613 research outputs found
Some integrability conditions for almost K\"ahler manifolds
Among other results, a compact almost K\"ahler manifold is proved to be
K\"ahler if the Ricci tensor is semi-negative and its length coincides with
that of the star Ricci tensor or if the Ricci tensor is semi-positive and its
first order covariant derivatives are Hermitian. Moreover, it is shown that
there are no compact almost K\"ahler manifolds with harmonic Weyl tensor and
non-parallel semi-positive Ricci tensor. Stronger results are obtained in
dimension 4.Comment: Latex2e, 13 page
The in-plane electrodynamics of the superconductivity in Bi2Sr2CaCu2O8+d: energy scales and spectral weight distribution
The in-plane infrared and visible (3 meV-3 eV) reflectivity of
Bi2Sr2CaCu2O8+d (Bi-2212) thin films is measured between 300 K and 10 K for
different doping levels with unprecedented accuracy. The optical conductivity
is derived through an accurate fitting procedure. We study the transfer of
spectral weight from finite energy into the superfluid as the system becomes
superconducting. In the over-doped regime, the superfluid develops at the
expense of states lying below 60 meV, a conventional energy of the order of a
few times the superconducting gap. In the underdoped regime, spectral weight is
removed from up to 2 eV, far beyond any conventional scale. The intraband
spectral weight change between the normal and superconducting state, if
analyzed in terms of a change of kinetic energy is ~1 meV. Compared to the
condensation energy, this figure addresses the issue of a kinetic energy driven
mechanism.Comment: 13 pages with 9 figures include
Resistance to autosomal dominant Alzheimer's disease in an APOE3 Christchurch homozygote: a case report.
We identified a PSEN1 (presenilin 1) mutation carrier from the world's largest autosomal dominant Alzheimer's disease kindred, who did not develop mild cognitive impairment until her seventies, three decades after the expected age of clinical onset. The individual had two copies of the APOE3 Christchurch (R136S) mutation, unusually high brain amyloid levels and limited tau and neurodegenerative measurements. Our findings have implications for the role of APOE in the pathogenesis, treatment and prevention of Alzheimer's disease
Phase 3 Trial of 177Lu-Dotatate for Midgut Neuroendocrine Tumors
Background Patients with advanced midgut neuroendocrine tumors who have had disease progression during first-line somatostatin analogue therapy have limited therapeutic options. This randomized, controlled trial evaluated the efficacy and safety of lutetium-177 (177Lu)-Dotatate in patients with advanced, progressive, somatostatin-receptor-positive midgut neuroendocrine tumors. Methods We randomly assigned 229 patients who had well-differentiated, metastatic midgut neuroendocrine tumors to receive either 177Lu-Dotatate (116 patients) at a dose of 7.4 GBq every 8 weeks (four intravenous infusions, plus best supportive care including octreotide long-acting repeatable [LAR] administered intramuscularly at a dose of 30 mg) (177Lu-Dotatate group) or octreotide LAR alone (113 patients) administered intramuscularly at a dose of 60 mg every 4 weeks (control group). The primary end point was progression-free survival. Secondary end points included the objective response rate, overall survival, safety, and the side-effect profile. The final analysis of overall survival will be conducted in the future as specified in the protocol; a prespecified interim analysis of overall survival was conducted and is reported here. Results At the data-cutoff date for the primary analysis, the estimated rate of progression-free survival at month 20 was 65.2% (95% confidence interval [CI], 50.0 to 76.8) in the 177Lu-Dotatate group and 10.8% (95% CI, 3.5 to 23.0) in the control group. The response rate was 18% in the 177Lu-Dotatate group versus 3% in the control group (P<0.001). In the planned interim analysis of overall survival, 14 deaths occurred in the 177Lu-Dotatate group and 26 in the control group (P=0.004). Grade 3 or 4 neutropenia, thrombocytopenia, and lymphopenia occurred in 1%, 2%, and 9%, respectively, of patients in the 177Lu-Dotatate group as compared with no patients in the control group, with no evidence of renal toxic effects during the observed time frame. Conclusions Treatment with 177Lu-Dotatate resulted in markedly longer progression-free survival and a significantly higher response rate than high-dose octreotide LAR among patients with advanced midgut neuroendocrine tumors. Preliminary evidence of an overall survival benefit was seen in an interim analysis; confirmation will be required in the planned final analysis. Clinically significant myelosuppression occurred in less than 10% of patients in the 177Lu-Dotatate group. (Funded by Advanced Accelerator Applications; NETTER-1 ClinicalTrials.gov number, NCT01578239 ; EudraCT number 2011-005049-11
Use of a colonoscope for distal duodenal stent placement in patients with malignant obstruction
Background: Stent placement in the distal duodenum or proximal jejunum with a therapeutic gastroscope can be difficult, because of the reach of the endoscope, loop formation in the stomach, and flexibility of the gastroscope. The use of a colonoscope may overcome these problems. Objective: To report our experience with distal duodenal stent placement in 16 patients using a colonoscope. Methods: Multicenter, retrospective series of patients with a malignant obstruction at the level of the distal duodenum and proximal jejunum and treated by stent placement using a colonoscope. Main outcome measurements are technical success, ability to eat, complications, and survival. Results: Stent placement was technically feasible in 93% (15/16) of patients. Food intake improved from a median gastric outlet obstruction scoring system (GOOSS) score of 1 (no oral intake) to 3 (soft solids) (p = 0.001). Severe complications were not observed. One patient had persistent obstructive symptoms presumably due to motility problems. Recurrent obstructive symptoms were caused by tissue/tumor ingrowth through the stent mesh [n = 6 (38%)] and stent occlusion by debris [n = 1 (6%)]. Reinterventions included additional stent placement [n = 5 (31%)], gastrojejunostomy [n = 2 (12%)], and endoscopic stent cleansing [n = 1 (6%)]. Median survival was 153 days. Conclusion: Duodenal stent placement can effectively and safely be performed using a colonoscope in patients with an obstruction at the level of the distal duodenum or proximal jejunum. A colonoscope has the advantage that it is long enough and offers good endoscopic stiffness, which avoids looping in the stomach
A common variant of the latrophilin 3 gene, LPHN3, confers susceptibility to ADHD and predicts effectiveness of stimulant medication
Attention-Deficit/Hyperactivity Disorder (ADHD) has a very high heritability (0.8), suggesting that about 80% of phenotypic variance is due to genetic factors. We used the integration of statistical and functional approaches to discover a novel gene that contributes to ADHD. For our statistical approach, we started with a linkage study based on large multigenerational families in a population isolate, followed by fine mapping of targeted regions using a family-based design. Family- and population-based association studies in five samples from disparate regions of the world were used for replication. Brain imaging studies were performed to evaluate gene function. The linkage study discovered a genome region harbored in the Latrophilin 3 gene (LPHN3). In the world-wide samples (total n=6360, with 2627 ADHD cases and 2531 controls) statistical association of LPHN3 and ADHD was confirmed. Functional studies revealed that LPHN3 variants are expressed in key brain regions related to attention and activity, affect metabolism in neural circuits implicated in ADHD, and are associated with response to stimulant medication. Linkage and replicated association of ADHD with a novel non-candidate gene (LPHN3) provide new insights into the genetics, neurobiology, and treatment of ADHD
Plasma-Based Surface Modification of Polydimethylsiloxane for PDMS-PDMS Molding
We present and compare two processes for plasma-based surface modification of Polydimethylsiloxane (PDMS) to achieve the antisticking behavior needed for PDMS-PDMS molding. The studied processes were oxygen plasma activation for vapor phase silanization and plasma polymerization with tetrafluoromethane/hydrogen mixtures under different processing conditions. We analyzed topography changes of the treated surfaces by atomic force microscopy and contact angle measurements. Plasma treatment were conducted in a parallel plate reactive ion etching reactor at a pressure of 300 mTorr, 30 Watts of RF power and a total flow rate of 30 sccm of a gas mixture. We found for both processes that short, low power, treatments are better to create long-term modifications of the chemistry of the polymer surface while longer processes or thicker films tend to degrade faster with the use leaving rough surfaces with higher adherence to the molded material.</jats:p
Kvaliteta sjemena u ovaca
Reproductive evaluation, the selection of individual breeders, and reproductive biotechnologies are important tools in developing productive and reproductive rates. When choosing a male as a breeding future, determining its general health status and genotypic and phenotypic superiority are necessary. This study evaluated the conventional and functional seminal quality in ovine males. The semen of eleven ovines of different pure races was collected by electroejaculation. The following average values were observed for each conventional parameter: scrotal circumference (CE, 34.3 cm), seminal volume (vol, 1.63 mL), concentration (C, 768.4 x 106/mL), individual motility (MI, 80%), masal motility (MM, 4) and vigor (Vi, 3.7). On the other hand, functional analysis showed plasma membrane integrity (PMI) of 45.7%, mitochondrial membrane potential (MMP) of 38.5%, DNA fragmentation index (DFI) of 17.0%, lipoperoxidation of the membrane (LPO) of 32.7%, and the production of reactive oxygen species (ROS) of 28.56%. Additionally, a high and positive correlation was found for variables concerning seminal quality: Vi and MM, Vi and MI, MMP and MM, MMP and MI, PMI and MMP, as well as ROS and MMP. In contrast, two strongly negative correlations were obtained (C vs. Vol and LPO vs. CE). These are the first estimates of functional seminal quality evaluation of sheep in Colombia. In addition, this study provides a baseline for conventional and functional seminal parameters in the region.Reproduktivna procjena, odabir pojedinačnih rasplodnih mužjaka i reproduktivne biotehnologije važni su alati u unaprjeđenju produktivnih i reproduktivnih stopa. Pri odabiru mužjaka za rasplod, potrebno je određivanje općeg zdravstvenog statusa te genotipske i fenotipske superiornosti. Ovaj rad procjenjuje konvencionalnu i funkcionalnu kvalitetu sjemena u ovnova. Sjeme jedanaest ovnova različitih čistokrvnih pasmina prikupljeno je elektroejakulacijom. Zamijećene su sljedeće prosječne vrijednosti za svaki konvencionalni parametar: opseg skrotuma (CE, 34,3 cm), volumen sjemena (vol, 1,63 mL), koncentracija (C, 768,4 x 106/mL), pojedinačna pokretljivost (MI, 80 %), ukupna pokretljivost (MM, 4) i vitalnost (Vi, 3,7). S druge strane, funkcionalna analiza pokazala je integritet stanične membrane (PMI) od 45,7 %, potencijal mitohondrijske membrane (MMP) od 38,5 %, indeks fragmentacije DNK (DFI) od 17,0%, lipoperoksidaciju membrane (LPO) od 32,7 % i proizvodnju reaktivnih kisikovih spojeva (ROS) od 28,56 %. Uz to je otkrivena i visoka i pozitivna korelacija za varijable o kvaliteti sjemena: Vi i MM, Vi i MI, MMP i MM, MMP i MI, PMI i MMP, kao i ROS i MMP. Suprotno tome, dobivene su dvije vrlo negativne korelacije (C nasuprot Vol i LPO nasuprot CE). To su prve procjene ocjenjivanja funkcionalne kvalitete sjemena ovaca u Kolumbiji. Uz to, ova studija osigurava početnu vrijednost za sve konvencionalne i funkcionalne parametre sjemena u regiji
CARACTERIZACIÓN DE LA CALIDAD FÍSICA DEL CAFÉ DE LOS MUNICIPIOS CAFETEROS DEL NORTE DE ANTIOQUIA-FASE 1
Colombia es considerado uno de los países con mayor biodiversidad a nivel mundial, y por tal motivo tiene un gran potencial para exportar diferentes productos agrícolas, entre los cuales está el café. Como objetivo del presente artículo se tiene caracterizar la calidad física del grano de café de los municipios cafeteros del norte de Antioquia, fase 1, para entrar en el mercado del café tostado y ser competitivos en la producción de café. Por esta razón, se utilizó una metodología tipo descriptiva y cualitativa en la que se tostó los granos de café almendra, se determinó el color de los granos tostados para establecer los grados de tostión, se les determinó el porcentaje de merma y, por último, se hizo un análisis organoléptico al café tostado. En la actualidad, el departamento de Antioquia cuenta con 79.452 caficultores y 122.206 hectáreas de café, según la Federación Nacional de Cafeteros; los municipios más representativos de la subregión norte de Antioquia con respecto al café son Angostura, Ituango, Santa Rosa de Osos (especialmente los corregimientos de San Pablo y San Isidro), Don Matías (especialmente la vereda Bellavista), Campamento, Gómez Plata, Guadalupe, Briceño y Yarumal. Como conclusión, se tiene que en la prueba de granulometría de las muestras de café almendra se identificó que el 60 % del grano de café se encontraba por encima de la malla 15, y los mejores resultados de las curvas de tostión del café almendra sana del municipio de Santa Rosa de Osos se obtuvieron con un tiempo de 480 a 660 segundos, y a una temperatura de 185 a 198 °C
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