bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydride Reactivity of NiIIXNiII Entities: Mixed‐Valent Hydrido Complexes and Reversible Metal Reduction
Authors: Gehring Henrike , Metzinger Ramona , Herwig Christian , Intemann Julia , Harder Sjoerd , Limberg Christian
Published: January 2013

After the lithiation of PYR‐H2 (PYR2−=[{NC(Me)C(H)C(Me)NC6H3(iPr)2}2(C5H3N)]2−), which is the precursor of an expanded β‐diketiminato ligand system with two binding pockets, its reaction with [NiBr2(dme)] led to a dinuclear nickel(II)–bromide complex, [(PYR)Ni(μ‐Br)NiBr] (1). The bridging bromide ligand could be selectively exchanged for a thiolate ligand to yield [(PYR)Ni(μ‐SEt)NiBr] (3). In an attempt to introduce hydride ligands, both compounds were treated with KHBEt3. This treatment afforded [(PYR)Ni(μ‐H)Ni] (2), which is a mixed valent NiIμ‐HNiII complex, and [(PYR‐H)Ni(μ‐SEt)Ni] (4), in which two tricoordinated NiI moieties are strongly antiferromagnetically coupled. Compound 4 is the product of an initial salt metathesis, followed by an intramolecular redox process that separates the original hydride ligand into two electrons, which reduce the metal centres, and a proton, which is trapped by one of the binding pockets, thereby converting it into an olefin ligand on one of the NiI centres. The addition of a mild acid to complex 4 leads to the elimination of H2 and the formation of a NiIINiII compound, [(PYR)Ni(μ‐SEt)NiOTf] (5), so that the original NiII(μ‐SEt)NiIIX core of compound 3 is restored. All of these compounds were fully characterized, including by X‐ray diffraction, and their molecular structures, as well as their formation processes, are discussed.
Isomerization Energy Decomposition Analysis for Highly Ionic Systems: Case Study of Starlike E5Li7+ Clusters
Authors: Contreras Maryel , Osorio Edison , Ferraro Franklin , Puga Gustavo , Donald Kelling J. , Harrison Jason G. , Merino Gabriel , Tiznado William
Published: January 2013

The most stable forms of E5Li7+ (E=Ge, Sn, and Pb) have been explored by means of a stochastic search of their potential‐energy surfaces by using the gradient embedded genetic algorithm (GEGA). The preferred isomer of the Ge5Li7+ ion is a slightly distorted analogue of the D5h three‐dimensional seven‐pointed starlike structure adopted by the lighter C5Li7+ and Si5Li7+ clusters. In contrast, the preferred structures for Sn5Li7+ and Pb5Li7+ are quite different. By starting from the starlike arrangement, corresponding lowest‐energy structures are generated by migration of one of the E atoms out of the plane with the a corresponding rearrangement of the Li atoms. To understand these structural preferences, we propose a new energy decomposition analysis based on isomerizations (isomerization energy decomposition analysis (IEDA)), which enable us to extract energetic information from isomerization between structures, mainly from highly charged fragments.
Harnessing the Flexibility of Peptidic Scaffolds to Control their Copper(II)‐Coordination Properties: A Potentiometric and Spectroscopic Study
Authors: Fragoso Ana , Lamosa Pedro , Delgado Rita , Iranzo Olga
Published: January 2013

Designing small peptides that are capable of binding Cu2+ions mainly through the side‐chain functionalities is a hard task because the amide nitrogen atoms strongly compete for Cu2+ion coordination. However, the design of such peptides is important for obtaining biomimetic small systems of metalloenyzmes as well as for the development of artificial systems. With this in mind, a cyclic decapeptide, C‐Asp, which contained three His residues and one Asp residue, and its linear derivative, O‐Asp, were synthesized. The C‐Asp peptide has two ProGly β‐turn‐inducer units and, as a result of cyclization, and as shown by CD spectroscopy, its backbone is constrained into a more defined conformation than O‐Asp, which is linear and contains a single ProGly unit. A detailed potentiometric, mass spectrometric, and spectroscopic study (UV/Vis, CD, and EPR spectroscopy) showed that at a 1:1 Cu2+/peptide ratio, both peptides formed a major [CuHL]2+species in the pH range 5.0–7.5 (C‐Asp) and 5.5–7.0 (O‐Asp). The corrected stability constants of the protonated species (log K*CuH(O−Asp)=9.28 and log K*CuH(C−Asp)=10.79) indicate that the cyclic peptide binds Cu2+ions with higher affinity. In addition, the calculated value ofKeffshows that this higher affinity for Cu2+ions prevails at all pH values, not only for a 1:1 ratio but even for a 2:1 ratio. The spectroscopic data of both [CuHL]2+species are consistent with the exclusive coordination of Cu2+ions by the side‐chain functionalities of the three His residues and the Asp residue in a square‐planar or square‐pyramidal geometry. Nonetheless, although these data show that, upon metal coordination, both peptides adopt a similar fold, the larger conformational constraints that are present in the cyclic scaffold results in different behaviour for both [CuHL]2+species. CD and NMR analysis revealed the formation of a more rigid structure and a slower Cu2+‐exchange rate for [CuH(C‐Asp)]2+compared to [CuH(O‐Asp]2+. This detailed comparative study shows that cyclization has a remarkable effect on the Cu2+‐coordination properties of the C‐Asp peptide, which binds Cu2+ions with higher affinity at all pH values, stabilizes the [CuHL]2+species in a wider pH range, and has a slower Cu2+‐exchange rate compared to O‐Asp.
Development of Palladium Surface‐Enriched Heteronuclear Au–Pd Nanoparticle Dehalogenation Catalysts in an Ionic Liquid
Authors: Yuan Xiao , Sun Geng , Asakura Hiroyuki , Tanaka Tsunehiro , Chen Xi , Yuan Yuan , Laurenczy Gabor , Kou Yuan , Dyson Paul J. , Yan Ning
Published: January 2013

Heteronuclear Au–Pd nanoparticles were prepared and immobilized in the functionalized ionic liquid [C2OHmim][NTf2]. The structural and electronic properties of the nanoparticles were characterized by a range of techniques and the surface of the nanoparticles was found to be enriched in Pd. Moreover, the extent of Pd enrichment is easily controlled by varying the ratio of Au and Pd salts used in the synthesis. The heteronuclear nanoparticles were found to be effective catalysts in dehalogenation reactions with no activity observed for the pure Au nanoparticles and only limited activity for the pure Pd nanoparticles. The activity of the heteronuclear nanoparticles may be attributed to charge transfer from Pd to Au and consequently to more efficient reductive elimination.
An Examination of the Palladium/Mor‐DalPhos Catalyst System in the Context of Selective Ammonia Monoarylation at Room Temperature
Authors: Alsabeh Pamela G. , Lundgren Rylan J. , McDonald Robert , Johansson Seechurn Carin C. C. , Colacot Thomas J. , Stradiotto Mark
Published: January 2013

An examination of the [{Pd(cinnamyl)Cl}2]/Mor‐DalPhos (Mor‐DalPhos=di(1‐adamantyl)‐2‐morpholinophenylphosphine) catalyst system in Buchwald–Hartwig aminations employing ammonia was conducted to better understand the catalyst formation process and to guide the development of precatalysts for otherwise challenging room‐temperature ammonia monoarylations. The combination of [{Pd(cinnamyl)Cl}2] and Mor‐DalPhos afforded [(κ2‐P,N‐Mor‐DalPhos)Pd(η1‐cinnamyl)Cl] (2), which, in the presence of a base and chlorobenzene, generated [(κ2‐P,N‐Mor‐DalPhos)Pd(Ph)Cl] (1 a). Halide abstraction from 1 a afforded [(κ3‐P,N,O‐Mor‐DalPhos)Pd(Ph)]OTf (5), bringing to light a potential stabilizing interaction that is offered by Mor‐DalPhos. An examination of [(κ2‐P,N‐Mor‐DalPhos)Pd(aryl)Cl] (1 b–f) and related precatalysts for the coupling of ammonia and chlorobenzene at room temperature established the suitability of 1 a in such challenging applications. The scope of reactivity for the use of 1 a (5 mol %) encompassed a range of (hetero)aryl (pseudo)halides (X=Cl, Br, I, OTs) with diverse substituents (alkyl, aryl, ether, thioether, ketone, amine, fluoro, trifluoromethyl, and nitrile), including chemoselective arylations.
Structural Aspects of Gut Peptides with Therapeutic Potential for Type 2 Diabetes
Authors: Hewage Chandralal M. , Venneti Kalyana C.
Published: January 2013

Gut hormones represent a niche subset of pharmacologically active agents that are rapidly gaining importance in medicine. Due to their exceptional specificity for their receptors, these hormones along with their analogues have attracted considerable pharmaceutical interest for the treatment of human disorders including type 2 diabetes. With the recent advances in the structural biology, a significant amount of structural information for these hormones is now available. This Minireview presents an overview of the structural aspects of these hormones, which have roles in physiological processes such as insulin secretion, as well as a discussion on the relevant structural modifications used to improve these hormones for the treatment of type 2 diabetes.
Electrochemically Modified Carbon and Chromium Surfaces for AFM Imaging of Double‐Strand DNA Interaction with Transposase Protein
Authors: Esnault Charles , Chénais Benoît , Casse Nathalie , Delorme Nicolas , Louarn Guy , Pilard Jean‐François
Published: January 2013

Carbon and chromium surfaces were modified by electrochemical reduction of a diazonium salt formed in situ from the sulfanilic acid. The organic layer formed was activated by phosphorus pentachloride (PCl5) to form a benzene sulfonil chloride (ArSO2Cl). An electrochemical study of the blocking effect and the activity of this surface was carried out on a carbon electrode. The chromium surface study was completed by X‐ray photoelectron spectroscopy and atomic force microscopy to characterize the formation of a compact monolayer (0.8 nm height and roughness 0.2–0.3 nm). The compactness and the activity of this organic monolayer allowed us to affix a length dsDNA with the aim of analyzing the formation of a complex between dsDNA and a protein. The interaction of a transposase protein with its target dsDNA was investigated. The direct imaging of the nucleoproteic complex considered herein gives new insights in the comprehension of transposase–DNA interaction in agreement with biochemical data.
Dietary exposure of mink (Mustela vison) to fish from the upper Hudson River, New York, USA: Effects on reproduction and offspring growth and mortality
Authors: Bursian Steven J. , Kern John , Remington Richard E. , Link Jane E. , Fitzgerald Scott D.
Published: January 2013

The effects of feeding farm-raised mink (Mustela vison) diets containing polychlorinated biphenyl (PCB)–contaminated fish from the upper Hudson River (New York, USA) on adult reproductive performance and kit growth and mortality were evaluated. Diets contained 2.5 to 20% Hudson River fish, providing 0.72 to 6.1 µg ∑PCBs/g feed (4.8–38 pg toxic equivalents [TEQWHO 2005]/g feed). The percentage of stillborn kits per litter was significantly increased by dietary concentrations of 4.5 µg ∑PCBs/g feed (28 pg TEQWHO 2005/g feed) and greater. All offspring exposed to dietary concentrations of 4.5 and 6.1 µg ∑PCBs/g feed (28 and 38 pg TEQWHO 2005/g feed) died by 10 weeks of age, and all offspring exposed to 1.5 and 2.8 µg ∑PCBs/g feed (10 and 18 pg TEQWHO 2005/g feed) died by 31 weeks of age, leaving juveniles in the control and 0.72 µg ∑PCBs/g feed (0.41- and 4.8 pg TEQWHO 2005/g feed) groups only. The dietary concentration predicted to result in 20% kit mortality (LC20) at six weeks of age was 0.34 µg ∑PCBs/g feed (2.6 pg TEQWHO 2005/g feed). The corresponding maternal hepatic concentration was 0.80 µg ∑PCBs/g liver, wet weight (13 pg TEQWHO 2005/g liver, wet wt). Mink residing in the upper Hudson River would be expected to consume species of fish that contain an average of 4.0 µg ∑PCBs/g tissue. Thus, a daily diet composed of less than 10% Hudson River fish could provide a dietary concentration of ∑PCBs that resulted in 20% kit mortality in the present study. Environ. Toxicol. Chem. 2013;32:780–793. © 2013 SETAC
Dietary exposure of mink (Mustela vison) to fish from the upper Hudson River, New York, USA: Effects on organ mass and pathology
Authors: Bursian Steven J. , Kern John , Remington Richard E. , Link Jane E. , Fitzgerald Scott D.
Published: January 2013

The authors evaluated effects of feeding ranch mink (Mustela vison) diets containing polychlorinated biphenyl (PCB)–contaminated fish from the upper Hudson River (New York, USA) on adult and offspring organ mass and pathology. Diets contained 2.5 to 20% Hudson River fish, providing 0.72 to 6.1 µg ΣPCBs/g feed (4.8–38 pg toxic equivalents [TEQWHO 2005]/g feed). Absolute thyroid and adrenal gland masses were increased in adult females and 31-week-old juveniles, respectively, and absolute liver and heart masses were decreased in six-week-old kits exposed to dietary PCBs. Dietary concentrations of 0.72 µg ΣPCBs/g feed (4.8 pg TEQWHO 2005/g feed) and greater induced mandibular and maxillary squamous epithelial proliferation in adult animals. The dietary concentration of ΣPCBs predicted to result in 20% incidence of the jaw lesion (EC20) was 2.3 µg ΣPCBs/g feed (15 pg TEQWHO 2005/g feed), and the hepatic concentration was 2.8 µg ΣPCBs/g liver (89 pg TEQWHO 2005/g liver). The EC20 values were greater than the dietary and hepatic concentrations predicted to result in a 20% increase in kit mortality (LC20) at six weeks of age (0.34 µg ΣPCBs/g feed or 2.6 pg TEQWHO 2005/g feed and 0.80 µg ΣPCBs/g liver or 13 pg TEQWHO 2005/g liver). However, the EC20 values reflect exposure of adults to PCBs for approximately six months, and the LC20 values reflect exposure of offspring from conception onward. Environ. Toxicol. Chem. 2013;32:794–801. © 2013 SETAC
Study on Noninvasive Laboratory Tests for Fibrosis in Chronic HBV Infection and Their Evaluation
Authors: Chen Jing , Liu Can , Chen Huijuan , Liu Qicai , Yang Bin , Ou Qishui
Published: January 2013

Background

Noninvasive laboratory tests have been widely used in the diagnosis of liver fibrosis. This study was designed to evaluate the diagnostic value of the four serum markers detected on a JETLIA‐962 chemiluminescence analyzer and the FibroTest index for chronic hepatitis B (CHB) related liver fibrosis. J. Clin. Lab. Anal. 27:5–11, 2013. © 2012 Wiley Periodicals, Inc.

Methods

A JETLIA‐962 chemiluminescence analyzer was used to measure the hyaluronic acid (HA), laminin (LN), procollagen III N‐terminal peptide (PIIINP), and type IV collagen (CIV) contents in the sera of CHB patients and controls.

Results

In our research, it was found that serum HA, LN, PIIINP, and CIV concentrations and the FibroTest index were correlated with fibrosis stage. The FibroTest index had the largest area under the receiver operating characteristic (ROC) curve for fibrosis and cirrhosis (0.80 and 0.776, respectively). The five indices together were able to exclude fibrosis with a negative likelihood ratio <0.1. The logistic regression equations for diagnosing liver fibrosis and early cirrhosis were separately established.

Conclusions

We found that the JETLIA‐962 chemiluminescence analyzer was of great value in diagnosis of liver fibrosis. Combining five indices improved the diagnostic efficiency and reduced the incidences of unnecessary liver biopsies. Two logistic regression equations established may be helpful in diagnosing liver fibrosis and early cirrhosis, which need to be further evaluated.
The Tetrad BMI, Leptin, Leptin/Adiponectin (L/A) Ratio and CA 15‐3 are Reliable Biomarkers of Breast Cancer
Authors: Santillán‐Benítez Jonnathan G. , Mendieta‐Zerón Hugo , Gómez‐Oliván Leobardo M. , Torres‐Juárez Juan J. , González‐Bañales Juan M. , Hernández‐Peña Lorena V. , Ordóñez‐Quiroz Angel
Published: January 2013

Background

Several studies have reported that leptin levels, the leptin/adiponectin (L/A) ratio and carbohydrate antigen (CA) 15‐3 are especially elevated in breast cancer patients with high body mass index (BMI). The purpose of this study was to evaluate BMI, leptin, L/A ratio and CA 15‐3 all together as reliable biomarkers for breast cancer. J. Clin. Lab. Anal. 27:12–20, 2013. © 2012 Wiley Periodicals, Inc.

Methods

Serum levels of leptin, adiponectin and CA 15‐3, as well as anthropometric and biochemical parameters were analysed in 88 female patients who participated in a mammography study. Predictive values of BMI, leptin, L/A ratio and CA 15‐3 were determined with a 95% confidence interval.

Results

Women were diagnosed with either breast cancer (n = 40) or benign breast lesions (n = 48). Among anthropometric parameters, age (P ≤ 0.001), weight (P ≤ 0.05) and waist circumference (P ≤ 0.02) were higher in patients with breast cancer than in patients without this pathology. The 75th percentile values for BMI, leptin, L/A ratio and CA 15‐3 were 29.24 kg/m2, 26.65 ng/ml, 2.37 and 18.45 IU, respectively. The suggested odds ratio for breast cancer patients with the values that were above the 75th percentile of the tetrad was 6.7 (0.7505–60.0665 confidence interval).

Conclusion

When the four variables were analysed together, a sensitivity of 83.3%, specificity of 80%, positive predictive value of 83.3% and negative predictive value of 80% were obtained. Results indicate that using the 75th percentile set points for BMI, leptin, L/A ratio and CA 15‐3 together could offer a reliable approach to determine which women are at high risk for developing breast cancer.
Increased Serum Hepcidin and Ghrelin Levels in Children Treated for Iron Deficiency Anemia
Authors: Dogan Ayse , Alioglu Bulent , Dindar Nermin , Dallar Yildiz
Published: January 2013

Background

The aim of this study was to determine the relation between iron deficiency anemia (IDA) and serum leptin, hepcidin, and ghrelin levels. J. Clin. Lab. Anal. 27:81–5, 2013. © 2012 Wiley Periodicals, Inc.

Methods

Thirty children with IDA and 28 healthy children between the ages of 6 months and 6 years admitted to our hospital were evaluated prospectively. IDA was diagnosed based on clinical and laboratory findings. All children with IDA were treated with iron II‐glycine‐sulphate complex for 3 months. Complete blood count; iron metabolism parameters; and serum leptin, hepcidin, and ghrelin levels were studied in all healthy children and in children with IDA before and after treatment.

Results

In children with IDA, the decrease seen in serum leptin levels after the iron treatment was not statistically significant. However, the increase seen in serum hepcidin levels after the iron treatment was statistically significant (P = 0.038). Hepcidin levels were significantly higher in children with IDA who received iron treatment compared to healthy children (P = 0.008). After the iron treatment, serum ghrelin levels in children with IDA were also significantly higher compared to the levels before treatment and healthy children (P = 0.019 and 0.000, respectively).

Conclusion

Serum ghrelin and hepcidin levels increase with iron treatment in children with IDA. In view of the higher serum ghrelin and hepcidin levels after iron treatment when compared to pretreatment levels and the healthy children, we suggest that the iron treatment has an important role in serum hepcidin and ghrelin synthesis. J. Clin. Lab. Anal. 00:1‐5, 2012. © 2012 Wiley Periodicals, Inc.
Morphology of the elygium and developing umbraculum in the eye of Amietia vertebralis tadpoles
Authors: Kruger Donnavan J.D. , Weldon Ché , Minter Les R. , Du Preez Louis H.
Published: January 2013

The elygium is a darkly pigmented projection over the pupil of the tadpoles of certain species that live mostly at high altitudes. It has been suggested that this structure shades the retina, protecting it from high UV levels. In post‐metamorphic individuals, the elygium is replaced by a structure known as an umbraculum. Confusion arose in the past from the inconsistent use of terminology when referring to these two structures. While they may serve the same function, these structures differ fundamentally in structure and origin. Our investigation of the ultrastructure of the eye in Amietia vertebralis tadpoles, using electron and light microscopy, revealed that the elygium consists of an accumulation of melanophores situated within the inner cornea, whereas the umbraculum is a dorsal extension of the iris pigment epithelium, analogous to the ventral pupillary nodule, which is present in most frog species. In A. vertebralis, the umbraculum starts to develop on the iris of older tadpoles (Gosner [1960] stage 37 Herpetologica 16:183–190), medial to the overlying elygium. A smaller, ventral elygium is also present in this species and is similar in structure to the dorsal elygium. The development of the elygium over a six‐month period is also described. J. Morphol., 2013. © 2013 Wiley Periodicals, Inc.
Heating of metallic rods induced by time‐varying gradient fields in MRI
Authors: El Bannan Khaled , Handler William , Chronik Blaine , Salisbury Shaun P.
Published: January 2013

Purpose

To develop and validate an analytical technique to estimate the heating of metallic rods by magnetic resonance imaging (MRI) gradient fields to aid developers of MRI‐compatible devices.

Materials and Methods

Twelve rods (12.7 mm diameter, 127 mm long) were used. The magnetic field was provided by a custom‐made water‐cooled solenoid driven by a 1 kHz sinusoidal waveform with a 7.2 A peak current. The sample was insulated with polystyrene and the temperature measured using an MR‐compatible thermocouple system (Sa1‐E from Omega). Measurements were recorded using a National Instruments SCXI‐1303. The AC/DC module of COMSOL 3.4 was used for finite element analysis of the power deposited.

Results

Finite element analysis (FEA) showed good correspondence with the analytical estimates for the rod parallel to the field and then FEA was used to determine the scaling function for the rod perpendicular to the field. The experimental results showed good correlation with the theoretical estimate when the finite length of the test coil was accounted for.

Conclusion

A new scaling function for the rod perpendicular to the field was developed. Heating in this orientation is double that of the parallel case. The results will aid developers of MRI‐compatible devices in estimating heating before testing in the MRI. J. Magn. Reson. Imaging 2013;38:411–416. © 2013 Wiley Periodicals, Inc.
Exploring ΔR2* and ΔR1 as imaging biomarkers of tumor oxygenation
Authors: Burrell Jake S. , Walker‐Samuel Simon , Baker Lauren C.J. , Boult Jessica K.R. , Jamin Yann , Halliday Jane , Waterton John C. , Robinson Simon P.
Published: January 2013

Purpose

To investigate the combined use of hyperoxia‐induced ΔR2* and ΔR1 as a noninvasive imaging biomarker of tumor hypoxia.

Materials and Methods

MRI was performed on rat GH3 prolactinomas (n = 6) and human PC3 prostate xenografts (n = 6) propagated in nude mice. multiple gradient echo and inversion recovery truefisp images were acquired from identical transverse slices to quantify tumor R2* and R1 before and during carbogen (95% O2/5% CO2) challenge, and correlates of ΔR2* and ΔR1 assessed.

Results

Mean baseline R2* and R1 were 119 ± 7 s−1 and 0.6 ± 0.03 s−1 for GH3 prolactinomas and 77 ± 12 s−1 and 0.7 ± 0.02 s−1 for PC3 xenografts, respectively. During carbogen breathing, mean ΔR2* and ΔR1 were −20 ± 8 s−1 and 0.08 ± 0.03 s−1 for GH3 and −0.5 ± 1 s−1 and 0.2 ± 0.08 s−1 for the PC3 tumors, respectively. A pronounced relationship between ΔR2* and ΔR1 was revealed.

Conclusion

Considering the blood oxygen–hemoglobin dissociation curve, fast R2* suggested that GH3 prolactinomas were more hypoxic at baseline, and their carbogen response dominated by increased hemoglobin oxygenation, evidenced by highly negative ΔR2*. PC3 tumors were less hypoxic at baseline, and their response to carbogen dominated by increased dissolved oxygen, evidenced by highly positive ΔR1. Because the two biomarkers are sensitive to different oxygenation ranges, the combination of ΔR2* and ΔR1 may better characterize tumor hypoxia than each alone. J. Magn. Reson. Imaging 2013;38:429–434. © 2013 Wiley Periodicals, Inc.
Automated T2* measurements using supplementary field mapping to assess cardiac iron content
Authors: Taylor Brian A. , Loeffler Ralf B. , Song Ruitian , McCarville Mary E. , Hankins Jane S. , Hillenbrand Claudia M.
Published: January 2013

Purpose

To develop and evaluate an algorithm that automatically identifies high‐susceptibility areas and excludes them from T2* measurements in the left ventricle (LV) for myocardial iron measurements.

Materials and Methods

An autoregressive moving average (ARMA) model was implemented on multigradient echo scans of 24 patients (age range 3–45 years, 10 male/14 female). Voxels with relatively high susceptibility (>3 Hz/mm) were flagged and deselected from the T2* calculations for iron quantification. The mean, standard deviation, and coefficient of variation (CoV) of the ARMA‐defined region were compared to the CoV of four distinct regions of the LV and the entire LV using a Student's t‐test (α = 0.05).

Results

The CoV of T2* values obtained by the ARMA method are comparable with that in the interventricular septum (IS), where susceptibility was the lowest (CoV = 0.31). The ARMA method provides a greater area (51.9 ± 13.7% of the LV) to measure T2* than that using the IS alone (21.1 ± 3.4%, P < 0.0001). Areas where low susceptibility are measured corroborate with areas reported in previous studies that investigated T2* variations throughout the LV.

Conclusion

An automated method to measure T2* relaxation in the LV with minimal effects from susceptibility has been developed. Variability is reduced while covering more regions for cardiac T2* calculation. J. Magn. Reson. Imaging 2013;38:441–447. © 2012 Wiley Periodicals, Inc.
Ovarian imaging by magnetic resonance in adolescent girls with polycystic ovary syndrome and age‐matched controls
Authors: Brown Michele , Park Alice S. , Shayya Rana F. , Wolfson Tanya , Su H. Irene , Chang R. Jeffrey
Published: January 2013

Purpose:

To compare ovarian morphology in adolescent girls with and without polycystic ovary syndrome (PCOS) using magnetic resonance imaging (MRI).

Materials and Methods:

In 21 adolescent girls (age 12–18 years) without and 19 adolescents with PCOS (diagnosis based on excessive hair growth and irregular menstrual cycles) ovarian volume, antral follicle count (AFC) per ovary, and follicle size were evaluated. MRI was performed at 1.5 T or 3 T and axial or angled‐axial single‐shot echo‐train spin echo images of 6 mm slice thickness were acquired. In a subset of subjects, 2‐mm images were also obtained. PCOS and non‐PCOS groups were compared using mixed affects regression.

Results:

Mean AFC per ovary and ovarian volume were substantially greater in PCOS subjects compared to non‐PCOS subjects. Mean follicle size was similar between groups. Follicles exceeding 10 mm were seen in 2/19 PCOS subjects versus 9/21 non‐PCOS subjects. Consistently higher follicle counts were detected in images obtained at 2 mm compared to 6‐mm slice thickness.

Conclusion:

In adolescence, MRI of the ovary reveals distinct differences between girls with and without PCOS. MRI may help evaluate young patients in whom transvaginal ultrasound is contraindicated. J. Magn. Reson. Imaging 2013;38:689–693. © 2013 Wiley Predicals, Inc.
Transmit field inhomogeneity and T1estimation errors in breast DCE‐MRI at 3 tesla
Authors: Sung Kyunghyun , Daniel Bruce L. , Hargreaves Brian A.
Published: January 2013

Purpose

To quantifyvariation across the breasts and to evaluate the accuracy of precontrast T1estimation with and withoutvariation in breast MRI patients at 3 Tesla (T).

Materials and Methods

and variable flip angle (VFA) T1mapping were included in our dynamic contrast‐enhanced (DCE) breast imaging protocol to study a total of 25 patients on a 3.0T GE MR 750 system. We computed precontrast T1relaxation in fat, which we assumed to be consistent across a cohort of breast imaging subjects, with and without compensation forvariation. The mean and standard deviation ofand T1values were calculated for statistical data analysis.

Results

Our measurements showed a consistentfield difference between the left and right breasts. The left breast has an average 15.4% higher flip angle than the prescribed flip angle, and the right breast has an average 17.6% lower flip angle than the prescribed flip angle. This average 33% flip angle difference, which can be vendor and model specific, creates a 52% T1estimation bias in fat between breasts using the VFA T1mapping technique. The T1variation is reduced to 7% by includingcorrection.

Conclusion

We have shown that severevariation over the breasts can cause a substantial error in T1estimation between the breasts, in VFA T1maps at 3T, but that compensating for these variations can considerably improve accuracy of T1measurements, which can directly benefit quantitative breast DCE‐MRI at 3T. J. Magn. Reson. Imaging 2013;38:454–459. © 2012 Wiley Periodicals, Inc.
Reproducibility of brain spectroscopy at 7T using conventional localization and spectral editing techniques
Authors: Wijtenburg S. Andrea , Rowland Laura M. , Edden Richard A.E. , Barker Peter B.
Published: January 2013

Purpose

To evaluate the reproducibility of spectroscopic measurements from the anterior cingulate (AC) and the dorsolateral prefrontal cortex (DLPFC) regions at 7T using a 32‐channel head coil.

Materials and Methods

Spectra were acquired in four healthy subjects each scanned twice using a stimulated echo acquisition mode (STEAM) sequence, and a MEGA‐PRESS‐IVS sequence for gamma‐aminobutyric acid (GABA) editing. STEAM spectra were quantified using LCModel, whereas MEGA‐PRESS‐IVS data were analyzed using peak integrals determined using in‐house software. Mean coefficient of variation (CV) and mean absolute difference between visits were calculated.

Results

For the AC STEAM dataset, the mean CV between visits was 6.2% for prominent metabolites such as N‐acetylaspartate (NAA), total creatine (tCr), and total choline (tCho) and 6.3% for low signal‐to‐noise ratio (SNR) metabolites such as glutamate (Glu), glutamine (Gln), and GABA. The mean CV between visits for the DLPFC STEAM dataset was 8.5% for prominent metabolites and 21% for lower SNR metabolites. In the AC, the reproducibility measures for GABA were superior for STEAM compared to MEGA‐PRESS‐IVS (mean CV of 3.5% vs. 13.6%), but the opposite pattern was observed in the DLPFC region (mean CV of 16.2% vs. 13.4%).

Conclusion

7T MR spectroscopy of the AC and DLPFC using both short TE STEAM and MEGA‐PRESS‐IVS sequences provide excellent reproducibility of 12 metabolites, including GABA. J. Magn. Reson. Imaging 2013;38:460–467. © 2012 Wiley Periodicals, Inc.
Analysis of 16 phthalic acid esters in food simulants from plastic food contact materials by LC‐ESI‐MS/MS
Authors: Li Xiaojing , Xiong Wenming , Lin Hua , Zhuo Liyang , Lv Shuiyuan , Tang Xi , Chen Minshi , Zou Zhexiang , Lin Zhenyu , Qiu Bin , Chen Guonan
Published: January 2013

An RP LC‐ESI‐MS/MS method for the determination of the migration of 16 primary phthalic acid esters from plastic samples has been developed using distilled water, 3% acetic acid, 10% alcohol, and olive oil as food simulants. Detection limits were 1.6–18.5 μg/kg in distilled water, 1.4–17.3 μg/kg in 3% acetic acid, 1.4–19.2 μg/kg in 10% alcohol, and 31.9–390.8 μg/kg in olive oil. The RSDs were in the range of 0.07–11.28%. The real plastic products inspection showed that only few analyzed samples were phthalates contaminated. Bis‐2‐ethylhexyl ester and dibutyl phthalate were the common items migrated from the plastic products into food and feeds, but the migration concentrations were far below the limits set by European Union (1.5 mg/kg for bis‐2‐ethylhexyl ester and 0.3 mg/kg for dibutyl phthalate).
Large‐scale forest composition influences northern goshawk nesting in Wisconsin
Authors: Donner Deahn M. , Anderson Dean , Eklund Daniel , St. Pierre Matthew
Published: January 2013

The northern goshawk (Accipiter gentilis atricapillus) is a woodland raptor that uses a variety of forest types for nesting across its breeding range, but strongly depends on older forests with large trees and open understories. Goshawks may select nesting locations by maximizing the convergence of nesting and foraging habitats. Insights into goshawk responses to heterogeneous landscapes can be gained by examining the location of active nest sites through time and at multiple spatial scales. We examined the landscape‐scale forest conditions that influenced the probability of active goshawk nests in the United States Forest Service, Chequamegon‐Nicolet National Forest (CNNF) in northern Wisconsin. We used goshawk nest survey and monitoring data from 1997 to 2006 to determine the probability of an active nest site over time in relation to forest composition and road density at 3 scales (200‐m, 500‐m, and 1,000‐m radii). Goshawk nests were located primarily in upland hardwood (64%), conifer (23%), and older aspen–birch (≥26 yrs old; 11%) habitat cover types. We used Bayesian temporal autoregressive models of nest locations across multiple spatial scales to analyze these data. The probability of active goshawk nest occurrence increased with increasing conifer cover (1,000 m) and decreased with increasing cover of older aspen–birch and density of primary roads (500 m). In addition, lesser proportions of older aspen–birch at intermediate scales around goshawk nests had a stronger effect on the probability of a nest being active than conifer and primary roads. Thus, the ratio of conifer cover (within 1,000 m) to older aspen–birch cover (within 500 m) in landscapes surrounding nest sites was the key driver in predicting the probability of an active nest site. This finding can be used by forest managers to help sustain the active status of a goshawk nesting area through time (i.e., annually), and foster goshawk nesting activity in areas where active nesting is not currently occurring. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.
Analysis of regional species distribution models based on radio‐telemetry datasets from multiple small‐scale studies
Authors: Rice Mindy B. , Apa Anthony D. , Phillips Michael L. , Gammonley James H. , Petch Bradford B. , Eichhoff Karin
Published: January 2013

The identification of core habitat areas and resulting prediction maps are vital tools for land managers. Often, agencies have large datasets from multiple studies over time that could be combined for a more informed and complete picture of a species. Colorado Parks and Wildlife has a large database for greater sage‐grouse (Centrocercus urophasianus) including 11 radio‐telemetry studies completed over 12 years (1997–2008) across northwestern Colorado. We divided the 49,470‐km2 study area into 1‐km2 grids with the number of sage‐grouse locations in each grid cell that contained at least 1 location counted as the response variable. We used a generalized linear mixed model (GLMM) using land cover variables as fixed effects and individual birds and populations as random effects to predict greater sage‐grouse location counts during breeding, summer, and winter seasons. The mixed effects model enabled us to model correlations that may exist in grouped data (e.g., correlations among individuals and populations). We found only individual groupings accounted for variation in the summer and breeding seasons, but not the winter season. The breeding and summer seasonal models predicted sage‐grouse presence in the currently delineated populations for Colorado, but we found little evidence supporting a winter season model. According to our models, about 50% of the study area in Colorado is considered highly or moderately suitable habitat in both the breeding and summer seasons. As oil and gas development and other landscape changes occur in this portion of Colorado, knowledge of where management actions can be accomplished or possible restoration can occur becomes more critical. These seasonal models provide data‐driven, distribution maps that managers and biologists can use for identification and exploration when investigating greater sage‐grouse issues across the Colorado range. Using historic data for future decisions on species management while accounting for issues found from combining datasets allows land managers the flexibility to use all information available. © 2013 The Wildlife Society.
Relationships between grazing and waterfowl production in the Canadian prairies
Authors: Bloom Pauline M. , Howerter David W. , Emery Robert B. , Armstrong Llwellyn M.
Published: January 2013

The survival of waterfowl nests is positively correlated with the amount of grassland on the landscape, and population growth rates of some waterfowl species (e.g., mallards [Anas platyrhynchos]) are sensitive to nest survival rates. Thus, the effect of actions that alter grassland vegetation physiognomy, such as grazing, on waterfowl production is of interest to waterfowl habitat managers. Additionally, grasslands contribute other ecological goods (e.g., forage for livestock and wildlife) and services (e.g., photosynthesis, carbon sequestration), which can be influenced by grazing practices. We address key uncertainties about the linkages between grazing, vegetation physiognomy, and the survival and density of duck nests at study‐site, field, and nest‐site spatial scales. Using data from 2,554 duck nests found in 434 grazed or idled fields (median field size = 48.0 ha) in the Canadian Prairie Pothole Region between 2002 and 2009, we found that vegetation physiognomy affected nest survival at both the field and nest‐site scales, such that nest survival increased with nest‐site vegetation density and late‐season field vegetation density. Nest survival also responded to early‐season within‐field variation in vegetation height in a quadratic manner, such that survival was greatest in fields with moderate variation in vegetation height. Nest survival was negatively related to the intensity of grazing and to the amount of cropland in the surrounding landscape. Both the abundance of wetlands and the average vegetation height in the field had a positive influence on nest density. Fields idled during the breeding season had greater densities of nests than fields grazed either early or late in the breeding season. Leaving lands idled may be the most effective way to increase both waterfowl nest survival and nest density. When management of upland vegetation is required, we recommend grazing at moderate stocking rates (between 2 and 2.5 animal unit months [AUM]/ha) after the waterfowl breeding season is complete and monitoring vegetative characteristics to ensure they remain suitable to attract nesting waterfowl (e.g., leaving vegetation height >28 cm). Where grazing must be carried out during the breeding season, low to moderate stocking rates should be encouraged as these rates appear to have the least negative impact on both waterfowl nest survival and nest density. These stocking rates also will maintain rangeland in good condition to the long‐term benefit of producers. © 2013 The Wildlife Society.
The global regulator Crc plays a multifaceted role in modulation of type III secretion system in Pseudomonas aeruginosa
Authors: Dong Yi‐Hu , Zhang Xi‐Fen , Zhang Lian‐Hui
Published: January 2013

The opportunistic pathogen Pseudomonas aeruginosa utilizes type III secretion system (T3SS) to translocate effector proteins into eukaryotic host cells that subvert normal host cell functions to the benefit of the pathogen, and results in serious infections. T3SS in P. aeruginosa is controlled by a complex system of regulatory mechanisms and signaling pathways. In this study, we described that Crc, an RNA‐binding protein, exerts a positive impact on T3SS in P. aeruginosa, as evidenced by promoter activity assays of several key T3SS genes, transcriptomics, RT‐PCR, and immunoblotting in crc mutant. We further demonstrated that the regulatory function of Crc on the T3SS was mediated through the T3SS master regulator ExsA and linked to the Cbr/Crc signaling system. Expression profiling of the crc mutant revealed a downregulation of flagship T3SS genes as well as 16 other genes known to regulate T3SS gene expression in P. aeruginosa. On the basis of these data, we proposed that Crc may exert multifaceted control on the T3SS through various pathways, which may serve to fine‐tune this virulence mechanism in response to environmental changes and nutrient sources.
A two‐grid characteristic finite volume element method for semilinear advection‐dominated diffusion equations
Authors: Chen Chuanjun , Liu Wei , Bi Chunjia
Published: January 2013

A two‐grid finite volume element method, combined with the modified method of characteristics, is presented and analyzed for semilinear time‐dependent advection‐dominated diffusion equations in two space dimensions. The solution of a nonlinear system on the fine‐grid space (with grid size h) is reduced to the solution of two small (one linear and one nonlinear) systems on the coarse‐grid space (with grid size H) and a linear system on the fine‐grid space. An optimal error estimate in H1 ‐norm is obtained for the two‐grid method. It shows that the two‐grid method achieves asymptotically optimal approximation, as long as the mesh sizes satisfy h = O(H2). Numerical example is presented to validate the usefulness and efficiency of the method. © 2013 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2013
The effect of hereditary versus acquired thrombophilia on triple test Down's syndrome screening
Authors: Frank Maya , Maymon Ron , Wiener Yifat , Neeman Ortal , Kurzweil Yaffa , Bar Jacob
Published: January 2013

Objective

To compare the profile of mid gestation triple test serum markers between a cohort of women with history of pregnancy complications with hereditary versus acquired thrombophilia. All were treated with low molecular weight heparin (LMWH) prior to 12 weeks' gestation.

Methods

A retrospective analysis of second trimester maternal serum screening results for Down syndrome was performed comparing women with inherited versus acquired thrombophilia, all treated with LMWH. The test results were calculated from the combination of triple serum markers and maternal age, and expressed as a multiple of the gestation normal medians (MoM). Results in the study groups were compared with MoM values calculated from our local population (controls).

Results

The median human chorionic gonadotropin (hCG) level was higher only in the acquired thrombophilia group (N = 47) as compared with the control group (1.3 vs. 0.99 MoM, P = 0.005), and not different between the hereditary thrombophilia group (N = 60) (1.1 MoM) and the control group. Alpha‐fetoprotein and unconjugated estriol MoMs did not differ between women with inherited (0.95, 0.97), acquired thrombophilia (0.99, 0.90), and controls (1.01, 0.98), respectively.

Conclusion

In the interpretation of second trimester maternal serum screening, consideration should be given to the higher hCG maternal serum levels that may occur in women with acquired thrombophilia, even those treated early in pregnancy with LMWH. The higher hCG serum levels may signal the possibility of placental dysfunction, rather than fetal aneuploidy © 2013 John Wiley & Sons, Ltd.
Ground Thermal Regime and Permafrost Distribution under a Changing Climate in Northern Norway
Authors: Farbrot Herman , Isaksen Ketil , Etzelmüller Bernd , Gisnås Kjersti
Published: January 2013

Since 2002, ground and ground surface temperatures have been systematically measured in the mountains of Troms and Finnmark, northern Norway. These data were used to calibrate and validate a transient heat flow model and a spatial permafrost model, to address ground thermal development since the end of the Little Ice Age, as well as possible permafrost responses to anticipated future climate changes. Approximately 20 per cent of the land area is underlain by permafrost, and in Finnmark, permafrost in palsa mires seems to dominate. Both observations and modelling show that the present permafrost is mainly ‘warm’, with mean ground temperatures above ‐3 °C. Permafrost has warmed during the last century, and at one site our ground temperature observations show the degradation of permafrost over the intervening decade. The study identifies three major permafrost regions in northern Norway: (1) maritime mountain permafrost in western Troms; (2) continental permafrost above the treeline and in bogs in Finnmark; and (3) Low Arctic permafrost on the peninsula of Varangerhalvøya, forming a transition between the Scandinavian mountain‐dominated permafrost in the south and the arctic permafrost towards the north and east. Copyright © 2013 John Wiley & Sons, Ltd.
Radiation transformation of the oxygen‐containing impurity in LiF crystals doped with different polyvalent cations
Authors: Dauletbekova Alma , Lisitsyna Liudmila , Korepanov Vladimir , Lisitsyn Victor , Trefilova Larisa , Kassymkanova Raigul
Published: January 2013

Time‐resolved spectroscopy and infrared spectroscopy were used to investigate radiation transformation of the oxygen–hydrogen impurity in LiF crystals doped with oxides of different metals Li, W, Ti and Fe with the ab‐sorbed dose range of 101–105Gy in the time interval of 10‐9–10‐1s and in the temperature interval of 15–300 K (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Antioxidant and In Vitro Anticancer Effect of 2‐Pyrrolidinone Rich Fraction of Brassica oleracea var. capitata Through Induction of Apoptosis in Human Cancer Cells
Authors: Thangam Ramar , Suresh Veeraperumal , Rajkumar Mayan , Vincent Jally Damien , Gunasekaran Palani , Anbazhagan Chinnathambi , Kaveri Krishnasamy , Kannan Soundarapandian
Published: January 2013

The aim of this study was to analyze if the 2‐pyrrolidinone rich fraction of Brassica oleracea var. capitata exhibiting antioxidant and in vitro anticancer activities. 2‐Pyrrolidinone is an active compound present in Brassica oleracea var. capitata. Our findings explored the potential use of 2‐pyrrolidinone in cancer treatment. This compound was identified and isolated by gas chromatography–mass spectrometry and high‐performance liquid chromatography from the leaf of Brassica oleracea var. capitata. The resultant rich active compound exhibited in vitro cytotoxicity in HeLa and PC‐3 human cancer cell lines, and it also exhibited antioxidant activity in cell free assays. DAPI staining, an apoptotic analysis and cell cycle analysis were performed to evaluate the anticancer activity of 2‐pyrrolidinone against the above cell lines. The IC50 value of 2‐pyrrolidinone was determined to be of 2.5 µg/ml for HeLa, 3 µg/ml for PC‐3 cells at 24 h and 1.5 µg/ml for HeLa and 2 µg/ml for PC‐3 cells at 48 h, respectively. However, cell cycle analysis revealed that the anti‐proliferative effects of the 2‐pyrrolidinone were mediated through cell cycle arrest in the G0/G1 phase. These results from the current study suggest that the 2‐pyrrolidinone have potential anticancer effects, which will lead to the development of new anticancer agents for arresting cancer cells growth in vitro. Copyright © 2012 John Wiley & Sons, Ltd.