RESUMEN

Dark matter (DM) particles with sufficiently large cross sections may scatter as they travel through Earth's bulk. The corresponding changes in the DM flux give rise to a characteristic daily modulation signal in detectors sensitive to DM-electron interactions. Here, we report results obtained from the first underground operation of the DAMIC-M prototype detector searching for such a signal from DM with MeV-scale mass. A model-independent analysis finds no modulation in the rate of 1 e^{-} events with sidereal period, where a DM signal would appear. We then use these data to place exclusion limits on DM in the mass range [0.53,2.7] MeV/c^{2} interacting with electrons via a dark photon mediator. Taking advantage of the time-dependent signal we improve by ∼2 orders of magnitude on our previous limit obtained from the total rate of 1 e^{-} events, using the same dataset. This daily modulation search represents the current strongest limit on DM-electron scattering via ultralight mediators for DM masses around 1 MeV/c^{2}.

RESUMEN

We report constraints on sub-GeV dark matter particles interacting with electrons from the first underground operation of DAMIC-M detectors. The search is performed with an integrated exposure of 85.23 g days, and exploits the subelectron charge resolution and low level of dark current of DAMIC-M charge-coupled devices (CCDs). Dark-matter-induced ionization signals above the detector dark current are searched for in CCD pixels with charge up to 7e^{-}. With this dataset we place limits on dark matter particles of mass between 0.53 and 1000 MeV/c^{2}, excluding unexplored regions of parameter space in the mass ranges [1.6,1000] MeV/c^{2} and [1.5,15.1] MeV/c^{2} for ultralight and heavy mediator interactions, respectively.

RESUMEN

No disponible

Asunto(s)

Asunto(s)

RESUMEN

We present constraints on the existence of weakly interacting massive particles (WIMPs) from an 11 kg d target exposure of the DAMIC experiment at the SNOLAB underground laboratory. The observed energy spectrum and spatial distribution of ionization events with electron-equivalent energies >200 eV_{ee} in the DAMIC CCDs are consistent with backgrounds from natural radioactivity. An excess of ionization events is observed above the analysis threshold of 50 eV_{ee}. While the origin of this low-energy excess requires further investigation, our data exclude spin-independent WIMP-nucleon scattering cross sections σ_{χ-n} as low as 3×10^{-41} cm^{2} for WIMPs with masses m_{χ} from 7 to 10 GeV c^{-2}. These results are the strongest constraints from a silicon target on the existence of WIMPs with m_{χ}<9 GeV c^{-2} and are directly relevant to any dark matter interpretation of the excess of nuclear-recoil events observed by the CDMS silicon experiment in 2013.

RESUMEN

We report direct-detection constraints on light dark matter particles interacting with electrons. The results are based on a method that exploits the extremely low levels of leakage current of the DAMIC detector at SNOLAB of 2-6×10^{-22} A cm^{-2}. We evaluate the charge distribution of pixels that collect <10e^{-} for contributions beyond the leakage current that may be attributed to dark matter interactions. Constraints are placed on so-far unexplored parameter space for dark matter masses between 0.6 and 100 MeV c^{-2}. We also present new constraints on hidden-photon dark matter with masses in the range 1.2-30 eV c^{-2}.

RESUMEN

Matrix metalloproteinases (MMPs) have been identified as biomarkers for cancer, offering prognostic potential; however, non-invasive detection protocols are currently lacking. Herein, we describe the synthesis of a DOTA-containing peptide sequence that can be radiolabelled easily with 68Gallium or can be incorporated with gadolinium for possible MRI applications with clear selectivity for MMP-2 over other members of the MMP family, giving MMP-2 selective cleavage of the labelled peptides.

Asunto(s)

RESUMEN

In the present work, the influence of external cooling on the temperature rise in the tooth pulpal chamber during femtosecond laser ablation was investigated. The influence of the cooling method on the morphology and constitution of the laser-treated surfaces was studied as well. The ablation experiments were performed on dentin specimens using an Yb:KYW chirped-pulse-regenerative amplification laser system (560 fs, 1030 nm). Cavities were created by scanning the specimens at a velocity of 5 mm/s while pulsing the stationary laser beam at 1 kHz and with fluences in the range of 2-14 J/cm2. The experiments were performed in air and with surface cooling by a lateral air jet and by a combination of an air jet and water irrigation. The temperature in the pulpal chamber of the tooth was measured during the laser experiments. The ablation surfaces were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The temperature rise reached 17.5 °C for the treatments performed with 14 J/cm2 and without cooling, which was reduced to 10.8 ± 1.0 and 6.6 ± 2.3 °C with forced air cooling and water cooling, respectively, without significant reduction of the ablation rate. The ablation surfaces were covered by ablation debris and resolidified droplets containing mainly amorphous calcium phosphate, but the amount of redeposited debris was much lower for the water-cooled specimens. The redeposited debris could be removed by ultrasonication, revealing that the structure and constitution of the tissue remained essentially unaltered. The present results show that water cooling is mandatory for the femtosecond laser treatment of dentin, in particular, when high fluences and high pulse repetition rates are used to achieve high material removal rates.

Asunto(s)

RESUMEN

INTRODUCTION: Congenital hypofibrinogenaemia is a quantitative fibrinogen disorder characterized by proportionally decreased levels of functional and antigenic fibrinogen. Mutations accounting for quantitative fibrinogen disorders are relatively frequent in the conserved COOH-terminal globular domains of the γ and Bß chains. The latter mutations are of particular interest since the Bß-chain is considered the rate-limiting chain in the hepatic production of the fibrinogen hexamer. AIM: The aim of this study was to study the molecular pattern of four patients with congenital hypofibrinogenaemia. METHODS: Four novel fibrinogen Bß-chain mutations leading to congenital hypofibrinogenaemia were identified in four women with heterogeneous symptoms. The human fibrinogen beta chain precursor protein sequence (P02675) was obtained from the UniProt database. The resulting models were analysed using swisspdbviewer 4.1.0. RESULTS: Three patients were heterozygous for different missense mutations located in the highly conserved ß nodule: c.882G>C:Arg294Ser (Arg264Ser), c.1298G>T:Trp433Leu (Trp403Leu) and c.1329C>G:Asn443Lys (Asn413Lys). Modelling analyses predicted major structural modifications likely to result in impaired fibrinogen secretion. One patient was heterozygous for an intron 7 donor splice mutation (c.1244 + 1G>A), leading to the complete abolishment of the donor site. CONCLUSIONS: Protein modelling of new causative mutations and comparison of molecular, biochemical and clinical data continue to yield valuable information on the development and course of fibrinogen disorders as well as on the choice of the most appropriate treatments.

Asunto(s)

RESUMEN

Essentials Hypodysfibrinogenemia is rarely reported among the congenital fibrinogen disorders. This first systematic literature review led to identification of 51 hypodysfibrinogenemic cases. Diagnosis based only on functional/antigenic fibrinogen ratio may be insufficient. Family studies show an incomplete segregation of mutation with the clinical phenotypes. SUMMARY: Background Hypodysfibrinogenemia is a rare disease characterized by decreased levels of a dysfunctional fibrinogen. It shares features with both hypo- and dysfibrinogenemia, although with specific molecular patterns and clinical phenotypes. Objectives To better define the genetics, the diagnosis and the clinical features of hypodysfibrinogenemia. Patients/Methods A systematic literature search led to 167 records. After removal of duplicates, abstract screening and full-text reviewing, 56 molecular and/or clinical studies were analyzed, including a novel FGB missense mutation in a woman with a mild bleeding phenotype. Results A total of 32 single causative mutations were reported, mainly in the COOH-terminal region of the γ or Aα chains at heterozygous or homozygous state. Seven additional hypodysfibrinogenemias were due to compound heterozygosity. The hypofibrinogenemic phenotypes were a result of an impaired assembly or secretion or an increased clearance of the fibrinogen variant, whereas the dysfibrinogenemic phenotype was mainly a result of a defective fibrin polymerization and an abnormal calcium or tPA binding. Among 51 identified index cases, a functional/antigenic fibrinogen ratio < 0.7 had a sensitivity of 86% for the diagnosis of hypodysfibrinogenemia. Eleven patients (22%) were asymptomatic at time of diagnosis, 23 (45%) had a mild bleeding phenotype with mainly obstetrical or gynecologic-related hemorrhage and 22 (43%) had experienced at least one thrombotic event, including 23 venous and eight arterial thromboses. Conclusions This first systematic review on hypodysfibrinogenemia shows the heterogeneity of causative mutations and that misdiagnosis could occur in relation to the functional and antigenic fibrinogen levels. Family studies reveal an incomplete segregation of the mutation with the clinical phenotype.

Asunto(s)

RESUMEN

Biocompatibility has long been associated with surface microtopography, microtexture, and microchemistry. The surface topography eventually affects the nature and the intensity of the interactions that occur at biomaterial-biological interface (cell adhesion, mobility, spreading, and proliferation). Therefore, it is necessary to produce and work with controlled microtopographical surfaces that present reproducible microdomains of a dimension similar to that of the biological elements of interest (in this case, osteoblasts). There are a number of substrates that already have been studied in terms of surface topography; however, few studies are related to hydroxyapatite (HA) substrates. As it is well established, HA is a well-known ceramic that is extremely used in medical applications, namely implants and coatings. In this work, the surface topography of dense HA substrates was altered by using KFr excimer laser. The surface was characterized by atomic force microscopy and contact angle measurements, while the cell distribution and morphology was assessed by scanning electron microscopy and confocal laser scanning microscopy. Results revealed that the surface is characterized by a homogeneous columnar structure with high specific area. Moreover, cells were able to attach and spread on the surface of the samples, and gradually grow into nearly confluent monolayers.

Asunto(s)

RESUMEN

Genetic predisposition, environmental toxins and aging contribute to Parkinson's disease (PD) multifactorial etiology. Weak environmental neurotoxic factors may accumulate over time increasing the disease risk in genetically predisposed subjects. Polymorphic genes encoding drug-metabolizing-enzymes (DMEs) are considered to account for PD susceptibility by determining individual toxic response variability. In this work, the allelic distributions and genotype associations of three major brain-expressed DMEs were characterized, in sporadic PD cases and controls. No significant association was found between CYP2D6 genotype and PD, but subjects with extensive metabolizer (EM) CYP2D6 phenotype, and the variant GSTP1*B genotype were at significantly higher PD risk than the corresponding poor or intermediary metabolizers (CYP2D6 poor metabolizer phenotype+intermediary metabolizers). A significant association was observed between the GSTP1*B allele and zygosity with PD (GSTP1*A/*B- 51.58%/34.37%, odds ratio (OR) = 2.29; 95% confidence interval (95% CI) = 1.25-4.18; *B/*B- 6.32%/1.05%, OR = 10.67; 95% CI = 1.19-94.79). This association was particularly strong in the elder patients group (> or =69 year) who showed double PD risk for GSTP1*B heterozygous, whilst GSTP1*B/*B homozygous were exclusively found amongst patients. An interaction between GSTM1 and GSTP1 was observed in this late onset PD group. The present results suggest that native GSTP1 encoding the fully active transferase variant should play a relevant role in dopaminergic neuroprotection.

Asunto(s)

RESUMEN

In the present paper, the influence of tubule orientation on surface texture development was studied. Specimens of dentin with a wide range of tubule orientations were extracted from caries-free human teeth, processed using KrF laser radiation, and analyzed by scanning electron microscopy. When a transverse cross section of dentin cut perpendicularly to the tooth axis is processed with KrF laser radiation, a cone-like topography develops in the inner dentin where tubules are parallel to the laser beam. When laser processing is carried out in the outer dentin, because tubules are significantly tilted with respect to the laser beam, flat surfaces are achieved. The surface texture after laser processing depends effectively on the angle between the tubules and the laser beam. The dependency of cone growth on tubule orientation was confirmed using a simple differential ablation model.

Asunto(s)

RESUMEN

OBJECTIVES: To determine the prevalence of type 2 diabetes in preoperative anesthetic assessment interviews during May 2004 and to compare the results to prevalences reported in other studies. PATIENTS AND METHODS: Patients over the age of 20 years who received an assessment interview were included. Type 1 diabetics, pregnant women, and critically ill patients were excluded. We followed the 1997 diagnostic guidelines of the American Diabetes Association. RESULTS: The prevalence of previously diagnosed type 2 diabetes was 10.3%. Three patients were diabetics unaware of their disease. The overall prevalence of type 2 diabetes was 11% in this population. CONCLUSIONS: Type 2 diabetes has a high prevalence among surgical patients in our hospital, higher than that reported for the general population based on other studies.

Asunto(s)

RESUMEN

OBJETIVOS: Conocer la prevalencia de diabetes tipo 2en una consulta de valoración preoperatoria durante elmes de mayo de 2004. Comparar la prevalencia halladacon otros estudios.PACIENTES Y MÉTODOS: Se incluyeron los pacientesmayores de 20 años que acudieron a la consulta. Seexcluyeron los diabéticos tipo 1, embarazadas y pacientescríticos. Se siguieron los criterios de diagnóstico dediabetes de la Sociedad Americana de Diabetes de1997.RESULTADOS: Un 10,3% de los pacientes eran diabéticostipo 2 conocidos. Tres pacientes eran diabéticos perodesconocían su enfermedad. En total 11% de la poblaciónestudiada era diabética tipo 2.CONCLUSIONES: La diabetes tipo 2 es una enfermedadfrecuente en los pacientes quirúrgicos de nuestro hospitaly la prevalencia es mayor que la hallada en otrosestudios de población general

OBJECTIVES: To determine the prevalence of type 2diabetes in preoperative anesthetic assessment interviewsduring May 2004 and to compare the results toprevalences reported in other studies.PATIENTS AND METHODS: Patients over the age of 20years who received an assessment interview were included.Type 1 diabetics, pregnant women, and criticallyill patients were excluded. We followed the 1997 diagnosticguidelines of the American Diabetes Association.RESULTS: The prevalence of previously diagnosed type2 diabetes was 10.3%. Three patients were diabeticsunaware of their disease. The overall prevalence of type2 diabetes was 11% in this population.CONCLUSIONS: Type 2 diabetes has a high prevalenceamong surgical patients in our hospital, higher than thatreported for the general population based on other studies

Asunto(s)

RESUMEN

OBJECTIVES: To describe the neuropsychological status of patients with intracranial aneurysms and to compare the cognitive status of patients with intracranial aneurysm treated by surgical or endovascular methods. MATERIAL AND METHODS: Ninety-three cases with intracranial aneurysms treated with surgery (n = 56) or embolization (n = 37) were included. A neuropsychological assessment was applied to both groups retrospectively, at least one year after treatment. RESULTS: Neuropsychological impairment was found in both groups. 35.7% of the patients treated with surgery and 43.2%, of those treated with embolization did not show any cognitive impairment. Visual Memory and Cued Recall of verbal information are better in patients treated by embolization. CONCLUSIONS: Our results show that a large proportion of patients with intracranial aneurysms have cognitive impairment after treatment. Endovascular management may cause less impairment in visual and verbal memory. However, bleeding may be the most important factor to explain these cognitive impairments.

Asunto(s)

RESUMEN

Objetivos. Describir el rendimiento neuropsicológico de pacientes con aneurismas cerebrales que han sido tratados mediante cirugía o embolización, y determinarla existencia de diferencias en función de la modalidad de tratamiento. Material y métodos. Serie clínica compuesta por 93pacientes voluntarios, con aneurismas cerebrales, tratados mediante cirugía (n = 56) o embolización (n = 37). A ambos grupos se les realizó una evaluación neuropsicológica retrospectiva, al menos un año después de realizar el tratamiento. Resultados. En ambos grupos se encontraron pacientes con déficit neuropsicológicos. En el grupo de pacientes tratados quirúrgicamente el porcentaje de pacientes sin ninguna afectación neuropsicológica es del 35.7%, mientras que en el grupo de pacientes embolizados este porcentaje asciende al 43.2%. Los análisis muestran una ejecución mejor en el grupo de tratamiento endovascular, respecto al quirúrgico, sólo en memoria visual y en el recuerdo con claves de la memoria verbal. Conclusiones. Años después del tratamiento, un importante porcentaje de pacientes presenta alteraciones neuropsicológicas. El tratamiento endovascular se asocia con un mejor rendimiento en memoria visual yen el recuerdo con claves de la memoria verbal, aunque explica un porcentaje muy escaso de la varianza. Por lo tanto, en la explicación del deterioro neuropsicológico parece más importante el propio efecto de la hemorragia que la modalidad de intervención

Objectives. To describe the neuropsychological status of patients with intracranial aneurysms and to compare the cognitive status of patients with intracranial aneurysm treated by surgical or endovascular methods. Material and methods. Ninety-three cases with intracranial aneurysms treated with surgery (n = 56) or embolization (n = 37) were included. A neuropsychological assessment was applied to both groups retrospectively, at least one year after treatment. Results. Neuropsychological impairment was found in both groups. 35.7% of the patients treated with surgery and 43.2%, of those treated with embolization did not show any cognitive impairment. Visual Memory and Cued Recall of verbal information are better inpatients treated by embolization. Conclusions. Our results show that a large proportion of patients with intracranial aneurysms have cognitive impairment after treatment. Endovascular management may cause less impairment in visual and verbal memory. However, bleeding may be the most important factor to explain these cognitive impairments

Asunto(s)

RESUMEN

An angular analysis of B0-->J/psiK(*0) and B(0)(s)-->J/psistraight phi has been used to determine the decay amplitudes with parity-even longitudinal ( A0) and transverse ( A( parallel)) polarization and parity-odd transverse ( A( perpendicular)) polarization. The measurements are based on 190 B0 and 40 B(0)(s) candidates obtained from 89 pb(-1) of &pmacr;p collisions at the Fermilab Tevatron. The longitudinal decay amplitude dominates with |A0|(2) = 0.59+/-0. 06+/-0.01 for B0 and |A0|(2) = 0.61+/-0.14+/-0.02 for B(0)(s) decays. The parity-odd amplitude is found to be small with |A( perpendicular)|(2) = 0.13(+0.12)(-0.09)+/-0.06 for B0 and |A( perpendicular)|(2) = 0.23+/-0.19+/-0.04 for B(0)(s) decays.

RESUMEN

We report the first observation of dijet events with a double Pomeron exchange topology produced in &pmacr;p collisions at sqrt[s] = 1800 GeV. The events are characterized by a leading antiproton, two jets in the central pseudorapidity region, and a large rapidity gap on the outgoing proton side. We present results on jet kinematics and production rates, compare them with corresponding results from single diffractive and inclusive dijet production, and test factorization.

RESUMEN

This Letter describes a direct measurement of the W boson total decay width, gamma(W), using the Collider Detector at Fermilab. The measurement uses an integrated luminosity of 90 pb(-1), collected during the 1994-1995 run of the Fermilab Tevatron p&pmacr; collider. The width is determined by normalizing predicted signal and background distributions to 49 844 W-->enu candidates and 21 806 W-->&mgr;nu candidates in the transverse-mass region M(T)<200 GeV and then fitting the predicted shape to the 438 electron events and 196 muon events in the high- M(T) region, 100