bluuebunny/crossref_metadata_2025 huggingface dataset:
Observational infant exploratory [14C]‐paracetamol pharmacokinetic microdose/therapeutic dose study with accelerator mass spectrometry bioanalysis
Authors: Garner Colin R. , Park Kevin B. , French Neil S. , Earnshaw Caroline , Schipani Alessandro , Selby Andrew M. , Byrne Lindsay , Siner Sarah , Crawley Francis P. , Vaes Wouter H. J. , van Duijn Esther , deLigt Rianne , Varendi Heili , Lass Jane , Grynkiewicz Grzegorz , Maruszak Wioletta , Turner Mark A.
Published: January 2015

Aims

The aims of the study were to compare [14C]‐paracetamol ([14C]‐PARA) paediatric pharmacokinetics (PK) after administration mixed in a therapeutic dose or an isolated microdose and to develop further and validate accelerator mass spectrometry (AMS) bioanalysis in the 0–2 year old age group.

Methods

[14C]‐PARA concentrations in 10–15 µl plasma samples were measured after enteral or i.v. administration of a single [14C]‐PARA microdose or mixed in with therapeutic dose in infants receiving PARA as part of their therapeutic regimen.

Results

Thirty‐four infants were included in the PARA PK analysis for this study: oral microdose (n = 4), i.v. microdose (n = 6), oral therapeutic (n = 6) and i.v. therapeutic (n = 18). The respective mean clearance (CL) values (SDs in parentheses) for these dosed groups were 1.46 (1.00) l h–1, 1.76 (1.07) l h–1, 2.93 (2.08) l h–1 and 2.72 (3.10) l h–1, t1/2 values 2.65 h, 2.55 h, 8.36 h and 7.16 h and dose normalized AUC(0‐t) (mg l–1 h) values were 0.90 (0.43), 0.84 (0.57), 0.7 (0.79) and 0.54 (0.26).

Conclusions

All necessary ethical, scientific, clinical and regulatory procedures were put in place to conduct PK studies using enteral and systemic microdosing in two European centres. The pharmacokinetics of a therapeutic dose (mg kg–1) and a microdose (ng kg–1) in babies between 35 to 127 weeks post‐menstrual age. [14C]‐PARA pharmacokinetic parameters were within a two‐fold range after a therapeutic dose or a microdose. Exploratory studies using doses significantly less than therapeutic doses may offer ethical and safety advantages with increased bionalytical sensitivity in selected exploratory paediatric pharmacokinetic studies.
Adenomas with high‐grade dysplasia and early adenocarcinoma are more likely to be sessile in the proximal colon
Authors: Sawhney M. S. , Dickstein J. , LeClair J. , Lembo C. , Yee E.
Published: January 2015

Aim

Size and the sessile morphology of an adenoma may explain why colonoscopy is less effective in preventing proximal colonic cancer than distal cancers. We wanted to determine if advanced polypoid neoplasms (APNs, i.e. adenoma with high‐grade dysplasia or early adenocarcinoma) are more likely to be sessile and/or smaller in the proximal colon.

Method

We searched our institution's pathology database from 2004 to 2012 and identified patients with APNs. Polyps were categorized by size, morphology and location in the colon. Average polyp size and morphology were determined for each location.

Results

During the study period, 564 patients with APNs were identified. Of these, adenocarcinoma was noted in 21.6% and high‐grade dysplasia in 78.4%. The average patient age was 64.4 years and 54.9% were men. The proportion of APNs that were ≤ 5 mm was 1.7%, ≤ 10 mm 19.3% and ≤ 15 mm 39%. APNs in the proximal colon were larger than those in the distal colon, but the difference was not statistically significant (27 vs 24 mm; P = 0.06). Eighty‐three per cent of APNs in the proximal colon were sessile vs 57% in the distal colon (P = 0.001). APNs in the proximal colon were almost four times more likely to be sessile than in the distal colon (OR = 3.7). A similar association was noted for polyps ≤ 20 mm or polyps with high‐grade dysplasia.

Conclusion

APNs in the proximal colon were almost four‐times more likely to be sessile than those in the distal colon. No difference in the size of polyps was noted.
Exploration of the dynamics between brain regions associated with the default‐mode network and frontostriatal pathway with regards to task familiarity
Authors: Provost Jean‐Sebastien , Monchi Oury
Published: January 2015

Specific brain regions have consistently been reported to be activated during resting state period, and they were described as being part of a particular network called the default‐mode network (DMN). It has been shown that the DMN would deactivate during goal‐directed tasks, but the actual relationship between them is still a matter of debate. In a previous study, we reported a specific pattern of activation of the frontostriatal regions during a set‐shifting task in which these regions were increasing their activity as set‐shifts were performed continuously and decreasing when the same rule was executed repeatedly. The present study aimed at assessing the relationship between the frontostriatal regions and the DMN. We hypothesized that the DMN would be anticorrelated with the frontostriatal regions so the DMN would be more deactivated as set‐shifts are executed for a long period, but would start increasing when the same rule is being executed for a long period. Here, 15 participants underwent functional magnetic resonance imaging while performing a card‐sorting task. We observed increased activity in the frontostriatal regions as more set‐shifts are being performed while the DMN gets more deactivated. Interestingly, as decreased activity was observed in the frontostriatal regions during the execution of the same rule for a long period, the DMN showed increasing activity. We argue that there is an anticorrelation between the frontostriatal regions and the DMN, but also that the DMN could show positive activation during performance of a familiar goal‐directed task.
Activation of the mouse odorant receptor 37 subsystem coincides with a reduction of novel environment‐induced activity within the paraventricular nucleus of the hypothalamus
Authors: Klein Bettina , Bautze Verena , Maier Anna‐Maria , Deussing Jan , Breer Heinz , Strotmann Jörg
Published: January 2015

Within the main olfactory system of mammals, a unique subsystem exists that is comprised of sensory neurons expressing odorant receptors (ORs) of the OR37 subfamily. These receptors are exclusive for mammals and are highly conserved across species. The mouse OR37 receptor subtypes A, B and C were shown to be activated by the long‐chain aliphatic aldehydes pentadecanal, hexadecanal and heptadecanal, respectively. The search for biological sources of these compounds showed that bodily secretions from conspecifics activated the OR37A, B and C glomerulus. At the same time, the activity of cells in a target region of projection neurons from OR37 glomeruli, the paraventricular nucleus of the hypothalamus (PVN), was reduced compared with controls (clean test box). A large number of the activated cells in the PVN of mice that were placed into a clean test box were corticotropin‐releasing hormone cells, indicating an induction of the stress axis due to the novel environment. The much lower number of activated cells of mice in a box enriched with bodily secretions from conspecifics indicated a reduced stress response. As bodily secretions from conspecifics activated the OR37 system and simultaneously reduced stress‐induced activation of the PVN, it was tested whether the ligands for OR37 receptors could induce this effect. Indeed, a similarly reduced activity in the PVN was found in mice kept in a clean test box and exposed to a mixture of the OR37 ligands delivered via an air stream. These data indicate that the OR37 system may play a role in mediating a phenomenon called social buffering.
Overexpression of microRNA‐30a inhibits hepatitis B virus X protein‐induced autophagosome formation in hepatic cells
Authors: Kumar Satendra , Gupta Parul , Khanal Sweta , Shahi Aashirwad , Kumar Pushpendra , Sarin Shiv K. , Venugopal Senthil K.
Published: January 2015

Hepatitis B virus (HBV) enters the host and survives by using several mechanisms. One of the ways that HBV survives and replicates in the host cells is by inducing autophagy. Previous reports have shown that microRNA (miRNA)‐30a inhibits autophagosome formation in cancer cells. Hence, we hypothesized that overexpression of miRNA‐30a could inhibit HBV‐induced autophagosome formation in hepatic cells. To study this, both HepG2 cells and HepG2.2.1.5 cells (HBV‐expressing stable cell line) were transfected with miRNA‐30a, and the cells were collected either for RNA isolation or protein isolation after 72 h of transfection. Beclin‐1 expression was significantly higher in untransfected HepG2.2.1.5 cells than in HepG2 cells. Western blots showed that miRNA‐30a overexpression resulted in a significant decrease in beclin‐1 expression (eight‐fold and four‐fold in HepG2 and HepG2.2.1.5 cells, respectively) and c‐myc expression, whereas the numbers of terminal deoxynucleotidyl transferase‐mediated dUTP nick end labeling (TUNEL)‐positive cells were increased. In contrast, overexpression of HBV X protein (HBx) in HepG2 cells resulted in the enhancement of beclin‐1 (six‐fold increase as compared with the empty vector‐transfected cells) and c‐myc expression, whereas the numbers of TUNEL‐positive cells were reduced. To confirm these findings, HBx and miRNA‐30a were coexpressed in HepG2 cells, and the results showed significant inhibition of autophagosome formation and beclin‐1 and c‐myc expression, whereas apoptosis increased. These data demonstrate that HBx induces autophagosome formation via beclin‐1 expression, whereas miRNA‐30a overexpression could successfully inhibit the beclin‐1 expression induced by HBx, thereby modulating autophagosome formation in hepatic cells.
Structural insights into the broad substrate specificity of carboxypeptidase T from Thermoactinomyces vulgaris
Authors: Akparov Valery Kh. , Timofeev Vladimir I. , Khaliullin Ilyas G. , Švedas Vytas , Chestukhina Galina G. , Kuranova Inna P.
Published: January 2015

The crystal structures of carboxypeptidase T (CpT) complexes with phenylalanine and arginine substrate analogs – benzylsuccinic acid and (2‐guanidinoethylmercapto)succinic acid – were determined by the molecular replacement method at resolutions of 1.57 Å and 1.62 Å to clarify the broad substrate specificity profile of the enzyme. The conservative Leu211 and Leu254 residues (also present in both carboxypeptidase A and carboxypeptidase B) were shown to be structural determinants for recognition of hydrophobic substrates, whereas Asp263 was for recognition of positively charged substrates. Mutations of these determinants modify the substrate profile: the CpT variant Leu211Gln acquires carboxypeptidase B‐like properties, and the CpT variant Asp263Asn the carboxypeptidase A‐like selectivity. The Pro248‐Asp258 loop interacting with Leu254 and Tyr255 was shown to be responsible for recognition of the substrate's C‐terminal residue. Substrate binding at the S1′ subsite leads to the ligand‐dependent shift of this loop, and Leu254 side chain movement induces the conformation rearrangement of the Glu277 residue crucial for catalysis. This is a novel insight into the substrate selectivity of metallocarboxypeptidases that demonstrates the importance of interactions between the S1′ subsite and the catalytic center.
How pyridoxal 5′‐phosphate differentially regulates human cytosolic and mitochondrial serine hydroxymethyltransferase oligomeric state
Authors: Giardina Giorgio , Brunotti Paolo , Fiascarelli Alessio , Cicalini Alessandra , Costa Mauricio G. S. , Buckle Ashley M. , di Salvo Martino L. , Giorgi Alessandra , Marani Marina , Paone Alessio , Rinaldo Serena , Paiardini Alessandro , Contestabile Roberto , Cutruzzolà Francesca
Published: January 2015

Adaptive metabolic reprogramming gives cancer cells a proliferative advantage. Tumour cells extensively use glycolysis to sustain anabolism and produce serine, which not only refuels the one‐carbon units necessary for the synthesis of nucleotide precursors and for DNA methylation, but also affects the cellular redox homeostasis. Given its central role in serine metabolism, serine hydroxymethyltransferase (SHMT), a pyridoxal 5′‐phosphate (PLP)‐dependent enzyme, is an attractive target for tumour chemotherapy. In humans, the cytosolic isoform (SHMT1) and the mitochondrial isoform (SHMT2) have distinct cellular roles, but high sequence identity and comparable catalytic properties, which may complicate development of successful therapeutic strategies. Here, we investigated how binding of the cofactor PLP controls the oligomeric state of the human isoforms. The fact that eukaryotic SHMTs are tetrameric proteins while bacterial SHMTs function as dimers may suggest that the quaternary assembly in eukaryotes provides an advantage to fine‐tune SHMT function and differentially regulate intertwined metabolic fluxes, and may provide a tool to address the specificity problem. We determined the crystal structure of SHMT2, and compared it to the apo‐enzyme structure, showing that PLP binding triggers a disorder‐to‐order transition accompanied by a large rigid‐body movement of the two cofactor‐binding domains. Moreover, we demonstrated that SHMT1 exists in solution as a tetramer, both in the absence and presence of PLP, while SHMT2 undergoes a dimer‐to‐tetramer transition upon PLP binding. These findings indicate an unexpected structural difference between the two human SHMT isoforms, which opens new perspectives for understanding their differing behaviours, roles or regulation mechanisms in response to PLP availability in vivo.
A landscape ecology approach identifies important drivers of urban biodiversity
Authors: Turrini Tabea , Knop Eva
Published: January 2015

Cities are growing rapidly worldwide, yet a mechanistic understanding of the impact of urbanization on biodiversity is lacking. We assessed the impact of urbanization on arthropod diversity (species richness and evenness) and abundance in a study of six cities and nearby intensively managed agricultural areas. Within the urban ecosystem, we disentangled the relative importance of two key landscape factors affecting biodiversity, namely the amount of vegetated area and patch isolation. To do so, we a priori selected sites that independently varied in the amount of vegetated area in the surrounding landscape at the 500‐m scale and patch isolation at the 100‐m scale, and we hold local patch characteristics constant. As indicator groups, we used bugs, beetles, leafhoppers, and spiders. Compared to intensively managed agricultural ecosystems, urban ecosystems supported a higher abundance of most indicator groups, a higher number of bug species, and a lower evenness of bug and beetle species. Within cities, a high amount of vegetated area increased species richness and abundance of most arthropod groups, whereas evenness showed no clear pattern. Patch isolation played only a limited role in urban ecosystems, which contrasts findings from agro‐ecological studies. Our results show that urban areas can harbor a similar arthropod diversity and abundance compared to intensively managed agricultural ecosystems. Further, negative consequences of urbanization on arthropod diversity can be mitigated by providing sufficient vegetated space in the urban area, while patch connectivity is less important in an urban context. This highlights the need for applying a landscape ecological approach to understand the mechanisms shaping urban biodiversity and underlines the potential of appropriate urban planning for mitigating biodiversity loss.
A pan‐Arctic synthesis of CH4 and CO2 production from anoxic soil incubations
Authors: Treat Claire C. , Natali Susan M. , Ernakovich Jessica , Iversen Colleen M. , Lupascu Massimo , McGuire Anthony David , Norby Richard J. , Roy Chowdhury Taniya , Richter Andreas , Šantrůčková Hana , Schädel Christina , Schuur Edward A. G. , Sloan Victoria L. , Turetsky Merritt R. , Waldrop Mark P.
Published: January 2015

Permafrost thaw can alter the soil environment through changes in soil moisture, frequently resulting in soil saturation, a shift to anaerobic decomposition, and changes in the plant community. These changes, along with thawing of previously frozen organic material, can alter the form and magnitude of greenhouse gas production from permafrost ecosystems. We synthesized existing methane (CH4) and carbon dioxide (CO2) production measurements from anaerobic incubations of boreal and tundra soils from the geographic permafrost region to evaluate large‐scale controls of anaerobic CO2 and CH4 production and compare the relative importance of landscape‐level factors (e.g., vegetation type and landscape position), soil properties (e.g., pH, depth, and soil type), and soil environmental conditions (e.g., temperature and relative water table position). We found fivefold higher maximum CH4 production per gram soil carbon from organic soils than mineral soils. Maximum CH4 production from soils in the active layer (ground that thaws and refreezes annually) was nearly four times that of permafrost per gram soil carbon, and CH4 production per gram soil carbon was two times greater from sites without permafrost than sites with permafrost. Maximum CH4 and median anaerobic CO2 production decreased with depth, while CO2:CH4 production increased with depth. Maximum CH4 production was highest in soils with herbaceous vegetation and soils that were either consistently or periodically inundated. This synthesis identifies the need to consider biome, landscape position, and vascular/moss vegetation types when modeling CH4 production in permafrost ecosystems and suggests the need for longer‐term anaerobic incubations to fully capture CH4 dynamics. Our results demonstrate that as climate warms in arctic and boreal regions, rates of anaerobic CO2 and CH4 production will increase, not only as a result of increased temperature, but also from shifts in vegetation and increased ground saturation that will accompany permafrost thaw.
Aeromonas biofilm on stainless steel: efficiency of commonly used disinfectants
Authors: Craveiro Sara , Alves‐Barroco Cynthia , Barreto Crespo Maria Teresa , Salvador Barreto António , Semedo‐Lemsaddek Teresa
Published: January 2015

Aeromonas spp. are ubiquitous bacteria widely distributed among aquatic environments that have the ability to form biofilms. This aptitude allows them to persist in water distribution systems, contaminating drinking water, food processing surfaces and ultimately food. For this study, the biofilm‐forming ability of aeromonads was evaluated after 48‐h incubation on stainless steel discs at both 4 and 20 °C. Subsequently, disinfectants based on amphoteric surfactants and chlorine compounds were evaluated regarding the capacity to eradicate preformed biofilm and inhibit biofilm formation. Results obtained demonstrated that all strains under analysis were able to form biofilm at both room and refrigeration temperatures. The chlorine‐based disinfectant demonstrated to be efficient in removing preformed biofilm, but both were unsuccessful in preventing biofilm formation, highlighting the importance of adequate cleaning and disinfection procedures, with emphasis on food processing surfaces.
Purification and enzymatic characteristics of a novel polyphenol oxidase from lotus seed (Nelumbo nucifera Gaertn.)
Authors: Cai Xi‐Xi , Hong Yong‐Xiang , Wang Shao‐Yun , Zhao Li‐Na , Rao Ping‐Fan
Published: January 2015

A polyphenol oxidase (PPO) from lotus seed was purified by the procedures including ammonium sulphate precipitation and affinity chromatography. The apparent molecular mass was 38.6 kDa by SDS‐PAGE. Kinetic studies showed that the Km and Vmax values for catechol were 6.04 mm and 416.67 U, respectively. The PPO performed optimal activity in 20 °C and pH 7.0. The enzymatic activity could be mainly maintained up to 50 °C and pH 4.0–7.0. The activity could be inhibited by various inhibitors including thiourea, urea, sodium hydrogen sulphite, EDTA·2Na, SDS, citric acid, guanidine hydrochloride, ascorbic acid, sodium sulphite and sodium thiosulphate. The metal ions Ba2+, Mg2+, Ca2+, Mn2+, Co2+ and Zn2+ could inhibit the activity of PPO, while Cu2+ performed obvious enhancement. The enzymatic properties of PPO could probably provide practical application in inhibiting the PPO activity and preventing enzymatic browning in the process of picking, transportation, processing and storage of fresh lotus seeds.
Evolución de la reglamentación laboral y de las condiciones de trabajo en China. Visión retrospectiva y retos
Authors: CHAN Chris King‐Chi , NADVI Khalid
Published: January 2015

La fuerza económica mundial de China reside en su capacidad manufacturera, gracias a una mano de obra disciplinada y calificada, cuya remuneración es, sin embargo, relativamente baja. Esto explica tanto los crecientes conflictos laborales como las iniciativas normativas estatales en respuesta. En la presente introducción, los coordinadores de este número monográfico contextualizan los demás artículos respecto de los debates generales sobre reglamentación laboral de la producción mundial –concretamente sobre la regulación vinculante y no vinculante–, y de la evolución del mercado de trabajo, la reglamentación laboral, las condiciones de trabajo y las relaciones laborales en China en el último decenio. Concluyen con propuestas para futuras investigaciones.
Escasez de mano de obra y déficit de seguridad social para los migrantes nacionales en China
Authors: WANG Zhikai
Published: January 2015

En 2004 se paralizó la migración interna masiva de trabajadores rurales excedentarios en China, y la región costera oriental experimenta ahora una escasez de trabajadores. Este fenómeno con repercusiones en el desarrollo económico y social del país se debe al déficit de seguridad social para los trabajadores migrantes nacionales. Todavía hay un excedente enorme de trabajadores rurales. Si se mejora el régimen que rige los derechos laborales y sociales de los migrantes, se aliviaría la aparente escasez de mano de obra, se incrementaría la productividad y se impulsaría el crecimiento económico del país a largo plazo.
A Developmental Perspective on Children's Economic Agency
Authors: FRIEDLINE TERRI
Published: January 2015

Understanding children's development is critical in the midst of efforts that teach children about money and open savings accounts for them early in life. These efforts are delivered at a time of extensive developmental change, yet with limited attention to this context. Through a review of research, this study unveils the ages at which children may be able to save and to use savings accounts—specific aspects of economic knowledge and behavior—based on cognitive, social, and linguistic development. Children are developmentally capable of saving by age five or six. Children's developmental gains at this age may prepare them for the gains they make in economic knowledge and behavior. Implications are discussed with regard to policy efforts like Child Development Accounts (CDAs) that open savings accounts for young children and encourage saving behaviors. CDAs should take development into consideration if children are to use their accounts for their benefit.
Relative adrenal insufficiency in severe acute variceal and non‐variceal bleeding: influence on outcomes
Authors: Graupera Isabel , Pavel Oana , Hernandez‐Gea Virginia , Ardevol Alba , Webb Susan , Urgell Eulalia , Colomo Alan , Llaó Jordina , Concepción Mar , Villanueva Càndid
Published: January 2015

Background & Aims

Relative adrenal insufficiency (RAI) is common in critical illness and in cirrhosis, and is related with worse outcomes. The prevalence of RAI may be different in variceal and non‐variceal bleeding and whether it may influence outcomes in these settings is unclear. This study assesses RAI and its prognostic implications in cirrhosis with variceal bleeding and in peptic ulcer bleeding.

Methods

Patients with severe bleeding (systolic pressure <100 mmHg and/or haemoglobin <8 g/L) from oesophageal varices or from a peptic ulcer were included. Adrenal function was evaluated within the first 24 h and RAI was diagnosed as delta cortisol <250 nmol/L after 250 μg of i.v. corticotropin.

Results

Sixty‐two patients were included, 36 had cirrhosis and variceal bleeding and 26 without cirrhosis had ulcer bleeding. Overall, 15 patients (24%) had RAI, 8 (22%) with variceal and 7 (24%) with ulcer bleeding. Patients with RAI had higher rate of bacterial infections. Baseline serum and salivary cortisol were higher in patients with RAI (P < 0.001) while delta cortisol was lower (P < 0.001). There was a good correlation between plasma and salivary cortisol (P < 0.001). The probability of 45‐days survival without further bleeding was lower in cirrhotic patients with variceal bleeding and RAI than in those without RAI (25% vs 68%, P = 0.02), but not in non‐cirrhotic patients with peptic ulcer bleeding with or without RAI (P = 0.75).

Conclusion

The prevalence of RAI is similar in ulcer bleeding and in cirrhosis with variceal bleeding. Cirrhotic patients with RAI, but not those with bleeding ulcers, have worse prognosis.
Predictors of interleukin‐33 and thymic stromal lymphopoietin levels in cord blood
Authors: Ashley‐Martin Jillian , Dodds Linda , Arbuckle Tye E. , Levy Adrian R. , Platt Robert W. , Marshall Jean S.
Published: January 2015

Background

The fetal immune system is a critical window of development. The epithelial cell‐derived cytokines, thymic stromal lymphopoietin (TSLP), and interleukin‐33 (IL‐33) have received attention for their role in allergic responses but not been studied during this critical window. The objectives were to assess correlations among IL‐33, TSLP, and IgE in umbilical cord blood samples and identify prenatal predictors of these biomarkers.

Methods

This study utilized data and banked cord blood collected in the Maternal‐Infant Research on Environmental Chemicals (MIREC) Study, a trans‐Canada cohort study of 2001 pregnant women. Our analytic sample comprised the 1254 women with a singleton, term birth with a cord blood sample. Spearman correlation coefficients (SCC) and logistic regression models were used to examine associations between biomarkers and identify potential predictors of elevated biomarker levels.

Results

Thymic stromal lymphopoietin and IL‐33 were more strongly correlated with each other (SCC = 0.75, p < 0.0001) than with IgE (IL‐33 SCC = 0.14, TSLP SCC = 0.21). Maternal allergy, heavy street traffic, and elevated birth weight were significantly associated with jointly elevated TSLP and IL‐33 levels, whereas maternal age and female infant sex were inversely associated with elevated IgE.

Conclusions

In this population of Canadian women and infants, TSLP and IL‐33 were detectable in cord blood, more strongly correlated with each other than with IgE, and associated with maternal characteristics indicative of inflammatory responses. This study motivates investigation into the value of cord blood IL‐33 and TSLP levels as childhood allergy predictors and raises interesting questions regarding in utero coordinated regulation of these cytokines.
Optically excited nanoscale ultrasonic transducers
Authors: Smith Richard J. , Cota Fernando Perez , Marques Leonel , Chen Xuesheng , Arca Ahmet , Webb Kevin , Aylott Jonathon , Somekh Micheal G. , Clark Matt
Published: January 2015

In order to work at higher ultrasonic frequencies, for instance, to increase the resolution, it is necessary to fabricate smaller and higher frequency transducers. This paper presents an ultrasonic transducer capable of being made at a very small size and operated at GHz frequencies. The transducers are activated and read optically using pulsed lasers and without physical contact between the instrumentation and the transducer. This removes some of the practical impediments of traditional piezoelectric architectures (such as wiring) and allows the devices to be placed immediately on or within samples, reducing the significant effect of attenuation which is very strong at frequencies above 1 GHz. The transducers presented in this paper exploit simultaneous optical and mechanical resonances to couple the optical input into ultrasonic waves and vice versa. This paper discusses the mechanical and optical design of the devices at a modest scale (a few μm) and explores the scaling of the transducers toward the sub-micron scale. Results are presented that show how the transducers response changes depending on its local environment and how the resonant frequency shifts when the transducer is loaded by a printed protein sample.
A spatial compression technique for head-related transfer function interpolation and complexity estimation
Authors: Shekarchi Sayedali , Christensen-Dalsgaard Jakob , Hallam John
Published: January 2015

A head-related transfer function (HRTF) model employing Legendre polynomials (LPs) is evaluated as an HRTF spatial complexity indicator and interpolation technique in the azimuth plane. LPs are a set of orthogonal functions derived on the sphere which can be used to compress an HRTF dataset by transforming it into a lower dimensional space. The LP compression technique was applied to various HRTF datasets, both real and synthetic, to determine how much different HRTFs can be compressed with respect to their structural complexity and their spatial resolution. The spatial complexity of different datasets was evaluated quantitatively by defining an HRTF spatial complexity index, which considers the rate of change in HRTF power spectrum with respect to spatial position. The results indicate that the compression realized by the LP technique is largely independent of the number of spatial samples in the HRTF dataset, while compressibility tracks the HRTF spatial complexity index so that more LP coefficients are needed to represent an HRTF dataset with a larger complexity index. The slope of the complexity index with respect to sub-sampling density can be used as a predictor for high interpolation error.
Longitudinal annoyance responses to a road traffic noise management strategy that reduced heavy vehicles at night
Authors: Brown A. L.
Published: January 2015

A traffic management strategy was designed to reduce trucks using an urban corridor. The intervention had potential to affect night-time truck flows, but did not target truck traffic in the day, or vehicles other than trucks at any hour. A two-year long panel study measured the community's response to this intervention, using five repeated measurements of response. There were significant reductions in the panel's response to noise, both for night-time annoyance and for interference with activities. This was remarkable given that noise monitoring showed that the intervention produced no change in conventional traffic noise indicators. However, there were measureable changes in the number of articulated truck movements at night, and the benefit can be attributed to reduction in the number of noise events from heavy vehicles. The parallel tracking of changes in reported noise effects and the numbers of heavy vehicles in the night hours in this longitudinal study provides strong support to the notion that noise effects at night depend on the number of noise events experienced, not only on the overall level of traffic noise. The latter appear to be unresponsive indicators by which to assess the noise-effect benefit of heavy vehicle reduction strategies.
Extraction of plate bending stiffness from coincidence angles of sound transmission measurements
Authors: Anderson Brian E. , Shaw Matthew D. , Harker Blaine M.
Published: January 2015

The bending stiffness in a homogeneous, isotropic, thin plate is experimentally derived from measurements of coincidence angles extracted from supercritical sound transmission versus frequency measurements. A computer controlled turn table rotates a plate sample and a receiver array, placed in the near field of the plate. The array is used to track the transmitted sound through the plate, generated by a far-field stationary source, using beam forming. The array technique enables measurement of plates measuring only one wavelength in width. Two examples are used for proof of concept, including an aluminum plate in air and an alumina plate under water.
Experimental investigation of chair type, row spacing, occupants, and carpet on theatre chair absorption
Authors: Choi Young-Ji , Bradley John S. , Jeong Dae-Up
Published: January 2015

This paper examines how the individual variations of chair type, row spacing, as well as the presence of occupants and carpet, combine to influence the absorption characteristics of theater chairs as a function of sample perimeter-to-area (P/A) ratios. Scale models were used to measure the interactive effects of the four test variables on the chair absorption characteristics, avoiding the practical difficulties of full scale measurements. All of the test variables led to effects that could lead to important changes to auditorium acoustics conditions. At mid and higher frequencies, the various effects can usually be explained as due to, more or less, porous absorbing material. In the 125 and 250 Hz octave bands, the major changes were attributed to resonant absorbing mechanisms. The results indicate that for accurate predictions of the effective absorption of the chairs in an auditorium, one should use the P/A method and reverberation chamber tests of the chair absorption coefficients to predict the absorption coefficients of each block of chairs and use these results as input in a room acoustics computer model of the auditorium. The application of these results to auditorium acoustics design is described, more approximate approaches are considered, and relations to existing methods are discussed.
Ultrasonic reflectometry in air: Errors of sample positioning
Authors: Kaczmarek Mariusz , Piwakowski Bogdan , Drelich Radoslaw
Published: January 2015

The reflection coefficient of ultrasonic waves propagating in air and interacting with a plane surface of a solid is considered. The simulation of dependence of the reflection coefficient on errors of sample positioning is performed using a finite beam model along with an angular spectrum method, and next the results are validated experimentally. The simulations show that for the considered range of geometrical parameters, the role of the wave divergence for the reflection coefficient in air is insignificant. The important consequences of errors of the sample positioning are that the shift of the sample influences mostly the phase, while the errors of inclination of the sample mainly affect the magnitude of the reflection coefficient. The experiments confirm simulation results pointing out the necessity of high precision of measurements for ultrasonic reflectometry in air. The results can be used for assessment of precision, calibration, and reduction of errors in applications of the reflectometry tests.
Enhancing the absorption properties of acoustic porous plates by periodically embedding Helmholtz resonators
Authors: Groby J.-P. , Lagarrigue C. , Brouard B. , Dazel O. , Tournat V. , Nennig B.
Published: January 2015

This paper studies the acoustical properties of hard-backed porous layers with periodically embedded air filled Helmholtz resonators. It is demonstrated that some enhancements in the acoustic absorption coefficient can be achieved in the viscous and inertial regimes at wavelengths much larger than the layer thickness. This enhancement is attributed to the excitation of two specific modes: Helmholtz resonance in the viscous regime and a trapped mode in the inertial regime. The enhancement in the absorption that is attributed to the Helmholtz resonance can be further improved when a small amount of porous material is removed from the resonator necks. In this way the frequency range in which these porous materials exhibit high values of the absorption coefficient can be extended by using Helmholtz resonators with a range of carefully tuned neck lengths.
Sensitivity of odd-harmonic amplitudes to open quotient and skewing quotient in glottal airflow
Authors: Titze Ingo R.
Published: January 2015

It is well known that a half-sinusoid has no odd harmonics other than the fundamental. If glottal flow in phonation were to approximate this exact waveshape, which is generally unlikely, some misperception of pitch and loss of vowel intelligibility would occur. The sensitivity of the glottal waveshape to this special shape is explored by systematically varying two parameters, open quotient and skewing quotient. Mild asymmetry (open quotient below 0.45 or above 0.55 and/or skewing quotient greater than 2.0) equalizes the odd-even harmonic series. Singers and speakers avoid the exact symmetry by skewing the flow pulse with source-filter interaction.
Scattering of flexural waves from a hole in a thin plate with an internal beam
Authors: Climente A. , Norris Andrew N. , Sánchez-Dehesa José
Published: January 2015

The scattering of flexural waves by a hole in a thin plate traversed by a beam is modeled here by coupling the Kirchhoff–Love and the Euler–Bernoulli theories. A closed form expression is obtained for the transfer matrix (T-matrix) relating the incident wave to the scattered cylindrical waves. For this purpose, a general method has been developed, based on an analogous impedance method for acoustic waves, for calculating the T-matrix for flexural wave scattering problems. The T-matrix for the problem considered displays a simple structure, composed of distinct sub-matrices which decouple the inside and the outside fields. The conservation of energy principle and numerical comparisons with a commercial finite element simulator have been used to prove the theory.
Age effects in discrimination of intervals within rhythmic tone sequences
Authors: Fitzgibbons Peter J. , Gordon-Salant Sandra
Published: January 2015

This study measured listener sensitivity to increments of a target inter-onset interval (IOI) embedded within tone sequences that featured different rhythmic patterns. The sequences consisted of six 50-ms 1000-Hz tone bursts separated by silent intervals that were adjusted to create different timing patterns. Control sequences were isochronous, with all tonal IOIs fixed at either 200 or 400 ms, while other patterns featured combinations of the two IOIs arranged to create different sequential tonal groupings. Duration difference limens in milliseconds for increments of a single sequence IOI were measured adaptively by adjusting the duration of an inter-tone silent interval. Specific target IOIs within sequences differed across discrimination conditions. Listeners included younger normal-hearing adults and groups of older adults with and without hearing loss. Discrimination performance measured for each of the older groups of listeners was observed to be equivalent, with each group exhibiting significantly poorer discrimination performance than the younger listeners in each sequence condition. Additionally, the specific influence of variable rhythmic grouping on temporal sensitivity was found to be greatest among older listeners.
The impact of musical training and tone language experience on talker identification
Authors: Xie Xin , Myers Emily
Published: January 2015

Listeners can use pitch changes in speech to identify talkers. Individuals exhibit large variability in sensitivity to pitch and in accuracy perceiving talker identity. In particular, people who have musical training or long-term tone language use are found to have enhanced pitch perception. In the present study, the influence of pitch experience on talker identification was investigated as listeners identified talkers in native language as well as non-native languages. Experiment 1 was designed to explore the influence of pitch experience on talker identification in two groups of individuals with potential advantages for pitch processing: musicians and tone language speakers. Experiment 2 further investigated individual differences in pitch processing and the contribution to talker identification by testing a mediation model. Cumulatively, the results suggested that (a) musical training confers an advantage for talker identification, supporting a shared resources hypothesis regarding music and language and (b) linguistic use of lexical tones also increases accuracy in hearing talker identity. Importantly, these two types of hearing experience enhance talker identification by sharpening pitch perception skills in a domain-general manner.
Contribution of double scattering in diffuse ultrasonic backscatter measurements
Authors: Hu Ping , Turner Joseph A.
Published: January 2015

Diffuse ultrasonic backscatter measurements are used to describe the effective grain scattering present during high frequency ultrasonic inspections. Accurate modeling of the backscatter is important for both flaw detection and microstructural characterization. Previous models have been derived under the assumption of single scattering for which the ultrasound is assumed to scatter only once in the time between excitation and detection. This assumption has been shown to be valid in many experiments for which the time scales are short or the frequency is sufficiently low. However, there are also many instances (e.g., for strongly scattering materials, unfocused beams, or long propagation paths) for which the single scattering assumption appears to break down. In this article, a model for the double scatter is developed within the previous formalism based on Wigner distribution functions. The final expression allows the effect of double scattering to be estimated for any combination of experimental parameters. The improved proposed model is anticipated to increase the capabilities of ultrasonic microstructural evaluation, especially in terms of probability of detection estimates.
Large-Scale
13
C Flux Profiling Reveals Conservation of the Entner-Doudoroff Pathway as a Glycolytic Strategy among Marine Bacteria That Use Glucose
Authors: Klingner Arne , Bartsch Annekathrin , Dogs Marco , Wagner-Döbler Irene , Jahn Dieter , Simon Meinhard , Brinkhoff Thorsten , Becker Judith , Wittmann Christoph
Published: January 2015

Marine bacteria form one of the largest living surfaces on Earth, and their metabolic activity is of fundamental importance for global nutrient cycling. Here, we explored the largely unknown intracellular pathways in 25 microbes representing different classes of marine bacteria that use glucose:
Alphaproteobacteria
,
Gammaproteobacteria
, and
Flavobacteriia
of the
Bacteriodetes
phylum. We used
13
C isotope experiments to infer metabolic fluxes through their carbon core pathways. Notably, 90% of all strains studied use the Entner-Doudoroff (ED) pathway for glucose catabolism, whereas only 10% rely on the Embden-Meyerhof-Parnas (EMP) pathway. This result differed dramatically from the terrestrial model strains studied, which preferentially used the EMP pathway yielding high levels of ATP. Strains using the ED pathway exhibited a more robust resistance against the oxidative stress typically found in this environment. An important feature contributing to the preferential use of the ED pathway in the oceans could therefore be enhanced supply of NADPH through this pathway. The marine bacteria studied did not specifically rely on a distinct anaplerotic route, but the carboxylation of phosphoenolpyruvate (PEP) or pyruvate for fueling of the tricarboxylic acid (TCA) cycle was evenly distributed. The marine isolates studied belong to clades that dominate the uptake of glucose, a major carbon source for bacteria in seawater. Therefore, the ED pathway may play a significant role in the cycling of mono- and polysaccharides by bacterial communities in marine ecosystems.
Elucidation of Echovirus 30's Origin and Transmission during the 2012 Aseptic Meningitis Outbreak in Guangdong, China, through Continuing Environmental Surveillance
Authors: Lu Jing , Zheng Huanying , Guo Xue , Zhang Yong , Li Hui , Liu Leng , Zeng Hanri , Fang Ling , Mo Yanling , Yoshida Hiromu , Yi Lina , Liu Tao , Rutherford Shannon , Xu Wenbo , Ke Changwen
Published: January 2015

An aseptic meningitis outbreak occurred in Luoding City of Guangdong, China, in 2012, and echovirus type 30 (ECHO30) was identified as the major causative pathogen. Environmental surveillance indicated that ECHO30 was detected in the sewage of a neighboring city, Guangzhou, from 2010 to 2012 and also in Luoding City sewage samples (6/43, 14%) collected after the outbreak. In order to track the potential origin of the outbreak viral strains, we sequenced the VP1 genes of 29 viral strains from clinical patients and environmental samples. Sequence alignments and phylogenetic analyses based on VP1 gene sequences revealed that virus strains isolated from the sewage of Guangzhou and Luoding cities matched well the clinical strains from the outbreak, with high nucleotide sequence similarity (98.5% to 100%) and similar cluster distribution. Five ECHO30 clinical strains were clustered with the Guangdong environmental strains but diverged from strains from other regions, suggesting that this subcluster of viruses most likely originated from the circulating virus in Guangdong rather than having been more recently imported from other regions. These findings underscore the importance of long-term, continuous environmental surveillance and genetic analysis to monitor circulating enteroviruses.
Large Fractions of CO
2
-Fixing Microorganisms in Pristine Limestone Aquifers Appear To Be Involved in the Oxidation of Reduced Sulfur and Nitrogen Compounds
Authors: Herrmann Martina , Rusznyák Anna , Akob Denise M. , Schulze Isabel , Opitz Sebastian , Totsche Kai Uwe , Küsel Kirsten
Published: January 2015

The traditional view of the dependency of subsurface environments on surface-derived allochthonous carbon inputs is challenged by increasing evidence for the role of lithoautotrophy in aquifer carbon flow. We linked information on autotrophy (Calvin-Benson-Bassham cycle) with that from total microbial community analysis in groundwater at two superimposed—upper and lower—limestone groundwater reservoirs (aquifers). Quantitative PCR revealed that up to 17% of the microbial population had the genetic potential to fix CO
2
via the Calvin cycle, with abundances of
cbbM
and
cbbL
genes, encoding RubisCO (ribulose-1,5-bisphosphate carboxylase/oxygenase) forms I and II, ranging from 1.14 × 10
3
to 6 × 10
6
genes liter
−1
over a 2-year period. The structure of the active microbial communities based on 16S rRNA transcripts differed between the two aquifers, with a larger fraction of heterotrophic, facultative anaerobic, soil-related groups in the oxygen-deficient upper aquifer. Most identified CO
2
-assimilating phylogenetic groups appeared to be involved in the oxidation of sulfur or nitrogen compounds and harbored both RubisCO forms I and II, allowing efficient CO
2
fixation in environments with strong oxygen and CO
2
fluctuations. The genera
Sulfuricella
and
Nitrosomonas
were represented by read fractions of up to 78 and 33%, respectively, within the
cbbM
and
cbbL
transcript pool and accounted for 5.6 and 3.8% of 16S rRNA sequence reads, respectively, in the lower aquifer. Our results indicate that a large fraction of bacteria in pristine limestone aquifers has the genetic potential for autotrophic CO
2
fixation, with energy most likely provided by the oxidation of reduced sulfur and nitrogen compounds.