bluuebunny/crossref_metadata_2025 huggingface dataset:
Risk Factors, Radiological Features, and Infarct Topography of Craniocervical Arterial Dissection
Authors: Thomas Lucy Caroline , Rivett Darren A. , Parsons Mark , Levi Christopher
Published: September 2012

Background

Craniocervical arterial dissection is a common cause of ischemic stroke in the young to middle-aged population. There have been a number of previous studies where radiological features have been described but few with detailed mapping of infarct topography and none where these features have been related to the reported risk factors.

Aims

The aims of this study were to describe the radiological characteristics of dissection patients ≤55 years and relate these to reported risk factors.

Methods

Craniocervical arterial dissection cases ≤55 years, and age- and gender-matched controls were identified from a medical records database between 1998 and 2009. Control cases had stroke from another cause than dissection. Records and radiology were reviewed.

Results

Thirty-six radiologically confirmed dissection cases [20 (56%) vertebral artery, 16 (44%) internal carotid], and 43 controls were identified. Dissections were extracranial with intracranial extension in 10 (28%) cases. Infarction was demonstrated in 22 (61%) dissection cases. The most common wall deficit identified was an intimal flap. Twenty-three (64%) dissection cases had a recent history of neck trauma ( P > 0·000) and 13 (36%) had vascular variants ( P = 0·013). Conclusion Craniocervical arterial dissection cases, particularly vertebral artery, were more likely to have a history of neck trauma. Dissections were most commonly extracranial, in the upper cervical region, with intracranial extension in 28%. Dissection cases with trauma more commonly had a dissection flap and evidence of infarction in the lateral medulla, anterior or posterior inferior cerebellar artery territory. Close inspection of the V3 segment of the vertebral or skull base for internal carotid artery may be warranted with a history of neck trauma.
Riesgos de invalidez previsional: el caso argentino
Authors: Belliard Matías , Grushka Carlos , De Biase Marcelo
Published: September 2012

El objetivo del estudio es analizar los riesgos de invalidez (RI) a los que se exponen los trabajadores cotizantes al Sistema Integrado Previsional Argentino (SIPA). El período bajo estudio fue 2000‐2006, y se utilizaron registros administrativos como fuente de datos. Los resultados indican que 1,46 personas por cada 1.000 trabajadores se invalidaron anualmente. Los hombres muestran mayores RI que las mujeres y el comportamiento con la edad es creciente para ambos. Adicionalmente, se evalúan los RI por patología y régimen previsional, considerando su comportamiento con la edad y el sexo.
Conservation potential for heathland carabid beetle fauna of linear trackways within a plantation forest
Authors: Bertoncelj Irena , Dolman Paul M.
Published: September 2012

Exploring conservation and connectivity potential of landscape linkages implies studies on the level of population and community structure.

We examined carabid beetle communities within a network of open linear trackways embedded in a plantation forest, in a region where conservation interest focuses on heathland associated species. The relative importance of environmental characteristics such as width, orientation, age of surrounding plantations and vegetation height on species associated with grassland, heathland and sandy habitats (GHS species) was explored in 36 trackway elements.

A total of 3554 individuals were collected of which 1465 were GHS specialists. Linear trackways supported important carabid beetle diversity including 17 GHS species of which six are nationally scarce within the UK.

The age of adjacent plantations was the most important factor determining community composition of carabids with GHS species favouring trackways surrounded by younger plantations. For predicting number and abundance of GHS species within a subset of trackways surrounded by younger plantations, models incorporating sward height in verges showed the strongest relationships. But results were statistically significant only for predicting abundance of the dominant GHS species Harpalus rufipalpis, which favoured wider trackways with lower vegetation and greater cover of bare sand.

Current conservation management using forage harvesting of trackways does not improve habitat quality for GHS carabids. Seemingly continuous network of linear linkages is interrupted by sections of less suitable habitat surrounded by older plantations. Conservation potential could be enhanced by widening of trackways and management by physical disturbance of soil and vegetation.
Locally enhanced early bone formation of zoledronic acid incorporated into a bone cement plug in vivo
Authors: Sörensen Torben C , Arnoldi Jörg , Procter Philip , Beimel Claudia , Jönsson Anders , Lennerås Maria , Emanuelsson Lena , Palmquist Anders , Thomsen Peter , Robioneck Bernd , Steckel Hartwig
Published: September 2012

Objectives

The aim of the study was to gain experience about the short-term effects of zoledronic acid (ZOL) on bone-implant contact (BIC), bone regeneration and bone area (BA).

Methods

In this in-vivo study, ZOL was released locally from a drug-loaded pre-shaped calcium phosphate bone cement plug which was implanted into a bone defect in the proximal tibia of rats. At 1 and 3 weeks post implantation, tissue reactions as well as bone regeneration capabilities at the implant site were investigated. Furthermore, tissue samples, harvested at placebo and verum plug sites were used to analyse the gene expression of selected bone-specific markers by using quantitative polymerase chain reaction. Data were normalized against ribosomal RNA (Rn18s) subunits.

Key findings

In the placebo interface a higher amount of cells could be detected as indicated by higher expression of small subunit Rn18s. Nevertheless, comparing the normalized data of the selected gene expression levels, no significant differences were detected. The histomorphometric results showed a significant higher BIC and BA for ZOL-loaded plugs at 3 weeks after implantation.

Conclusions

In this model, ZOL was demonstrated to be effective in impacting the bone regeneration process towards reduction of early bone resorption and enhanced bone formation.
Phonological awareness and oral language proficiency in learning to read English among Chinese kindergarten children in Hong Kong
Authors: Yeung Susanna S. , Chan Carol K. K.
Published: September 2012

Background

Learning to read is very challenging for Hong Kong children who learn English as a second language (ESL), as they must acquire two very different writing systems, beginning at the age of three. Few studies have examined the role of phonological awareness at the subsyllabic levels, oral language proficiency, and L1 tone awareness in L2 English reading among Hong Kong ESL kindergarteners.

Aims

This study aims to investigate L1 and L2 phonological awareness and oral language proficiency as predictors of English reading among children with Chinese as L1.

Sample

One hundred and sixty‐one typically developing children with a mean age of 5.16 (SD=.35) selected from seven preschools in Hong Kong.

Method

Participants were assessed for English reading, English and Chinese phonological awareness at different levels, English oral language skills, and letter naming ability.

Results

Hierarchical regression analyses indicated that both oral language proficiency and phonological awareness measures significantly predicted L2 word reading, when statistically controlled for age and general intelligence. Among various phonological awareness units, L2 phonemic awareness was the best predictor of L2 word reading. Cross‐language transfer was shown with L1 phonological awareness at the tone level, uniquely predicting L2 word reading.

Conclusions

The present findings show the important role of phonological awareness at the subsyllabic levels (rime and phoneme) and oral language proficiency in the course of L2 reading development in Chinese ESL learners. The significant contribution of L1 tone awareness to L2 reading suggests that phonological sensitivity is a general competence that ESL children need to acquire in early years. The findings have significant implications for understanding L2 reading development and curriculum development.
Academic self‐efficacy in study‐related skills and behaviours: Relations with learning‐related emotions and academic success
Authors: Putwain Dave , Sander Paul , Larkin Derek
Published: September 2012

Background

Academic self‐efficacy, when operationalized as mastery over domain‐specific knowledge, has been found to be a predictor of academic achievement and emotions. Although academic emotions are also a predictor of academic achievement, there is limited evidence for reciprocal relations with academic achievement.

Aims

To examine whether academic self‐efficacy, when operationalized as confidence in study‐related skills and behaviours, is also a predictor of academic achievement and emotions and to test reciprocal relations between academic emotions and achievement.

Sample

Two hundred and six first‐year undergraduate students.

Methods

Academic self‐efficacy was measured at the beginning of the first semester and learning‐related emotions (LREs) at the beginning of the second semester. Academic performance was aggregated across assessments in semester one and semester two.

Results

Self‐efficacy in study‐related skills and behaviours predicted: (1) better semester one academic performance and (2) more pleasant and fewer unpleasant LREs at the beginning of the second semester directly and (3) indirectly through semester one academic performance. Reciprocal relations between academic performance and emotions were supported, but only for pleasant emotions.

Conclusions

Self‐efficacy in study‐related skills was the critical academic self‐efficacy variable in this study. It may play an important role in maintaining challenge appraisals to maintain pleasant emotions and better academic performance. Accordingly, practitioners in higher education may wish to consider the value of assessing and developing students' self‐efficacy in relation to their independent study skills.
Apoplastic Na+ in Vicia faba Leaves Rises After Short‐Term Salt Stress and Is Remedied by Silicon
Authors: Shahzad M. , Zörb C. , Geilfus C.‐M. , Mühling K. H.
Published: September 2012

Salinity primarily affects plants by inhibiting shoot growth. Salt‐sensitive plants have been suggested to accumulate Na+ within their leaf apoplast under salinity, leading to a reduced water status. Evidence related to apoplastic Na+ accumulation is still enigmatic. We have focused on the effect of a short‐term salt treatment by using the salt‐sensitive Vicia faba. Moreover, we have examined the role of silicon in alleviating sodium accumulation in the apoplast. Salt‐sensitive field beans have been subjected to increasing levels of salinity, with and without the addition of silicon under hydroponic conditions. We have demonstrated that the dicot Vicia faba exhibits a rise in Na+ concentration in the leaf apoplast at higher salinity levels; this is significantly ameliorated by the addition of silicon. Further, enhanced shoot growth under high salt treatment in the presence of added silicon is correlated with a significant decrease in Na+ concentration in the leaves. The novelty of the current study is the detection of a high Na+ concentration in the leaf apoplast of the salt‐sensitive dicot field bean. Our results support Oertli's hypothesis that extracellular salt accumulation can lead to wilting leaves, plant growth reduction and cell death.
Photoactivated disinfection using light‐emitting diode as an adjunct in the management of chronic periodontitis: a pilot double‐blind split‐mouth randomized clinical trial
Authors: Bassir Seyed H. , Moslemi Neda , Jamali Raika , Mashmouly Samira , Fekrazad Reza , Chiniforush Nasim , Shamshiri Ahmad R. , Nowzari Hessam
Published: September 2012

Aim

This split‐mouth double‐masked randomized controlled clinical study evaluated the effectiveness of photoactivated disinfection (PAD) using light‐emitting diode (LED) as an adjunct in the management of patients affected by moderate to severe chronic periodontitis.

Materials and Methods

Sixteen patients affected by moderate to severe chronic periodontitis were enrolled. After scaling and root planing (SRP), each quadrant was assigned to one of the following groups: LED group (625–635 nm, maximum power density: 2000 mW/cm2), photosensitizer group (tolouidine blue O, 0.1 mg/ml), PAD group (photosensitizer and LED) and control group (no adjunctive treatment). The adjunctive treatments were repeated after 7 and 14 days. The clinical parameters of bleeding on probing, probing pocket depth and clinical attachment level were measured at baseline and 1 and 3 months after SRP.

Results

At 1 and 3 months, all groups showed significant improvements with regard to all clinical parameters compared to baseline (all p: <0.001). There were no significant differences among groups in terms of changes of clinical parameters in any time interval (all p > 0.05).

Conclusion

The application of PAD using LED with the current setting did not have additional effects on clinical parameters in patients diagnosed with moderate to severe chronic periodontitis compared with SRP alone.
Nitric oxide‐mediated regulation of ‐amyloid clearance via alterations of MMP‐9/TIMP‐1
Authors: Ridnour Lisa A. , Dhanapal Sneha , Hoos Michael , Wilson Joan , Lee Jennifer , Cheng Robert Y. S. , Brueggemann Ernst E. , Hines Harry B. , Wilcock Donna M. , Vitek Michael P. , Wink David A. , Colton Carol A.
Published: September 2012

Fibrillar amyloid plaques are largely composed of amyloid‐beta (Aβ) peptides that are metabolized into products, including Aβ1‐16, by proteases including matrix metalloproteinase 9 (MMP‐9). The balance between production and degradation of Aβ proteins is critical to amyloid accumulation and resulting disease. Regulation of MMP‐9 and its endogenous inhibitor tissue inhibitor of metalloproteinase (TIMP)‐1 by nitric oxide (NO) has been shown. We hypothesize that nitric oxide synthase (NOS2) protects against Alzheimer's disease pathology by increasing amyloid clearance through NO regulation of MMP‐9/TIMP‐1 balance. We show NO‐mediated increased MMP‐9/TIMP‐1 ratios enhanced the degradation of fibrillar Aβ in vitro, which was abolished when silenced for MMP‐9 protein translation. The in vivo relationship between MMP‐9, NO and Aβ degradation was examined by comparing an Alzheimer's disease mouse model that expresses NOS2 with a model lacking NOS2. To quantitate MMP‐9 mediated changes, we generated an antibody recognizing the Aβ1‐16 fragment, and used mass spectrometry multi‐reaction monitoring assay for detection of immunoprecipitated Aβ1‐16 peptides. Aβ1‐16 levels decreased in brain lysates lacking NOS2 when compared with strains that express human amyloid precursor protein on the NOS2 background. TIMP‐1 increased in the APPSwDI/NOS2−/− mice with decreased MMP activity and increased amyloid burden, thereby supporting roles for NO in the regulation of MMP/TIMP balance and plaque clearance.
A nicotinic acetylcholine receptor transmembrane point mutation (G275E) associated with resistance to spinosad in Frankliniella occidentalis
Authors: Puinean Alin M. , Lansdell Stuart J. , Collins Toby , Bielza Pablo , Millar Neil S.
Published: September 2012

High levels of resistance to spinosad, a macrocyclic lactone insecticide, have been reported previously in western flower thrips, Frankliniella occidentalis, an economically important insect pest of vegetables, fruit and ornamental crops. We have cloned the nicotinic acetylcholine receptor (nAChR) α6 subunit from F. occidentalis (Foα6) and compared the nucleotide sequence of Foα6 from susceptible and spinosad‐resistant insect populations (MLFOM and R1S respectively). A single nucleotide change has been identified in Foα6, resulting in the replacement of a glycine (G) residue in susceptible insects with a glutamic acid (E) in resistant insects. The resistance‐associated mutation (G275E) is predicted to lie at the top of the third α‐helical transmembrane domain of Foα6. Although there is no direct evidence identifying the location of the spinosad binding site, the analogous amino acid in the C. elegans glutamate‐gated chloride channel lies in close proximity (4.4 Å) to the known binding site of ivermectin, another macrocyclic lactone pesticide. The functional consequences of the resistance‐associated mutation have been examined in the human nAChR α7 subunit. Introduction of an analogous (A272E) mutation in α7 abolishes the modulatory effects of spinosad whilst having no significant effect upon activation by acetylcholine, consistent with spinosad having an allosteric mechanism of action.
Role of TrkB expression in rat adrenal gland during acute immobilization stress
Authors: Kondo Yusuke , To Masahiro , Saruta Juri , Hayashi Takashi , Sugiyama Hiroki , Tsukinoki Keiichi
Published: September 2012

Expression of tyrosine receptor kinase B (TrkB), a receptor for brain‐derived neurotrophic factor (BDNF), is markedly elevated in the adrenal medulla during immobilization stress. Catecholamine release was confirmed in vitro by stimulating chromaffin cells with recombinant BDNF. We investigated the role of TrkB and the localization of BDNF in the adrenal gland during immobilization stress for 60 min. Blood catecholamine levels increased after stimulation with TrkB expressed in the adrenal medulla during 60‐min stress; however, blood catecholamine levels did not increase in adrenalectomized rats. Furthermore, expression of BDNF mRNA and protein was detected in the adrenal medulla during 60‐min stress. Similarly, in rats undergoing sympathetic nerve block with propranolol, BDNF mRNA and protein were detected in the adrenal medulla during 60‐min stress. These results suggest that signal transduction of TrkB in the adrenal medulla evokes catecholamine release. In addition, catecholamine release was evoked by both the hypothalamic–pituitary–adrenal axis and autocrine signaling by BDNF in the adrenal gland. BDNF–TrkB interaction may play a role in a positive feedback loop in the adrenal medulla during immobilization stress.
Forecasting with prediction intervals for periodic autoregressive moving average models
Authors: Anderson Paul L. , Meerschaert Mark M. , Zhang Kai
Published: September 2012

Periodic autoregressive moving average (PARMA) models are indicated for time series whose mean, variance and covariance function vary with the season. In this study, we develop and implement forecasting procedures for PARMA models. Forecasts are developed using the innovations algorithm, along with an idea of Ansley. A formula for the asymptotic error variance is provided, so that Gaussian prediction intervals can be computed. Finally, an application to monthly river flow forecasting is given, to illustrate the method.
Involvement of WalK (VicK) phosphatase activity in setting WalR (VicR) response regulator phosphorylation level and limiting cross‐talk in Streptococcus pneumoniaeD39 cells
Authors: Wayne Kyle J. , Li Shuo , Kazmierczak Krystyna M. , Tsui Ho‐Ching T. , Winkler Malcolm E.
Published: September 2012

WalRK (YycFG) two‐component systems (TCSs) of low‐GC Gram‐positive bacteria play critical roles in regulating peptidogylcan hydrolase genes involved in cell division and wall stress responses. The WalRK (VicRK) TCSs of Streptococcus pneumoniae (pneumococcus) and other Streptococcus species show numerous differences with those of other low‐GC species. Notably, the pneumococcal WalK sensor kinase is not essential for normal growth in culture, unlike its homologues in Bacillus and Staphylococcus species. The WalK sensor kinase possesses histidine autokinase activity and mediates dephosphorylation of phosphorylated WalR∼P response regulator. To understand the contributions of these two WalK activities to pneumococcal growth, we constructed and characterized a set of walK kinase and phosphatase mutants in biochemical reactions and in cells. We identified an amino acid substitution in WalK that significantly reduces phosphatase activity, but not other activities. Comparisons were made between WalRK regulon expression levels and WalR∼P amounts in cells determined by Phos‐tag SDS‐PAGE. Reduction of WalK phosphatase activity resulted in nearly 90% phosphorylation to WalR∼P, consistent with the conclusion that WalK phosphatase is strongly active in exponentially growing cells. WalK phosphatase activity was also shown to depend on the WalK PAS domain and to limit cross‐talk and the recovery of WalR∼P from walK+ cells.
Determinants of substrate specificity and biochemical properties of the sn‐glycerol‐3‐phosphate ATP binding cassette transporter (UgpB–AEC2) of Escherichia coli
Authors: Wuttge Steven , Bommer Martin , Jäger Franziska , Martins Berta M. , Jacob Sophie , Licht Anke , Scheffel Frank , Dobbek Holger , Schneider Erwin
Published: September 2012

Under phosphate starvation conditions, Escherichia coli can utilize sn‐glycerol‐3‐phosphate (G3P) and G3P diesters as phosphate source when transported by an ATP binding cassette importer composed of the periplasmic binding protein, UgpB, the transmembrane subunits, UgpA and UgpE, and a homodimer of the nucleotide binding subunit, UgpC. The current knowledge on the Ugp transporter is solely based on genetic evidence and transport assays using intact cells. Thus, we set out to characterize its properties at the level of purified protein components. UgpB was demonstrated to bind G3P and glycerophosphocholine with dissociation constants of 0.68 ± 0.02 μM and 5.1 ± 0.3 μM, respectively, while glycerol‐2‐phosphate (G2P) is not a substrate. The crystal structure of UgpB in complex with G3P was solved at 1.8 Å resolution and revealed the interaction with two tryptophan residues as key to the preferential binding of linear G3P in contrast to the branched G2P. Mutational analysis validated the crucial role of Trp‐169 for G3P binding. The purified UgpAEC2 complex displayed UgpB/G3P‐stimulated ATPase activity in proteoliposomes that was neither inhibited by phosphate nor by the signal transducing protein PhoU or the phosphodiesterase UgpQ. Furthermore, a hybrid transporter composed of MalFG–UgpC could be functionally reconstituted while a UgpAE–MalK complex was unstable.
Epidural blood patches are effective for postdural puncture headache in pediatrics – a 10‐year experience
Authors: Kokki Merja , Sjövall Sari , Kokki Hannu
Published: September 2012

Background

Postdural puncture headache (PDPH) is a relatively common complication after lumbar punctures (LP). If conservative treatment is not sufficient within a few days and the symptoms are severe, an epidural blood patch (EBP) may be performed.

Aim

A chart review to evaluate the need and effectiveness of EBPs in children and adolescents over a 10‐year period at Kuopio University Hospital (KUH) and Satakunta Central Hospital (SCH).

Methods

The information system patient measures databases were reviewed to identify patients who had received an EBP. Then, the pediatric patients' medical records were compared to the characteristics of the PDPH and associated symptoms and were evaluated for the effectiveness of EBPs.

Results

Forty‐two EBPs were performed in 41 patients (24 girls, 17 boys), 26 at KUH and 15 at SCH. Five patients, all at KUH, were children aged 3–12 years, and 36 patients were adolescents, aged 13–18 years. The indications for LPs were diagnostic (n = 26), spinal anesthesia/analgesia (n = 11), or introduction of chemotherapy (n = 2), and four patients developed PDPH after an inadvertent dural puncture with an epidural needle. The first EBP provided a complete relief of symptoms in 37 children, an initial success rate of 90%, and permanent relief in 85%. At KUH, the need for EBPs after spinal anesthesia/analgesia was <1/1000 in children and 2–3/1000 in adolescents, and that after chemotherapy 1–2/1000. No serious adverse effects related to EBPs were recorded.

Conclusion

If PDPH symptoms are severe and are not relieved with conservative treatment, EBP is a highly effective procedure in pediatric patients.
From Ethnic Nationalisms to Clashing Civilizations: Reconfigurations of (Un)Civil Religion in an Era of Globalization
Authors: Busher Joel
Published: September 2012

One of the main questions currently facing scholars of civil religion is how civil religions, and in particular national civil religions, are being reconfigured in response to the contemporary repositioning of the nation state within the supra‐national political, economic, legal and cultural orders entailed by globalization. This article first surveys some of the main arguments to emerge from the civil religion literature in this regard. It then contributes to these debates by outlining how current reconfigurations of national civil religion manifest in the case of a protest movement called the English Defence League (EDL). Specifically, this article describes how rituals and symbols of national belonging have, at least for adherents and supporters of this group, been reinvigorated by infusing them with symbols that invoke notions of civilizational belonging and are replete with references to an imminent “clash of civilizations.”
RNA polymerase V targets transcriptional silencing components to promoters of protein‐coding genes
Authors: Zheng Qi , Rowley M. Jordan , Böhmdorfer Gudrun , Sandhu Davinder , Gregory Brian D. , Wierzbicki Andrzej T.
Published: September 2012

Transcriptional gene silencing controls transposons and other repetitive elements through RNA‐directed DNA methylation (RdDM) and heterochromatin formation. A key component of the Arabidopsis RdDM pathway is ARGONAUTE4 (AGO4), which associates with siRNAs to mediate DNA methylation. Here, we show that AGO4 preferentially targets transposable elements embedded within promoters of protein‐coding genes. This pattern of AGO4 binding cannot be simply explained by the sequences of AGO4‐bound siRNAs; instead, AGO4 binding to specific gene promoters is also mediated by long non‐coding RNAs (lncRNAs) produced by RNA polymerase V. lncRNA‐mediated AGO4 binding to gene promoters directs asymmetric DNA methylation to these genomic regions and is involved in regulating the expression of targeted genes. Finally, AGO4 binding overlaps sites of DNA methylation affected by the biotic stress response. Based on these findings, we propose that the targets of AGO4‐directed RdDM are regulatory units responsible for controlling gene expression under specific environmental conditions.
Nuclear ubiquitin proteasome degradation affects WRKY45 function in the rice defense program
Authors: Matsushita Akane , Inoue Haruhiko , Goto Shingo , Nakayama Akira , Sugano Shoji , Hayashi Nagao , Takatsuji Hiroshi
Published: September 2012

The transcriptional activator WRKY45 plays a major role in the salicylic acid/benzothiadiazole‐induced defense program in rice. Here, we show that the nuclear ubiquitin–proteasome system (UPS) plays a role in regulating the function of WRKY45. Proteasome inhibitors induced accumulation of polyubiquitinated WRKY45 and transient up‐regulation of WRKY45 target genes in rice cells, suggesting that WRKY45 is constantly degraded by the UPS to suppress defense responses in the absence of defense signals. Mutational analysis of the nuclear localization signal indicated that UPS‐dependent WRKY45 degradation occurs in the nuclei. Interestingly, the transcriptional activity of WRKY45 after salicylic acid treatment was impaired by proteasome inhibition. The same C‐terminal region in WRKY45 was essential for both transcriptional activity and UPS‐dependent degradation. These results suggest that UPS regulation also plays a role in the transcriptional activity of WRKY45. It has been reported that AtNPR1, the central regulator of the salicylic acid pathway in Arabidopsis, is regulated by the UPS. We found that OsNPR1/NH1, the rice counterpart of NPR1, was not stabilized by proteasome inhibition under uninfected conditions. We discuss the differences in post‐translational regulation of salicylic acid pathway components between rice and Arabidopsis.
Evolution of peripheral nerve function in humans: novel insights from motor nerve excitability
Authors: Farrar Michelle A. , Park Susanna B. , Lin Cindy S.‐Y. , Kiernan Matthew C.
Published: September 2012

Key points

The evolution of human peripheral nerve function after birth to facilitate more complex neural tasks has not been fully elucidated.

The present study has established the changes that occur in nerve function in developing humans using specialized non‐invasive excitability techniques in infants, children, adolescents and young adults for the first time.

The activity of axonal K+ conductances reduces with formation of the axo‐glial junction. This occurs simultaneously with alterations in passive membrane properties and conductance (axonal diameter and myelination).

These functional alterations serve to enhance the efficiency and speed of impulse conduction, whilst maintaining membrane stability, concurrent with the acquisition of motor skills in childhood.

Significantly, these findings bring the dynamics of axonal development to the clinical domain and serve to further illuminate pathophysiological mechanisms that occur during development.

Abstract  While substantial alterations in myelination and axonal growth have been described during maturation, their interactions with the configuration and activity of axonal membrane ion channels to achieve impulse conduction have not been fully elucidated. The present study utilized axonal excitability techniques to compare the changes in nerve function across healthy infants, children, adolescents and adults. Multiple excitability indices (stimulus–response curve, strength–duration time constant, threshold electrotonus, current–threshold relationship and recovery cycle) combined with conventional neurophysiological measures were investigated in 57 subjects (22 males, 35 females; age range 0.46–24 years), stimulating the median motor nerve at the wrist. Maturational changes in conduction velocity were paralleled by significant alterations in multiple excitability parameters, similarly reaching steady values in adolescence. Maturation was accompanied by reductions in threshold (P < 0.005) and rheobase (P= 0.001); depolarizing and hyperpolarizing electrotonus progressively reduced (P < 0.001), or ‘fanned‐in’; resting current–threshold slope increased (P < 0.0001); accommodation to depolarizing currents prolonged (P < 0.0001); while greater threshold changes in refractoriness (P= 0.001) and subexcitability (P < 0.01) emerged. Taken together, the present findings suggest that passive membrane conductances and the activity of K+ conductances decrease with formation of the axo‐glial junction and myelination. In turn, these functional alterations serve to enhance the efficiency and speed of impulse conduction concurrent with the acquisition of motor skills during childhood, and provide unique insight into the evolution of postnatal human peripheral nerve function. Significantly, these findings bring the dynamics of axonal development to the clinical domain and serve to further illuminate pathophysiological mechanisms that occur during development.
Nanofabrication of high aspect ratio (∼50:1) sub-10 nm silicon nanowires using inductively coupled plasma etching
Authors: Mirza Muhammad M. , Zhou Haiping , Velha Philippe , Li Xu , Docherty Kevin E. , Samarelli Antonio , Ternent Gary , Paul Douglas J.
Published: September 2012

The development of nanofabrication techniques for creating high aspect ratio (∼50:1) sub-10 nm silicon nanowires (SiNWs) with smooth, uniform, and straight vertical sidewalls using an inductively coupled plasma (ICP) etching process at 20 °C is reported. In particular, to improve the quality and flexibility of the pattern transfer process for high aspect ratio SiNWs, hydrogen silsesquioxane, a high-resolution, inorganic, negative-tone resist for electron-beam lithography has been used as both the resist for defining sub-10 nm patterns and the hard mask for etching the underneath silicon material. The effects of SF6/C4F8 gas flow rates, chamber pressure, platen power and ICP power on the etch rate, selectivity, and sidewall profile are investigated. To minimize plasma-induced sidewall damage, moderate plasma excitation power (ICP power of 600 W) and low ion energy (platen power of 6–12 W) were used. Using the optimized etch process at room temperature (20 °C), the authors have successfully fabricated sub-10 nm SiNWs, which have smooth vertical sidewall profile and aspect ratios up to ∼50:1. This optimized etch combined with a controlled thermal oxidation allows the realization of consistent, reproducible, and reliable SiNW devices with nominal widths from 100 nm down to sub-5 nm in silicon on top of SiO2 fabricated on silicon on insulator substrates.
Mixed Magnesium and Zinc Oxide Prepared by Co-precipitation and Analyzed by XPS
Authors: Khairallah Fares , Glisenti Antonella , Galenda Alessandro , Natile Marta Maria
Published: September 2012

Two Zinc-Magnesium Oxide powders were prepared by means of a sol-gel method based on the mixing of nitrates of Mg and Zn, followed by complexation with citric acid. The samples are characterized by a nominal (i.e. calculated from the weighted amount of precursors) Zn/Mg atomic ratio of 0.01 (specimen 1, Accession #1232), and 0.5 (specimen 2, Accession #1233). The surface properties and the influence of the Zn/Mg atomic ratio are investigated by means of XPS (using a standard Al Kα). Besides the wide scan spectra, detailed spectra for the Mg 1s, Zn 2p3/2 and O 1s regions and related data are presented and discussed. XP analysis confirms the presence of Mg (II) and Zn (II). The XPS Zn/Mg atomic ratio is always lower than the nominal one; this is particularly evident in specimen 1 (Accession #1232) thus suggesting a certain surface segregation of magnesium. The O/(Mg + Zn) atomic ratio is higher than the nominal one and decreases with increasing the Zn/Mg atomic ratio (from 1.5 for [Zn/Mg]nom = 0.01 to 1.3 for [Zn/Mg]nom = 0.5).
Quantification of arterial flow using digital subtraction angiography
Authors: Bonnefous Odile , Pereira Vitor Mendes , Ouared Rafik , Brina Olivier , Aerts Hans , Hermans Roel , van Nijnatten Fred , Stawiaski Jean , Ruijters Daniel
Published: September 2012

Purpose:

In this paper, a method for the estimation of arterial hemodynamic flow from x‐ray video densitometry data is proposed and validated using anin vitro setup.

Methods:

The method is based on the acquisition of three‐dimensional rotational angiography and digital subtraction angiography sequences. A modest contrast injection rate (between 1 and 4 ml/s) leads to a contrast density that is modulated by the cardiac cycle, which can be measured in the x‐ray signal. An optical flow based approach is used to estimate the blood flow velocities from the cyclic phases in the x‐ray signal.

Results:

The authors have validated this methodin vitro, and present three clinical cases. The in vitro experiments compared the x‐ray video densitometry results with the gold standard delivered by a flow meter. Linear correlation analysis and regression fitting showed that the ideal slope of 1 and intercept of 0 were contained within the 95 percentile confidence interval. The results show that a frame rate higher than 50 Hz allows measuring flows in the range of 2 ml/s to 6 ml/s within an accuracy of 5%.

Conclusions:

Thein vitro and clinical results indicate that it is feasible to estimate blood flow in routine interventional procedures. The availability of an x‐ray based method for quantitative flow estimation is particularly clinically useful for intra‐cranial applications, where other methods, such as ultrasound Doppler, are not available.
Patient radiation doses in interventional cardiology in the U.S.: Advisory data sets and possible initial values for U.S. reference levels
Authors: Miller Donald L. , Hilohi C. Michael , Spelic David C.
Published: September 2012

Purpose:

To determine patient radiation doses from interventional cardiology procedures in the U.S and to suggest possible initial values for U.S. benchmarks for patient radiation dose from selected interventional cardiology procedures [fluoroscopically guided diagnostic cardiac catheterization and percutaneous coronary intervention (PCI)].

Methods:

Patient radiation dose metrics were derived from analysis of data from the 2008 to 2009 Nationwide Evaluation of X‐ray Trends (NEXT) survey of cardiac catheterization. This analysis used deidentified data and did not require review by an IRB. Data from 171 facilities in 30 states were analyzed. The distributions (percentiles) of radiation dose metrics were determined for diagnostic cardiac catheterizations, PCI, and combined diagnostic and PCI procedures. Confidence intervals for these dose distributions were determined using bootstrap resampling.

Results:

Percentile distributions (advisory data sets) and possible preliminary U.S. reference levels (based on the 75th percentile of the dose distributions) are provided for cumulative air kerma at the reference point (Ka,r), cumulative air kerma‐area product (PKA), fluoroscopy time, and number of cine runs. Dose distributions are sufficiently detailed to permit dose audits as described in National Council on Radiation Protection and Measurements Report No. 168. Fluoroscopy times are consistent with those observed in European studies, but PKA is higher in the U.S.

Conclusions:

Sufficient data exist to suggest possible initial benchmarks for patient radiation dose for certain interventional cardiology procedures in the U.S. Our data suggest that patient radiation dose in these procedures is not optimized in U.S. practice.
Positional accuracy of novel x‐ray‐image‐based dynamic tumor‐tracking irradiation using a gimbaled MV x‐ray head of a Vero4DRT (MHI‐TM2000)
Authors: Mukumoto Nobutaka , Nakamura Mitsuhiro , Sawada Akira , Takahashi Kunio , Miyabe Yuki , Takayama Kenji , Mizowaki Takashi , Kokubo Masaki , Hiraoka Masahiro
Published: September 2012

Purpose:

To verify the positional accuracy of a novel x‐ray‐image‐based dynamic tumor‐tracking (DTT) irradiation technique using the gimbaled MV x‐ray head of a Vero4DRT (MHI‐TM2000).

Methods:

Verification of the x‐ray‐image‐based DTT was performed using three components: a three‐dimensional moving phantom with a steel ball target, a laser displacement gauge, and an orthogonal kV x‐ray imaging subsystem with a gimbaled MV x‐ray head and the system controller of the Vero4DRT. The moving phantom was driven based on seven periodic patterns [peak‐to‐peak amplitude (A): 20–40 mm, breathing period (T): 2–5 s] and 15 patients’ aperiodic respiratory patterns (A: 6.5–22.9 mm, T: 1.9–5.8 s). The target position was detected in real time with the orthogonal kV x‐ray imaging subsystem using the stereo vision technique. Subsequently, the Vero4DRT predicted the next position of the target, and then the gimbaled MV x‐ray head tracked the corresponding orientation of the target. The displacements of the target were measured synchronously using the laser displacement gauge. The difference between the target positions predicted by the Vero4DRT and those measured by the laser displacement gauge was computed as the prediction error (EP), and the difference between the target positions tracked by the gimbaled MV x‐ray head and predicted target positions was computed as the mechanical error (EM). Total tracking system error (ET) was defined as the difference between the tracked and measured target positions.

Results:

The root mean squares (RMSs) of EP, EM, and ET were up to 0.8, 0.3, and 0.7 mm, respectively, for the periodic patterns. Regarding the aperiodic patterns, the median RMSs of EP, EM, and ET were 1.2 (range, 0.9–1.8) mm, 0.1 (range, 0.1–0.5) mm, and 1.2 (range, 0.9–1.8) mm, respectively. From the results of principal component analysis, tracking efficiency, defined as the ratio of twice the RMS of ET to A, was improved for patients with high respiratory function (R = 0.91; p < 0.01).

Conclusions:

The present study demonstrated that the Vero4DRT is capable of high‐accuracy x‐ray‐image‐based DTT. ET was caused primarily by EP, and EM was negligible. Furthermore, principal component analysis showed that tracking efficiency could be improved with this system, especially for patients with high respiratory function.
SlicerRT: Radiation therapy research toolkit for 3D Slicer
Authors: Pinter Csaba , Lasso Andras , Wang An , Jaffray David , Fichtinger Gabor
Published: September 2012

Purpose:

Interest in adaptive radiation therapy research is constantly growing, but software tools available for researchers are mostly either expensive, closed proprietary applications, or free open‐source packages with limited scope, extensibility, reliability, or user support. To address these limitations, we propose SlicerRT, a customizable, free, and open‐source radiation therapy research toolkit. SlicerRT aspires to be an open‐source toolkit for RT research, providing fast computations, convenient workflows for researchers, and a general image‐guided therapy infrastructure to assist clinical translation of experimental therapeutic approaches. It is a medium into which RT researchers can integrate their methods and algorithms, and conduct comparative testing.

Methods:

SlicerRT was implemented as an extension for the widely used 3D Slicer medical image visualization and analysis application platform. SlicerRT provides functionality specifically designed for radiation therapy research, in addition to the powerful tools that 3D Slicer offers for visualization, registration, segmentation, and data management. The feature set of SlicerRT was defined through consensus discussions with a large pool of RT researchers, including both radiation oncologists and medical physicists. The development processes used were similar to those of 3D Slicer to ensure software quality. Standardized mechanisms of 3D Slicer were applied for documentation, distribution, and user support. The testing and validation environment was configured to automatically launch a regression test upon each software change and to perform comparison with ground truth results provided by other RT applications.

Results:

Modules have been created for importing and loading DICOM‐RT data, computing and displaying dose volume histograms, creating accumulated dose volumes, comparing dose volumes, and visualizing isodose lines and surfaces. The effectiveness of using 3D Slicer with the proposed SlicerRT extension for radiation therapy research was demonstrated on multiple use cases.

Conclusions:

A new open‐source software toolkit has been developed for radiation therapy research. SlicerRT can import treatment plans from various sources into 3D Slicer for visualization, analysis, comparison, and processing. The provided algorithms are extensively tested and they are accessible through a convenient graphical user interface as well as a flexible application programming interface.
An efficient protocol for radiochromic film dosimetry combining calibration and measurement in a single scan
Authors: Lewis David , Micke Andre , Yu Xiang , Chan Maria F.
Published: September 2012

Purpose:

Radiochromic film provides dose measurement at high spatial resolution, but often is not preferred for routine evaluation of patient‐specific intensity modulated radiation therapy (IMRT) plans owing to ease‐of‐use factors. The authors have established an efficient protocol that combines calibration and measurement in a single scan and enables measurement results to be obtained in less than 30 min. This avoids complications due to postexposure changes in radiochromic film that delay the completion of a measurement, often for up to 24 h, in commonly used methods. In addition, the protocol addresses the accuracy and integrity of the measurement by eliminating environmental and interscan variability issues.

Methods:

The authors collected dose–response data from six production lots of Gafchromic EBT3 film and three production lots of EBT2 film at doses up to 480 cGy. In this work, the authors used seven different scanners of two different models—Epson 10000XL and V700; postexposure times before scanning from 30 min to 9 days; ambient temperatures for scanning spanning 11 °C; and two film orientations. Scanning was in 48‐bit RGB format at 72 dpi resolution. Dose evaluation was conducted using a triple‐channel dosimetry method. To evaluate the measurement protocol, patient specific IMRT and volumetric modulated arc therapy (VMAT) plans were exposed onto EBT3 films on a Varian Trilogy Linac. Film scanning was done following the protocol under a number of different conditions and the dose maps were analyzed to demonstrate the equivalence of results.

Results:

The results indicated that the dose–response data could be fit by a set of related rational functions leading to the description of a generic calibration curve. A simplified dosimetry protocol was established where dose–response data for a specific film lot, scanner, and scanning conditions could be derived from two films exposed to known doses. In most cases only one calibrated exposure was required since the dose for one of the films could be zero. Using the Gamma test criterion of 2%/2 mm to evaluate the measurements, similar passing rates ranging between about 95% and 99% for the fields studied were obtained from application films digitized under a variety of conditions all of them different than the conditions under which the calibration films were scanned.

Conclusions:

The authors have developed a simplified and efficient protocol to measure doses delivered by an IMRT or VMAT plan using only the patient film, one calibration film, one unexposed film, and applying a single scan to acquire a digital image for calculation and analysis. The simplification and timesaving offer a potential practical solution for using radiochromic film for routine treatment plan quality assurance without sacrificing spatial resolution for convenience.
Successful management of congenital chylous ascites with early octreotide and total parenteral nutrition in a newborn
Authors: Olivieri Claudio , Nanni Lorenzo , Masini Lucia , Pintus Claudio
Published: September 2012

Congenital chylous ascites (CCA) is a rare disease that results from maldevelopment of the intra-abdominal lymphatic system. Few cases have been described and no gold standard treatment has been defined so far. Octreotide, a somatostatin analogue, has been used for the treatment of CCA, but always after a failed conservative approach with fasting, total parenteral nutrition (TPN) or medium chain triglyceride (MCT) feeds. We report the case of a newborn with CCA treated by fasting, TPN and octreotide for a period of 15 days until the abdominal distension was successfully reduced at which point treatment was switched to an MCT formula. On day 25 the patient was breastfed and was discharged on day 33. No recurrence of chylous ascites was noted. Our experience highlights the successful treatment with TPN and octreotide as the first step for the conservative approach of CCA in a newborn, reducing the length of treatment and hospitalisation.