bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantitative cartilage degeneration associated with spontaneous osteoarthritis in a guinea pig model
Authors: Fenty Matthew C. , Dodge George R. , Kassey Victor Babu , Witschey Walter R.T. , Borthakur Arijitt , Reddy Ravinder
Published: December 2011

Purpose:

To determine (i) the feasibility and intra‐ and inter‐scan reproducibility of T1ρ MRI in assessing cartilage degeneration in a guinea pig model with naturally occurring joint disease that closely mimics human osteoarthritis (OA), (ii) demonstrate the sensitivity of T1ρ MRI in assessing the age dependent cartilage degeneration in OA progression as compared to histopathological changes.

Materials and Methods:

Duncan‐Hartley guinea pigs were obtained at various ages and maintained under an IACUC approved protocol. The left hind stifle joint was imaged using T1ρ MRI on a 9.4 Tesla Varian horizontal 20 cm bore scanner using a custom surface coil. Reproducibility of T1ρ MRI was assessed using 4‐month‐old guinea pigs (N = 3). Three age cohorts; 3 month (N = 8), 5 month (N = 6), and 9 month (N = 5), were used to determine the age‐dependent osteoarthritic changes as measured by T1ρ MRI. Validation of age‐dependent cartilage degeneration was confirmed by histology and Safranin‐O staining.

Results:

T1ρ values obtained in the cartilage of the stifle joint in guinea pigs were highly reproducible with an inter‐scan mean coefficient of variation (CV) of 6.57% and a maximum intra‐scan CV of 9.29%. Mean cartilage T1ρ values in animals with late stage cartilage degeneration were 56.3–56.9 ms (5–9 month cohorts) were both significantly (P < 0.01) higher than that obtained from 3‐month‐old cohort (44 ms) demonstrating an age‐dependent variation. T1ρ was shown to be significantly greater than T2. T1ρ dispersion was observed in this animal model for the first time showing an increase of 45% between 500 Hz and 1500 Hz spin‐locking frequency. Cartilage thickness measurements were calculated from single mid‐coronal histology sections from same animals used for T1ρ MRI. Thickness calculations showed insignificant differences between 3‐ and 5‐month cohorts and was significantly decreased by 9 months of age (P < 0.01). A moderate correlation (R2 = 0.45) existed between T1ρ values and signal intensity of Safranin‐O stain.

Conclusion:

The data presented demonstrate that T1ρ MRI is highly reproducible in this spontaneous model of OA and may serve as a noninvasive tool to characterize joint cartilage degeneration during OA. Age‐dependent changes, verified with histological measurements of proteoglycan loss, correlated with T1ρ across different age groups. T1ρ has adequate dynamic range and is sensitive to detect and track the progression of cartilage degeneration in the guinea pig model before gross anatomical changes such as cartilage thinning has occurred. This study presents a technological advancement that would permit longitudinal studies of evaluating disease‐modifying therapies useful for treating human OA. J. Magn. Reson. Imaging 2012;35:891–898. © 2011 Wiley Periodicals, Inc.
Segmentation of carotid plaque using multicontrast 3D gradient echo MRI
Authors: Liu Wenbo , Balu Niranjan , Sun Jie , Zhao Xihai , Chen Huijun , Yuan Chun , Zhao Huilin , Xu Jianrong , Wang Guangzhi , Kerwin William S.
Published: December 2011

Purpose:

To evaluate the performance of automatic segmentation of atherosclerotic plaque components using solely multicontrast 3D gradient echo (GRE) magnetic resonance imaging (MRI).

Materials and Methods:

A total of 15 patients with a history of recent transient ischemic attacks or stroke underwent carotid vessel wall imaging bilaterally with a combination of 2D turbo spin echo (TSE) sequences and 3D GRE sequences. The TSE sequences included T1‐weighted, T2‐weighted, and contrast‐enhanced T1‐weighted scans. The 3D GRE sequences included time‐of‐flight (TOF), magnetization‐prepared rapid gradient echo (MP‐RAGE), and motion‐sensitized driven equilibrium prepared rapid gradient echo (MERGE) scans. From these images, the previously developed morphology‐enhanced probabilistic plaque segmentation (MEPPS) algorithm was retrained based solely on the 3D GRE sequences to segment necrotic core (NC), calcification (CA), and loose matrix (LM). Segmentation performance was assessed using a leave‐one‐out cross‐validation approach via comparing the new 3D‐MEPPS algorithm to the original MEPPS algorithm that was based on the traditional multicontrast protocol including 2D TSE and TOF sequences.

Results:

Twenty arteries of 15 subjects were found to exhibit significant plaques within the coverage of all imaging sequences. For these arteries, between new and original MEPPS algorithms, the areas per slice exhibited correlation coefficients of 0.86 for NC, 0.99 for CA, and 0.80 for LM; no significant area bias was observed.

Conclusion:

The combination of 3D imaging sequences (TOF, MP‐RAGE, and MERGE) can provide sufficient contrast to distinguish NC, CA, and LM. Automatic segmentation using 3D sequences and traditional multicontrast protocol produced highly similar results. J. Magn. Reson. Imaging 2012;35:812–819. © 2011 Wiley Periodicals, Inc.
Contribution of MRI to ultrasound in the diagnosis of fetal anomalies
Authors: Kul Sibel , Korkmaz Hatice Ayca Ata , Cansu Aysegul , Dinc Hasan , Ahmetoglu Ali , Guven Suleyman , Imamoglu Mustafa
Published: December 2011

Purpose:

To evaluate the contribution of MRI to ultrasound (US) in the diagnosis of fetal anomalies.

Materials and Methods:

After informed consent and institutional review board approval, concomitant US and MR imaging were performed for 184 fetuses with suspected anomalies in university hospital. Postnatal final diagnoses were obtained for 183 anomalies in 151 fetuses either by radiological examination, surgery, autopsy, or inspection. The prenatal US and MR diagnoses were compared with respect to postnatal diagnoses. Sign test was used to determine the statistical significance.

Results:

Both ultrasound and MR imaging correctly diagnosed 93 (50%) cases and failed in 12 (7%) cases. Ultrasound was superior in 7 (4%) cases. MR imaging was superior in 71 (39%) cases (P < 0.001). MR contributed to the prenatal diagnosis by the confirmation of the suspected US diagnosis in 13%, by demonstration of additional findings in 31% and by changing the diagnosis in 56% of the cases. The contribution rates were 55% for the central nervous system (CNS) (P < 0.001), 44% for thorax (P = 0.016), 38% for gastrointestinal system (GIS) (P = 0.031) and 29% for genitourinary system (GUS) (P = 0.003) anomalies. In facial, cardiac and extremity‐skeletal system anomalies, there was not a significant contribution of MR imaging over US.

Conclusion:

MR imaging can be used as an adjunct to US in the prenatal diagnosis of fetal anomalies of not only the CNS but also the non‐CNS origin especially those involving the GIS, GUS and thorax. J. Magn. Reson. Imaging 2012;35:882–890. © 2011 Wiley Periodicals, Inc.
Characterization of the regional distribution of skeletal muscle adipose tissue in type 2 diabetes using chemical shift‐based water/fat separation
Authors: Karampinos Dimitrios C. , Baum Thomas , Nardo Lorenzo , Alizai Hamza , Yu Huanzhou , Carballido‐Gamio Julio , Yap S. Paran , Shimakawa Ann , Link Thomas M. , Majumdar Sharmila
Published: December 2011

Purpose:

To show the feasibility of assessing the spatial distribution of skeletal muscle adipose tissue using chemical shift‐based water/fat separation and to characterize differences in calf intermuscular adipose tissue (IMAT) compartmentalization in patients with type 2 diabetes mellitus (T2DM) compared to healthy age‐matched controls.

Materials and Methods:

A chemical shift‐based water/fat separation approach using a multiecho 3D spoiled gradient echo sequence was applied in a study of 64 patients, including 35 healthy controls and 29 subjects with T2DM. Masks were defined based on manual segmentations to compute fat volume within different compartments, including regions of subcutaneous adipose tissue (SAT) and six muscular regions. IMAT was divided into two compartments representing fat within the muscular regions (intraMF) and fat between the muscular regions (interMF). Two‐sample Student's t‐tests were used to compare fat volumes between the two groups.

Results:

The subjects with T2DM had a lower volume of SAT compared to the healthy controls (P = 4 × 10−5). There was no statistically significant difference in the IMAT volume between the two groups. However, the intraMF volume normalized by the IMAT volume was higher in the diabetics compared to the controls (P = 0.006).

Conclusion:

Chemical shift‐based water/fat separation enables the quantification of fat volume within localized muscle regions, showing that the IMAT regional distribution is significantly different in T2DM compared to normal controls. J. Magn. Reson. Imaging 2012;35:899–907. © 2011 Wiley Periodicals, Inc.
Study of photorespiration in marine microalgae through the determination of glycolic acid using hydrophilic interaction liquid chromatography
Authors: Rigobello‐Masini Marilda , Penteado José C. P. , Tiba Maurício , Masini Jorge C.
Published: December 2011

Determination of organic acids in intracellular extracts and in the cultivation media of marine microalgae aid investigations about metabolic routes related to assimilation of atmospheric carbon by these organisms, which are known by their role in the carbon dioxide sink. The separation of these acids was investigated by hydrophilic interaction liquid chromatography (HILIC) using isocratic elution with a mobile phase composed of 70:30 v/v acetonitrile/20 mmol/L ammonium acetate buffer (pH 6.8) and detection at 220 nm. HILIC allowed the determinations of glycolic acid, the most important metabolite for the evaluation of the photorespiration process in algae, to be made with better selectivity than that achieved by reversed phase liquid chromatography, but with less detectability. The concentration of glycolic acid was determined in the cultivation media and in intracellular extracts of the algae Tetraselmis gracilis and Phaeodactylum tricornutum submitted to different conditions of aeration: (i) without forced aeration, (ii) aeration with atmospheric air, and (iii) bubbling with N2. The concentration of glycolic acid had a higher increase as the cultures were aerated with nitrogen, showing higher photorespiratory flux than that occurring in the cultures aerated with atmospheric air.
Determination of trace amount of enantiomeric impurity in therapeutic nicotine derivative using capillary electrophoresis with new imaging technology detection
Authors: Dahab Ali A. , Smith Norman W.
Published: December 2011

One of the many attempts to stop the danger of tobacco smoking is the development of an anti‐smoking vaccine using nicotine butyric acid (NBA) linked to a carrier protein to produce anti‐nicotine antibodies. NBA is a chiral molecule and there is a need to obtain a high degree of enantiomeric purity. The aim of this work is to develop a novel method for the enantioseparation of NBA and the determination of trace amounts of enantiomeric impurity required by regulatory authorities. This was achieved successfully using high‐performance capillary electrophoresis combined with label‐free intrinsic imaging as new imaging technology. A 50 μm id fused‐silica capillary was used with UV detection at λ214 nm and label‐free intrinsic imaging. The background electrolyte consisted of highly sulphated β‐cyclodextrin 10% m/V as a chiral selector in 75 mM phosphoric acid–triethylamine at pH 7.0. Baseline separation and detection of 0.1% and possibly less of the unwanted impurity (R‐enantiomer) were achieved. Also, the detection limits were calculated for both enantiomers. The use of label‐free intrinsic imaging has improved the sensitivity, enabling us to detect trace amounts of enantiomeric impurities.
Nevus of Ota in Dark Skin—An Uncommon but Treatable Entity
Authors: Fusade Thierry , Lafaye Severine , Laubach Hans‐Joachim
Published: December 2011

Background

Nevus of Ota can be effectively and safely treated since the arrival of q‐switched lasers in dermatology. However, available literature is scarce regarding the treatment of Nevus of Ota in skin types darker than IV.

Objectives

We report about four Fitzpatrick phototype V patients treated for Nevus of Ota with a q‐switched Nd:YAG laser at 1,064 nm.

Methods

Four patients with Fitzpatrick phototype V were treated for Nevus of Ota with a q‐switched Nd:YAG laser at 1,064 nm in a private practice setting. Pulse diameter for the treatments was 2 mm and pulses were applied typically in a non‐overlapping fashion. Treatment energies ranged from 4.1 to 9.5 J/cm2.

Results

All four patients of this case series showed significant cosmetic improvement. Improvement ratings, based upon pre‐ and post‐treatment photographs rated by blinded investigators, were in between 6 and 10 with a mean of 8.5 on a 10‐point scale. Side effects were mostly short termed and typical for this laser technique. No post‐inflammatory hyperpigmentation was observed however one case of permanent drop‐like hypopigmentation was encountered.

Conclusions

A 1,064 nm q‐switched Nd:YAG laser treatment could be an effective and reasonably safe treatment for patients with Nevus of Ota and Fitzpatrick skin type V. Patients should be counselled before treatment regarding the risk of permanent hypopigmentation. Lasers Surg. Med. 43:960–964, 2011. © 2011 Wiley Periodicals, Inc.
Management of heat in laser tissue welding using NIR cover window material
Authors: Sriramoju Vidyasagar , Alfano Robert R.
Published: December 2011

Background

Laser tissue welding (LTW) is a novel method of surgical wound closure by the use of laser radiation to induce fusion of the biological tissues. Molecular dynamics associated with LTW is a result of thermal and non‐thermal mechanisms.

Objectives

This research focuses exclusively on better heat management to reduce thermal damage of tissues in LTW using a near infrared laser radiation.

Methods

An infrared continuous‐wave (CW) laser radiation at 1,450 nm wavelength corresponding to the absorption band from combination vibrational modes of water is used to weld together ex vivo porcine aorta.

Results

In these studies we measured the optimal laser power and scan speed, for better tensile strength of the weld and lesser tissue dehydration. Significant amount of water loss from the welded tissue results in cellular death and tissue buckling. Various thermally conductive optical cover windows were used as heat sinks to reduce thermal effects during LTW for the dissipation of the heat. The optimal use of the method prevents tissue buckling and minimizes the water loss. Diamond, sapphire, BK7, fused silica, and IR quartz transparent optical cover windows were tested.

Conclusions

The data from this study suggests that IR‐quartz as the material with optimal thermal conductivity is ideal for laser welding of the porcine aorta. Lasers Surg. Med. 43:991–997, 2011. © 2011 Wiley Periodicals, Inc.
Micro‐patterned drug delivery device for light‐activated drug release
Authors: Zaman Raiyan T. , Gopal Ashwini , Starr Kathryn , Zhang Xiaojing , Thomsen Sharon , Tunnell James W. , Welch Ashley J. , Rylander Henry G.
Published: December 2011

Background

The primary goal of this study was the fabrication, long‐term stability, and measured release of a marker dye from a micro‐patterned drug delivery device using (i) mechanical puncture and (ii) photodisruption with an ophthalmic Nd:YAG laser.

Materials and Methods

A drug delivery device was made from a transparent bio‐compatible polymer. The device consisted of two 2.6 mm diameter reservoirs containing 10% Na fluorescein dye. The device was implanted in the rabbit's eye (n = 2) with the cap of the device facing toward the exterior of the eye. Once the animals recovered from the implant surgery, 100% anhydrous glycerol was topically applied to the eye at the implantation site to decrease light scattering in the conjunctiva and sclera. The dye was released from one of the reservoir either using a 28 G ½ needle or an ophthalmic Q‐switched Nd:YAG laser. A fluorescence spectrophotometer (FS) with fiber optic probe was used to measure the half‐life of the dye in the eye. Measurements of fluorescence intensity were collected until the measurements return to baseline and histology was done on the tissue surrounded the device.

Results

None of the devices leaked of 10% Na fluorescein dye after implant. The ablation threshold of the drug delivery device was between 6 and 10 mJ to create 100–500 µm holes. The half‐life measurement of the dye was found to be 13 days at the vitreous chamber after measuring the fluorescence intensity through the dilated cornea. Histology study showed minimal immune and foreign body response such as mild inflammation.

Conclusion

This study established that the drug delivery device seemed to elicit minimal inflammatory response and retained its fluidic content until it was released with relatively longer retention time (half‐life). Thus, similar device could be used for controlled release of drugs for certain ocular diseases. Lasers Surg. Med. 44:30–48, 2012. © 2011 Wiley Periodicals, Inc.
Fast design of local N‐gram‐specific absorption rate–optimized radiofrequency pulses for parallel transmit systems
Authors: Sbrizzi Alessandro , Hoogduin Hans , Lagendijk Jan J. , Luijten Peter , Sleijpen Gerard L. G. , van den Berg Cornelis A. T.
Published: December 2011

Designing multidimensional radiofrequency pulses for clinical application must take into account the local specific absorption rate (SAR) as controlling the global SAR does not guarantee suppression of hot spots. The maximum peak SAR, averaged over an N grams cube (local NgSAR), must be kept under certain safety limits. Computing the SAR over a three‐dimensional domain can require several minutes and implementing this computation in a radiofrequency pulse design algorithm could slow down prohibitively the numerical process. In this article, a fast optimization algorithm is designed acting on a limited number of control points, which are strategically selected locations from the entire domain. The selection is performed by comparing the largest eigenvalues and the corresponding eigenvectors of the matrices which locally describe the tissue's amount of heating. The computation complexity is dramatically reduced. An additional critical step to accelerate the computations is to apply a multi shift conjugate gradient algorithm. Two transmit array setups are studied: a two channel 3 T birdcage body coil and a 12‐channel 7 T transverse electromagnetic (TEM) head coil. In comparison with minimum power radiofrequency pulses, it is shown that a reduction of 36.5% and 35%, respectively, in the local NgSAR can be achieved within short, clinically feasible, computation times. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
Feasibility, reproducibility, and reliability for the T*2 iron evaluation at 3 T in comparison with 1.5 T
Authors: Meloni Antonella , Positano Vincenzo , Keilberg Petra , De Marchi Daniele , Pepe Pasquale , Zuccarelli Angelo , Campisi Saveria , Romeo Maria Antonietta , Casini Tommaso , Bitti Pier Paolo , Gerardi Calogera , Lai Maria Eliana , Piraino Basilia , Giuffrida Gaetano , Secchi Giuseppina , Midiri Massimo , Lombardi Massimo , Pepe Alessia
Published: December 2011

This study aimed to determine the feasibility, reproducibility, and reliability of the multiecho T*2 Magnetic resonance imaging technique at 3 T for myocardial and liver iron burden quantification and the relationship between T*2 values at 3 and 1.5 T. Thirty‐eight transfusion‐dependent patients and 20 healthy subjects were studied. Cardiac segmental and global T*2 values were calculated after developing a correction map to compensate the artifactual T*2 variations. The hepatic T*2 value was determined over a region of interest. The intraoperator and interoperator reproducibility for T*2 measurements at 3 T was good. A linear relationship was found between patients' R (1000/T*2) values at 3 and 1.5 T. Segmental correction factors were significantly higher at 3 T. A conversion formula returning T*2 values at 1.5 T from values at 3 T was proposed. A good diagnostic reliability for T*2 assessment at 3 T was demonstrated. Lower limits of normal for 3 T T*2 values were 23.3 ms, 21.1 ms, and 11.7 ms, for the global heart, mid‐ventricular septum, and liver, respectively. In conclusion, T*2 quantification of iron burden in the mid‐ventricular septum, global heart, and no heavy–moderate livers resulted to be feasible, reproducible, and reliable at 3 T. Segmental heart T*2 analysis at 3 T may be challenging due to significantly higher susceptibility artifacts. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.
DC electrical conduction and morphological behavior of counter anion‐governed genesis of electrochemically synthesized polypyrrole films
Authors: Singh Rajiv K. , Kumar Amit , Agarwal Khushboo , Kumar Mahesh , Singh H. K. , Srivastava Pankaj , Singh Ramadhar
Published: December 2011

Highly conducting polypyrrole (PPY) films, doped with various anions [pTS−, ClO4−, and NO3− and mixed electrolyte system (pTS− + ClO4−)], have been electrochemically synthesized in aqueous solution at ∼275 K in an inert atmosphere. PPY exhibits metallic order dc conductivity at room temperature and shows variation of conductivity with respect to time of polymerization. Effect of dopant anion on growth mechanism of PPY is evident from its surface morphology. X‐ray photoelectron spectroscopy (XPS), used to examine the surface composition and doping level of various PPY films, confirms the anionic doping into the polymer backbone. Both XPS and ultraviolet–visible spectroscopy give evidence of formation of polarons and bipolarons. The temperature (4.2–320 K)‐dependent dc conductivity data of these PPY films have been explained by Mott's 3D variable‐range hopping conduction model. Mott's parameters have been estimated, and structural disorder with doping is correlated for all the samples. Mott's criterion for distant hopping sites prevails in case of moderately doped samples (PPY3, PPY4, and PPY5), whereas the hopping to nearest neighbor sites is found more suitable in case of highly doped samples (PPY1 and PPY2). The origin of these changes is due to the modification in the molecular structure of PPY, which is governed by different growth mechanisms for organic (pTS−) and inorganic (ClO4− and NO3−) counter anions. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012
Derivatization of Plasma Polymerized Thin Films and Attachment of Biomolecules to Influence HUVEC‐Cell Adhesion
Authors: Lotz Alexander , Heller Martin , Brieger Jürgen , Gabriel Matthias , Förch Renate
Published: December 2011

Plasma polymerized films of allylamine were surface derivatized in subsequent wet chemical processes using a diepoxy‐PEG linker to covalently bind different biomolecules that are known to influence cell adhesion. The initial attachment of human umbilical vein endothelial cells (HUVECs) was studied on (i) unmodified PTFE, (ii) PTFE modified with a layer of plasma polymerized allylamine (pp‐AA), and (iii) PTFE modified with a layer pp‐AA which was further modified using known adhesion molecules coupled to the functional surface via a linker molecule. Statistical analysis of the data initially show significant adhesion improvement of HUVECs on pp‐AA and on pp‐AA modified with either L‐RGD or C‐RGD in comparison to the bare PTFE. The statistical significances between the pp‐AA surface and the modified pp‐AA/RGD surface were however found to be negligible. A significant further improvement was observed for the modified surfaces derivatized with the very much larger fibronectin.

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Secretory phospholipase A2‐IIa is a target gene of the HER/HER2‐elicited pathway and a potential plasma biomarker for poor prognosis of prostate cancer
Authors: Oleksowicz Leslie , Liu Yin , Bracken R. Bruce , Gaitonde Krishnanath , Burke Barbara , Succop Paul , Levin Linda , Dong Zhongyun , Lu Shan
Published: December 2011

BACKGROUND

Our previous study showed that prostate cancer cells overexpress and secrete secretory phospholipases A2 group IIa (sPLA2‐IIa) and plasma sPLA2‐IIa was elevated in prostate cancer patients. The current study further explored the underlying mechanism of sPLA2‐IIa overexpression and the potential role of sPLA2‐IIa as a prostate cancer biomarker.

METHODS

Plasma and tissue specimens from prostate cancer patients were analyzed for sPLA2‐IIa levels. Regulation of sPLA2‐IIa expression by Heregulin‐α was determined by Western blot and reporter assay.

RESULTS

We found that Heregulin‐α enhanced expression of the sPLA2‐IIa gene via the HER2/HER3‐elicited pathway. The EGFR/HER2 dual inhibitor Lapatinib and the NF‐kB inhibitor Bortezomib inhibited sPLA2‐IIa expression induced by Heregulin‐α. Heregulin‐α upregulated expression of the sPLA2‐IIa gene at the transcriptional level. We further confirmed that plasma sPLA2‐IIa secreted by mouse bearing human prostate cancer xenografts reached detectable plasma concentrations. A receiver operating characteristic (ROC) analysis of patient plasma specimens revealed that high levels of plasma sPLA2‐IIa, with the optimum cutoff value of 2.0 ng/ml, were significantly associated with high Gleason score (8–10) relative to intermediate Gleason score (6–7) prostate cancers and advanced relative to indolent cancers. The area under the ROC curve (area under curve, AUC) was 0.73 and 0.74, respectively.

CONCLUSION

We found that Heregulin‐α, in addition to EGF, contributes to sPLA2‐IIa overexpression in prostate cancer cells. Our findings support the notion that high levels of plasma sPLA2‐IIa may serve as a poor prognostic biomarker capable of distinguishing aggressive from indolent prostate cancers, which may improve decision‐making and optimize patient management. Prostate 72:1140–1149, 2012. © 2011 Wiley Periodicals, Inc.
Why Do Nurses Choose to Work in the Perioperative Field?
Authors: Støren Ingeborg , Hanssen Ingrid
Published: December 2011

It is important for educators to know why nursing students choose perioperative nursing so that they can help these students become knowledgeable and perceptive professionals. The purpose of this study was to learn why perioperative nurses chose their specialty and why they chose to leave former positions. We used a Likert‐type questionnaire with 26 statements and one open‐ended question. Ninety of approximately 180 perioperative nursing students in Norway returned the questionnaire. The three most important reasons for choosing perioperative nursing were interest, being able to help patients, and being useful to others, and the three most important reasons for leaving former jobs were wanting more than working on typical patient care units, insufficient staff to provide high‐quality care, and being responsible for too many patients.
Developmental responses of the diamondback moth parasitoidDiadegma semiclausum(Hellén) (Hymenoptera: Ichneumonidae) to temperature and host plant species
Authors: Dosdall L.M. , Zalucki M.P. , Tansey J.A. , Furlong M.J.
Published: December 2011

Effects of constant rearing temperature and the plant species fed upon by its hosts were investigated for several developmental parameters ofDiadegma semiclausum(Hellén), an important parasitoid of the diamondback moth,Plutella xylostella(L.). Temperature had highly significant effects on all developmental parameters measured, and effects were usually both linear and quadratic with increasing temperature. Host plant species, comprisingBrassica napusL.,Brassica rapaL. ssp.pekinensisandBrassica oleraceaL. var.capitata, also affected development of the parasitoid, and significant interactions were observed between plant species and rearing temperature for all developmental parameters measured. Development ofD. semiclausumoccurred successfully on all host plant species tested for the temperature range of 10 to 25°C. However, when itsP. xylostellahosts consumed leaf tissue ofB. napus, no specimens survived to pupate at 30°C, whilst pupation and adult eclosion occurred at 30°C onB. rapassp.pekinensisandB. oleraceavar. capitata. At high ambient temperatures, such as those characteristic of tropical or subtropical regions (especially at low elevations) or regions that undergo temperature increases due to climate change,P. xylostellais predicted to occur at a higher range of temperatures than its biocontrol agent,D. semiclausum. Effects of high temperatures are expected to be more profound on the parasitoid for some host plants than others, with greater developmental limitations for the parasitoid onB. napusthan onB. rapaorB. oleracea.
Patterns of co-morbidity with anxiety disorders in Chinese women with recurrent major depression
Authors: Li Y. , Shi S. , Yang F. , Gao J. , Li Youhui , Tao M. , Wang G. , Zhang K. , Gao C. , Liu L. , Li Kan , Li Keqing , Liu Y. , Wang Xumei , Zhang J. , Lv L. , Wang Xueyi , Chen Q. , Hu J. , Sun L. , Shi J. , Chen Y. , Xie D. , Flint J. , Kendler K. S. , Zhang Z.
Published: December 2011

Background

Studies conducted in Europe and the USA have shown that co-morbidity between major depressive disorder (MDD) and anxiety disorders is associated with various MDD-related features, including clinical symptoms, degree of familial aggregation and socio-economic status. However, few studies have investigated whether these patterns of association vary across different co-morbid anxiety disorders. Here, using a large cohort of Chinese women with recurrent MDD, we examine the prevalence and associated clinical features of co-morbid anxiety disorders.

Method

A total of 1970 female Chinese MDD patients with or without seven co-morbid anxiety disorders [including generalized anxiety disorder (GAD), panic disorder, and five phobia subtypes] were ascertained in the CONVERGE study. Generalized linear models were used to model association between co-morbid anxiety disorders and various MDD features.

Results

The lifetime prevalence rate for any type of co-morbid anxiety disorder is 60.2%. Panic and social phobia significantly predict an increased family history of MDD. GAD and animal phobia predict an earlier onset of MDD and a higher number of MDD episodes, respectively. Panic and GAD predict a higher number of DSM-IV diagnostic criteria. GAD and blood-injury phobia are both significantly associated with suicidal attempt with opposite effects. All seven co-morbid anxiety disorders predict higher neuroticism.

Conclusions

Patterns of co-morbidity between MDD and anxiety are consistent with findings from the US and European studies; the seven co-morbid anxiety disorders are heterogeneous when tested for association with various MDD features.
Stress sensitization following a disaster: a prospective study
Authors: Smid G. E. , van der Velden P. G. , Lensvelt-Mulders G. J. L. M. , Knipscheer J. W. , Gersons B. P. R. , Kleber R. J.
Published: December 2011

Background

According to the stress sensitization hypothesis, prior exposure to extreme stressors may lead to increased responsiveness to subsequent stressors. It is unclear whether disaster exposure is associated with stress sensitization and, if so, whether this effect is lasting or temporary. This study aimed to investigate the occurrence and duration of stress sensitization prospectively following a major disaster.

Method

Residents affected by a fireworks disaster (n=1083) participated in surveys 2–3 weeks (T1), 18–20 months (T2) and almost 4 years (T3) after the disaster. Participants reported disaster exposure, including direct exposure, injury and damage to their home at T1, and also stressful life events (SLEs) at T2 and T3. Feelings of anxiety and depression, concentration difficulty, hostility, sleep disturbance, and intrusion and avoidance of disaster-related memories were used as indicators of distress.

Results

Residents whose home was completely destroyed responded with greater distress to SLEs reported 18–20 months following the disaster than residents whose home was less damaged. There were no differences in stress responsiveness almost 4 years after the disaster.

Conclusions

During the first years after a disaster, stress sensitization may occur in disaster survivors who experienced extreme disaster exposure. Stress sensitization may explain the persistence or progression of distress over time following extreme stressor exposure.
Morphological differences in human zygotes and embryos cultured in different media
Authors: Di Falco Cossiello Raquel , Aggelis Alexandros , Faúndes Daniel , Petta Carlos A.
Published: December 2011

Purpose: To compare the effects of four culture media on the quality of human zygotes and embryos. Methods: Prospective study analyzing 2289 human embryos cultivated simultaneously in two different culture media: HTF, the default medium, with either Universal IVF, Global or IVF-30 as the secondary media. The sibling oocytes by each patient were randomly divided between the two culture media following intracytoplasmic sperm injection (ICSI). On day 1 the pronuclear stage of zygotes were evaluated and on day 2 embryos were evaluated according to the number of cells, percentage of fragmentation and number of nuclei. Z-test and odds ratios were used in the statistical analysis. Results: There was a higher percentage (55.2%) of class A1 + A2 zygotes with IVF-30 compared with HTF, Global or Universal IVF media (49.1%, 44.7% and 44.2%, respectively). The percentage of Top embryos was significantly higher with Global (40.2%) compared with HTF (21.3%), IVF-30 (25.0%) or Universal IVF media (11.2%). Conclusions: Global medium produced more Top embryos evaluated on day 2 of development.
Improvement of the envelope – transient S-parameters' simulation in circuit and system simulation
Authors: Mehdi Hassan , Mons Sebastien , Bennadji Abderrazak , Ngoya Edouard , Quere Raymond
Published: December 2011

This paper focuses on the behavioral modeling of the passive RF blocks from frequency-domain samples. This work is based on vector fitting (VF) approach which is a robust method for MIMO system identification in the frequency domain. This paper addresses firstly the problem of convergence using envelope transient (ET) on complex circuits, i.e. power amplifiers (PAs), where linear sub-circuits are widely described through S-parameters matrices derived from ElectroMagnetic (EM) simulations. An alternative way leads to combine VF method with an RLC synthesis process at the circuit level. This approach is validated on a simple circuit case and generalized to MIMO systems. Second application is the behavioral modeling of MIMO blocks at system level in a high-level spice-like system simulation tool which allows “Control Flow” simulations. The proposed approach combines on one hand the VF method with and impulse responses evaluation on the other hand. In consequence, bilateral behavioral models of MIMO system can be efficiently achieved irrespective of the number of access. This method is validated at once on simple and complex MIMO blocks. As a result, the topological behavioral modeling of complex PAs, which distinguish linear sub-circuits and nonlinear ones, is now possible in a high-level time-domain CAD tool.
Magnetic properties of fault pseudotachylytes in granites
Authors: Ferré E. C. , Geissman J. W. , Zechmeister M. S.
Published: December 2011

We investigate the petrographic, geochemical and magnetic properties of fault pseudotachylytes formed by frictional melting in granitic rocks from Southern California, the Italian Alps and Kyushyu, Japan. The main magnetic remanence carriers are mixtures of grain sizes of fine grained magnetite. These ferrimagnetic grains record a stable, multicomponent magnetization that consists of one or more of the following: coseismic thermal remanent magnetization, coseismic lightning isothermal remanent magnetization and post‐seismic chemical remanent magnetization. Fault pseudotachylytes from the three localities display contrasting magnetic properties, which suggests that oxygen fugacity and host rock composition ultimately control the magnetic assemblage.
Drizzle rates and large sea‐salt nuclei in small cumulus
Authors: Gerber H. , Frick G.
Published: December 2011

The role of large sea‐salt condensation nuclei generated by wind blowing over the ocean surface is evaluated by applying a Lagrangian parcel model to a range of conditions based on observations made during NCAR research flight RF12 of the Rain in Cumulus over the Ocean (RICO) trade wind cumulus (Cu) study in the Caribbean near Antigua. The model utilizes droplet condensation growth, a simplified droplet sedimentation scheme, and quasi‐stochastic coalescence to calculate drizzle rates 1100 m above Cu base. The calculations are repeated without the sea‐salt solution droplets to permit calculation of a drizzle rate enhancement factor (Df) owing to the large nuclei. The model predicts a small effect of the large nuclei on the RF12 drizzle rate, as well as suggesting the same for other RICO flights in agreement with radar studies of the same Cu that also show at most a small effect on precipitation due to the large nuclei. These findings are contrary to those some other studies of the Cu. The present study agrees with several previous studies that large nuclei affect the drizzle rate for wind speeds greater than about 10 m s−1, that the rate increases as wind speed increases, and that the rate increases as droplet concentration becomes larger at constant wind speed. Df values are fit with an analytical expression relating drizzle rate with wind speed and in‐cloud droplet concentration.
Structure of turbulent flow in a meander bend of a lowland river
Authors: Sukhodolov Alexander N.
Published: December 2011

The effects of channel curvature on turbulent flow in meander bends have been the main focus of extensive experimental and theoretical research hitherto. This paper is motivated by growing evidence that riffle‐pool morphology in bends can also have strong implications for the flow structure. Flow in a bend of a lowland river with a shallow riffle and a deep pool is examined in this study by using the results of field measurements. In the study, reach flow is quasi‐uniform in the riffle. In the pool, two layers compose the vertical structure of flow with a quasi‐uniform flow near the riverbed. The upper layer is affected by lateral advection of fluid with low momentum from the inner bank that results in reduced tangential velocities, submergence of velocity maximum, and almost zero shear stress. Bed shear stress is estimated from the local profiles of turbulent shear stress and is shown to comply with values computed with the modified length scale. The maximum bed shear stress is situated in the riffle while theoretical considerations based on the effect of curvature suggest the pool as the most probable location of the maximum. This fact supports the hypothesis that the effects of riffle‐pool morphology are dominant for the study reach. The study contributes to the clarification of up‐scaling results from laboratory experiments to natural rivers by providing a detailed analysis of turbulence profiles. It shows that parameters of turbulence profiles, scaled with the proper velocity and length scales, are similar to those reported by previous experimental studies for open‐channel flow.
Hydroperoxide and peroxynitrite reductase activity of poplar thioredoxin-dependent glutathione peroxidase 5: kinetics, catalytic mechanism and oxidative inactivation
Authors: Selles Benjamin , Hugo Martin , Trujillo Madia , Srivastava Vaibhav , Wingsle Gunnar , Jacquot Jean-Pierre , Radi Rafael , Rouhier Nicolas
Published: December 2011

Gpxs (glutathione peroxidases) constitute a family of peroxidases, including selenocysteine- or cysteine-containing isoforms (SeCys-Gpx or Cys-Gpx), which are regenerated by glutathione or Trxs (thioredoxins) respectively. In the present paper we show new data concerning the substrates of poplar Gpx5 and the residues involved in its catalytic mechanism. The present study establishes the capacity of this Cys-Gpx to reduce peroxynitrite with a catalytic efficiency of 106 M−1·s−1. In PtGpx5 (poplar Gpx5; Pt is Populus trichocarpa), Glu79, which replaces the glutamine residue usually found in the Gpx catalytic tetrad, is likely to be involved in substrate selectivity. Although the redox midpoint potential of the Cys44–Cys92 disulfide bond and the pKa of Cys44 are not modified in the E79Q variant, it exhibited significantly improved kinetic parameters (Kperoxide and kcat) with tert-butyl hydroperoxide. The characterization of the monomeric Y151R variant demonstrated that PtGpx5 is not an obligate homodimer. Also, we show that the conserved Phe90 is important for Trx recognition and that Trx-mediated recycling of PtGpx5 occurs via the formation of a transient disulfide bond between the Trx catalytic cysteine residue and the Gpx5 resolving cysteine residue. Finally, we demonstrate that the conformational changes observed during the transition from the reduced to the oxidized form of PtGpx5 are primarily determined by the oxidation of the peroxidatic cysteine into sulfenic acid. Also, MS analysis of in-vitro-oxidized PtGpx5 demonstrated that the peroxidatic cysteine residue can be over-oxidized into sulfinic or sulfonic acids. This suggests that some isoforms could have dual functions potentially acting as hydrogen-peroxide- and peroxynitrite-scavenging systems and/or as mediators of peroxide signalling as proposed for 2-Cys peroxiredoxins.
Functional mapping of the disparate activities of the yeast moonlighting protein Hal3
Authors: Abrie J. Albert , González Asier , Strauss Erick , Ariño Joaquín
Published: December 2011

The Saccharomyces cerevisiae Hal3 protein is a moonlighting protein, able to function both as an inhibitory subunit of the Ppz1 protein phosphatase and as a constituent protomer of an unprecedented heterotrimeric PPCDC (phosphopantothenoylcysteine decarboxylase), the third enzyme of the CoA biosynthetic pathway. In the present study we initiated the dissection of the structural elements required for both disparate cellular tasks by using a combination of biochemical and genetic approaches. We show that the conserved Hal3 core [PD (PPCDC domain)] is necessary for both functions, as determined by in vitro and in vivo assays. The Hal3 NtD (N-terminal domain) is not functional by itself, although in vitro experiments indicate that when this domain is combined with the core it has a relevant function in Hal3's heteromeric PPCDC activity. Both the NtD and the acidic CtD (C-terminal domain) also appear to be important for Hal3's Ppz1 regulatory function, although our results indicate that the CtD fulfils the key role in this regard. Finally, we show that the introduction of two key asparagine and cysteine residues, essential for monofunctional PPCDC activity but absent in Hal3, is not sufficient to convert it into such a homomeric PPCDC, and that additional modifications of Hal3's PD aimed at increasing its resemblance to known PPCDCs also fails to introduce this activity. This suggests that Hal3 has undergone significant evolutionary drift from ancestral PPCDC proteins. Taken together, our work highlights specific structural determinants that could be exploited for full understanding of Hal3's cellular functions.
Diet and Exercise Improve Neutrophil to Lymphocyte Ratio in Overweight Adolescents
Authors: Wang R. , Chen P. , Chen W.
Published: December 2011

Neutrophil to lymphocyte ratio and levels of pro-inflammatory cytokines were evaluated in overweight, male Chinese adolescents upon completing a 4-week diet and physical exercise intervention. 43 recruited, non-randomized adolescents (body mass index >25 kg/m2) completed the controlled study. Anthropometric and biologic parameters were measured pre- and post-intervention. After the 4-week intervention, participants exhibited a significant decrease in body mass, body mass index, percentage body fat, basal heart rate, diastolic blood pressure, and all body shape indices tested. A significant decrease in serum lipids (except high-density lipoprotein cholesterol) and insulin levels was observed post-intervention. The neutrophil to lymphocyte ratio was significantly lower post-intervention. Bivariate correlation analyses showed that decrement in Δneutrophil to lymphocyte ratio significantly correlated with decrement in Δinterleukin-6 and Δwhite blood cell count. Thus, a 4-week diet and physical exercise intervention significantly reduces the neutrophil to lymphocyte ratio in a population of overweight, male adolescents. Weight loss caused by the intervention was associated with a significant decrease of pro-inflammatory cytokine levels.
The magnetic properties of potassium holmium double tungstate
Authors: Borowiec M. T. , Dyakonov V. P. , Khatsko E. N. , Zayarnyuk T. , Zubov E. E. , Szewczyk A. , Gutowska M. U. , Rykova A. I. , Piętosa J. , Majchrowski A. , Michalski E. , Hoffmann J.-U. , Prokes K. , Woźniak K. , Dobrzycki Ł. , Barański M. , Domukhovski V. , Shtyrkhunova V. , Żmija J. , Szymczak H.
Published: December 2011

The magnetic investigations of potassium holmium double tungstate KHo(WO4)2 have been performed. The results of measurements of magnetic susceptibility and magnetization as a function of temperature (T from 0.3 K up to 100 K) and magnetic field (up to 1.5 T) are presented. A strong anisotropy of magnetic properties was found. The magnetic measurements data were used to calculate the interaction energy. It was shown that the interactions between nearest neighbors Ho3+ ions have antiferromagnetic character.
Dynamical theory: Application to spin-echo resolved grazing incidence scattering from periodic structures
Authors: Ashkar Rana , Schaich W. L. , de Haan V. O. , van Well A. A. , Dalgliesh R. , Plomp J. , Pynn Roger
Published: December 2011

Neutron spin-echo resolved grazing incidence scattering (SERGIS) measurements performed on a silicon diffraction grating with a rectangular profile were shown in our previous publications to be well explained by dynamical theory calculations. The theory is based on a Bloch wave expansion of the neutron wavefunction in the periodic layer of the grating, which includes all multiple scattering within that layer. Calculations show that the spin-echo polarization should be very sensitive to the scattering geometry (i.e., incident angle, sample alignment and beam divergence) and the sample specifications (i.e., grating period, groove depth). To test these predictions, SERGIS measurements have been performed on a set of gratings with different specifications in various scattering geometries. In all cases, simulations based on the dynamical theory, with all the parameters set to their known values, are in good agreement with the collected data.
Surfactant enhanced solid phase epitaxy of Ge/CaF2/Si(111): Synchrotron x-ray characterization of structure and morphology
Authors: Wollschläger J. , Deiter C. , Wang C. R. , Müller B. H. , Hofmann K. R.
Published: December 2011

The structure and morphology of CaF2/Si(111) and Ge/CaF2/Si(111) layered structures with film thicknesses in the range of very few nanometers has been studied with synchrotron-based radiation. While the CaF2 film is grown via molecular beam epitaxy, the Ge film is fabricated by surfactant enhanced solid phase epitaxy with Sb as surfactant. The CaF2 film forms two laterally separated phases of relaxed CaF2 and pseudomorphic CaF2, respectively, although the film thickness is very homogeneous. The Ge film is completely relaxed and forms A-oriented parts as well as B-oriented parts, due to twinning. In spite of the large surface roughness of the Ge film, it completely wets CaF2/Si(111) also after annealing at 600 °C, due to the application of Sb during the annealing process.