bluuebunny/crossref_metadata_2025 huggingface dataset:
The Role of Values-Based Leadership in Sustaining a Culture of Caring
Authors: Faith Karen E.
Published: April 2013

At the heart of healthcare are fundamental values like caring and compassion as well as the duty shared by healthcare organizations to address the care needs of those in their communities who are vulnerable, injured, or ill. A concern being raised by some political analysts in Canada is that fundamental values are being challenged by current economic and political influences that are reshaping the landscape of healthcare in this country. Influences from industry, technology, and business have significantly shifted healthcare from its moral foundations. A culture of caring is also challenged by the values and behaviours of individuals that negatively impact staff morale and inter-professional collaboration in many work settings. If a “culture of caring” is to survive the canons of cost containment, the impact of recurrent political wrangling, and other substantive influences, then healthcare must be guided by committed values-based leadership. Using case illustrations, this article attempts to explain the characteristics and role of values-based leaders in promoting those values that inspire a culture of caring.
Increasing Revenue through Idea Generation at University Health Network
Authors: Alcia Lisa , Wan Simmy
Published: April 2013

To enhance products and services provided to researchers and generate external revenue, research operations at the University Health Network implemented an ideation revenue generation framework for evaluation of product ideas for launch to external market. The framework consists of coordinated cross-functional teamwork in idea development and formal evaluation by research operations senior management based on standard criteria. The framework accelerates launch to market of products and services, facilitates due diligence review, increases staff competencies and engagement, and helps foster innovative thinking.
Overexpression of LC3A autophagy protein in follicular and diffuse large B-cell lymphomas
Authors: Giatromanolaki Alexandra , Koukourakis Michael I , Pouliliou Stamatia , C Gatter Kevin , Pezzella Francesco , L Harris Adrian , Sivridis Efthimios
Published: April 2013

BACKGROUND AND OBJECTIVES:

Autophagy is a self-degradation mechanism induced under stress conditions in all eukaryotic cells. Its activity in human lymphomas has not been studied as yet.

METHODS:

In this study, the autophagic activity of lymphoid cells was investigated in follicular lymphomas (FL; 48 cases), diffuse large B-cell lymphomas (DLBCL; 78 cases), and in reactive follicular hyperplasias (41 cases), using the light chain 3A (LC3A) antibody and a standard immunohistochemical technique.

RESULTS:

In all cases, the pattern of LC3A reactivity was uniformly diffuse cytoplasmic, but expressed more frequently in FLs (68.8%) than in DLBCLs (41%) (p = 0.02), and much more commonly in DLBCLs than in reactive lymph nodes (24.3%) (p < 0.006). Interestingly, FLs expressing LC3A in >10% of lymphoid cells (high reactivity) were associated with the hypoxia-related protein HIF1α and the enzyme of anaerobic metabolism lactate dehydrogenase LDH5 (p = 0.004 and p = 0.003, respectively). Such associations, however, were not a feature in DLBCLs of increased LC3A activity.

CONCLUSIONS:

LC3A expression in FLs is hypoxia-induced, whereas its expression in DLBCLs may be regulated by other molecular mechanisms. The current study provides a tool for further assessment of autophagic activity in translational and autophagy targeting therapy studies.
Orbital myeloid sarcoma presenting as massive proptosis
Authors: Dinand Veronique , Prakash Yadav Satya , Kumar Grover Ashok , Bhalla Sunita , Sachdeva Anupam
Published: April 2013

A 10-year-old boy presented with right proptosis for 8 months. The eyeball was grossly pushed down, with diffuse corneal haze and non-reactive pupil. Systemic examination was normal. Previous investigations in another centre included a computerized tomography scan, which showed a well-defined enhancing retro-bulbar mass, a non-contributory fine needle aspiration cytology and a biopsy showing fibrocollagenous tissue with moderate lympho-monocytic infiltrate suggestive of non-specific inflammation. PET-CT scan revealed the presence of enlarged fluoro-deoxyglucose-avid cervical and mesenteric lymph nodes. Biopsy of the retro-bulbar mass was repeated in our centre. It showed fibrocollagenous and skeletal muscle tissue infiltrated by lymphoid follicles, dispersely lying lymphocytes and plasma cells, and admixed large atypical cells with vesicular nuclei, prominent nucleoli and scanty cytoplasm, strongly positive for myeloperoxidase, CD43 and CD99 immunohistochemistry. Hemogram was normal. Bone marrow aspiration/biopsy and CSF showed no evidence of acute myeloid leukemia. The child received chemotherapy in another centre and is in complete remission 6 months after completion.
A developmental perspective on adult hippocampal neurogenesis
Authors: Encinas Juan M. , Sierra Amanda , Valcárcel‐Martín Roberto , Martín‐Suárez Soraya
Published: April 2013

The generation of new neurons from neural stem cells (NSCs) throughout adult life in the mammalian brain is a biological process that fascinates scientists for its uniqueness and restorative potential. In the dentate gyrus (DG) of the hippocampus NSCs are able to self‐renew and generate new granule cells and astrocytes through a complex and plastic mechanism that can be regulated by endogenous and exogenous cues at different levels. Unexpected recent findings suggest that the population of NSCs is heterogeneous in morphology and behavior. We herein explore the hypothesis that NSC heterogeneity and the neurogenic potential of the DG depends on their developmental origin. We provide an up‐to‐date picture of the process of neurogenesis in the adult hippocampus with an especial focus on NSCs and outline key unsolved aspects. Further, we discuss the origin of NSCs in the adult DG from a developmental perspective and explore the possibility of NSC heterogeneity being determined from early postnatal periods and being responsible for the neurogenic output of the DG in the long term.
The value implications of restrictions on asset sales
Authors: Sibilkov Valeriy , Straska Miroslava , Waller H. Gregory
Published: April 2013

This paper examines the effect of restrictions over asset disposition, measured by the ratio of secured debt to fixed assets, on firm value. We find evidence consistent with two non‐mutually exclusive hypotheses. (1) Restrictions on the disposition of assets reduce firm value by limiting a firm's ability to restructure assets or to raise funds to finance higher NPV projects. (2) Restrictions on asset disposition increase firm value by limiting agency costs of managerial discretion over uncommitted assets. The net effect of restrictions over asset disposition on firm value is determined by potential agency problems and the need for operating flexibility.
Financial reforms and technical efficiency in Indian commercial banking: A generalized stochastic frontier analysis
Authors: Bhattacharyya Aditi , Pal Sudeshna
Published: April 2013

In this study we estimate technical efficiency of Indian commercial banks from 1989 to 2009, using a multiple‐output generalized stochastic production frontier and analyze the effects of financial reforms on estimated efficiency. The generalized method estimates technical efficiency in the presence of multiple outputs, filling a gap in the existing literature. Our results show that Indian commercial banks were operating with 64% efficiency on average during the sample period. The initial phase of reform had a positive impact on while the later phase adversely affected technical efficiency of banks. Public sector banks show higher efficiency levels compared to private and foreign banks.
Transient receptor potential ankyrin 1 (TRPA1) ion channel in the pathophysiology of peripheral diabetic neuropathy
Authors: Koivisto Ari , Pertovaara Antti
Published: April 2013

Background

Transient receptor potential ankyrin 1 (TRPA1) is a non-selective cation channel permeable to calcium that is expressed on pain-mediating primary afferent nerve fibers. Here we review recent experimental evidence supporting the hypothesis that activation of the TRPA1 channel by reactive compounds generated in diabetes mellitus, such as 4-hydroxynonenal and methylglyoxal, exerts an important role in the pathophysiology of peripheral diabetic neuropathy (PDN). The hypothesis includes development of the early diabetic pain hypersensitivity and the later loss of cutaneous nerve endings of pain fibers and their dysfunction, which are hallmarks of peripheral diabetic neuropathy (PDN).

Methods

The evidence for a role of the TRPA1 channel in PDN consists of in vitro patch clamp and calcium imaging data and assessments of pain behavior, axon reflex measurements, and immunohistochemical analyses of cutaneous innervation in an experimental animal model of diabetes. The experiments were combined with blocking the TRPA1 channel with selective antagonists Chembridge-5861528 or A-967079.

Results

In vitro studies indicate that under physiological concentration of Ca2+, methylglyoxal and 4-hydroxynonenal produce sustained activation of the TRPA1 channel and sustained inflow of calcium. In vivo studies indicate that diabetic pain hypersensitivity is maintained by the TRPA1 channel as indicated by the antihypersensitivity effect induced by acute blocking of the TRPA1 channel. Moreover, TRPA1 channel is involved in the development of diabetic hypersensitivity as indicated by prevention of the development of pain hypersensitivity in diabetic animals treated daily with Chembridge-5861528. The diabetes-induced loss of substance P-like cutaneous innervation and that of the TRPA1 channel-mediated cutaneous axon reflex function during the later phase of diabetes were also prevented or delayed by prolonged blocking of the TRPA1 channel. No motor impairment or other obvious side-effects were observed following block of the TRPA1 channel.

Conclusions

Together the in vitro and in vivo results indicate that reactive compounds generated in diabetes exert, through action on the TRPA1 channel, an important role in the pathophysiology of PDN. Sustained activation of the TRPA1 channel is a plausible mechanism that contributes to the early diabetic pain hypersensitivity and the later loss of cutaneous pain fiber endings and their dysfunction with prolonged diabetes.

Implications

Blocking the TRPA1 channel with a selective antagonist provides a promising disease-modifying treatment for PDN, with only minor, if any, side-effects.
Seasonal density and distribution of Octopus tehuelchus in the intertidal of North Patagonia
Authors: Storero Lorena P. , Narvarte Maite A. , González Raúl A.
Published: April 2013

The abundance and distribution of coastal cephalopods are strongly influenced by the environmental conditions. This study evaluates the seasonal distribution and density of Octopus tehuelchus in three intertidal environments of San Matías Gulf (Patagonia). To estimate and compare density and distribution, monthly transects were carried out, and analysed in relation to the coastlines obtained with satellite images. Densities of O. tehuelchus ranged between 0 and 34 individuals per transect (0–0.11 octopus m−2), and varied between sites. Islote Lobos (IL) had the highest densities (mean octopus per transect 7.32 ± 1.16) followed by El Fuerte (EF) (5.55 ± 0.94) and San Antonio Bay (SAB) (3.40 ± 0.85). Within each site, octopus densities varied between seasons. The highest densities were observed during warm months (SAB = 5.96, EF = 9.52, IL = 14.15) and the lowest during cold ones (SAB = 1.45, EF = 2.6, IL = 3.32). Octopus tehuelchus showed an aggregated spatial distribution, and the nearest neighbour value varied between 0.21 and 0.83 in SAB, 0.27 and 0.78 in EF and 0.23 and 0.53 in IL. Considering the coast lines, the distribution pattern along the intertidal varied seasonally. During warm months this species is widely distributed throughout the intertidal, from the low-tide line to 300 m (in SAB), 500 m (in EL) and 200 m (in IL). On the contrary, during cold months most individuals were found near the low-tide line. These results may be associated with the availability of shelter in the intertidal and the activity and physiology of this species.
Hyperprolactinemia in antipsychotic-naive patients with first-episode psychosis
Authors: Riecher-Rössler A. , Rybakowski J. K. , Pflueger M. O. , Beyrau R. , Kahn R. S. , Malik P. , Fleischhacker W. W.
Published: April 2013

Background

Hyperprolactinemia is frequent in patients with schizophrenic psychoses. It is usually regarded as an adverse effect of antipsychotics but has recently also been shown in patients without antipsychotic medication. Our objective was to test whether hyperprolactinemia occurs in antipsychotic-naive first-episode patients (FEPs).

Method

In the framework of the European First Episode Schizophrenia Trial (EUFEST), 249 out of 498 FEPs were eligible for this study, of whom 74 were antipsychotic naive. All patients were investigated regarding their serum prolactin levels with immunoassays standardized against the 3rd International Reference Standard 84/500.

Results

Twenty-nine (39%) of the 74 antipsychotic-naive patients showed hyperprolactinemia not explained by any other reason, 11 (50%) of 22 women and 18 (35%) of 52 men.

Conclusions

Hyperprolactinemia may be present in patients with schizophrenic psychoses independent of antipsychotic medication. It might be stress induced. As enhanced prolactin can increase dopamine release through a feedback mechanism, this could contribute to explaining how stress can trigger the outbreak of psychosis.
Examinations of Oxidation and Sulfidation of Grain Boundaries in Alloy 600 Exposed to Simulated Pressurized Water Reactor Primary Water
Authors: Schreiber D.K. , Olszta M.J. , Saxey D.W. , Kruska K. , Moore K.L. , Lozano-Perez S. , Bruemmer S.M.
Published: April 2013

High-resolution characterizations of intergranular attack in alloy 600 (Ni-17Cr-9Fe) exposed to 325°C simulated pressurized water reactor primary water have been conducted using a combination of scanning electron microscopy, NanoSIMS, analytical transmission electron microscopy, and atom probe tomography. The intergranular attack exhibited a two-stage microstructure that consisted of continuous corrosion/oxidation to a depth of ~200 nm from the surface followed by discrete Cr-rich sulfides to a further depth of ~500 nm. The continuous oxidation region contained primarily nanocrystalline MO-structure oxide particles and ended at Ni-rich, Cr-depleted grain boundaries with spaced CrS precipitates. Three-dimensional characterization of the sulfidized region using site-specific atom probe tomography revealed extraordinary grain boundary composition changes, including total depletion of Cr across a several nm wide dealloyed zone as a result of grain boundary migration.
Inadequacy of Micronutrients, Fat, and Fiber Consumption in the Diets of Haitian-, African- and Cuban-Americans with and without Type 2 Diabetes
Authors: Huffman Fatma G. , Vaccaro Joan A. , Zarini Gustavo G. , Biller Daiane , Dixon Zisca
Published: April 2013

Micronutrient insufficiency, low dietary fiber, and high saturated fat intake have been associated with chronic diseases. Micronutrient insufficiencies may exacerbate poor health outcomes for persons with type 2 diabetes and minority status. We examined dietary intakes using the Recommended Dietary Allowances (RDAs) of micronutrients, and Adequate Intakes (AIs) of fiber, and Dietary Guidelines for Americans (DGA) for saturated fat in Haitian-, African-, and Cuban- Americans (n = 868), approximately half of each group with type 2 diabetes. Insufficient intakes of vitamins D and E and calcium were found in over 40 % of the participants. Over 50 % of African- and Cuban- Americans consumed over 10 % of calories from saturated fat. Haitian-Americans were more likely to have insufficiencies in iron, B-vitamins, and vitamins D and E, and less likely to have inadequate intake of saturated fat as compared to Cuban-Americans. Vitamin D insufficiency was more likely for Haitian-Americans as compared to African- Americans. Diabetes status alone did not predict micronutrient insufficiencies; however, Haitian-Americans with no diabetes were more likely to be insufficient in calcium. Adjusting for age, gender, energy, smoking, physical activity, access to health care, and education negated the majority of micronutrient insufficiency differences by ethnicity. These findings suggest that policies are needed to ensure that low-cost, quality produce can be accessed regardless of neighborhood and socioeconomic status.
Associations Between Retinal Microvascular Changes and Dementia, Cognitive Functioning, and Brain Imaging Abnormalities: A Systematic Review
Authors: Heringa Sophie M , Bouvy Willem H , van den Berg Esther , Moll Annette C , Kappelle L Jaap , Biessels Geert Jan
Published: April 2013

Retinal microvascular changes can be visualized noninvasively and have been associated with cognitive decline and brain changes in relation to aging and vascular disease. We systematically reviewed studies, published between 1990 and November 2012, on the association between retinal microvascular changes and dementia, cognitive functioning, and brain imaging abnormalities, in the context of aging and vascular risk factors. In cross-sectional studies (k = 26), retinal microvascular changes were associated with the presence of dementia (range of odds ratios (ORs) 1.17;5.57), with modest decrements in cognitive functioning in nondemented people (effect sizes -0.25;0.03), and with brain imaging abnormalities, including atrophy and vascular lesions (ORs 0.94;2.95). Longitudinal studies were more sparse ( k = 9) and showed no consistent associations between retinal microvascular changes and dementia or cognitive dysfunctioning 3 to 15 years later (ORs and hazard ratios 0.77;1.55). However, there were indications of prospective associations with brain imaging abnormalities ((ORs) 0.81;3.19). In conclusion, particularly in cross-sectional studies there is a correlation between retinal microvascular changes and dementia, cognitive impairment, and brain imaging abnormalities. Associations are strongest for more severe retinal microvascular abnormalities. Retinal microvascular abnormalities may offer an important window on the brain for etiological studies.
Mitochondrial Calcium Uptake Capacity Modulates Neocortical Excitability
Authors: Sanganahalli Basavaraju G , Herman Peter , Hyder Fahmeed , Kannurpatti Sridhar S
Published: April 2013

Local calcium (Ca2 +) changes regulate central nervous system metabolism and communication integrated by subcellular processes including mitochondrial Ca2 + uptake. Mitochondria take up Ca2 + through the calcium uniporter (mCU) aided by cytoplasmic microdomains of high Ca2 +. Known only in vitro, the in vivo impact of mCU activity may reveal Ca2 + -mediated roles of mitochondria in brain signaling and metabolism. From in vitro studies of mitochondrial Ca2 + sequestration and cycling in various cell types of the central nervous system, we evaluated ranges of spontaneous and activity-induced Ca2 + distributions in multiple subcellular compartments in vivo. We hypothesized that inhibiting (or enhancing) mCU activity would attenuate (or augment) cortical neuronal activity as well as activity-induced hemodynamic responses in an overall cytoplasmic and mitochondrial Ca2 + -dependent manner. Spontaneous and sensory-evoked cortical activities were measured by extracellular electrophysiology complemented with dynamic mapping of blood oxygen level dependence and cerebral blood flow. Calcium uniporter activity was inhibited and enhanced pharmacologically, and its impact on the multimodal measures were analyzed in an integrated manner. Ru360, an mCU inhibitor, reduced all stimulus-evoked responses, whereas Kaempferol, an mCU enhancer, augmented all evoked responses. Collectively, the results confirm aforementioned hypotheses and support the Ca2 + uptake-mediated integrative role of in vivo mitochondria on neocortical activity.
Proof of unitarity of multidimensional discrete Fourier transform
Authors: Angeletti P.
Published: April 2013

The multidimensional discrete Fourier transform (MD‐DFT) plays an important role in a growing number of signal processing applications. The fundamentals of its applicability as a unitary transform between discrete periodic sequences defined on multidimensional lattices stand on the Hermitian orthogonality of the vectors defining the MD‐DFT matrix. A proof of the consistency of the MD‐DFT formulation was first provided by Bernardini and Manduchi in 1994 using the Smith normal form theorem of integer matrices. In this reported work, a new proof is provided based on the nullity of the cardinal function on the nonzero cardinal points.
High‐performance bulk silicon interdigital capacitive temperature sensor based on graphene oxide
Authors: Cai Chun‐Hua , Qin Ming
Published: April 2013

A high‐performance bulk silicon interdigital capacitive temperature sensor based on graphene oxide (GO) is presented. Compared with typical CMOS integrated temperature sensors, the sensitivity of this bulk silicon interdigital capacitive temperature sensor was improved significantly by using GO as sensing material, and this temperature sensor can operate in the range of − 70 to 40°C.
Square root algorithm in 𝔽q for q ≡ 2s + 1 (mod 2s+1)
Authors: Koo Namhun , Cho Gook Hwa , Kwon Soonhak
Published: April 2013

Presented is a square root algorithm in 𝔽q which generalises Atkins's square root algorithm [see reference 6] for q ≡ 5 (mod 8) and Müller's algorithm [see reference 7] for q ≡ 9 (mod 16). The presented algorithm precomputes a primitive 2s‐th root of unity ξ where s is the largest positive integer satisfying 2s|q−1, and is applicable for the cases when s is small. The proposed algorithm requires one exponentiation for square root computation and is favourably compared with the algorithms of Atkin, Müuller and Kong et al.
Single‐stage LED driver with low bus voltage
Authors: Wang Yijie , Guan Yueshi , Zhang Xiangjun , Xu Dianguo
Published: April 2013

A single‐stage driver is proposed. The LED driver is obtained by integrating an interleaved boost circuit and an LLC resonant converter. Since the interleaved circuit is adopted here, the input voltage is divided into two parts, each part sharing with one switch of the LLC resonant converter forms a boost circuit in discontinuous mode, and the power factor correction function and low bus voltage are realised. Since the LLC resonant converter is adopted, the converter works in soft switching state, which increases the efficiency of the system. A 100 W prototype is achieved to prove the analysis of the LED driver, and the efficiency of the LED driver is as high as 91% in full load.
Compression of redundancy free trellis stages in turbo‐decoder
Authors: Boutillon E. , Sánchez‐Rojas J. , Marchand C.
Published: April 2013

For turbo codes with a coding rate close to one, the high puncturing rate induces long sequences of trellis without a redundancy bit. A simplification technique to compute the final state of a sequence of redundancy free trellis stages (RFTSs) is presented. It compresses a sequence of RFTSs of length N into a sequence of RFTSs of length m − 1 + (N mod (m − 1)), where m is the number of states of the trellis. The computation is reduced accordingly.
SU‐8 micromachined WR‐3 band waveguide bandpass filter with low insertion loss
Authors: Chen Q. , Shang X. , Tian Y. , Xu J. , Lancaster M.J.
Published: April 2013

Presented is a WR‐3 band (220–325 GHz) waveguide bandpass filter, which is constructed from three offset waveguide resonators operating at TE101 mode. This directly coupled resonator filter with Chebyshev response is designed to have a centre frequency of 300 GHz, a fractional bandwidth of 3.3% and a passband return loss of 20 dB. This filter is fabricated using thick SU‐8 photoresist micromachining technique and has been tested. The measured average passband insertion loss is as low as around 0.4 dB. The measured return loss is better than 15 dB across the whole passband.
InGaSb/AlSb p‐channel HFETs with hydrogen plasma treatment
Authors: Ho Han‐Chieh , Gao Zong‐Yan , Lin Heng‐Kuang , Chiu Pei‐Chin , Hsin Yue‐Ming , Chyi Jen‐Inn
Published: April 2013

This reported work investigates InGaSb/AlSb p‐channel HFETs with hydrogen plasma treatment. The study found that hydrogen plasma treatment can effectively shift threshold voltage from 0.47 to 0 V. A 0.2 µm gate‐length device exhibited DC performances of a maximum drain current of 61 mA/mm, and a peak gm of 83 mS/mm.
20 krad/s endless optical polarisation and phase control
Authors: Koch B. , Noé R. , Mirvoda V. , Sandel D.
Published: April 2013

Presented is endless optical control not only of the state‐of‐polarisation of an analysed signal and its orthogonal, but also of the phase difference between the two. The normalised Stokes vector space is thereby stabilised, at the polarisation scrambling speeds of up to 20 krad/s.
0.6mW 6.3 GHz 40nm CMOS divide‐by‐2/3 prescaler using heterodyne phase‐locking technique
Authors: Yu X.P. , Lu Z.H. , Lim W.M. , Yeo K.S.
Published: April 2013

A dual‐modulus prescaler based on the heterodyne phase‐locking technique is presented. Different to the conventional LC tank based phase‐locked loop, by directly locking at two injection‐locked ring oscillators simultaneously, a dual‐modulus operation is achieved while a wide‐range operating, significantly reduced settling time and low power consumption are achieved. Implemented in a standard 40nm CMOS process, the proposed divide‐by‐2 and 3 dual‐modulus prescaler achieves an operating frequency of 6.3GHz with a measured power consumption of 0.6mW from a 1.1V supply.
Some new results about the massless Dirac operator
Authors: Zhong Y. , Gao G. L.
Published: April 2013

In this paper, we give a method to construct the zero mode and zero resonance of the massless Dirac operator H = α·D + Q(x) and obtain some special examples to show the sharpness of some existing results. On the other hand, we extend the previous results of H about the vanishing properties of the zero mode and the existence of the zero resonance. In Sec. IV, we consider the local version and get some improvements and extensions.
A global potential energy surface for the H2 + OH ↔ H2O + H reaction using neural networks
Authors: Chen Jun , Xu Xin , Xu Xin , Zhang Dong H.
Published: April 2013

A global potential energy surface for the H2 + OH ↔ H2O + H reaction has been constructed using the neural networks method based on ∼17 000 ab initio energies calculated at UCCSD(T)-F12a/AVTZ level of theory. Time-dependent wave packet calculations showed that the new potential energy surface is very well converged with respect to the number of ab initio data points, as well as to the fitting process. Various tests revealed that the new surface is considerably more smooth and accurate than the existing YZCL2 and XXZ surfaces, representing the best available potential energy surface for the benchmark four-atom system. Equally importantly, the number of ab initio energies required to obtain the well converged potential energy surface is rather limited, indicating the neural network fitting is a powerful method to construct accurate potential energy surfaces for polyatomic reactions.
Size dependent ferromagnetic resonance and magnetic anisotropy of hexagonal barium and strontium ferrite powders
Authors: Chao Liu , Afsar Mohammed N.
Published: April 2013

Ferrite powders with different particle diameters were characterized in millimeter wave frequency range. Quasi-optical spectrometer in transmission mode powered by high power backward wave oscillator was employed to measure the transmittance of the powder samples. Strong ferromagnetic absorptions were acquired in the millimeter wave frequency range. The absorption frequencies exhibit distinct shift related to the size of ferrite particles. The complex dielectric permittivity and magnetic permeability are determined from the transmittance spectra. The size dependence of ferromagnetic resonance is clearly observed.
Phase-coded approach for controllable generation of acoustical vortices
Authors: Yang Ling , Ma Qingyu , Tu Juan , Zhang Dong
Published: April 2013

Based on the acoustic radiation of point source, a phase-coded approach is proposed as a general technology to generate controllable acoustical vortices. For N sources, acoustical vortices can be generated with the phase difference of 2πm/N for the source topological charge m. It is proved that more circular pressure distributions of acoustical vortices with higher pressure peak amplitude can be generated for more sources. The number and spiral direction of phase twists are demonstrated to be determined by m and the maximum topological charge of acoustical vortices is |L|=Fix[(N−1)/2], where Fix(x) rounds the element x toward zero. To produce acoustical vortices with a maximum topological charge L, the minimum source number of Nmin=max(2|L|+1,4) should be employed with the phase difference of 2πL/Nmin and the phase difference resolution is also demonstrated to be π. The phase-coded approach has been verified by a 6-source experiment. The measured distributions of pressure and phase as well as the topological charge of acoustical vortices agree well with theoretical results, which suggest the feasibility of the phase-coded approach for controllable generation of acoustical vortices.
Intensity and wavelength dependence of bimolecular recombination in P3HT:PCBM solar cells: A white-light biased external quantum efficiency study
Authors: Cowan Sarah R. , Wang Jian , Yi Juan , Lee Yun-Ju , Olson Dana C. , Hsu Julia W. P.
Published: April 2013

Bimolecular recombination is often a major photogenerated charge carrier loss mechanism in organic photovoltaic (OPV) devices, resulting in lower fill factor (FF) compared to inorganic devices. The recombination parameter α can be obtained from the power law fitting of short-circuit current (Jsc) on illumination intensity (I),  Jsc∝Iα, with α values less than unity taken as an indication of reduced photon-to-electron extraction efficiency and the presence of bimolecular recombination in OPV. Here, we show that this intensity-averaged measurement is inadequate. An external quantum efficiency (EQE) apparatus under constant white-light bias can be used to measure the recombination parameter (αEQE*) as a function of wavelength and carrier density (white-light intensity). Examining the dependence of α on background white-light bias intensity and excitation wavelength provides further understanding of photon-to-electron conversion loss mechanisms in P3HT:PCBM bulk heterojunction devices in standard and inverted architectures. In order to compare EQE and current-voltage (JV) measurements, we discuss the special case of devices exhibiting sub-linear intensity response (α < 1). Furthermore, we demonstrate several important advantages of the white-light biased EQE method of measuring bimolecular recombination compared to existing methods, including sensitivity in probing intensity-dependent recombination compared to steady-state JV measurements, the correlation of αEQE* and FF in devices, elucidation of recombination mechanisms through spectral dependence of carrier loss, and the robustness of αEQE* obtained via integration over the entire absorption region. Furthermore, this technique for measuring recombination is immediately accessible to the vast majority of researchers as the EQE apparatus is ubiquitous in PV research laboratories.
Perpendicularly magnetized τ-MnAl (001) thin films epitaxied on GaAs
Authors: Nie S. H. , Zhu L. J. , Lu J. , Pan D. , Wang H. L. , Yu X. Z. , Xiao J. X. , Zhao J. H.
Published: April 2013

Perpendicularly magnetized τ-MnAl films have been epitaxied on GaAs (001) by molecular-beam epitaxy. Crystalline quality and magnetic properties of the samples were strongly dependent on growth temperature. The highest coercivity of 10.7 kOe, saturation magnetization of 361.4 emu/cm3, perpendicular magnetic anisotropy constant of 13.65 Merg/cm3, and magnetic energy product of 4.44 MGOe were achieved. These tunable magnetic properties make MnAl films valuable as excellent and cost-effective alternative for not only high density perpendicular magnetic recording storage and spintronics devices but also permanent magnets.
Near-field infrared absorption of plasmonic semiconductor microparticles studied using atomic force microscope infrared spectroscopy
Authors: Felts Jonathan R. , Law Stephanie , Roberts Christopher M. , Podolskiy Viktor , Wasserman Daniel M. , King William P.
Published: April 2013

We report measurements of near-field absorption in heavily silicon-doped indium arsenide microparticles using atomic force microscope infrared spectroscopy (AFM-IR). The microparticles exhibit an infrared absorption peak at 5.75 μm, which corresponds to a localized surface plasmon resonance within the microparticles. The near-field absorption measurements agree with far-field measurements of transmission and reflection, and with results of numerical solutions of Maxwell equations. AFM-IR measurements of a single microparticle show the temperature increase expected from Ohmic heating within the particle, highlighting the potential for high resolution infrared imaging of plasmonic and metamaterial structures.
Aluminum nitride piezo-acousto-photonic crystal nanocavity with high quality factors
Authors: Fan Linran , Sun Xiankai , Xiong Chi , Schuck Carsten , Tang Hong X.
Published: April 2013

We develop a piezoelectrically actuated, one-dimensional acoustic and photonic crystal nanocavity fabricated from aluminum nitride (AlN). Through simultaneous band structure engineering in both photonic and acoustic domains, we obtain high-quality piezo-acousto-photonic crystal nanocavities with intrinsic optical Q of 1.2 × 105. The piezoelectric actuation of the confined mechanical mode at 3.18 GHz is demonstrated with mechanical Q exceeding 10 000. Such piezo-acousto-photonic crystal nanocavities will find important applications in cavity optomechanics that desire effective coupling to the electrical degree of freedom.
Mastered dispersion of material resonators: Broad corrugated waveguides working under the Littrow regime
Authors: Benisty H. , Piskunov N.
Published: April 2013

An anomalous dispersion for modes of a material resonator is highly desired to form frequency combs. A resonator free-spectral-range (FSR) controlled by shape so as to increase with frequency ω/2π compensates the normal index dispersion ∂n/∂ω > 0, producing evenly spaced resonances. Only special shapes achieve this scope. We show here that broad periodic corrugated waveguides working at Littrow regime feature such an increasing trend ∂FSR/∂ω > 0. We outline experimentally this trend on silicon-on-insulator devices designed for 45° Littrow operation. We predict dispersion-free silicon-based designs across the 1.4–4.0 μm mid-infrared range.
Spin transport and accumulation in the persistent photoconductor Al0.3Ga0.7As
Authors: Misuraca Jennifer , Kim Joon-Il , Lu Jun , Meng Kangkang , Chen Lin , Yu Xuezhe , Zhao Jianhua , Xiong Peng , von Molnár Stephan
Published: April 2013

Electrical spin transport and accumulation have been measured in highly Si doped Al0.3Ga0.7As utilizing a lateral spin transport device. Persistent photoconductivity allows for the tuning of the effective carrier density of the channel material in situ via photodoping. Hanle effect measurements are completed at various carrier densities, and the measurements yield spin lifetimes on the order of nanoseconds, an order of magnitude smaller than in bulk GaAs. These measurements illustrate that this methodology can be used to obtain a detailed description of how spin lifetimes depend on carrier density in semiconductors across the metal-insulator transition.
Field-enhanced Raman scattering by silver nanoparticle with graded SiO2 coating
Authors: Liu Tung-Kai , Tsai Ming-Shan , Hung Wen-Chi , Kuo Chie-Tong , Wang Dong-Po , Jiang I-Min
Published: April 2013

A reusable metallic substrate of surface-enhanced-Raman-scattering (SERS) was fabricated with field-enhancement property. Silver nanoparticles spread on a glass substrate and covered with a graded SiO2 coating were employed to enhance and to modulate the Raman scattering signal of probed samples. In the study, the Raman scattering enhancement of the crystal violet dye depended on the thickness of the SiO2 coating and the optimal Raman signal occurred as the SiO2 coating thickness was around 8.7 nm. Moreover, the SiO2 coating that functioned as a protector, maintaining the activity of the Ag nanoparticles, led to a reusable SERS-active substrate.
Influence of friction on the residual morphology, the penetration load and the residual stress distribution of a Zr-based bulk metallic glass
Authors: Huang Hu , Shi Chengli , Zhao Hongwei , Zhang Lin
Published: April 2013

In this paper, frictionbetween the Cube-Corner indenter and the sample surface of a Zr-based bulk metallic glass(BMG) was analyzed and discussed by the experimental method, the theoretical method and the finite element simulation. Linear residua are observed on the surfaceof the indenter for the first time, which gives the direct evidence that strong interaction processes exist between the indenter surface and the sample surface because of strong friction and local high contact press. A simplified model was developed to correct the penetration load with the consideration of friction.Effects of friction on the penetration load-depth curves, plastic flow, surfacedeformation and residual stress distribution of the sample with different friction coefficients were investigated by the finite element simulation.
Separate feeding of calcium improves performance and ileal nutrient digestibility in broiler chicks
Authors: Wilkinson S. J. , Selle P. H. , Bedford M. R. , Cowieson A. J.
Published: April 2013

A total of 144 Cobb 500 broilers were used to investigate if modern commercial broilers could regulate their calcium (Ca) intake using choice feeding and whether separating the delivery of a portion of the Ca from the mixed ration would be advantageous for performance and nutrient recovery. Birds were fed corn+soy-based diets formulated to contain 2.5, 5.0, 7.5 or 10.0 g/kg total Ca and all groups had access to a separate Ca source (CaCO3). The trial was conducted from Day 1 to Day 21 and birds had ad libitum access to both the experimental diets and a separate Ca source throughout. Total feed and separate Ca intake were monitored daily, weight gain and feed intake weekly and on Day 21, the apparent ileal digestibility of DM, nitrogen, selected minerals and amino acids were determined. Consumption of the separate Ca source increased (P < 0.05) with decreasing total Ca concentration of the mixed ration. No differences (P > 0.05) in toe ash were found. Increasing dietary Ca concentration negatively influenced the apparent ileal digestibility of DM, nitrogen, minerals and amino acids. It can be concluded that broilers can select and consume Ca from a separate source to broadly maintain their requirement. Feeding a separate source of Ca in combination with reduced dietary Ca in the mixed ration had beneficial effects on nutrient digestibility, phosphorus excretion and performance.
Ovarian synchronisation in wood bison (Bison bison athabascae) during the anovulatory season
Authors: Palomino J. Manuel , McCorkell Robert B. , Woodbury Murray R. , Adams Gregg P.
Published: April 2013

Two experiments were performed in wood bison during the anovulatory season to establish an effective protocol for ovarian synchronisation. In an untreated control phase, bison cows (n = 19) were examined daily to establish the interval to new follicular wave emergence (4.9 ± 0.7 days) for the purposes of comparison with the experimental treatments. In Experiment 1, bison were treated by transvaginal ultrasound-guided follicular ablation (n = 9) or with 2 mg, i.m., 17β-oestradiol (n = 10). In Experiment 2, bison were treated by follicular ablation (n = 9) or with 2 mg, i.m., 17β-oestradiol +100 mg, i.m., progesterone (n = 10). In Experiment 1, the interval to new wave emergence for control, follicular ablation and 17β-oestradiol-treated groups was 4.9 ± 0.7, 1.1 ± 0.1 and 3.1 ± 0.4 days, respectively (P < 0.05). The degree of synchrony was 2.4 ± 0.4, 0.2 ± 0.1 and 0.8 ± 0.2 days, respectively (P < 0.05). In Experiment 2, the interval to new wave emergence for control, follicular ablation and 17β-oestradiol + progesterone-treated groups was 4.9 ± 0.7, 1.2 ± 0.2 and 3.3 ± 0.3 days, respectively (P < 0.05), and the degree of synchrony was 2.4 ± 0.4, 0.2 ± 0.1, and 0.8 ± 0.2 days, respectively (P < 0.05). The degree of synchrony did not differ between ablation and hormone treatment groups in either experiment, but was greater in treatment groups than in the untreated control phase. Both follicular ablation and hormone treatment shortened and decreased the variability in the interval to follicular wave emergence in bison, but wave emergence occurred earlier after follicular ablation.
Rac-specific guanine nucleotide exchange factor DOCK1 is a critical regulator of HER2-mediated breast cancer metastasis
Authors: Laurin Mélanie , Huber Jennifer , Pelletier Ariane , Houalla Tarek , Park Morag , Fukui Yoshinori , Haibe-Kains Benjamin , Muller William J. , Côté Jean-François
Published: April 2013

Progression of solid tumors to the metastatic stage is accountable for the majority of cancer-related deaths. Further understanding of the molecular mechanisms governing metastasis is essential for the development of antimetastatic regimens. Here, we aimed to identify Rac activators that could promote metastasis downstream of human epithelial growth factor receptor 2 (HER2). We investigated if Dedicator of Cytokinesis 1 (DOCK1), based on its evolutionarily conserved role in receptor tyrosine kinases (RTKs)-mediated Rac activation and cell invasion, could be a regulator of metastasis. We report that high expression of
DOCK1
in HER2
+
and basal breast cancer subtypes inversely correlates with human patients’ survival. Mechanistically, DOCK1 interacts with HER2 and promotes HER2-induced Rac activation and cell migration. To gain further insight, we developed a HER2 breast cancer mouse model with mammary-gland–specific inactivation of
DOCK1
. In this in vivo model, a significant decrease in tumor growth and metastasis in lungs was found in animals where
DOCK1
is inactivated. Furthermore, we found that DOCK1 is required for maximal activation of two HER2 effectors, c-JUN and STAT3. Using an unbiased gene profiling approach, we identified a mammary tumor
DOCK1
-associated gene signature enriched for genes implicated in response to IFN type I. This analysis revealed a unique set of genes, including Receptor Transporter Protein 4 (
RTP4
) and
STAT1
, for which the expression levels can be used to independently predict breast cancer outcome in HER2
+
patients. Our work demonstrates DOCK1–Rac signaling as an HER2 effector pathway essential for HER2-mediated breast cancer progression to metastasis and offers a therapeutic opportunity to limit the spread of metastatic breast cancers.
Performance of United States Serologic Assays in the Diagnosis of Lyme Borreliosis Acquired in Europe
Authors: Branda John A. , Strle Franc , Strle Klemen , Sikand Nikhil , Ferraro Mary Jane , Steere Allen C.
Published: April 2013

Background.  Physicians in the United States sometimes need to evaluate a patient for suspected Lyme borreliosis (LB) who may have acquired the infection in Europe. Using serum samples from European LB patients, we compared the performance of European and US serodiagnostic tests, including newer-generation assays containing Vmp-like sequence, expressed or its C6 peptide.

Methods.  The sensitivity of each assay was determined using 64 serum samples from LB patients with early or late disease manifestations who acquired the infection in Europe. Specificity was measured using 100 sera from healthy subjects from a nonendemic area.

Results.  For the detection of European-acquired infection, conventional 2-tiered testing (enzyme-linked immunosorbent assay [ELISA] followed by immunoblotting) using US assays had an overall sensitivity and specificity of 52% and 100%, compared with 81% (P = .0007) and 99% (P = 1.00) using analogous European tests. The sensitivity of a US C6 ELISA used as a stand-alone test (88% overall) was statistically comparable to that of conventional 2-tiered testing using European tests (P = .47) and was 100% specific. Similarly, an alternative 2-tiered algorithm using a standard US ELISA followed by a C6 ELISA was comparably sensitive (84% overall) compared with conventional 2-tiered testing using European assays (P = .82), and specificity remained 100%.

Conclusions.  European assays outperformed analogous US assays in a conventional 2-tiered testing algorithm. However, a C6 ELISA used as a stand-alone test or in the second tier of a 2-tiered algorithm performed comparably to conventional 2-tiered testing using European assays, and can be used for evaluation of any patient, regardless of travel history.
Population Genetic Analysis Reveals Diversity inLasiodiplodiaSpecies Infecting Date Palm,Citrus, and Mango in Oman and the UAE
Authors: Al-Sadi A. M. , Al-Wehaibi A. N. , Al-Shariqi R. M. , Al-Hammadi M. S. , Al-Hosni I. A. , Al-Mahmooli I. H. , Al-Ghaithi A. G.
Published: April 2013

Lasiodiplodia is a common pathogen causing dieback, gummosis, or root necrosis on the three most important fruit crops in Oman and the United Arab Emirates (UAE): date palm (Phoenix dactylifera), Citrus spp., and mango (Mangifera indica). A study was conducted to examine diversity in 64 Lasiodiplodia isolates infecting date palm (24), Citrus (11), and mango (29) in Oman and the UAE. Identification based on sequences of the internal transcribed spacer (ITS) rDNA and EF1α gene showed that date palm isolates belonged to L. hormozganensis (75% of isolates) and L. theobromae (25%); Citrus isolates belonged to L. hormozganensis (45%), L. theobromae (45%), and L. iraniensis (10%); and mango isolates belonged to L. theobromae (59%), L. iraniensis (34%), and L. hormozganensis (7%). Amplified fragment length polymorphism (AFLP) fingerprinting of the 64 isolates using four primer pair combinations produced 64 genotypes and 972 polymorphic alleles. Cluster analysis separated the isolates into four clusters representing the three species. A higher level of genetic diversity was observed in L. iraniensis (0.3105) compared to L. hormozganensis (0.2503) and L. theobromae (0.2331) in Oman. Analysis of molecular variance (AMOVA) indicated the existence of low levels of genetic differentiation among date palm populations of L. hormozganensis obtained from Oman and the UAE (FST= 0.025) and among populations of L. hormozganensis (0.0485) and L. theobromae (0.0703) from date palm, Citrus, and mango. These findings imply a high rate of movement of L. hormozganensis and L. theobromae isolates among date palm, Citrus, and mango and between the two countries. Findings from the pathogenicity test supported the AMOVA analysis and suggested a lack of host specialization in L. hormozganensis, L. iraniensis, and L. theobromae on date palm, acid lime, and mango. Although this is the first record of L. hormozganensis and L. iraniensis in Oman, the relatively moderate level of genetic diversity in the two species compared to L. theobromae suggests that the two species have been in Oman for a long time but misidentified by morphology and ITS rDNA sequences as L. theobromae. This study is also the first record of date palm and acid lime as natural hosts for L. hormozganensis and the first record of L. hormozganensis in the UAE. The diversity in Lasiodiplodia species affecting date palm, Citrus, and mango in Oman and the UAE should be taken into consideration when planning future management programs for diseases caused by these pathogens.