julilili42/papers huggingface dataset:
Parkin protects mitochondrial genome integrity and supports mitochondrial DNA repair
2009-07-19

Mutations in the parkin gene are the most common cause of recessive familial Parkinson disease (PD). Parkin has been initially characterized as an ubiquitin E3 ligase, but the pathological relevance of this activity remains uncertain. Recently, an impressive amount of evidence has accumulated that parkin is involved in the maintenance of mitochondrial function and biogenesis. We used a human neuroblastoma cell line as a model to study the influence of endogenous parkin on mitochondrial genomic integrity. Using an unbiased chromatin immunoprecipitation approach, we found that parkin is associated physically with mitochondrial DNA (mtDNA) in proliferating as well as in differentiated SH-SY5Y cells. In vivo, the association of parkin with mtDNA could be confirmed in brain tissue of mouse and human origin. Replication and transcription of mtDNA were enhanced in SH-SY5Y cells over-expressing the parkin gene. The ability of parkin to support mtDNA-metabolism was impaired by pathogenic parkin point mutations. Most importantly, we show that parkin protects mtDNA from oxidative damage and stimulates mtDNA repair. Moreover, higher susceptibility of mtDNA to reactive oxygen species and reduced mtDNA repair capacity was observed in parkin-deleted fibroblasts of a PD patient. Our data indicate a novel role for parkin in directly supporting mitochondrial function and protecting mitochondrial genomic integrity from oxidative stress.
Worker Remittances and Capital Flows to Developing Countries
2009-07-20

Abstract Worker remittances constitute an increasingly important channel for the transfer of resources to developing countries. Behind foreign direct investment, remittances are the second‐largest source of external funding for developing countries. Yet, literature on worker remittances has traditionally focused on the impact of remittances on income distribution within countries, on the determinants of remittances at a micro‐level, or on the effects of migration and remittances for specific countries or regions. Macroeconomic determinants and effects of remittances have received more attention only recently. Hence, the focus of this paper is on the macroeconomic determinants of remittances and on differences in these determinants between remittances and other capital flows. We find that remittances respond more to demographic variables while private capital flows respond more to macroeconomic conditions.
THE PHYSICS OF PROTOPLANETESIMAL DUST AGGLOMERATES. IV. TOWARD A DYNAMICAL COLLISION MODEL
2009-07-20

Recent years have shown many advances in our knowledge of the collisional evolution of protoplanetary dust. Based on a variety of dust-collision experiments in the laboratory, our view of the growth of dust aggregates in protoplanetary disks is now supported by a deeper understanding of the physics involved in the interaction between dust agglomerates. However, the parameter space, which determines the collisional outcome, is huge and sometimes inaccessible to laboratory experiments. Very large or fluffy dust aggregates and extremely low collision velocities are beyond the boundary of today's laboratories. It is therefore desirable to augment our empirical knowledge of dust-collision physics with a numerical method to treat arbitrary aggregate sizes, porosities and collision velocities. In this article, we implement experimentally-determined material parameters of highly porous dust aggregates into a Smooth Particle Hydrodynamics (SPH) code, in particular an omnidirectional compressive-strength and a tensile-strength relation. We also give a prescription of calibrating the SPH code with compression and low-velocity impact experiments. In the process of calibration, we developed a dynamic compressive-strength relation and estimated a relation for the shear strength. Finally, we defined and performed a series of benchmark tests and found the agreement between experimental results and numerical simulations to be very satisfactory. SPH codes have been used in the past to study collisions at rather high velocities. At the end of this work, we show examples of future applications in the low-velocity regime of collisional evolution.
CD8+/perforin+/granzyme B+effector cells infiltrating cerebellum and inferior olives in gluten ataxia
2009-07-20

Up to 8% of patients with gluten sensitivity (GS) develop neurological symptoms such as ataxia, dementia, seizures or peripheral neuropathy. The underlying immunological mechanisms still remain to be elucidated. We here report the case of a 68-year-old male patient suffering from progressive ataxia and dementia associated with chronic diarrhea and both elevated IgG and IgA antigliadin-antibodies. At autopsy, frequent argyrophilic glial and neuronal inclusions within the basal nucleus of Meynert were considered as the structural correlative for the cognitive decline. Significant neuronal loss in the cerebellar cortex and the inferior olives was accompanied by infiltrating CD8(+)/perforin(+)/granzyme B(+) cells as well as reactive astrogliosis and microglial activation. These CD8(+) cytotoxic T and NK cells are likely to act as effector cells responsible for neuronal cell death in patients with gluten sensitivity and neurological disease and might therefore at least partly be responsible for cerebellar symptoms in gluten ataxia. In conclusion, our results, showing an absence of B- or plasma cells but multiple CD8(+) as well as granzyme B and perforin expressing cells in ataxia-associated brain areas, suggest that there are also prominent cytotoxic effects in neuropathogenesis of GS.
Periphilin is strongly expressed in the murine nervous system and is indispensable for murine development
2009-07-20

Abstract Periphilin is involved in multiple processes in vivo. To explore its physiological role from an organismic perspective, we generated mice with a gene trap insertion in the periphilin‐1 gene. Based on β‐gal reporter activity, a widespread periphilin expression was evident, especially in the developing somites and limbs, the embryonic nervous system, and the adult brain. In accordance with this broad expression, homozygous deficiency of periphilin was lethal in early embryogenesis. Mice with a heterozygous deficiency did not show any abnormalities of brain morphology and function, neither histologically nor regarding the transcriptome. Interestingly, the reduction of the periphilin‐1 gene dosage was compensated by an increased expression of the remaining wild‐type allele in the brain. These results point to an indispensable function of periphilin during murine development and an important role in the nervous system, reflected by a strong and tightly regulated expression in the murine brain. genesis 47:697–707, 2009. © 2009 Wiley‐Liss, Inc.
Platonic polyhedra tune the three-sphere: II. Harmonic analysis on cubic spherical three-manifolds
2009-07-20

From the homotopy groups of two cubic spherical 3-manifolds we construct the isomorphic groups of deck transformations acting on the 3-sphere. These groups become the cyclic group of order eight and the quaternion group respectively. By reduction of representations from the orthogonal group to the identity representation of these subgroups we provide two subgroup-periodic bases for the harmonic analysis on the 3-manifolds. This harmonic analysis has applications to cosmic topology.
Expression of platelet glycoprotein VI is associated with transient ischemic attack and stroke
2009-07-21

Background and purpose: Platelet collagen receptor glycoprotein VI (GPVI) contributes significantly to platelet adhesion and thrombus formation. We aimed to investigate GPVI in patients presenting with symptoms of acute cerebrovascular disease and to define GPVI as biomarker for acute stroke. Methods: We consecutively evaluated 205 patients, who admitted the stroke unit with symptoms for stroke. Surface expression of the platelet activation markers (GPVI, CD62P, GPIb) was determined by two‐color whole blood flow cytometry. Results: Patients with transient ischemic attack (TIA) ( n = 18; 8.8%) as well as with stroke ( n = 133; 64.9%) showed a significantly enhanced GPVI expression (mean fluorescence intensity ± SD) on admission compared to patients with non‐ischemic (NI) events ( n = 54; 26.3%) (TIA: 20.9 ± 7.1 vs. NI: 16.2 ± 3.9; P = 0.002; stroke: 20.4 ± 5.7 vs. NI; P = 0.002). Neither CD62P nor GPIb surface expression showed a significant difference. Logistic regression analysis revealed that on admission GPVI was associated with stroke independent of conventional laboratory markers such as C‐reactive protein, blood glucose, and creatine kinase. Using a receiver operating characteristic curve on GPVI, we have determined the cut off value of 18.2 for stroke. Thus, patients with enhanced GPVI expression levels (≥18.2) had a 2.4‐fold relative risk for stroke. Patients with elevated platelet GPVI expression level had a poorer clinical outcome in cumulative event‐free survival for stroke, myocardial infarction, and cerebro‐/cardiovascular death at 3‐month follow‐up (log rank; P = 0.045). Conclusions: These findings indicate that platelet GPVI surface expression is significantly enhanced in patients with TIA and stroke compared to patients with NI events. Determination of platelet‐specific GPVI may be useful as an early biomarker for cerebral ischemia.
Bone stable isotopic signatures (15N, 18O) as tracers of temperature variation during the Late‐glacial and early Holocene: case study on red deer Cervus elaphus from Rochedane (Jura, France)
2009-07-21

Abstract Stable isotopes in mammal bones are mainly used to reconstruct dietary preferences and their use as palaeoclimatic indicators is less developed. However, important variations in 15 N abundances observed in the bone collagen of large mammals during the Late‐glacial and early Holocene have been tentatively linked to a general increase in temperature. In order to test this hypothesis, we analysed nitrogen and oxygen isotopic abundances from bones of red deer ( Cervus elaphus ) from the Rochedane site (Jura, France). We observe a clear linear relationship between 15 N and 18 O that demonstrates the effect of temperature on the abundance of 15 N in red deer bone collagen. These results suggest that an increase in soil maturation during global warming of the Late‐glacial and early Holocene led to an increase of 15 N in soils and plants that was passed on to their consumers. Red deer seem to be particularly suited for palaeoclimatic reconstruction based on the isotopic signatures of their bones. Copyright © 2009 John Wiley &amp; Sons, Ltd.
Controlling the optical properties of single molecules by optical confinement in a tunable microcavity
2009-07-21

We present experimental results on changing the fluorescence spectrum of a single molecule by embedding it within a tunable optical microresonator with subwavelength spacing. The cavity length is reversibly changed across the entire visible range with nanometer precision by using a piezoelectric actuator. By varying its length, the local mode structure of the electromagnetic field is changed together with the radiative coupling of the emitting molecule to the field. Since mode structure and coupling are both frequency dependent, this leads to a renormalization of the emission spectrum of the molecule. Moreover, we use doughnut laser modes in the tunable microcavity to determine the longitudinal position of an isotropic emitter. By analyzing the excitation patterns resulting from the illumination of a single fluorescent bead in the focus of a radially polarized doughnut mode laser beam we can determine the longitudinal position of this bead in the microcavity with an accuracy of a few nanometers.
Induction of cerebral β-amyloidosis: Intracerebral versus systemic Aβ inoculation
2009-07-22

Despite the importance of the aberrant polymerization of Aβ in the early pathogenic cascade of Alzheimer's disease, little is known about the induction of Aβ aggregation in vivo. Here we show that induction of cerebral β-amyloidosis can be achieved in many different brain areas of APP23 transgenic mice through the injection of dilute Aβ-containing brain extracts. Once the amyloidogenic process has been exogenously induced, the nature of the induced Aβ-deposition is determined by the brain region of the host. Because these observations are reminiscent of a prion-like mechanism, we then investigated whether cerebral β-amyloidosis also can be induced by peripheral and systemic inoculations or by the intracerebral implantation of stainless steel wires previously coated with minute amounts of Aβ-containing brain extract. Results reveal that oral, intravenous, intraocular, and intranasal inoculations yielded no detectable induction of cerebral β-amyloidosis in APP23 transgenic mice. In contrast, transmission of cerebral β-amyloidosis through the Aβ-contaminated steel wires was demonstrated. Notably, plasma sterilization, but not boiling of the wires before implantation, prevented the induction of β-amyloidosis. Our results suggest that minute amounts of Aβ-containing brain material in direct contact with the CNS can induce cerebral β-amyloidosis, but that systemic cellular mechanisms of prion uptake and transport to the CNS may not apply to Aβ.
Rectification in a Stochastically Driven Three-Junction SQUID Rocking Ratchet
2009-07-22

A three-junction SQUID forms a rocking ratchet for the phase differences across the Josephson junctions. In this Letter we investigate its capability to rectify voltages under stochastic drive currents with a white frequency spectrum up to a cutoff frequency f_{cut}. Experimentally, we accessed the adiabatic regime and find very good agreement with theory. Numerically, we also investigated large values of f_{cut} and find, in agreement with the laws of thermodynamics, that the response disappears, as f_{cut} becomes much larger than the characteristic frequency scales of the system.
Gelation Behavior of N-Decane Organogels with Gelators C28and C40
2009-07-22

Organogel formation during paraffin crystallization is one of the causes of oilfield problems. We investigated the formation of n-alkane organogels having C10 as liquid phase and n-octacosane (C28) and n-tetracontane (C40) as solid gelators. It was seen that C10/C28 and C10/C40 form organogels with onset gelation temperatures of 33°C and 48°C respectively, while C10/C28/C40, gelify at 52°C. Replacement of C28 by n-heneicosane (C21) reduced the crystallization rate of C40. This result indicates that the onset temperatures and crystallization rates of organogels with gelators in the range of C28 to C40 could be modulated through the introduction of shorter chain n-alkanes.
Alkaline-Earth Metal Alkylaluminate Chemistry Revisited
2009-07-23

Heterobimetallic peralkylated calcium complexes [Ca(AlR4)2]n (R = Me, Et) were obtained from {Ca[N(SiMe3)2]2}2 and an excess AlR3 in almost quantitative yield. A similar silylamide elimination protocol was previously applied for the synthesis of the corresponding ytterbium and samarium complexes. The solid-state structure of polymeric [Ca(AlEt4)2]n revealed agostically linked right-handed helices featuring a pitch of ∼14 Å and a repeat length of ∼27 Å with the latter composed of nine alkyl-bridged [Ca(AlEt4)3]− and [Ca(AlEt4)]+ building units. Reaction of [Ca(AlR4)2]n (R = Me, Et) with equimolar amounts of donor molecules gave X-ray structurally authenticated hexacoordinate monomeric adducts Ca(AlMe4)2Phen (Phen = 1,10-phenanthroline) and Ca(AlEt4)2(thf)2. Treatment of [Ca(AlEt4)2]n, [Yb(AlEt4)2]n, and Mg(AlMe4)2 with excess thf resulted in the formation of solvent-separated ion pairs of composition [M(II)(thf)6][AlR4]2. Heating barely soluble [Ca(AlMe4)2]n in a pressure tube produced vinyloxide-bridged complex [{Ca(μ-OCH═CH2)(thf)4}2][AlMe4]2 via thf degradation. Furthermore, treatment of MgMe2 with thf yielded quantitatively the donor adduct [Mg(Me)(μ-Me)(thf)]2.
Impact of Variation Near MC4R on Whole‐body Fat Distribution, Liver Fat, and Weight Loss
2009-07-23

Polymorphisms near the melanocortin‐4 receptor ( MC4R ) gene locus are associated with body weight. Recent studies have shown that they influence insulin sensitivity and incidence of the metabolic syndrome. Thus, we hypothesized that the candidate single‐nucleotide polymorphism (SNP) rs17782313 near MC4R additionally influences body fat distribution and its change during lifestyle intervention. To test this, 343 German subjects were genotyped for SNP rs17782313. Body composition was assessed using magnetic resonance technique. Subjects were characterized by an oral glucose tolerance test (OGTT). A subgroup of 242 subjects participated in a 9‐month lifestyle intervention. In the overall cohort, the C allele was associated with a higher BMI ( P = 0.0013), but had no impact on glucose tolerance or insulin sensitivity (all P ≥ 0.10). There was an effect of the SNP on total body fat ( P = 0.022) and nonvisceral fat ( P = 0.017), but not on liver fat and visceral fat (all P ≥ 0.33). In the subgroup undergoing lifestyle intervention, SNP rs17782313 had no impact on changes in body weight or fat distribution. Despite an association with BMI and nonvisceral adipose tissue, the SNP rs17782313 did not influence visceral adipose tissue. Thus, this candidate SNP for human obesity may preferentially affect the accumulation of subcutaneous adipose tissue. Furthermore, the variation near MC4R has no effect on success of weight loss during lifestyle intervention.
Insulin detemir causes increased symptom awareness during hypoglycaemia compared to human insulin
2009-07-23

Aim: The long‐acting insulin analogue detemir (Levemir ® ) has structural and physicochemical properties which differ from human insulin. The aim of the present study was to test whether this leads to altered hormone and symptom response during hypoglycaemia. Methods: 12 healthy subjects [6f/6m, age 32 ± 6 years (mean ± s.d.), body mass index (BMI) 24.2 ± 2.5 kg/m 2 ] underwent a 200‐min stepwise hypoglycaemic clamp (45 min steps of 4.4, 3.7, 3.0 and 2.3 mmol/l) with either detemir or human insulin in random order. A bolus of detemir (660 mU/kg) or human insulin (60 mU/kg) was given before insulin was infused at a rate of 5 (detemir) or 2 (human insulin) mU/kg/min. Blood was drawn and a semi‐quantitative symptom questionnaire was administered before and after each plateau of the hypoglycaemic clamp. Cognitive function was assessed during each step. Results: Blood glucose levels and glucose infusion rates were comparable with detemir and human insulin. The total symptom score was higher with detemir during the 3 and 2.3 mmol glucose step compared to human insulin (p = 0.048). Especially sweating was increased with detemir (p = 0.02) with an earlier and faster increase during the clamp (interaction insulin × time: p = 0.04). No significant differences between detemir and human insulin in cortisol, norepinephrine, epinephrine, glucagon, growth hormone, lactate or free fatty acid (FFA) levels during hypoglycaemia were observed, and there were no significant differences in cognitive function tests. Conclusions: Insulin detemir increased symptom awareness during hypoglycaemia compared to human insulin in healthy individuals, whereas counter‐regulatory hormone response and cognitive function were unaltered.
Prediction of cell necrosis with sequential temperature mapping after radiofrequency ablation
2009-07-23

Abstract Purpose To assess the feasibility of magnetic resonance (MR) thermometry after thermoablative therapy and to quantitatively evaluate the ability of two sequence types to predict cell necrosis. Methods Twenty patients with hepatic tumors were treated by MR‐guided radiofrequency ablation. For each 10 patients, postinterventionally performed gradient echo and segmented echo planar imaging sequences were used to calculate temperature maps based on the proton resonance frequency shift method. Contrast‐enhanced images acquired 1 month after therapy were registered on the temperature maps and the necrotic, nonenhanced area was segmented and compared to the area with a displayed temperature above 60°C. Sensitivity and positive predictive value of the temperature map was calculated, using the follow‐up imaging as the gold standard. Results Temperature mapping reached acceptable image quality in 45/47 cases. Sensitivity, ie, the rate of correctly detected coagulated tissue was 0.82 ± 0.08 for the gradient echo imaging (GRE) sequence and 0.81 ± 0.14 for the echo planar imaging (EPI) sequence. Positive predictive value, ie, the rate of voxel in the temperature map over 60°C that actually developed necrosis, was 0.90 ± 0.07 for the GRE sequence and 0.84 ± 0.11 for the EPI sequence. Conclusion Sequential MR temperature mapping allows for the prediction of the coagulation zone with an acceptable sensitivity and positive predictive value using EPI and GRE sequences. J. Magn. Reson. Imaging 2009. © 2009 Wiley‐Liss, Inc.
Giant Infantile Fibroma of the Right Ventricle – Surgical Debulking and Tumor Plication
2009-07-23

Cardiac fibromas are rare lesions which occur predominantly in infants and children. In a 2-week-old premature infant with progressive exertional dyspnea, a huge cardiac tumor (5.0 x 4.5 x 5.0 cm) obstructing the right ventricle was diagnosed. Due to tumor progression with resulting obstruction of the right ventricular outflow tract (RVOT), surgery became necessary at 6 months. The tumor was partially resected, creating a crater-like defect, and the resection margins were subsequently plicated. Histological examination confirmed infantile fibroma. The combination of early diagnosis, the time and opportunity for cardiac development and immediate excision once symptoms occur is supposed to improve survival.
A new approach to children's footwear based on foot type classification
2009-07-24

Current shoe designs do not allow for the comprehensive 3-D foot shape, which means they are unable to reproduce the wide variability in foot morphology. Therefore, the purpose of this study was to capture these variations of children's feet by classifying them into groups (types) and thereby provide a basis for their implementation in the design of children's shoes. The feet of 2867 German children were measured using a 3-D foot scanner. Cluster analysis was then applied to classify the feet into three different foot types. The characteristics of these foot types differ regarding their volume and forefoot shape both within and between shoe sizes. This new approach is in clear contrast to previous systems, since it captures the variability of foot morphology in a more comprehensive way by using a foot typing system and therefore paves the way for the unimpaired development of children's feet. Previous shoe systems do not allow for the wide variations in foot morphology. A new approach was developed regarding different morphological foot types based on 3-D measurements relevant in shoe construction. This can be directly applied to create specific designs for children's shoes.
Initial molecular orientation of phthalocyanines on oxide substrates
2009-07-24

Abstract The molecular orientation of ultra‐thin films of copper phthalocyanine and perfluoro‐copper phthalocyanine (F 16 PcCu) on various oxide substrates is examined with polarisation dependent NEXAFS spectroscopy. The focus is on the adsorption geometry of the first adsorbed layers, which can strongly vary from the observed orientation in thin‐films above the few nanometre regime. Native silicon dioxide, indium tin oxide and titanium dioxide are chosen for their relevance to technical applications. On chemically and thermally cleaned oxide surfaces a predominantly standing initial orientation is preferred, while on ion bombarded activated surfaces the molecules prefer a lying orientation.