-effects meta-regression.

RESULTS

Systematic review identified 17 studies of diabetes and 13 of pregnancy outcomes. Analyses of these studies identified 0.50% reduction in HbA1c and 0.78 odds ratio for preterm births. The heterogeneity associated with the models was high (I2 = 92.4 and I2 = 62.7%, respectively). The adjusted models evaluating each systemic condition separately accounted for 52.2% of the effect for diabetes and 81.4% for pregnancy outcome effects independently, and 63.5% collectively, across interventional studies.

CONCLUSION

This systematic review with meta-regression analysis of heterogeneity demonstrates that disparate results seen in randomized controlled trials of periodontal therapy affecting systemic outcomes may be explained in large part by study design, specifically stringency in consideration of medical management and sample size. The potential for confounding factors to influence outcomes remains a concern in understanding the implications of oral health on systemic conditions.

KNOWLEDGE TRANSFER STATEMENT

The findings of this study demonstrate that much of the benefits seen from periodontal therapy on adverse systemic outcomes for diabetes and pregnancy are due to limitations in study design.

222 Rn emanation measurements for the XENON1T experiment

The selection of low-radioactive construction materials is of utmost importance for the success of low-energy rare event search experiments. Besides radioactive contaminants in the bulk, the emanation of radioactive radon atoms from material surfaces attains increasing relevance in the effort to further reduce the background of such experiments. In this work, we present the 222 Rn emanation measurements performed for the XENON1T dark matter experiment. Together with the bulk impurity screening campaign, the results enabled us to select the radio-purest construction materials, targeting a 222 Rn activity concentration of 10 μ Bq / kg in 3.2 t of xenon. The knowledge of the distribution of the 222 Rn sources allowed us to selectively eliminate problematic components in the course of the experiment. The predictions from the emanation measurements were compared to data of the 222 Rn activity concentration in XENON1T. The final 222 Rn activity concentration of ( 4.5 ± 0.1 ) μ Bq / kg in the target of XENON1T is the lowest ever achieved in a xenon dark matter experiment.

Search for Coherent Elastic Scattering of Solar ^{8}B Neutrinos in the XENON1T Dark Matter Experiment

We report on a search for nuclear recoil signals from solar ^{8}B neutrinos elastically scattering off xenon nuclei in XENON1T data, lowering the energy threshold from 2.6 to 1.6  keV. We develop a variety of novel techniques to limit the resulting increase in backgrounds near the threshold. No significant ^{8}B neutrinolike excess is found in an exposure of 0.6  t×y. For the first time, we use the nondetection of solar neutrinos to constrain the light yield from 1-2 keV nuclear recoils in liquid xenon, as well as nonstandard neutrino-quark interactions. Finally, we improve upon world-leading constraints on dark matter-nucleus interactions for dark matter masses between 3 and 11  GeV c^{-2} by as much as an order of magnitude.

Light Dark Matter Search with Ionization Signals in XENON1T

We report constraints on light dark matter (DM) models using ionization signals in the XENON1T experiment. We mitigate backgrounds with strong event selections, rather than requiring a scintillation signal, leaving an effective exposure of (22±3) tonne day. Above ∼0.4  keV_{ee}, we observe <1  event/(tonne day keV_{ee}), which is more than 1000 times lower than in similar searches with other detectors. Despite observing a higher rate at lower energies, no DM or CEvNS detection may be claimed because we cannot model all of our backgrounds. We thus exclude new regions in the parameter spaces for DM-nucleus scattering for DM masses m_{χ} within 3-6  GeV/c^{2}, DM-electron scattering for m_{χ}>30  MeV/c^{2}, and absorption of dark photons and axionlike particles for m_{χ} within 0.186-1  keV/c^{2}.

Search for Light Dark Matter Interactions Enhanced by the Migdal Effect or Bremsstrahlung in XENON1T

Direct dark matter detection experiments based on a liquid xenon target are leading the search for dark matter particles with masses above ∼5  GeV/c^{2}, but have limited sensitivity to lighter masses because of the small momentum transfer in dark matter-nucleus elastic scattering. However, there is an irreducible contribution from inelastic processes accompanying the elastic scattering, which leads to the excitation and ionization of the recoiling atom (the Migdal effect) or the emission of a bremsstrahlung photon. In this Letter, we report on a probe of low-mass dark matter with masses down to about 85  MeV/c^{2} by looking for electronic recoils induced by the Migdal effect and bremsstrahlung using data from the XENON1T experiment. Besides the approach of detecting both scintillation and ionization signals, we exploit an approach that uses ionization signals only, which allows for a lower detection threshold. This analysis significantly enhances the sensitivity of XENON1T to light dark matter previously beyond its reach.

Constraining the Spin-Dependent WIMP-Nucleon Cross Sections with XENON1T

We report the first experimental results on spin-dependent elastic weakly interacting massive particle (WIMP) nucleon scattering from the XENON1T dark matter search experiment. The analysis uses the full ton year exposure of XENON1T to constrain the spin-dependent proton-only and neutron-only cases. No significant signal excess is observed, and a profile likelihood ratio analysis is used to set exclusion limits on the WIMP-nucleon interactions. This includes the most stringent constraint to date on the WIMP-neutron cross section, with a minimum of 6.3×10^{-42}  cm^{2} at 30  GeV/c^{2} and 90% confidence level. The results are compared with those from collider searches and used to exclude new parameter space in an isoscalar theory with an axial-vector mediator.

First Results on the Scalar WIMP-Pion Coupling, Using the XENON1T Experiment

We present first results on the scalar coupling of weakly interacting massive particles (WIMPs) to pions from 1  t yr of exposure with the XENON1T experiment. This interaction is generated when the WIMP couples to a virtual pion exchanged between the nucleons in a nucleus. In contrast to most nonrelativistic operators, these pion-exchange currents can be coherently enhanced by the total number of nucleons and therefore may dominate in scenarios where spin-independent WIMP-nucleon interactions are suppressed. Moreover, for natural values of the couplings, they dominate over the spin-dependent channel due to their coherence in the nucleus. Using the signal model of this new WIMP-pion channel, no significant excess is found, leading to an upper limit cross section of 6.4×10^{-46}  cm^{2} (90% confidence level) at 30  GeV/c^{2} WIMP mass.

[Expression and clinical significance of KIAA1199 in primary hepatocellular carcinoma]

Objective: To investigate the expression and clinical significance of KIAA1199 in primary hepatocellular carcinoma. Methods: A total of 136 cases of primary hepatocellular carcinoma tissues and paired adjacent tissues were collected. Immunohistochemistry and Western blot were used to detect the expression of KIAA1199 in primary hepatocellular carcinoma tissues and paired adjacent tissues. The relationship between KIAA1199 and clinicopathological parameter of primary hepatocellular carcinoma was analyzed. Results: The positive rate of KIAA1199 in primary hepatocellular carcinoma was 82.3% (112/136), which was higher than that in paired para-cancerous tissues (14.7%, 20/136). High expression of KIAA1199 was significantly correlated with age, cirrhosis history, tumor size, tumor number, degree of differentiation, TNM staging and microvenous invasion (MVI) (P<0.05), but without gender, drinking alcohol hobby, hepatitis history, family genetic history, tumor location (P>0.05). The Kaplan-Meier survival curves indicated that high KIAA1199 expression was associated with poor survival (P<0.01). In addition, Cox proportional hazards model showed that the expression of KIAA1199 was related to age, cirrhosis history, tumor size, tumor number, degree of differentiation, TNM staging and MVI (P<0.05). Conclusion: The expression of KIAA1199 is up-regulated in primary hepatocellular carcinoma, which is significantly correlated with the clinicopathological features and prognosis, high expression of KIAA1199 increased the risk of death in patients with primary hepatocellular carcinoma.

Dark Matter Search Results from a One Ton-Year Exposure of XENON1T

We report on a search for weakly interacting massive particles (WIMPs) using 278.8 days of data collected with the XENON1T experiment at LNGS. XENON1T utilizes a liquid xenon time projection chamber with a fiducial mass of (1.30±0.01)  ton, resulting in a 1.0 ton yr exposure. The energy region of interest, [1.4,10.6]  keV_{ee} ([4.9,40.9] keV_{nr}), exhibits an ultralow electron recoil background rate of [82_{-3}^{+5}(syst)±3(stat)]  events/(ton yr keV_{ee}). No significant excess over background is found, and a profile likelihood analysis parametrized in spatial and energy dimensions excludes new parameter space for the WIMP-nucleon spin-independent elastic scatter cross section for WIMP masses above 6  GeV/c^{2}, with a minimum of 4.1×10^{-47}  cm^{2} at 30  GeV/c^{2} and a 90% confidence level.

First Dark Matter Search Results from the XENON1T Experiment

We report the first dark matter search results from XENON1T, a ∼2000-kg-target-mass dual-phase (liquid-gas) xenon time projection chamber in operation at the Laboratori Nazionali del Gran Sasso in Italy and the first ton-scale detector of this kind. The blinded search used 34.2 live days of data acquired between November 2016 and January 2017. Inside the (1042±12)-kg fiducial mass and in the [5,40]  keV_{nr} energy range of interest for weakly interacting massive particle (WIMP) dark matter searches, the electronic recoil background was (1.93±0.25)×10^{-4}  events/(kg×day×keV_{ee}), the lowest ever achieved in such a dark matter detector. A profile likelihood analysis shows that the data are consistent with the background-only hypothesis. We derive the most stringent exclusion limits on the spin-independent WIMP-nucleon interaction cross section for WIMP masses above 10  GeV/c^{2}, with a minimum of 7.7×10^{-47}  cm^{2} for 35-GeV/c^{2} WIMPs at 90% C.L.

Search for Electronic Recoil Event Rate Modulation with 4 Years of XENON100 Data

We report on a search for electronic recoil event rate modulation signatures in the XENON100 data accumulated over a period of 4 yr, from January 2010 to January 2014. A profile likelihood method, which incorporates the stability of the XENON100 detector and the known electronic recoil background model, is used to quantify the significance of periodicity in the time distribution of events. There is a weak modulation signature at a period of 431_{-14}^{+16} day in the low energy region of (2.0-5.8) keV in the single scatter event sample, with a global significance of 1.9σ; however, no other more significant modulation is observed. The significance of an annual modulation signature drops from 2.8σ, from a previous analysis of a subset of this data, to 1.8σ with all data combined. Single scatter events in the low energy region are thus used to exclude the DAMA/LIBRA annual modulation as being due to dark matter electron interactions via axial vector coupling at 5.7σ.

Characterization and application of a self-aspirating electrospray source with pneumatic-assisted ionization

A single gas-assisted electrospray ion source developed for ambient mass spectrometry is introduced in this paper. Simultaneous self-aspiration and electrospray could be achieved by using a constant sheath gas flow supplied from a mini air pump. A gas dynamic study of the spray module is carried out for structural optimization. The entire device exhibits a simplified design and has been systematically characterized through both simulated and experimental investigations. According to the results, the ion source exhibited satisfactory stability and the ability for quantitative operation in routine electrospray ionization mass spectrometry. Furthermore, the ion source can be operated as a desorption electrospray ionization source to perform direct desorption/ionization of the solid samples. The versatile source described here appears to provide a practical approach to perform ambient mass spectrometry analysis with unrestricted sampling operation, and the extensive gas dynamic studies together with the experimental characterization are believed to be helpful in building self-aspirating spray devices. Copyright © 2017 John Wiley & Sons, Ltd.

Molecular signatures associated with cognitive deficits in schizophrenia: a study of biopsied olfactory neural epithelium

Cognitive impairment is a key feature of schizophrenia (SZ) and determines functional outcome. Nonetheless, molecular signatures in neuronal tissues that associate with deficits are not well understood. We conducted nasal biopsy to obtain olfactory epithelium from patients with SZ and control subjects. The neural layers from the biopsied epithelium were enriched by laser-captured microdissection. We then performed an unbiased microarray expression study and implemented a systematic neuropsychological assessment on the same participants. The differentially regulated genes in SZ were further filtered based on correlation with neuropsychological traits. This strategy identified the SMAD 5 gene, and real-time quantitative PCR analysis also supports downregulation of the SMAD pathway in SZ. The SMAD pathway has been important in multiple tissues, including the role for neurodevelopment and bone formation. Here the involvement of the pathway in adult brain function is suggested. This exploratory study establishes a strategy to better identify neuronal molecular signatures that are potentially associated with mental illness and cognitive deficits. We propose that the SMAD pathway may be a novel target in addressing cognitive deficit of SZ in future studies.

Search for Event Rate Modulation in XENON100 Electronic Recoil Data

We have searched for periodic variations of the electronic recoil event rate in the (2-6) keV energy range recorded between February 2011 and March 2012 with the XENON100 detector, adding up to 224.6 live days in total. Following a detailed study to establish the stability of the detector and its background contributions during this run, we performed an unbinned profile likelihood analysis to identify any periodicity up to 500 days. We find a global significance of less than 1σ for all periods, suggesting no statistically significant modulation in the data. While the local significance for an annual modulation is 2.8σ, the analysis of a multiple-scatter control sample and the phase of the modulation disfavor a dark matter interpretation. The DAMA/LIBRA annual modulation interpreted as a dark matter signature with axial-vector coupling of weakly interacting massive particles to electrons is excluded at 4.8σ.

Miniature and robust optical fiber in-line Mach-Zehnder interferometer based on a hollow ellipsoid

An optical fiber in-line Mach-Zehnder interferometer based on a hollow ellipsoid fabricated by femtosecond laser micromachining and fusion-splicing technique is demonstrated. The surface of the hollow ellipsoid acts as an internal mirror that can be utilized for the construction of an interferometer. Such an interferometer device is miniature and robust and can perform external refractive index, curvature, and high-temperature sensing in a mutually independent way, and hence a simultaneous multiple parameter measurement capability can be readily achieved.

Limits on spin-dependent WIMP-nucleon cross sections from 225 live days of XENON100 data

We present new experimental constraints on the elastic, spin-dependent WIMP-nucleon cross section using recent data from the XENON100 experiment, operated in the Laboratori Nazionali del Gran Sasso in Italy. An analysis of 224.6 live days×34 kg of exposure acquired during 2011 and 2012 revealed no excess signal due to axial-vector WIMP interactions with 129Xe and 131Xe nuclei. This leads to the most stringent upper limits on WIMP-neutron cross sections for WIMP masses above 6 GeV/c², with a minimum cross section of 3.5×10(-40) cm² at a WIMP mass of 45 GeV/c², at 90% confidence level.

Unique pharmacological actions of atypical neuroleptic quetiapine: possible role in cell cycle/fate control

Quetiapine is an atypical neuroleptic with a pharmacological profile distinct from classic neuroleptics that function primarily via blockade of dopamine D2 receptors. In the United States, quetiapine is currently approved for treating patients with schizophrenia, major depression and bipolar I disorder. Despite its widespread use, its cellular effects remain elusive. To address possible mechanisms, we chronically treated mice with quetiapine, haloperidol or vehicle and examined quetiapine-specific gene expression change in the frontal cortex. Through microarray analysis, we observed that several groups of genes were differentially expressed upon exposure to quetiapine compared with haloperidol or vehicle; among them, Cdkn1a, the gene encoding p21, exhibited the greatest fold change relative to haloperidol. The quetiapine-induced downregulation of p21/Cdkn1a was confirmed by real-time polymerase chain reaction and in situ hybridization. Consistent with single gene-level analyses, functional group analyses also indicated that gene sets associated with cell cycle/fate were differentially regulated in the quetiapine-treated group. In cortical cell cultures treated with quetiapine, p21/Cdkn1a was significantly downregulated in oligodendrocyte precursor cells and neurons, but not in astrocytes. We propose that cell cycle-associated intervention by quetiapine in the frontal cortex may underlie a unique efficacy of quetiapine compared with typical neuroleptics.

Dark matter results from 225 live days of XENON100 data

We report on a search for particle dark matter with the XENON100 experiment, operated at the Laboratori Nazionali del Gran Sasso for 13 months during 2011 and 2012. XENON100 features an ultralow electromagnetic background of (5.3 ± 0.6) × 10(-3) events/(keV(ee) × kg × day) in the energy region of interest. A blind analysis of 224.6 live days × 34 kg exposure has yielded no evidence for dark matter interactions. The two candidate events observed in the predefined nuclear recoil energy range of 6.6-30.5 keV(nr) are consistent with the background expectation of (1.0 ± 0.2) events. A profile likelihood analysis using a 6.6-43.3 keV(nr) energy range sets the most stringent limit on the spin-independent elastic weakly interacting massive particle-nucleon scattering cross section for weakly interacting massive particle masses above 8 GeV/c(2), with a minimum of 2 × 10(-45) cm(2) at 55 GeV/c(2) and 90% confidence level.

Dark matter results from 100 live days of XENON100 data

We present results from the direct search for dark matter with the XENON100 detector, installed underground at the Laboratori Nazionali del Gran Sasso of INFN, Italy. XENON100 is a two-phase time-projection chamber with a 62 kg liquid xenon target. Interaction vertex reconstruction in three dimensions with millimeter precision allows the selection of only the innermost 48 kg as the ultralow background fiducial target. In 100.9 live days of data, acquired between January and June 2010, no evidence for dark matter is found. Three candidate events were observed in the signal region with an expected background of (1.8 ± 0.6) events. This leads to the most stringent limit on dark matter interactions today, excluding spin-independent elastic weakly interacting massive particle (WIMP) nucleon scattering cross sections above 7.0 × 10(-45) cm(2) for a WIMP mass of 50 GeV/c(2) at 90% confidence level.

Search for light dark matter in XENON10 data

We report results of a search for light (≲10  GeV) particle dark matter with the XENON10 detector. The event trigger was sensitive to a single electron, with the analysis threshold of 5 electrons corresponding to 1.4 keV nuclear recoil energy. Considering spin-independent dark matter-nucleon scattering, we exclude cross sections σ(n)>7×10(-42)  cm(2), for a dark matter particle mass m(χ)=7  GeV. We find that our data strongly constrain recent elastic dark matter interpretations of excess low-energy events observed by CoGeNT and CRESST-II, as well as the DAMA annual modulation signal.

First dark matter results from the XENON100 experiment

The XENON100 experiment, in operation at the Laboratori Nazionali del Gran Sasso in Italy, is designed to search for dark matter weakly interacting massive particles (WIMPs) scattering off 62 kg of liquid xenon in an ultralow background dual-phase time projection chamber. In this Letter, we present first dark matter results from the analysis of 11.17 live days of nonblind data, acquired in October and November 2009. In the selected fiducial target of 40 kg, and within the predefined signal region, we observe no events and hence exclude spin-independent WIMP-nucleon elastic scattering cross sections above 3.4 × 10⁻⁴⁴  cm² for 55  GeV/c² WIMPs at 90% confidence level. Below 20  GeV/c², this result constrains the interpretation of the CoGeNT and DAMA signals as being due to spin-independent, elastic, light mass WIMP interactions.

Limits on spin-dependent WIMP-nucleon cross sections from the XENON10 experiment

XENON10 is an experiment to directly detect weakly interacting massive particles (WIMPs), which may comprise the bulk of the nonbaryonic dark matter in our Universe. We report new results for spin-dependent WIMP-nucleon interactions with 129Xe and 131Xe from 58.6 live days of operation at the Laboratori Nazionali del Gran Sasso. Based on the nonobservation of a WIMP signal in 5.4 kg of fiducial liquid xenon mass, we exclude previously unexplored regions in the theoretically allowed parameter space for neutralinos. We also exclude a heavy Majorana neutrino with a mass in the range of approximately 10 GeV/c2-2 TeV/c2 as a dark matter candidate under standard assumptions for its density and distribution in the galactic halo.

First results from the XENON10 dark matter experiment at the Gran Sasso National Laboratory

The XENON10 experiment at the Gran Sasso National Laboratory uses a 15 kg xenon dual phase time projection chamber to search for dark matter weakly interacting massive particles (WIMPs). The detector measures simultaneously the scintillation and the ionization produced by radiation in pure liquid xenon to discriminate signal from background down to 4.5 keV nuclear-recoil energy. A blind analysis of 58.6 live days of data, acquired between October 6, 2006, and February 14, 2007, and using a fiducial mass of 5.4 kg, excludes previously unexplored parameter space, setting a new 90% C.L. upper limit for the WIMP-nucleon spin-independent cross section of 8.8x10(-44) cm2 for a WIMP mass of 100 GeV/c2, and 4.5x10(-44) cm2 for a WIMP mass of 30 GeV/c2. This result further constrains predictions of supersymmetric models.

Simultaneous measurement of ionization and scintillation from nuclear recoils in liquid xenon for a dark matter experiment

We report the first measurements of the absolute ionization yield of nuclear recoils in liquid xenon, as a function of energy and electric field. Independent experiments were carried out with two dual-phase time-projection chamber prototypes, developed for the XENON dark matter project. We find that the charge yield increases with decreasing recoil energy, and exhibits only a weak field dependence. These results are the first unambiguous demonstration of the capability of dual-phase xenon detectors to discriminate between electron and nuclear recoils down to 20 keV, a key requirement for a sensitive dark matter search.

Spectroscopic studies of interaction of chlorobenzylidine with DNA

Electronic absorbance and fluorescence titrations are used to probe the interaction of chlorobenzylidine with DNA. The binding of chlorobenzylidine to DNA results in hypochromism, a small shift to a longer wavelength in the absorption spectra, and emission quenching in the fluorescence spectra. These spectral characteristics suggest that chlorobenzylidine binds to DNA by an intercalative mode. This conclusion is reinforced by fluorescence polarization measurements. Scatchard plots constructed from fluorescence titration data give a binding constant of 1.3 x 10(5) M(-1) and a binding site size of 10 base pairs. This indicates that chlorobenzylidine has a high affinity with DNA. The intercalative interaction is exothermic with a Van't Hoff enthalpy of -143 kJ/mol. This result is obtained from the temperature dependence of the binding constant. The interaction of chlorobenzylidine with DNA is affected by the pH value of the solution. The binding constant has its maximum at pH 3.0. Upon binding to DNA, the fluorescence from chlorobenzylidine is quenched efficiently by the DNA bases and the fluorescence intensity tends to be constant at high concentrations of DNA when the binding is saturated. The Stern-Volmer quenching constant obtained from the linear quenching plot is 1.6 x 10(4) M(-1) at 25 degrees C. The measurements of the fluorescence lifetime and the dependence of the quenching constant on the temperature indicate that the fluorescence quenching process is static. The fluorescence lifetime of chlorobenzylidine is 1.9 +/- 0.4 ns.

Development of dendritic cells from GM-CSF-/- mice in vitro : GM-CSF enhances production and survival of cells

The production of dendritic cells (DC) from haemopoietic progenitors maintained in long term stroma-dependent cultures (LTC) of spleen or bone marrow (BM) occurs independently of added granulocyte/macrophage colony stimulating factor (GM-CSF). The possibility that cultures depend on endogenous GM-CSF produced in low levels was tested by attempting to generate LTC from spleen and BM of GM-CSF-/- mice. Multiple cultures from GM-CSF-/- and wild type mice were established and compared for cell production. GM-CSF-/- LTC developed more slowly, but by 16 weeks produced cells resembling DC in numbers comparable to wild type cultures. LTC maintained distinct populations of small and large cells, the latter resembling DC. Cells collected from GM-CSF-/- LTC were capable antigen presenting cells (APC) for T cell stimulation and morphologically resembled DC. Large cells expressed the CD11b, CD11c, CD86, 33D1 and Dec-205 markers of DC. Addition of GM-CSF to GM-CSF-/- LTC increased the proportion of large, mature DC present in culture. Stromal cells from GM-CSF-/- LTC could support the differentiation of DC from early progenitors maintained in LTC without addition of GM-CSF. However, GM-CSF is not a critical factor in the in vitro generation of DC from progenitors. It can, however, substitute for stromal cells in increasing the survival of mature DC.

Improved FACS analysis confirms generation of immature dendritic cells in long-term stromal-dependent spleen cultures

Cells produced in spleen stroma-dependent long-term cultures (LTC) have now been clearly defined as dendritic cells (DC). Characterization of cells by antibody staining and FACS analysis has only been possible using a procedure to quench the high autofluorescence of DC produced in LTC (LTC-DC). The population of large cells produced by the established LTC-X1 culture are homogeneously positive for a number of cell-surface markers expressed by DC. These include CD11c, CD11b, Dec-205, Fc receptor and CD86. They also express markers detectable with the F4/80 and 33D1 antibodies. Cells produced in LTC do not uniformly express the MHC II marker, consistent with an immature DC phenotype. Most cells are weakly positive for MHC II with a small subset of highly positive cells. The quenching method involves staining cells with crystal violet dye, which is taken up within the cell. The importance of optimizimg fluorescent antibody staining assays for delineating DC subsets is indicated and the LTC system is established as a valuable and continuous source of DC precursors.

Identification of progenitor cells in long-term spleen stromal cultures that produce immature dendritic cells

Dendritic cells (DC) are produced continuously by a unique, long-term culture (LTC) system in which hemopoiesis is supported by a splenic stromal cell layer in the absence of added growth factors. Flow cytometric analysis reveals the production of two distinct cell subsets. The more predominant large-cell subset resembles highly endocytic DC that are large, granular, and possess membrane extensions. They also express high levels of the DC markers CD11c, CD11b, DEC-205, and CD80 on their cell surface. They do not resemble mature DC because they express low levels of MHC type II and CD86 molecules, as well as c-kit and Fc receptor (FcR). These are known characteristics of immature DC. Small cells are smaller and less granular than large cells, with negative to low expression of CD11c, DEC-205, and CD86. A majority of small cells express varying levels of CD11b and CD80. Subpopulations of small cells express low levels of c-kit, FcR, and MHC type II, and only a 20% subpopulation is weakly endocytic. Upon transfer to an irradiated stromal layer, cells within the small subset proliferate and differentiate to resemble the large cells in size, complexity, membrane extensions, and CD11c and CD86 expression. The two cell subsets produced in LTC are developmentally linked, with the heterogeneous small-cell subset containing progenitors of the larger homogeneous, immature DC subset. LTC represent a valuable model system for studying DC development from hemopoietic progenitors.

Transient cardiac expression of the tinman-family homeobox gene, XNkx2-10

In Drosophila, the tinman homeobox gene is absolutely required for heart development. In the vertebrates, a small family of tinman-related genes, the cardiac NK-2 genes, appear to play a similar role in the formation of the vertebrate heart. However, targeted gene ablation of one of these genes, Nkx2-5, results in defects in only the late stages of cardiac development suggesting the presence of a rescuing gene function early in development. Here, we report the characterization of a novel tinman-related gene, XNkx2-10, which is expressed during early heart development in Xenopus. Using in vitro assays, we show that XNkx2-10 is capable of transactivating expression from promoters previously shown to be activated by other tinman-related genes, including Nkx2-5. Furthermore, Xenopus Nkx2-10 can synergize with the GATA-4 and SRF transcription factors to activate reporter gene expression.

Proliferation of dendritic cell progenitors in long term culture is not dependent on granulocyte macrophage-colony stimulating factor

A unique long term culture (LTC) system has been developed which supports the production of dendritic cells (DC). Cell production is dependent on a stromal cell layer derived from murine spleen. This LTC system produces a high turnover of non-adherent cells that express DC morphology, cell-surface markers, and antigen-presenting capacity.

OBJECTIVE

The long term production of these cells suggests that the LTC system supports hemopoiesis. It was of interest to examine the number and nature of hemopoietic progenitors present in LTC.

MATERIALS AND METHODS

A combination of approaches, including FACS analysis, spleen colony-forming unit assays, and in vitro colony assays were undertaken.

RESULTS

Pluripotent haemopoietic stem cells are not detectable among the non-adherent cell population produced in LTC. Instead, LTC support a replicating c-kit+ progenitor population, which generates only dendritic-like colonies in in vitro colony assays. In addition, this population does not respond to combinations of growth factors thought to stimulate DC proliferation, including granulocyte macrophage-colony stimulating factor (GM-CSF) and Flt3L. Production of DC occurs only in the presence of LTC-derived culture supernatant or a confluent stromal cell layer.

CONCLUSIONS

These results suggest that LTC contain a dendritic progenitor that is dependent upon the stromal cell network for proliferation and differentiation. The development of only DC within LTC allows easy collection of cells for experimentation. This, in combination with the fact that DC development occurs in the absence of exogenous growth factors, makes the LTC system a practical model for the study of DC function and development.

[Partial sympathectomy for treating palmar hyperhidrosis with VATS]

OBJECTIVE

To review the experience with partial sympathectomy for treating palmar hyperhidrosis with VATS.

METHODS

Between July 1995 and June 1999, 50 patients with palmar hyperhidrosis (26 males and 24 females, mean age 26.7 years) were operated. The major symptom was excessive sweating of hands, feet, and axcillaries, sometimes in drops. Thoracoscopy was performed under general anesthesia with a standard single-lumen endotracheal intubation with the patient in a semi-sitting position and arms stretched at 90 degrees. The approach through two small ports on the chest wall was done using VATS. As the lung was depressed by CO(2) insufflation in a low pressure, an excellent view of the upper mediastinum was obtained. Ganglia T(2) through T(4), sometimes T(5) were resected with a electrocautery probe. Bilateral procedures were completed in the same position.

RESULTS

All patients after operation became dry immediately after sympathetic denervation with a few minor complications. Occasional side effect was moderate compensatory sweating of the trunk. One case had recurrence but sweating was much less than before operation.

CONCLUSIONS

Because of excellent view of the upper mediastinum for sympathetic denervation of the hand and axcillaryies, the effect of partial sympathectomy for palmar hyperhidrosis is satisfactory and permanent.

Long-term stroma-dependent cultures are a consistent source of immunostimulatory dendritic cells

A long-term culture (LTC) system has been established that supports the continuous production of dendritic cells (DC) from haemopoietic cells present in the culture. The production of cells depends on the presence of an intact stromal cell layer containing a mixture of fibroblasts and endothelial cells. Cells are shed from foci of dividing cells in contact with the stromal cell matrix. They resemble DC in terms of morphology and cell surface marker expression. The LTC can be derived from different lymphoid tissues, but most success has been achieved with murine spleen. Different LTC vary in capacity to produce immunostimulatory DC. Some LTC produce DC that are very effective APC and can stimulate both mixed lymphocyte and antigen-specific T cell responses. The DC produced in others are weak APC. Different LTC appear to produce DC reflecting different stages of maturation or development, reflected by different phenotypic and functional characteristics. The production of cells within LTC occurs independently of added cytokines and is dependent on maintenance of the stromal cell layer and the presence of a subset of smaller progenitor cells. Long-term cultures remain a valuable source of cells for study of DC development and function.

Immunotherapeutic potential of dendritic cells generated in long-term stroma-dependent cultures

Long term cultures (LTC) producing dendritic cells (DC) have been established from spleen. A well developed stromal cell layer supported production of DC in numbers suitable for experimentation. Cells had obvious membrane pseudopodia and could be collected from culture every 2-3 days. Large cells produced in LTC stained with fluorescently labelled monoclonal antibodies specific for DC such as 33D1, and M1/70 which is specific for DC and myeloid cells. These staining patterns confirmed the presence of DC within the LTC population. LTC-DC were tested and shown capable of migration in vivo in B10.A(2R) mice following footpad inoculation. Most cells entered the spleen and a small number entered popliteal lymph node. LTC-DC have migratory capacity comparable with control spleen lymphocytes. LTC-DC were tested for capacity to induce an anti-tumour immune response after exposing cells to tumour cell membranes. LTC-DC pulsed with BL/VL3 tumour antigens were able to induce a BL/VL3-specific primary cytotoxic T lymphocyte (CTL) response detectable in popliteal lymph nodes and spleen of C57BL/6J mice within 6 days of priming. BL/VL3 tumour cells grew in sublethally irradiated C57BL/6J mice giving 100% mortality. Adoptive transfer of spleen cells from mice given BL/VL3 antigen-pulsed LTC-DC, two weeks previously, significantly slowed the growth of BL/VL3 tumour cells in mice. DC produced in LTC can function as antigen presenting cells (APC) when adoptively transferred into animals. Their capacity to migrate effectively, to induce a CTL response and to reduce tumour load suggests that DC grown using this in vitro system may have valuable clinical potential in humans.

Spleen stromal cells support haemopoiesis and in vitro growth of dendritic cells from bone marrow

Long-term stroma-dependent cultures from murine spleen have been previously shown to support dendritic cell (DC) development in vitro. Secondary cultures have now been established using a splenic stromal cell layer overlaid with cells from different lymphoid sites. Cells resembling DCs can be generated in vitro from unfractionated murine lymphoid cells in the absence of added growth factors. Bone marrow (BM) cultures are the most successful but some cultures have been derived from spleen and thymus. Large numbers of mononuclear cells with dendritic morphology can be generated from BM within 2 weeks and cell production in many cultures has been maintained for at least 6 months. A significant proportion of cells binds antibodies specific for DC markers. No lymphoid cells, mast cells or granulocytes are detectable in culture by antibody and histochemical staining and light and electron microscopy. As with cells generated in primary cultures, cells grown in secondary cultures are equally potent stimulators of both syngeneic and allogeneic mixed lymphocyte reactions, confirming their function as antigen-presenting cells. They are also capable of endocytosing and presenting protein antigen to the D10.G4.1 Th2 clone and to unprimed T cells. This study confirmed the presence of DC precursors in multiple lymphoid sites which can be induced to proliferate in the presence of a spleen stromal cell monolayer. The secondary culture system provides an ideal in vitro model for investigation of the development of DC from different tissue sites. It also provides a stable and continuous resource of cells for further studies on DC development.

Hemopoiesis in long-term stroma-dependent cultures from lymphoid tissue: production of cells with myeloid/dendritic characteristics

A long-term stroma-dependent culture system (LTC) has been developed which continuously produces hemopoietic cells providing an in vitro system for the study of cell differentiation. These nonadherent cell populations contain a large subpopulation of dendritic cells (DC). LTC producing DC were easily generated from spleen, but could also be established from bone marrow (BM) and lymph node with less success. It was difficult to establish DC-producing LTC from thymus. The properties of splenic and thymic stroma have been compared. Spleen stroma developed more complicated networks of fibroblasts, endothelial cells, macrophages, and DC. Thymic stromal monolayers were dominated by epithelial cells and fibroblasts, with a lower proportion of macrophages and endothelial cells. They had a relatively sparse structure of cell networks compared with spleen stroma. Cells with dendritiform morphology first appeared in cultures by 2-3 wk. The majority of cells produced were large cells which expressed DC-specific cell surface markers, major histocompatibility complex (MHC) Class II molecules, and the CD80/CD86(B7) costimulator. A high proportion of cells also expressed myeloid cell markers. No T or B lymphoid cells or granulocytes were present in the cultures. LTC continued to produce nonadherent cells resembling myeloid/DC for long periods, even after passage of stromal cells and stem cells at about 3-4 mo. after culture establishment. The LTC system offers potential to study the in vitro differentiation of myeloid/DC.

Long-term stromal cultures produce dendritic-like cells

A stromal cell-dependent long-term culture (LTC) system has been developed from spleen which continuously generates non-adherent cells with dendritic cell (DC) characteristics. Bioassays using factor-dependent cell lines have revealed that both spleen and thymic stromal cultures secrete interleukin (IL)-3 and IL-6-like growth factors. Conditioned medium from LTC also contains factors which appear to be unrelated to IL-3 and induces growth of stromal cells from bone marrow. Non-adherent cells generated in LTC were not T or B lymphoid cells or granulocytes, nor were mast cells detectable. Morphological and electron microscopic examination has also excluded the presence of macrophages (Mo). Cells with DC morphology have been detected by both light and electron microscopy. The majority of cells in the non-adherent population were found to have multiple membrane pseudopodia, with a small acentric nucleus. These appear to be the precursors of DC. They expressed cell surface markers detectable with DC-specific antibodies and antibody specific for major histocompatibility complex Class II molecules. A proportion of cells also expressed myeloid markers, but since this expression was not supported by histochemical staining for myeloperoxidase or non-specific esterase, it was concluded that the cells produced are not typical of the myeloid lineage. Cells generated in LTC were shown to be potent stimulators for allogeneic and syngeneic MLR and for antigen-specific T-cell proliferation.

The role of dendritic cells in T cell activation

Dendritic cells (DC) are distinguishable from other antigen-presenting cells by their potent antigen-presenting capacity. They are not only efficient at presenting peptide antigen but can also process and present soluble protein antigen sto antigen-specific T cells and cloned T cell lines. They are very strong stimulators of both allogeneic and syngeneic mixed lymphocyte reactions and have a unique capacity to stimulate naive T cells. The potent functional capacity of DC is related to a high-level expression of major histocompatibility complex class I/II molecules and constitutive expression of costimulatory molecules, such as CD80/CD86, as well as heat stable antigen, CD40 and the leucocyte function antigen (LFA) family of adhesion molecules. Recent studies have shown that DC are also involved in regulation of the immune response via induction of both central and peripheral tolerance.

[The effect of tinidazole in the treatment of adult periodontitis]

Fifty-two adult periodontitis patients were treated by the tablets of tinidazole (TNZ), and 23 patients treated by metronidazole (MNZ) served as control group. The effective rate of TNZ in adult periodontitis patients was 73.1%, which was significantly higher than that of the control group (43.5%). Antimicrobial studies showed that the capability of TNZ to kill the periodontal dominant anaerobic bacteria, especially B. gingivalis and B. melaninogenicus, was better than that of MNZ. The minimal inhibitory concentration (MIC) of TNZ to Bacteroides, Fusobacterium, Veillonella, Eubacterium, Antinomyces, Peotostreptococus and Anaerobic Streptococus was lower than that of MNZ and actylspiramycine.