bluuebunny/crossref_metadata_2025 huggingface dataset:
A Collaboration Between University and High School in Preparing Physics Teachers: Chicago State University's Teacher Immersion Institute
Authors: Sabella Mel S. , Van Duzor Andrea G. , Passehl Jennie , Weisenburger Kara
Published: April 2012

Because of the diverse character of colleges and universities throughout the United States, it is naive to believe that a one-size-fits-all model of teacher preparation aligns with specific resources and student population needs. Exploring innovative models that challenge traditional programs is now being encouraged by organizations such as the American Association of Physics Teachers and the American Physical Society. Chicago State University (CSU) is now exploring exciting changes to its physics teacher preparation program by utilizing the expertise of Chicago Area teachers and early teaching experiences for students interested in, but not yet committed to, the physics teaching profession.
Acoustic analysis of trill sounds
Authors: Dhananjaya N. , Yegnanarayana B. , Bhaskararao Peri
Published: April 2012

In this paper, the acoustic–phonetic characteristics of steady apical trills—trill sounds produced by the periodic vibration of the apex of the tongue—are studied. Signal processing methods, namely, zero-frequency filtering and zero-time liftering of speech signals, are used to analyze the excitation source and the resonance characteristics of the vocal tract system, respectively. Although it is natural to expect the effect of trilling on the resonances of the vocal tract system, it is interesting to note that trilling influences the glottal source of excitation as well. The excitation characteristics derived using zero-frequency filtering of speech signals are glottal epochs, strength of impulses at the glottal epochs, and instantaneous fundamental frequency of the glottal vibration. Analysis based on zero-time liftering of speech signals is used to study the dynamic resonance characteristics of vocal tract system during the production of trill sounds. Qualitative analysis of trill sounds in different vowel contexts, and the acoustic cues that may help spotting trills in continuous speech are discussed.
Blind deconvolution for robust signal estimation and approximate source localization
Authors: Abadi Shima H. , Rouseff Daniel , Dowling David R.
Published: April 2012

Synthetic time reversal (STR) is a technique for blind deconvolution in an unknown multipath environment that relies on generic features (rays or modes) of multipath sound propagation. This paper describes how ray-based STR signal estimates may be improved and how ray-based STR sound-channel impulse-response estimates may be exploited for approximate source localization in underwater environments. Findings are based on simulations and underwater experiments involving source-array ranges from 100 m to 1 km in 60 -m-deep water and chirp signals with a bandwidth of 1.5–4.0 kHz. Signal estimation performance is quantified by the correlation coefficient between the source-broadcast and the STR-estimated signals for a variable number N of array elements, 2 ≤ N ≤ 32, and a range of signal-to-noise ratio (SNR), −5 dB ≤ SNR ≤ 30 dB. At high SNR, STR-estimated signals are found to have cross-correlation coefficients of ∼90% with as few as four array elements, and similar performance may be achieved at a SNR of nearly 0 dB with 32 array elements. When the broadband STR-estimated impulse response is used for source localization via a simple ray-based backpropagation scheme, the results are less ambiguous than those obtained from conventional broadband matched field processing.
Sentence recognition in noise promoting or suppressing masking release by normal-hearing and cochlear-implant listeners
Authors: Kwon Bomjun J. , Perry Trevor T. , Wilhelm Cassie L. , Healy Eric W.
Published: April 2012

Normal-hearing (NH) listeners maintain robust speech understanding in modulated noise by “glimpsing” portions of speech from a partially masked waveform—a phenomenon known as masking release (MR). Cochlear implant (CI) users, however, generally lack such resiliency. In previous studies, temporal masking of speech by noise occurred randomly, obscuring to what degree MR is attributable to the temporal overlap of speech and masker. In the present study, masker conditions were constructed to either promote (+MR) or suppress (−MR) masking release by controlling the degree of temporal overlap. Sentence recognition was measured in 14 CI subjects and 22 young-adult NH subjects. Normal-hearing subjects showed large amounts of masking release in the +MR condition and a marked difference between +MR and −MR conditions. In contrast, CI subjects demonstrated less effect of MR overall, and some displayed modulation interference as reflected by poorer performance in modulated maskers. These results suggest that the poor performance of typical CI users in noise might be accounted for by factors that extend beyond peripheral masking, such as reduced segmental boundaries between syllables or words. Encouragingly, the best CI users tested here could take advantage of masker fluctuations to better segregate the speech from the background.
The role of stimulus cross-splicing in an event-related potentials study. Misleading formant transitions hinder automatic phonological processing
Authors: Steinberg Johanna , Truckenbrodt Hubert , Jacobsen Thomas
Published: April 2012

The mental organization of linguistic knowledge and its involvement in speech processing can be investigated using the mismatch negativity (MMN) component of the auditory event-related potential. A contradiction arises, however, between the technical need for strict control of acoustic stimulus properties and the quest for naturalness and acoustic variability of the stimuli. Here, two methods of preparing speech stimulus material were compared. Focussing on the automatic processing of a phonotactic restriction in German, two corresponding sets of various vowel-fricative syllables were used as stimuli. The former syllables were naturally spoken while the latter ones were created by means of cross-splicing. Phonetically, natural and spliced syllables differed with respect to the appropriateness of coarticulatory information about the forthcoming fricative within the vowels. Spliced syllables containing clearly misleading phonetic information were found to elicit larger N2 responses compared to their natural counterparts. Furthermore, MMN results found for the natural syllables could not be replicated with these spliced stimuli. These findings indicate that the automatic processing of the stimuli was considerably affected by the stimulus preparation method. Thus, in spite of its unquestioned benefits for MMN experiments, the splicing technique may lead to interference effects on the linguistic factors under investigation.
Talker-identification training using simulations of binaurally combined electric and acoustic hearing: Generalization to speech and emotion recognition
Authors: Krull Vidya , Luo Xin , Iler Kirk Karen
Published: April 2012

Understanding speech in background noise, talker identification, and vocal emotion recognition are challenging for cochlear implant (CI) users due to poor spectral resolution and limited pitch cues with the CI. Recent studies have shown that bimodal CI users, that is, those CI users who wear a hearing aid (HA) in their non-implanted ear, receive benefit for understanding speech both in quiet and in noise. This study compared the efficacy of talker-identification training in two groups of young normal-hearing adults, listening to either acoustic simulations of unilateral CI or bimodal (CI+HA) hearing. Training resulted in improved identification of talkers for both groups with better overall performance for simulated bimodal hearing. Generalization of learning to sentence and emotion recognition also was assessed in both subject groups. Sentence recognition in quiet and in noise improved for both groups, no matter if the talkers had been heard during training or not. Generalization to improvements in emotion recognition for two unfamiliar talkers also was noted for both groups with the simulated bimodal-hearing group showing better overall emotion-recognition performance. Improvements in sentence recognition were retained a month after training in both groups. These results have potential implications for aural rehabilitation of conventional and bimodal CI users.
Investigations into vocal doses and parameters pertaining to primary school teachers in classrooms
Authors: Bottalico Pasquale , Astolfi Arianna
Published: April 2012

Investigations into vocal doses and parameters were carried out on 40 primary school teachers (36 females and 4 males) in six schools in Italy, divided into two groups of three, A and B, on the basis of the type of building and the mid-frequency reverberation time in the classrooms, which was 1.13 and 0.79 s, respectively. A total of 73 working-day samples were collected (66 for females and 7 for males), from which 54 traditional lessons were analyzed separately. The average value over the working days of the mean sound pressure level of the voiced speech at 1 m from the teacher’s mouth was 62.1 dB for the females and 57.7 dB for the males, while the voicing time percentage was 25.9 and 25.1 %, respectively. Even though the vocal doses and parameters did not differ for the two school groups, the differences in the subjective scores were significant, with enhanced scores in group B. A 0.72 dB increase in speech level per 1 dB increase in background noise level, LA90, was found during traditional lessons, as well as an increase in the mean value of the fundamental frequency with an increase in LA90, at a rate of 1.0 Hz/dB.
Audience noise in concert halls during musical performances
Authors: Jeong Cheol-Ho , Marie Pierre , Brunskog Jonas , Møller Petersen Claus
Published: April 2012

Noise generated by the audience during musical performances is audible and sometimes disturbing. In this study, an attempt to estimate such audience noise was carried out. From the recordings of performances in five performance spaces (four concert halls and one opera house), probability density functions of the sound pressure levels were obtained in octave bands, which were fitted with three Gaussian distribution curves. The Gaussian distribution curve with the lowest mean value corresponds to a mixture of the technical background noise and audience generated noise, which is named the mixed background noise. Finally, the audience noise distribution is extracted by energy subtraction of the technical background noise levels measured in an empty condition from the mixed background noise levels. As a single index, L90 of the audience noise distribution is named the audience noise level. Empirical prediction models were made using the four orchestra concert halls, revealing that the audience noise level is significantly correlated with the technical background noise level. It is therefore concluded that a relaxation of the current background noise recommendations for concert halls is not recommended.
Comparison of methods for processing acoustic intensity from orthogonal multimicrophone probes
Authors: Wiederhold Curtis P. , Gee Kent L. , Blotter Jonathan D. , Sommerfeldt Scott D.
Published: April 2012

One design for three-dimensional multimicrophone probes is the four-microphone orthogonal design consisting of one microphone at an origin position with the other three microphones equally spaced along the three coordinate axes. Several distinct processing methods have been suggested for the estimation of active acoustic intensity with the orthogonal probe; however, the relative merits of each method have not been thoroughly studied. This comparative study is an investigation of the errors associated with each method. Considered are orthogonal probes consisting of matched point sensor microphones both freely suspended and embedded on the surface of a rigid sphere. Results are given for propagating plane-wave fields for all angles of incidence. It is shown that the lowest error for intensity magnitude results from having the microphones in a sphere and using just one microphone for the pressure estimate. For intensity direction, the lowest error results from having the microphones in a sphere and using Taylor approximations to estimate the particle velocity and pressure.
Low frequency seabed scattering at low grazing angles
Authors: Zhou Ji-Xun , Zhang Xue-Zhen
Published: April 2012

Low-frequency (LF) seabed scattering at low grazing angles (LGA) is almost impossible to directly measure in shallow water (SW), except through inversion from reverberation. The energy flux method for SW reverberation is briefly introduced in this paper. The closed-form expressions of reverberation in an isovelocity waveguide, derived from this method, indicate that in the three-halves law range interval multimode/ray sea bottom scattering with different incident and scattering angles in forming the reverberation may equivalently be represented by the bottom backscattering at a single range-dependent angle. This equivalent relationship is used to derive the bottom backscattering strength (BBS) as a function of angle and frequency. The LF&LGA BBS is derived in a frequency band of 200–2500 Hz and in a grazing angle range of 1.1°–14.0° from reverberation measurements at three sites with sandy bottoms. This is based on three previous works: (1) The closed-form expressions of SW reverberation [Zhou, (Chinese) Acta Acustica 5, 86–99 (1980)]; (2) the effective geo-acoustic model of sandy bottoms that follows the Biot model [Zhou et al., J. Acoust. Soc. Am. 125, 2847–2866 (2009)] and (3) A quality database of wideband reverberation level normalized to source level [Zhou and Zhang, IEEE J. Oceanic Eng. 30, 832–842 (2005)].
A Memory Retrieval-Extinction Procedure to Prevent Drug Craving and Relapse
Authors: Xue Yan-Xue , Luo Yi-Xiao , Wu Ping , Shi Hai-Shui , Xue Li-Fen , Chen Chen , Zhu Wei-Li , Ding Zeng-Bo , Bao Yan-ping , Shi Jie , Epstein David H. , Shaham Yavin , Lu Lin
Published: April 2012

Disrupting Drug Memories

In drug recovery programs, conditioned responses to drug cues can be inhibited by extinction protocols. However, extinguished behavioral responses can return after renewed exposure to the drug itself, or to drug-associated paraphernalia, and sometimes these responses reemerge spontaneously. Attempts have been made to disrupt cue-memory reconsolidation or to strengthen extinction learning, but these efforts have often relied on pharmacological agents that either are not approved for human use or cause problematic side effects.

Xue
et al.

(p.
241
; see the Perspective by

Milton and Everitt

) have tried to circumvent the limitations of pharmacological approaches in daily retrieval trials conducted in rats within the short timeframe of the “reconsolidation window” before the extinction sessions reduced drug-induced reinstatement, spontaneous recovery, and renewal of drug seeking. When translated to heroin-addicted humans, similar retrieval trials before extinction sessions impaired cue-induced heroin craving up to 6 months later. This retrieval-extinction procedure is thus a promising non-pharmacological treatment for addiction.
miRNA-Mediated Gene Silencing by Translational Repression Followed by mRNA Deadenylation and Decay
Authors: Djuranovic Sergej , Nahvi Ali , Green Rachel
Published: April 2012

Translation Block

MicroRNAs (miRNAs) are small, noncoding RNA genes that are found in the genomes of most eukaryotes, where they play an important role in the regulation of gene expression. Although whether gene activity is repressed by blocking translation of messenger RNA (mRNA) targets, or by promoting their deadenylation and then degradation, has been open to debate.

Bazzini
et al.

(p.
233
, published online 15 March) and

Djuranovic
et al.

(p.
237
) looked at early points in the repression reaction in the zebrafish embryo or in Drosophila tissue culture cells, respectively, and found that translation was blocked before target mRNAs were significantly deadenylated and degraded. Thus, miRNAs appear to interfere with the initiation step of translation.
Demonstration of Entanglement of Electrostatically Coupled Singlet-Triplet Qubits
Authors: Shulman M. D. , Dial O. E. , Harvey S. P. , Bluhm H. , Umansky V. , Yacoby A.
Published: April 2012

Entangling Qubits

The basic building block of a quantum computer, a qubit, has been realized in many physical settings, each of which has its advantages and drawbacks. Solid-state spin qubits interact weakly with their environment and each other, leading not only to long coherence times but also to difficulties in performing multiqubit operations.

Shulman
et al.

(p.
202
) used a double quantum dot to produce a singlet-triplet qubit, where the two quantum states available are a singlet and a triplet formed by two spin-1/2 electrons. Two such qubits are then entangled by electrical gating, which affects the charge configuration of one qubit and that, in turn, influences the electric field experienced by the other. This type of two-qubit entanglement is essential for further development of quantum computing in these systems.
Atg7 Modulates p53 Activity to Regulate Cell Cycle and Survival During Metabolic Stress
Authors: Lee In Hye , Kawai Yoshichika , Fergusson Maria M. , Rovira Ilsa I. , Bishop Alexander J. R. , Motoyama Noboru , Cao Liu , Finkel Toren
Published: April 2012

Starvation and Autophagy

Starvation stimulates withdrawal from the cell cycle, as well as stimulating autophagy. Are these two events connected?

Lee
et al.

(p.
225
) show a direct and nutrient-sensitive interaction between the tumor suppressor p53 and the essential autophagy gene Atg7. Further, in the absence of Atg7, the p53-dependent induction of the cyclin-dependent kinase inhibitor p21 is inhibited. This leads to Atg7-deficient cells being unable to properly withdraw from the cell cycle under starved conditions. While Atg7 deletion leads to an impairment of p53-mediated cell-cycle arrest, the Atg7-deficient cells hyperactivate p53-mediated cell-death pathways. The physiological importance of this hyperactivation is underscored by the observation that genetic blocking of p53-mediated cell death significantly extended neonatal survival of mice in which Atg7 had been deleted.
Beyond Turing's Machines
Authors: Hodges Andrew
Published: April 2012

Whether all types of computation—including that of our own minds—can be modeled as computer programs remains an open question.
Monkey See, Monkey Read
Authors: Platt Michael L. , Adams Geoffrey K.
Published: April 2012

Baboons can distinguish between written words and nonwords.
Icy-Hot Mercury's Water Pinned Down in the Dark
Authors: Kerr Richard A.
Published: April 2012

At the meeting, researchers heard that signs from the MESSENGER spacecraft orbiting Mercury strongly support the claim that the planet's polar regions harbor eons-old stores of water ice.
Efficacy of Dart or Booster Vaccination with Strain RB51 in Protecting Bison against Experimental Brucella abortus Challenge
Authors: Olsen S. C. , Johnson C. S.
Published: April 2012

This study characterized the efficacy of theBrucella abortusstrain RB51 vaccine in bison when delivered by single intramuscular vaccination (hand RB51), by single pneumatic dart delivery (dart RB51), or as two vaccinations approximately 13 months apart (booster RB51) in comparison to control bison. All bison were challenged intraconjunctivally in midgestation with 107CFU ofB. abortusstrain 2308 (S2308). Bison were necropsied and sampled within 72 h of abortion or delivery of a live calf. Compared to nonvaccinated bison, bison in the booster RB51 treatment had a reduced (P< 0.05) incidence of abortion, uterine infection, or infection in maternal tissues other than the mammary gland at necropsy. Bison in single-vaccination treatment groups (hand RB51 and dart RB51) did not differ (P> 0.05) from the control group in the incidence of abortion or recovery of S2308 from uterine, mammary, fetal, or maternal tissues at necropsy. Compared to nonvaccinated animals, all RB51 vaccination groups had reduced (P< 0.05) mean colonization or incidence of infection in at least 2 of 4 target tissues, with the booster RB51 group having reduced (P< 0.05) colonization and incidence of infection in all target tissues. Our data suggest that booster vaccination of bison with RB51 enhances protective immunity againstBrucellachallenge compared to single vaccination with RB51 by hand or by pneumatic dart. Our study also suggests that an initial vaccination of calves followed by booster vaccination as yearlings should be an effective strategy for brucellosis control in bison.
Drug and Multidrug Resistance among Mycobacterium leprae Isolates from Brazilian Relapsed Leprosy Patients
Authors: Rocha Adalgiza da Silva , Cunha Maria das Graças , Diniz Lucia Martins , Salgado Claudio , Aires Maria Araci P. , Nery José Augusto , Gallo Eugênia Novisck , Miranda Alice , Magnanini Monica M. F. , Matsuoka Masanori , Sarno Euzenir Nunes , Suffys Philip Noel , de Oliveira Maria Leide W.
Published: April 2012

Skin biopsy samples from 145 relapse leprosy cases and from five different regions in Brazil were submitted for sequence analysis of part of the genes associated withMycobacterium lepraedrug resistance. Single nucleotide polymorphisms (SNPs) in these genes were observed inM. lepraefrom 4 out of 92 cases with positive amplification (4.3%) and included a case with a mutation inrpoBonly, another sample with SNPs in bothfolP1andrpoB, and two cases showing mutations infolP1,rpoB, andgyrA, suggesting the existence of multidrug resistance (MDR). The nature of the mutations was as reported in earlier studies, being CCC to CGC in codon 55 infolP(Pro to Arg), while in the case ofrpoB, all mutations occurred at codon 531, with two being a transition of TCG to ATG (Ser to Met), one TCG to TTC (Ser to Phe), and one TCG to TTG (Ser to Leu). The two cases with mutations ingyrAchanged from GCA to GTA (Ala to Val) in codon 91. The median time from cure to relapse diagnosis was 9.45 years but was significantly shorter in patients with mutations (3.26 years;P= 0.0038). More than 70% of the relapses were multibacillary, including three of the mutation-carrying cases; one MDR relapse patient was paucibacillary.
Routine Identification of Medical Fungi by the New Vitek MS Matrix-Assisted Laser Desorption Ionization–Time of Flight System with a New Time-Effective Strategy
Authors: Iriart Xavier , Lavergne Rose-Anne , Fillaux Judith , Valentin Alexis , Magnaval Jean-François , Berry Antoine , Cassaing Sophie
Published: April 2012

We report here a clinical evaluation of the Vitek MS system for rapid fungal identification. A strategy that uses a single deposit without prior protein extraction was utilized to save time and money. Clinical isolates from the Toulouse University hospital were used to evaluate the performance of the Vitek MS compared to that of both routine laboratory techniques and Vitek2. The Vitek MS performed well in the identification of yeasts and
Aspergillus
fungi (93.2% of correct identifications).
Cysteines in the Stalk of the Nipah Virus G Glycoprotein Are Located in a Distinct Subdomain Critical for Fusion Activation
Authors: Maar Dianna , Harmon Brooke , Chu David , Schulz Belinda , Aguilar Hector C. , Lee Benhur , Negrete Oscar A.
Published: April 2012

Paramyxoviruses initiate entry through the concerted action of the tetrameric attachment glycoprotein (HN, H, or G) and the trimeric fusion glycoprotein (F). The ectodomains of HN/H/G contain a stalk region important for oligomeric stability and for the F triggering resulting in membrane fusion. Paramyxovirus HN, H, and G form a dimer-of-dimers consisting of disulfide-linked dimers through their stalk domain cysteines. The G attachment protein stalk domain of the highly pathogenic Nipah virus (NiV) contains a distinct but uncharacterized cluster of three cysteine residues (C146, C158, C162). On the basis of a panoply of assays, we report that C158 and C162 of NiV-G likely mediate covalent subunit dimerization, while C146 mediates the stability of higher-order oligomers. For HN or H, mutation of stalk cysteines attenuates but does not abrogate the ability to trigger fusion. In contrast, the NiV-G stalk cysteine mutants were completely deficient in triggering fusion, even though they could still bind the ephrinB2 receptor and associate with F. Interestingly, all cysteine stalk mutants exhibited constitutive exposure of the Mab45 receptor binding-enhanced epitope, previously implicated in F triggering. The enhanced binding of Mab45 to the cysteine mutants relative to wild-type NiV-G, without the addition of the receptor, implicates the stalk cysteines in the stabilization of a pre-receptor-bound conformation and the regulation of F triggering. Sequence alignments revealed that the stalk cysteines were adjacent to a proline-rich microdomain unique to the
Henipavirus
genus. Our data propose that the cysteine cluster in the NiV-G stalk functions to maintain oligomeric stability but is more importantly involved in stabilizing a unique microdomain critical for triggering fusion.
Human Galectin 3 Binding Protein Interacts with Recombinant Adeno-Associated Virus Type 6
Authors: Denard Jerome , Beley Cyriaque , Kotin Robert , Lai-Kuen René , Blot Stéphane , Leh Hervé , Asokan Aravind , Samulski R. Jude , Moullier Philippe , Voit Thomas , Garcia Luis , Svinartchouk Fedor
Published: April 2012

Recombinant adeno-associated viruses (rAAVs) hold enormous potential for human gene therapy. Despite the well-established safety and efficacy of rAAVs for
in vivo
gene transfer, there is still little information concerning the fate of vectors in blood following systemic delivery. We screened for serum proteins interacting with different AAV serotypes in humans, macaques, dogs, and mice. We report that serotypes rAAV-1, -5, and -6 but not serotypes rAAV-2, -7, -8, -9, and -10 interact in human sera with galectin 3 binding protein (hu-G3BP), a soluble scavenger receptor. Among the three serotypes, rAAV-6 has the most important capacities for binding to G3BP. rAAV-6 also bound G3BP in dog sera but not in macaque and mouse sera. In mice, rAAV-6 interacted with another protein of the innate immune system, C-reactive protein (CRP). Furthermore, interaction of hu-G3BP with rAAV-6 led to the formation of aggregates and hampered transduction when the two were codelivered into the mouse. Based on these data, we propose that species-specific interactions of AAVs with blood proteins may differentially impact vector distribution and efficacy in different animal models.
Classical Swine Fever Virus p7 Protein Is a Viroporin Involved in Virulence in Swine
Authors: Gladue Douglas P. , Holinka Lauren G. , Largo Eneko , Fernandez Sainz Ignacio , Carrillo Consuelo , O'Donnell Vivian , Baker-Branstetter Ryan , Lu Zhiqiang , Ambroggio Xavier , Risatti Guillermo R. , Nieva Jose L. , Borca Manuel V.
Published: April 2012

The nonstructural protein p7 of classical swine fever virus (CSFV) is a small hydrophobic polypeptide with an apparent molecular mass of 6 to 7 kDa. The protein contains two hydrophobic stretches of amino acids interrupted by a short charged segment that are predicted to form transmembrane helices and a cytosolic loop, respectively. Using reverse genetics, partial in-frame deletions of p7 were deleterious for virus growth, demonstrating that CSFV p7 function is critical for virus production in cell cultures. A panel of recombinant mutant CSFVs was created using alanine scanning mutagenesis of the p7 gene harboring sequential three- to six-amino-acid residue substitutions spanning the entire protein. These recombinant viruses allowed the identification of the regions within p7 that are critical for virus production
in vitro. In vivo
, some of these viruses were partially or completely attenuated in swine relative to the highly virulent parental CSFV Brescia strain, indicating a significant role of p7 in CSFV virulence. Structure-function analyses in model membranes emulating the endoplasmic reticulum lipid composition confirmed that CSFV p7 is a pore-forming protein, and that pore-forming activity resides in the C-terminal transmembrane helix. Therefore, p7 is a viroporin which is clearly involved in the process of CSFV virulence in swine.
Cdk1 Inhibition Induces Mutually Inhibitory Apoptosis and Reactivation of Kaposi's Sarcoma-Associated Herpesvirus
Authors: Li Xudong , Chen Shijia , Sun Ren
Published: April 2012

Primary effusion lymphoma (PEL) cells are predominantly infected by the latent form of Kaposi's sarcoma-associated herpesvirus (KSHV), with virus reactivation occurring in a small percentage of cells. Latency enables KSHV to persist in the host cell and promotes tumorigenesis through viral gene expression, thus presenting a major barrier to the elimination of KSHV and the treatment of PEL. Therefore, it is important to identify cellular genes that are essential for PEL cell survival or the maintenance of KSHV latency. Here we report that cyclin-dependent kinase 1 (Cdk1) inhibition can induce both apoptosis and KSHV reactivation in a population of PEL cells. Caspases, but not p53, are required for PEL cell apoptosis induced by Cdk1 inhibition. p38 kinase is activated by Cdk1 inhibition and mediates KSHV reactivation. Interestingly, upon Cdk1 inhibition, KSHV is reactivated predominantly in the nonapoptotic subpopulation of PEL cells. We provide evidence that this is due to mutual inhibition between apoptosis and KSHV reactivation. In addition, we found that KSHV reactivation activates protein kinase B (AKT/PKB), which promotes cell survival and facilitates KSHV reactivation. Our study thus establishes a key role for Cdk1 in PEL cell survival and the maintenance of KSHV latency and reveals a multifaceted relationship between KSHV reactivation and PEL cell apoptosis.
Integrin β1 Mediates Vaccinia Virus Entry through Activation of PI3K/Akt Signaling
Authors: Izmailyan Roza , Hsao Jye-Chian , Chung Che-Sheng , Chen Chein-Hung , Hsu Paul Wei-Che , Liao Chung-Lin , Chang Wen
Published: April 2012

Vaccinia virus has a broad range of infectivity in many cell lines and animals. Although it is known that the vaccinia mature virus binds to cell surface glycosaminoglycans and extracellular matrix proteins, whether additional cellular receptors are required for virus entry remains unclear. Our previous studies showed that the vaccinia mature virus enters through lipid rafts, suggesting the involvement of raft-associated cellular proteins. Here we demonstrate that one lipid raft-associated protein, integrin β1, is important for vaccinia mature virus entry into HeLa cells. Vaccinia virus associates with integrin β1 in lipid rafts on the cell surface, and the knockdown of integrin β1 in HeLa cells reduces vaccinia mature virus entry. Additionally, vaccinia mature virus infection is reduced in a mouse cell line, GD25, that is deficient in integrin β1 expression. Vaccinia mature virus infection triggers the activation of phosphatidylinositol 3-kinase (PI3K)/Akt signaling, and the treatment of cells with inhibitors to block P13K activation reduces virus entry in an integrin β1-dependent manner, suggesting that integrin β1-mediates PI3K/Akt activation induced by vaccinia virus and that this signaling pathway is essential for virus endocytosis. The inhibition of integrin β1-mediated cell adhesion results in a reduction of vaccinia virus entry and the disruption of focal adhesion and PI3K/Akt activation. In summary, our results show that the binding of vaccinia mature virus to cells mimics the outside-in activation process of integrin functions to facilitate vaccinia virus entry into HeLa cells.
Comparing two safety culture surveys: Safety Attitudes Questionnaire and Hospital Survey on Patient Safety
Authors: Etchegaray Jason M , Thomas Eric J
Published: April 2012

Objective

To examine the reliability and predictive validity of two patient safety culture surveys—Safety Attitudes Questionnaire (SAQ) and Hospital Survey on Patient Safety Culture (HSOPS)—when administered to the same participants. Also to determine the ability to convert HSOPS scores to SAQ scores.

Method

Employees working in intensive care units in 12 hospitals within a large hospital system in the southern United States were invited to anonymously complete both safety culture surveys electronically.

Results

All safety culture dimensions from both surveys (with the exception of HSOPS's Staffing) had adequate levels of reliability. Three of HSOPS's outcomes—frequency of event reporting, overall perceptions of patient safety, and overall patient safety grade—were significantly correlated with SAQ and HSOPS dimensions of culture at the individual level, with correlations ranging from r=0.41 to 0.65 for the SAQ dimensions and from r=0.22 to 0.72 for the HSOPS dimensions. Neither the SAQ dimensions nor the HSOPS dimensions predicted the fourth HSOPS outcome—number of events reported within the last 12 months. Regression analyses indicated that HSOPS safety culture dimensions were the best predictors of frequency of event reporting and overall perceptions of patient safety while SAQ and HSOPS dimensions both predicted patient safety grade. Unit-level analyses were not conducted because indices did not indicate that aggregation was appropriate. Scores were converted between the surveys, although much variance remained unexplained.

Conclusions

Given that the SAQ and HSOPS had similar reliability and predictive validity, investigators and quality and safety leaders should consider survey length, content, sensitivity to change and the ability to benchmark when selecting a patient safety culture survey.
Maternal mental health and social support: effect on childhood atopic and non-atopic asthma symptoms
Authors: Marques dos Santos Letícia , Neves dos Santos Darci , Rodrigues Laura Cunha , Barreto Maurício Lima
Published: April 2012

Background

Atopic and non-atopic asthma have distinct risk factors and immunological mechanisms, and few studies differentiate between the impacts of psychosocial factors on the prevalence of these disease phenotypes. The authors aimed to identify whether the effect of maternal mental health on prevalence of asthma symptoms differs between atopic and non-atopic children, taking into account family social support.

Methods

This is a cross-sectional study of 1013 children participating in the Social Change Allergy and Asthma in Latin America project. Psychosocial data were collected through a household survey utilising Self-Reporting Questionnaire and Medical Outcome Study Social Support Scale. Socioeconomic and wheezing information was obtained through the questionnaire of the International Study of Allergy and Asthma in Childhood, and level of allergen-specific IgE was measured to identify atopy. Polytomous logistic regression was used to estimate the association between maternal mental health, social support and atopic and non-atopic wheezing. Effect modification was evaluated through stratified polytomous regression according to social support level.

Results

Maternal mental disorder had the same impact on atopic and non-atopic wheezing, even after adjusting for confounding variables. Affective, material and informational supports had protective effects on non-atopic asthma, and there is some evidence that social supports may act as a buffer for the impact of maternal mental disorder on non-atopic wheezing.

Conclusion

Poor maternal mental health is positively associated with wheezing, independent of whether asthma is atopic or non-atopic, but perception of high levels of social support appears to buffer this relationship in non-atopic wheezers only.
Trends in condom use among female sex workers in Andhra Pradesh, India: the impact of a community mobilisation intervention
Authors: Erausquin Jennifer Toller , Biradavolu Monica , Reed Elizabeth , Burroway Rebekah , Blankenship Kim M
Published: April 2012

Background

Community mobilisation interventions for HIV prevention among female sex workers (FSWs) aim to organise FSWs for collective action and challenge the structures of power that underlie HIV risk. Assessing intervention impact is challenging because the importance of direct individual exposure to intervention components may decrease over time as change occurs at social-normative, policy and other structural levels. In this paper, the authors examine changes over time in consistent condom use among FSWs in Rajahmundry, Andhra Pradesh, the location of a long-standing community mobilisation intervention.

Methods

The authors analyse cross-sectional data collected among FSWs at three time points (n=2276) using respondent-driven sampling. Multiple logistic regression was used to assess the association of programme exposure with consistent condom use and whether this association varied over time.

Results

The proportion of FSWs having no exposure or only receptive exposure to the intervention decreased over time, while active utilisation increased from 19.4% in 2006 to 48.5% in 2009–2010. Consistent condom use with clients also increased from 56.3% in 2006 to 75.3% in 2009–2010. Multivariate analysis showed that age, age at start of sex work, venue, living conditions and programme exposure were significantly associated with condom use. The positive association between programme exposure and consistent condom use did not vary significantly over time.

Conclusions

Findings indicate improvements in HIV risk reduction behaviour among FSWs and suggest that the intervention has substantial reach in the FSW population. The intervention's strategies may be contributing to population-level HIV risk reduction among FSWs.
Minding the gap: changes in life expectancy in the Baltic States compared with Finland
Authors: Karanikolos Marina , Leon David A , Smith Peter C , McKee Martin
Published: April 2012

Background

In the 20 years since the three Baltic States, Estonia, Latvia and Lithuania, have been independent, they have converged progressively with a Western neighbours, politically economically and socially. In contrast, the health gap has widened.

Methods

Trends in life expectancy in the three Baltic States were compared with Finland and were decomposed by age for the years 1994, 1999, 2004 and 2009 and by cause of death for year 2009. 1994 was when life expectancy fell to its lowest level since the three countries regained independence.

Results

From the mid-1980s to the mid-1990s, the gap in life expectancy between the three Baltic States and Finland widened, especially for men. It then narrowed progressively, except Lithuania where it widened again after 1999. Decomposition by age reveals that the narrowing gap has been driven largely by reduced mortality at working ages, partly counteracted by a relative failure to improve at older ages, especially in Lithuania. Decomposition by cause of death identifies diseases of the circulatory system as the largest contributor to the gap, with the contribution largest at older ages. However, cancer deaths, especially among men, are also important as are deaths from external causes among younger men.

Conclusions

Although the gaps in life expectancy between the Baltic States and Finland have reduced, improvements, especially in Latvia and Lithuania, have been fragile. There is a clear need to act on the leading causes of the persisting gap with Finland, in particular through action on hazardous drinking and other risk factors for cardiovascular disease.
The manipulation of optical rogue waves for the nonautonomous nonlinear Schrödinger equation
Authors: Dai Chao-Qing , Zhu Hai-Ping
Published: April 2012

We obtain analytical solutions that describe self-similar rogue waves for the (1+1)-dimensional nonautonomous nonlinear Schrödinger equation with a linear potential. The explicit functions that describe the evolution of the width, peak, and phase are found exactly, from which it can be seen that the gain–loss parameter has no effect on the motion of rogue waves’ phases or their widths, and affects only the evolution of their peaks. We also find that the manipulation of rogue waves can be realized by modulating the values of the maximum accumulated time, Tm, and the accumulated time, T0, with the maximum amplitude of the rogue waves. The controllability for the type of excitation, such as sustainment, recurrence, and annihilation for rogue waves and the transverse position of excitation is exhibited.
Chaotic systems via multi-step differential transformation method
Authors: Yildirim Ahmet , Gökdoğan Ahmet , Merdan Mehmet
Published: April 2012

In this article, the multi-step differential transform method is implemented to give approximate and analytical solutions of nonlinear fractional order ordinary differential equation systems, such as Chen, Lorenz, Arneodo–Coullet, Genesio, Lui, and Rikitake chaotic systems. The numerical solutions obtained from the proposed method indicate that the approach is easy, simple, and accurate when applied to systems of fractional differential equations. Numerical simulations are given to verify the reliability and effectiveness of this method.
LYAPUNOV EXPONENTS AND MODULATED PHASES OF AN ISING MODEL ON CAYLEY TREE OF ARBITRARY ORDER
Authors: UGUZ SELMAN , GANIKHODJAEV NASIR , AKIN HASAN , TEMIR SEYIT
Published: April 2012

Different types of the lattice spin systems with the competing interactions have rich and interesting phase diagrams. In this study a system with competing nearest-neighbor interaction J1, prolonged next-nearest-neighbor interaction Jp and ternary prolonged interaction Jtp is considered on a Cayley tree of arbitrary order k. To perform this study, an iterative scheme is developed for the corresponding Hamiltonian model. At finite temperatures several interesting properties are presented for typical values of α = T/J1, β = −Jp/J1 and γ = -Jtp/J1. This study recovers as particular cases, previous work by Vannimenus1 with γ = 0 for k = 2 and Ganikhodjaev et al.2 in the presence J1, Jp, Jtp with k = 2. The variation of the wavevector q with temperature in the modulated phase and the Lyapunov exponent associated with the trajectory of our iterative system are studied in detail.
ENHANCED DUALITY SYMMETRIES FOR A PAIR OF DIRAC–BORN–INFELD ACTIONS
Authors: NISHINO HITOSHI , RAJPOOT SUBHASH
Published: April 2012

We consider a total action composed of two Dirac–Born–Infeld (DBI) actions: one for a vector field Aμ and another for an axial vector field Bμ. We impose a duality condition [Formula: see text], where [Formula: see text] is the Hodge dual of Gμν, and g is a DBI interaction constant. Interestingly, there are two different global duality rotation symmetries in the presence of DBI interactions: (i) [Formula: see text], [Formula: see text], and (ii) δζAμ = - ζBμ, δζBμ = + ζAμ. Both of these symmetry are on-shell symmetries, including nonlinear higher-order terms. The remarkable aspect is that these symmetries are valid even in the presence of DBI interactions. The coupling of this system to N = 1 supergravity is also discussed.
STATEMENT OF RETRACTION: "MEASUREMENT OF THE CASIMIR INTERACTION BETWEEN A Au SPHERE AND Au GRATINGS"
Authors: DECCA RICARDO S.
Published: April 2012

This article was published as a part of the conference proceedings for the Eighth Alexander Friedmann International Seminar on Gravitation and Cosmology and Satellite Symposium on the Casimir Effect, held in Rio de Janeiro, Brazil, 30 May–3 June 2011. In the article I described results of the force obtained in the Casimir regime between a Au coated sphere and a Au grating. The making of the grating required extensive development from my collaborators. The article was published without the proper authorship from the research groups involved. Against this background I thus retract my article and apologize for the damage I have caused.
INVESTIGATION OF SOL-GEL GROWN ZnO THIN FILM: WAVELET ANALYSIS AND SIMULATED ANNEALING OPTIMIZED X-RAY REFLECTIVITY
Authors: SOLOOKINEJAD GH. , ROZATIAN A. S. H. , HABIBI M. H.
Published: April 2012

In this study ZnO thin film was fabricated by sol-gel spin coating method on glass substrate. X-ray reflectivity (XRR) and its optimization by simulated annealing (SA) technique have been used for characterization and extracting physical parameters of the film. The model independent information was needed to establish data analyzing process for XRR before optimization process. This independent information was extracted from wavelet transform of Fresnel reflectivity normalized XRR. This transformation yields thickness of each coated layer. This information was a keynote for constructing optimization process. Specular XRR optimization yielded structural parameters such as thickness, roughness of surface and interface and electron density profile of the film. Acceptable agreement exists between results obtained from wavelet transformation and XRR fitting.
THE EFFECT OF ELECTRIC FIELD ON A QUANTUM ROD QUBIT
Authors: XIAO JING-LIN
Published: April 2012

The Hamiltonian of a quantum rod with an ellipsoidal boundary is given after a coordinate transformation, which changes the ellipsoidal boundary into a spherical one. We study the electron which is strongly coupled to the LO-phonon eigenenergies and eigenfunctions of the ground and the first-excited states in a quantum rod under an applied electric field by using variational method of Pekar type. This quantum rod system may be used as a two-level qubit. When the electron is in the superposition state of the ground and the first-excited states, we obtain the time evolution of the electron probability density. The probability density of the electron oscillates in the quantum rod with an oscillation period. It is found that due to the presence of the three-dimensional anisotropic harmonic potential in the radius and the length directions of the quantum rod, the electron probability density shows double-peak configuration, whereas there is only peak if the confinement is a two-dimensional symmetric one in the x- and y-directions. The oscillation period is an increasing function of the ellipsoid aspect ratio and the transverse and longitudinal effective confinement lengths of the quantum rod, whereas it is decreasing one of the electron–phonon coupling strength and the electric field.
IMPROVED EFFICIENCY IN CRYO-EM SECONDARY STRUCTURE TOPOLOGY DETERMINATION FROM INACCURATE DATA
Authors: BISWAS ABHISHEK , SI DONG , AL NASR KAMAL , RANJAN DESH , ZUBAIR MOHAMMAD , HE JING
Published: April 2012

The determination of the secondary structure topology is a critical step in deriving the atomic structure from the protein density map obtained from electron cryo-microscopy technique. This step often relies on the matching of two sources of information. One source comes from the secondary structures detected from the protein density map at the medium resolution, such as 5–10 Å. The other source comes from the predicted secondary structures from the amino acid sequence. Due to the inaccuracy in either source of information, a pool of possible secondary structure positions needs to be sampled. This paper studies the question, that is, how to reduce the computation of the mapping when the inaccuracy of the secondary structure predictions is considered. We present a method that combines the concept of dynamic graph with our previous work of using constrained shortest path to identify the topology of the secondary structures. We show a reduction of 34.55% of run-time as comparison to the naïve way of handling the inaccuracies. We also show an improved accuracy when the potential secondary structure errors are explicitly sampled verses the use of one consensus prediction. Our framework demonstrated the potential of developing computationally effective exact algorithms to identify the optimal topology of the secondary structures when the inaccuracy of the predicted data is considered.