Membrane mechanics govern spatiotemporal heterogeneity of endocytic clathrin coat dynamics.

Dynamics of endocytic clathrin-coated structures can be remarkably divergent across different cell types, cells within the same culture, or even distinct surfaces of the same cell. The origin of this astounding heterogeneity remains to be elucidated. Here we show that cellular processes associated with changes in effective plasma membrane tension induce significant spatiotemporal alterations in endocytic clathrin coat dynamics. Spatiotemporal heterogeneity of clathrin coat dynamics is also observed during morphological changes taking place within developing multicellular organisms. These findings suggest that tension gradients can lead to patterning and differentiation of tissues through mechanoregulation of clathrin-mediated endocytosis.

Exchange-Driven Spin Relaxation in Ferromagnet-Oxide-Semiconductor Heterostructures.

We demonstrate that electron spin relaxation in GaAs in the proximity of a Fe/MgO layer is dominated by interaction with an exchange-driven hyperfine field at temperatures below 60 K. Temperature-dependent spin-resolved optical pump-probe spectroscopy reveals a strong correlation of the electron spin relaxation with carrier freeze-out, in quantitative agreement with a theoretical interpretation that at low temperatures the free-carrier spin lifetime is dominated by inhomogeneity in the local hyperfine field due to carrier localization. As the regime of large nuclear inhomogeneity is accessible in these heterostructures for magnetic fields <3 kG, inferences from this result resolve a long-standing and contentious dispute concerning the origin of spin relaxation in GaAs at low temperature when a magnetic field is present. Further, this improved fundamental understanding clarifies the importance of future experiments probing the time-dependent exchange interaction at a ferromagnet-semiconductor interface and its consequences for spin dissipation and transport during spin pumping.

Native defects in ultra-high vacuum grown graphene islands on Cu(1 1 1).

We present a scanning tunneling microscopy (STM) study of native defects in graphene islands grown by ultra-high vacuum decomposition of ethylene on Cu(1 1 1). We characterize these defects through a survey of their apparent heights, atomic-resolution imaging, and detailed tunneling spectroscopy. Bright defects that occur only in graphene regions are identified as C site point defects in the graphene lattice and are most likely single C vacancies. Dark defect types are observed in both graphene and Cu regions, and are likely point defects in the Cu surface. We also present data showing the importance of bias and tip termination to the appearance of the defects in STM images and the ability to achieve atomic resolution. Finally, we present tunneling spectroscopy measurements probing the influence of point defects on the local electronic landscape of graphene islands.

Ferromagnetic Resonance Spin Pumping and Electrical Spin Injection in Silicon-Based Metal-Oxide-Semiconductor Heterostructures.

We present the measurement of ferromagnetic resonance (FMR-)driven spin pumping and three-terminal electrical spin injection within the same silicon-based device. Both effects manifest in a dc spin accumulation voltage V_{s} that is suppressed as an applied field is rotated to the out-of-plane direction, i.e., the oblique Hanle geometry. Comparison of V_{s} between these two spin injection mechanisms reveals an anomalously strong suppression of FMR-driven spin pumping with increasing out-of-plane field H_{app}^{z}. We propose that the presence of the large ac component to the spin current generated by the spin pumping approach, expected to exceed the dc value by 2 orders of magnitude, is the origin of this discrepancy through its influence on the spin dynamics at the oxide-silicon interface. This convolution, wherein the dynamics of both the injector and the interface play a significant role in the spin accumulation, represents a new regime for spin injection that is not well described by existing models of either FMR-driven spin pumping or electrical spin injection.

Nanogram calorimetry using microscale suspended SiNx platforms fabricated via focused ion beam patterning.

Comprehensive characterization of thermal properties in nanoscale heterostructures requires microscale thermally isolated platforms combined with sensitive thermometry in order to measure small heat accumulations. Amorphous SiNx membranes are often used for these measurements due to their low thermal conductivity and compatibility with standard fabrication techniques. The total thermal conductance of such SiNx membranes is typically microwatts per kelvin or higher. Here, we further reduce this thermal coupling to 120 nW/K by using a focused ion beam (FIB) to remove large portions of commercially available amorphous SiNx membranes, leaving a 100 µm × 100 µm square platform suspended by 10 µm wide by 325 µm long support legs. We demonstrate the capability of these platforms by measuring the heat capacity of a 6.2 ng Au sample and show that it matches well with established specific heat of bulk Au.

[Distribution of patients' complaints presented to the law court of the Israel Dental Association according to themes, dental area profession and the results].

The purpose of this study was to review the distribution of patients' complains presented to the law court of the Israel Dental Association in Tel Aviv district, according to their topics, dental areas and results. 260 complaint cases filed between 2000 and July 2008 were reviewed. only 186 cases, to which an arbitration proceeding conducted full appeal only, were taken into account . Dentists, who encountered many complaints, were classified according to their country of graduation, as specialists or general dentists. The complaints were classified according to their specific dental field, year of complaint, to the number of arbitrations each year, to the number of appeals each year, to the entity who submitted the appeal, to the difference between the verdict in the District compared to the national ruling, to the distribution of complaints by gender and to the frequency of complaints by anonymous doctors. The distribution of complaints in accordance with topics was as follows: 30% in oral rehabilitation 13.5% in Dental prosthesis, 12.4% in implants, in endodontics 5.3%, 3.7% in maxillofacial surgery, 3.2% on ethics, 2.7% in orthodontics, 1.1% in periodontology 0.5 % in pedodontics and 28% in combined dental domains. 92.5% of complaints filed against dentists who were not experts. 7.5% of the complaints were filed against s specialists. Specialists in the field of oral rehabilitation encountered the largest number of complaints, i.c. 30%. Approximately 35.2% of complaints filed against dentists who have completed their studies in Eastern European countries and 24.9% against the Israeli graduates. 63% of referrals to the Court from Tel Aviv district for which a full arbitration procedure / appeals were presented by women whereas only 37% were presented by men. An analysis of the findings in the difference between the verdicts in the District compared to the national ruling it showed a tendency to aggravation of punishment. (P = 0.003) The Greatest number of appeals was filed in 2001, mostly by patients. In 2004, the greatest number of appeals were filed mostly by dentists. Most appeals have been filed over the years by patients. Against a small number of doctors several complaints were filed. The majority of complaints that were filed in a specific period against one doctor was 6.

Giant spin Seebeck effect in a non-magnetic material.

The spin Seebeck effect is observed when a thermal gradient applied to a spin-polarized material leads to a spatially varying transverse spin current in an adjacent non-spin-polarized material, where it gets converted into a measurable voltage. It has been previously observed with a magnitude of microvolts per kelvin in magnetically ordered materials, ferromagnetic metals, semiconductors and insulators. Here we describe a signal in a non-magnetic semiconductor (InSb) that has the hallmarks of being produced by the spin Seebeck effect, but is three orders of magnitude larger (millivolts per kelvin). We refer to the phenomenon that produces it as the giant spin Seebeck effect. Quantizing magnetic fields spin-polarize conduction electrons in semiconductors by means of Zeeman splitting, which spin-orbit coupling amplifies by a factor of ∼25 in InSb. We propose that the giant spin Seebeck effect is mediated by phonon-electron drag, which changes the electrons' momentum and directly modifies the spin-splitting energy through spin-orbit interactions. Owing to the simultaneously strong phonon-electron drag and spin-orbit coupling in InSb, the magnitude of the giant spin Seebeck voltage is comparable to the largest known classical thermopower values.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus in Israel: dissemination of global clones and unique features.

From 2006 to 2009, 315 clinical methicillin-resistant Staphylococcus aureus (MRSA) isolates were collected from 5 hospitals across Israel. Most isolates (64%) were related to the global clones spa types t001-SCCmec-I (SCCmec-I stands for staphylococcal cassette chromosome mec type I) (n = 99; 31%), t002-SCCmec-II (n = 82; 26%), and t008-SCCmec-IV (n = 21; 7%), five of which were identified as MRSA strain USA-300. Seventeen strains unique to Israel were identified. SCCmec types IV and V were common among hospital-acquired isolates.

Electrical spin injection from an organic-based ferrimagnet in a hybrid organic-inorganic heterostructure.

We report the successful extraction of spin-polarized current from the organic-based room temperature ferrimagnetic semiconductor V[TCNE](x) (x∼2, TCNE: tetracyanoethylene; T(C)∼400 K, E(G)∼0.5 eV, σ(300 K)∼10(-2) S/cm) and its subsequent injection into a GaAs/AlGaAs light-emitting diode. The spin current tracks the magnetization of V[TCNE](x∼2), is weakly temperature dependent, and exhibits heavy-hole-light-hole asymmetry. This result has implications for room temperature spintronics and the use of inorganic materials to probe spin physics in organic and molecular systems.

Anisotropic thermopower and planar Nernst effect in Ga1-xMnxAs ferromagnetic semiconductors.

We present the first experimental study of the thermopower in Mn-doped GaAs ferromagnetic semiconductors. Large magnetothermopower effects in both longitudinal and transverse directions have been observed below the ferromagnetic transition temperature. Unlike magnetoresistance, neither the transverse thermopower (planar Nernst effect) nor the longitudinal thermopower explicitly depend on the strength of the in-plane magnetic field, but rather are intimately related to each other through the magnetization. These newly discovered effects can be satisfactorily explained by an extension of anisotropic magnetotransport model and place important constraints on potential microscopic descriptions of the scattering mechanisms in these materials.

Element resolved spin configuration in ferromagnetic manganese-doped gallium arsenide.

We report induced Ga and As moments in ferromagnetic Ga(1-x)MnxAs detected using x-ray magnetic circular dichroism at the Mn, Ga, and As L(3,2) edges. Across a broad composition range, we find As and Ga dichroism signals which indicate an As 4s moment coupled antiparallel to the Mn 3d moment, and a smaller parallel Ga 4s moment. The Ga moment follows that of Mn in both doping and temperature dependence. These results are consistent with recent predictions of induced GaAs host moments and support the model of carrier-mediated ferromagnetic ordering involving As-derived valence band states.

Detecting protein sequence conservation via metric embeddings.

MOTIVATION: Comparing two protein databases is a fundamental task in biosequence annotation. Given two databases, one must find all pairs of proteins that align with high score under a biologically meaningful substitution score matrix, such as a BLOSUM matrix (Henikoff and Henikoff, 1992). Distance-based approaches to this problem map each peptide in the database to a point in a metric space, such that peptides aligning with higher scores are mapped to closer points. Many techniques exist to discover close pairs of points in a metric space efficiently, but the challenge in applying this work to proteomic comparison is to find a distance mapping that accurately encodes all the distinctions among residue pairs made by a proteomic score matrix. Buhler (2002) proposed one such mapping but found that it led to a relatively inefficient algorithm for protein-protein comparison. RESULTS: This work proposes a new distance mapping for peptides under the BLOSUM matrices that permits more efficient similarity search. We first propose a new distance function on peptides derived from a given score matrix. We then show how to map peptides to bit vectors such that the distance between any two peptides is closely approximated by the Hamming distance (i.e. number of mismatches) between their corresponding bit vectors. We combine these two results with the LSH-ALL-PAIRS-SIM algorithm of Buhler (2002) to produce an improved distance-based algorithm for proteomic comparison. An initial implementation of the improved algorithm exhibits sensitivity within 5% of that of the original LSH-ALL-PAIRS-SIM, while running up to eight times faster.

Prospective study of neuropsychologic testing and quality-of-life assessment of adults with primary malignant brain tumors.

PURPOSE: To identify the characteristics of adult patients with newly diagnosed primary brain tumors associated with identifiable deficits in neuropsychologic function to target interventions to improve function and quality of life (QOL). MATERIALS AND METHODS: Adult patients with newly diagnosed primary brain tumors and their caregivers were enrolled and underwent a battery of standardized neuropsychologic tests, allowing for qualitative and quantitative assessment and sensitive to the effects of the brain tumor, QOL, or caregiver stress. RESULTS: We enrolled 68 patients with no prior radiotherapy. Patients with left hemisphere tumors reported significantly more memory problems and depressive symptoms. They also exhibited poorer attention and were more distractible, with poorer verbal fluency and poorer verbal learning. Patients with glioblastoma multiforme demonstrated poorer psychomotor speed and visual tracking than patients with non-glioblastoma multiforme histologic features. Patients and caregivers perceived QOL in a similar fashion, with significant correlation between patient and caregiver on hope testing and general QOL on the Linear Analog Self-Assessment Scale. CONCLUSIONS: Patients with left hemisphere tumors and glioblastoma multiforme histologic features demonstrated testable differences in neuropsychologic function and QOL that may be amenable to improvement with medical therapy or tailored rehabilitation programs. Caregiver assessments can predict patient QOL, which may be useful in patients with declining status.

Ferromagnetic imprinting of nuclear spins in semiconductors.

We examine how a ferromagnetic layer affects the coherent electron spin dynamics in a neighboring gallium arsenide semiconductor. Ultrafast optical pump-probe measurements reveal that the spin dynamics are unexpectedly dominated by hyperpolarized nuclear spins that align along the ferromagnet's magnetization. We find evidence that photoexcited carriers acquire spin-polarization from the ferromagnet, and dynamically polarize these nuclear spins. The resulting hyperfine fields are as high as 9000 gauss in small external fields (less than 1000 gauss), enabling ferromagnetic control of local electron spin coherence.

Should academic medical centers conduct clinical trials of the efficacy of intercessory prayer?

Intercessory prayers for health or healing are requests to an object of worship for the preservation or restoration of health. There has been a recent proliferation of clinical trials that compare the health outcome of a group of prayed-for patients with that of controls, to test the efficacy of intercessory prayer. In this essay, the author defines the concept of intercessory prayer, contrasts it with other forms of prayer, and reviews the literature concerning clinical trials of its efficacy. The arguments put forward in favor of conducting such trials and those against are described and the reader is invited to consider their relative merits. The author concludes by discussing the potential power of faith in healing, reviewing the philosophical basis and pitfalls of clinical trials of intercessory prayer, and urging readers to weigh the arguments for and against such trials in academic medicine.

Duration of symptoms prior to diagnosis is related inversely to presenting disease stage in children with medulloblastoma.

BACKGROUND: The authors tested the hypothesis that children with a longer duration of symptoms prior to diagnosis of medulloblastoma have more advanced disease. In addition, they evaluated whether there are correlations between gender, duration of presenting symptoms, and disease stage. METHODS: The study population consisted of 122 patients with medulloblastoma who were evaluated between 1974 and 1999. The data abstracted from each chart included the date of diagnosis, date of birth, gender, race, presenting symptoms, duration of symptoms in weeks, and disease stage. RESULTS: There were 70 males (57%) and 52 females (43%); 105 Caucasians (86%), 16 non-Caucasians (13%), and 1 patient of unknown race. Eighteen percent of the patients were age < or = 3 years, 59% were ages 4-16 years, and 23% were age > or = 17 years. The presenting stage was determined in 108 patients. Thirty-eight patients (35%) had high stage disease (T1-T4 M1-M4), and 70 patients (65%) had low stage disease (T1-T4 M0). The most common presenting symptoms were emesis (68%), headache (66%), nausea (40%), and ataxia (40%). The median symptom durations for patients ages 0-3 years were 4 weeks and 8 weeks for both those ages 4-16 years and those age > or = 17 years, respectively (P > 0.11). The median symptom duration for males (8 weeks) was longer than for females (5 weeks; P = 0.08). Patients with low stage disease had a median duration of symptoms (8 weeks) that was significantly greater compared with patients with high stage disease (4 weeks; P = 0.01). Relating patient age to disease stage, 47% of patients ages 0-3 years had high stage disease; 36% of patients ages 4-16 years had high stage disease; and 24% of patients age > or = 17 years had high stage disease (P = 0.20). Relating disease stage to gender, 40% of males had high stage disease compared with 28% of females (P = 0.20). Of the factors age, gender, race, and duration of symptoms, only the later was correlated significantly with disease stage at the time of presentation in both univariate and multivariate analyses. CONCLUSIONS: Contrary to expectations, the duration of presenting symptoms was correlated inversely with disease state at the time of presentation. This finding has implications for lawsuits alleging that a "delay in diagnosis" leads to more advanced disease. There is weak evidence (P = 0.08) that males have a longer duration of symptoms than females. This may be related to gender-associated behavior expectations.

Non-human to human organ transplantation: its biologic basis and a potential role for radiation therapy.

There is an inadequate supply of human donor organs for transplantation. Xenotransplantation, the transplantation of organs from non-human animals to humans, is one of the potential solutions to this problem. The pig appears to be the preferred donor. For xenotransplantation to be successful, researchers must deal with three fundamental problems: (1) Hyperacute rejection of porcine organs, related to binding of xenoreactive natural antibodies of the recipient to antigens on the graft's endothelial cells, must be overcome. (2) Transmission of animal pathogens to humans must be prevented. Concern about zoonosis is not only directed to the transplant recipient but also concerns the risk that an infectious agent will be transferred from the recipient to the general population. (3) The xenografted organ must be physiologically compatible with the recipient. The physiological function of a pig organ in a human and its ability to sustain a human are problematic. Total lymphoid irradiation (TLI) and thoraco-abdominal irradiation (TAI) as immunosuppressive modalities have been investigated in rodent-to-rodent, large mammals and non-human primates-to-primates, and pig-to-primate models. In certain clinical situations, TLI and TAI may prove to be important components for the preparation of the xenotransplant recipient. Progress in genetic engineering and cloning may soon lead to clinical trials in xenotransplantation.

Second malignant neoplasms of the head and neck in survivors of retinoblastoma.

Retinoblastoma is a malignant tumor of the embryonic retina. Although it is rare, it is the most common primary eye tumor of childhood. Life expectancy following treatment is now excellent, but survivors who have heritable retinoblastoma face an increased risk of a second malignant head or neck neoplasm. A second neoplasm, which often occurs in the irradiated field of the original tumor, has become the most significant threat to the survival of these patients. We report the case of a young girl who was cured of her retinoblastoma only to later develop a second nonocular tumor that metastasized to the superficial parotid gland. She underwent a superficial parotidectomy and neck dissection, but the malignancy eventually recurred and required further surgery and radiation therapy. In this article, we discuss the etiology, incidence, sites of occurrence, and management options for a second malignant neoplasm in retinoblastoma survivors. The head and neck surgeon must be vigilant in the diagnosis and management of second neoplasms in this patient population because they often occur in irradiated fields; surgical management is important to patient survival.