bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduction of 30‐day postdischarge hospital readmission or emergency department (ED) visit rates in high‐risk elderly medical patients through delivery of a targeted care bundle
Authors: Koehler Bruce E. , Richter Kathleen M. , Youngblood Liz , Cohen Brian A. , Prengler Irving D. , Cheng Dunlei , Masica Andrew L.
Published: April 2009

RATIONALE:

Care coordination has shown inconsistent results as a mechanism to reduce hospital readmission and postdischarge emergency department (ED) visit rates.

OBJECTIVE:

To assess the impact of a supplemental care bundle targeting high‐risk elderly inpatients implemented by hospital‐based staff compared to usual care on a composite outcome of hospital readmission and/or ED visitation at 30 and 60 days following discharge.

PATIENTS/METHODS:

Randomized controlled pilot study in 41 medical inpatients predisposed to unplanned readmission or postdischarge ED visitation, conducted at Baylor University Medical Center. The intervention group care bundle consisted of medication counseling/reconciliation by a clinical pharmacist (CP), condition specific education/enhanced discharge planning by a care coordinator (CC), and phone follow‐up.

RESULTS:

Groups had similar baseline characteristics. Intervention group readmission/ED visit rates were reduced at 30 days compared to the control group (10.0% versus 38.1%, P = 0.04), but not at 60 days (30.0% versus 42.9%, P = 0.52). For those patients who had a readmission/postdischarge ED visit, the time interval to this event was longer in the intervention group compared to usual care (36.2 versus 15.7 days, P = 0.05). Study power was insufficient to reliably compare the effects of the intervention on lengths of index hospital stay between groups.

CONCLUSIONS:

A targeted care bundle delivered to high‐risk elderly inpatients decreased unplanned acute health care utilization up to 30 days following discharge. Dissipation of this effect by 60 days postdischarge defines reasonable expectations for analogous hospital‐based educational interventions. Further research is needed regarding the impacts of similar care bundles in larger populations across a variety of inpatient settings. Journal of Hospital Medicine 2009;4:211–218. © 2009 Society of Hospital Medicine.
Home alone: Assessing mobility independence before discharge
Authors: Manning Dennis M. , Keller A. Scott , Frank Debra L.
Published: April 2009

Hospitalists are often confronted with discharge planning responsibility and decisions for elderly patients who live alone. The absence of an in‐home helper (spouse, partner, or care‐giver) reduces the margin of safety and resilience to any new debility. Research has documented that during hospital stays elderly patients tend to become deconditioned, even if there is no new specific neurologic or motor deficit. In the patient whose pre‐hospital mobility independence is not robust, and perhaps marginally compensated, inpatient stays for any diagnosis may result in critical decrements in mobility independence. The present study is an effort to design a bedside tool for the hospitalist by which to discern, or screen, for such debility. The tool is a hierarchical performance test we named I‐MOVE (Independent Mobility Validation Examination). It is a quick series of bedside mobility requests to demonstrate capability of fundamental movements critical to independent living. We describe manner in which I‐MOVE can be performed. Moreover, we describe the face validity and the high interrater reliability (> 0.90 intra‐class correlation coefficient) of two RNs who independently administered and scored I‐MOVE for 41 patients on a General Medical Care Unit. Although not yet studied in correlation with outcomes, nor with validated mobility assessment tools, we believe I‐MOVE can serve as a useful extension of the nurse's assessment, or the Hospitalist's physical examination. Discerning the continued capability of mobility independence is a desirable, on‐going insight for discharge planning of the elderly patient who resides alone. Journal of Hospital Medicine 2009;4:252–254. © 2009 Society of Hospital Medicine.
Discrepancy between admission and discharge diagnoses as a predictor of hospital length of stay
Authors: Johnson Tricia , McNutt Robert , Odwazny Richard , Patel Deval , Baker Seth
Published: April 2009

CONTEXT:

The addition of clinical data or present on admission (POA) codes to administrative databases improves the accuracy of predicting clinical outcomes, such as inpatient mortality. Other POA information may also explain variation in hospital outcomes, such as length of stay (LOS), but this potential has not been previously explored.

OBJECTIVES:

To assess whether a discrepancy between the diagnosis coded at the time of admission and the diagnoses coded at discharge independently explains variation in LOS for general internal medicine patients.

DESIGN, SETTING, AND PATIENTS:

A retrospective data review of patients age 18 years and older admitted to general internal medicine units at a large, urban academic medical center between July 2005 and June 2006. A generalized linear regression model was constructed to adjust for patient factors known to be associated with LOS.

OUTCOME MEASURE:

Average LOS among patients with a discrepancy between the admitting and discharge diagnosis codes versus those patients without a discrepancy.

MAIN RESULTS:

The average LOS for patients without a discrepancy between the admitting and discharge diagnosis codes, adjusted for comorbid conditions, was 3.4 days compared to 4.2 days with a discrepancy (0.76‐day increase; P < 0.01).

CONCLUSIONS:

Diagnosis discrepancy is associated with longer LOS. Diagnosis discrepancy on admission may be a marker of diagnosis uncertainty or poor patient assessment/documentation. Further research is needed to understand the underlying reasons for this discrepancy and its association with LOS, and, potentially, clinical outcomes. Journal of Hospital Medicine 2009;4:234–239. © 2009 Society of Hospital Medicine.
Peripheral moving‐table contrast‐enhanced magnetic resonance angiography (CE‐MRA) using a prototype 18‐channel peripheral vascular coil and scanning parameters optimized to the patient's individual hemodynamics
Authors: Potthast Silke , Wilson Gregory J. , Wang Maisie S. , Maki Jeffrey H.
Published: April 2009

Purpose

To demonstrate that with a priori determination of individual patient hemodynamics, peripheral contrast‐enhanced magnetic resonance angiography (pCE‐MRA) can be customized to maximize signal‐to noise ratio (SNR) and avoid venous enhancement.

Materials and Methods

Using a 1.5T MRI scanner and prototype 18‐channel peripheral vascular (PV) coil designed for highly accelerated parallel imaging, geometry (g)‐factor maps were determined. SNR‐maximized protocols considering the two‐dimensional sensitivity encoding (2D SENSE) factor, TE, TR, bandwidth (BW), and flip angle (FA) were precalculated and stored. For each exam, a small aortic timing bolus was performed, followed by dynamic three‐dimensional (3D)‐MRA of the calf. Using this information, the aorta to pedal artery and calf arteriovenous transit times were measured. This enabled estimation of the maximum upper and middle station acquisition duration to allow lower station acquisition to begin prior to venous arrival. The appropriately succinct SNR‐optimized protocol for each station was selected and moving‐table pCE‐MRA was performed using thigh venous compression and high‐relaxivity contrast material.

Results

The protocol was successfully applied in 15 patients and all imaging demonstrated good SNR without diagnosis‐hindering venous enhancement.

Conclusion

By knowing each patient's venous enhancement kinetics, scan parameters can be optimized to utilize maximum possible acquisition time. Some time is added for the timing scans, but in return time‐resolved calf CE‐MRA, maximized SNR, and decreased risk of venous enhancement are gained. J. Magn. Reson. Imaging 2009;29:1106–1115. © 2009 Wiley‐Liss, Inc.
3D diffusion tensor MRI with isotropic resolution using a steady‐state radial acquisition
Authors: Jung Youngkyoo , Samsonov Alexey A. , Block Walter F. , Lazar Mariana , Lu Aiming , Liu Jing , Alexander Andrew L.
Published: April 2009

Purpose

To obtain diffusion tensor images (DTI) over a large image volume rapidly with 3D isotropic spatial resolution, minimal spatial distortions, and reduced motion artifacts, a diffusion‐weighted steady‐state 3D projection (SS 3DPR) pulse sequence was developed.

Materials and Methods

A diffusion gradient was inserted in a SS 3DPR pulse sequence. The acquisition was synchronized to the cardiac cycle, linear phase errors were corrected along the readout direction, and each projection was weighted by measures of consistency with other data. A new iterative parallel imaging reconstruction method was also implemented for removing off‐resonance and undersampling artifacts simultaneously.

Results

The contrast and appearance of both the fractional anisotropy and eigenvector color maps were substantially improved after all correction techniques were applied. True 3D DTI datasets were obtained in vivo over the whole brain (240 mm field of view in all directions) with 1.87 mm isotropic spatial resolution, six diffusion encoding directions in under 19 minutes.

Conclusion

A true 3D DTI pulse sequence with high isotropic spatial resolution was developed for whole brain imaging in under 20 minutes. To minimize the effects of brain motion, a cardiac synchronized, multiecho, DW‐SSFP pulse sequence was implemented. Motion artifacts were further reduced by a combination of linear phase correction, corrupt projection detection and rejection, sampling density reweighting, and parallel imaging reconstruction. The combination of these methods greatly improved the quality of 3D DTI in the brain. J. Magn. Reson. Imaging 2009;29:1175–1184. © 2009 Wiley‐Liss, Inc.
Assessment of vascular remodeling under antiangiogenic therapy using DCE‐MRI and vessel size imaging
Authors: Zwick Stefan , Strecker Ralph , Kiselev Valerji , Gall Peter , Huppert Jochen , Palmowski Moritz , Lederle Wiltrud , Woenne Eva C. , Hengerer Arne , Taupitz Matthias , Semmler Wolfhard , Kiessling Fabian
Published: April 2009

Purpose

To assess vascular remodeling in tumors during two different antiangiogenic therapies with dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) and vessel size imaging and to evaluate the vessel size index (VSI) as a novel biomarker of therapy response.

Materials and Methods

In two independent experiments, nude mice bearing human skin squamous cell carcinoma xenografts were treated with a vascular endothelial growth factor (VEGF) inhibitor (bevacizumab) or a multitargeted tyrosine kinase inhibitor (SU11248). Changes in tumor vascularity were assessed by DCE‐MRI and vessel size imaging. DCE‐MRI data were analyzed applying a two‐compartment model (Brix), calculating the parameters Amplitude and kep.

Results

For both experiments Amplitude decreased significantly in treated tumors while kep did not change significantly. VSI showed controversial results. VSI was significantly increased in SU11248‐treated A431 tumors, whereas no changes were found in bevacizumab‐treated HaCaT‐ras‐A‐5RT3 tumors. Immunohistology confirmed these results and suggest differences in the maturation of tumor vascularization as a possible explanation.

Conclusion

DCE‐MRI and vessel size imaging provide reliable and supplementing biomarkers of antiangiogenic therapy response. The results of both methods are in excellent agreement with histology. Nevertheless, our results also indicate that vascular remodeling is complex and that a uniform response cannot be expected for different tumors and therapies. J. Magn. Reson. Imaging 2009;29:1125–1133. © 2009 Wiley‐Liss, Inc.
A fast, effective filtering method for improving clinical pulsed arterial spin labeling MRI
Authors: Tan Huan , Maldjian Joseph A. , Pollock Jeffrey M. , Burdette Jonathan H. , Yang Lucie Y. , Deibler Andrew R. , Kraft Robert A.
Published: April 2009

Purpose

To evaluate the effectiveness of a fully automated postprocessing filter algorithm in pulsed arterial spin labeling (PASL) MRI perfusion images in a large clinical population.

Materials and Methods

A mean and standard deviation‐based filter was implemented to remove outliers in the set of perfusion‐weighted images (control – label) before being averaged and scaled to quantitative cerebral blood flow (CBF) maps. Filtered and unfiltered CBF maps from 200 randomly selected clinical cases were assessed by four blinded raters to evaluate the effectiveness of the filter.

Results

The filter salvaged many studies deemed uninterpretable as a result of motion artifacts, transient gradient, and/or radiofrequency instabilities, and unexpected disruption of data acquisition by the technologist to communicate with the patient. The filtered CBF maps contained significantly (P < 0.05) fewer artifacts and were more interpretable than unfiltered CBF maps as determined by one‐tail paired t‐test.

Conclusion

Variations in MR perfusion signal related to patient motion, system instability, or disruption of the steady state can introduce artifacts in the CBF maps that can be significantly reduced by postprocessing filtering. Diagnostic quality of the clinical perfusion images can be improved by performing selective averaging without a significant loss in perfusion signal‐to‐noise ratio. J. Magn. Reson. Imaging 2009;29:1134–1139. © 2009 Wiley‐Liss, Inc.
Improved cerebellar tissue classification on magnetic resonance images of brain
Authors: Datta Sushmita , Tao Guozhi , He Renjie , Wolinsky Jerry S. , Narayana Ponnada A.
Published: April 2009

Purpose

To develop and implement a method for improved cerebellar tissue classification on the MRI of brain by automatically isolating the cerebellum prior to segmentation.

Materials and Methods

Dual fast spin echo (FSE) and fluid attenuation inversion recovery (FLAIR) images were acquired on 18 normal volunteers on a 3 T Philips scanner. The cerebellum was isolated from the rest of the brain using a symmetric inverse consistent nonlinear registration of individual brain with the parcellated template. The cerebellum was then separated by masking the anatomical image with individual FLAIR images. Tissues in both the cerebellum and rest of the brain were separately classified using hidden Markov random field (HMRF), a parametric method, and then combined to obtain tissue classification of the whole brain. The proposed method for tissue classification on real MR brain images was evaluated subjectively by two experts. The segmentation results on Brainweb images with varying noise and intensity nonuniformity levels were quantitatively compared with the ground truth by computing the Dice similarity indices.

Results

The proposed method significantly improved the cerebellar tissue classification on all normal volunteers included in this study without compromising the classification in remaining part of the brain. The average similarity indices for gray matter (GM) and white matter (WM) in the cerebellum are 89.81 (±2.34) and 93.04 (±2.41), demonstrating excellent performance of the proposed methodology.

Conclusion

The proposed method significantly improved tissue classification in the cerebellum. The GM was overestimated when segmentation was performed on the whole brain as a single object. J. Magn. Reson. Imaging 2009;29:1035–1042. © 2009 Wiley‐Liss, Inc.
MRI of late microstructural and metabolic alterations in radiation‐induced brain injuries
Authors: Chan Kevin C. , Khong Pek‐lan , Cheung Matthew M. , Wang Silun , Cai Ke‐xia , Wu Ed X.
Published: April 2009

Purpose

To evaluate the late effects of radiation‐induced damages in the rat brain by means of in vivo multiparametric MRI.

Materials and Methods

The right hemibrains of seven Sprague‐Dawley rats were irradiated with a highly collimated 6 MV photon beam at a single dose of approximately 28 Gy. Diffusion tensor imaging (DTI), proton MR spectroscopy (1H‐MRS), T2‐weighted imaging, and T1‐weighted imaging were performed to the same animals 12 months after radiation treatment.

Results

Compared with the contralateral side, a significantly higher percentage decrease in fractional anisotropy was observed in the ipsilateral fimbria of hippocampus (29%) than the external capsule (8%) in DTI, indicating the selective vulnerability of fimbria to radiation treatment. Furthermore, in1H‐MRS, significantly higher choline, glutamate, lactate, and taurine peaks by 24%, 25%, 87%, and 58%, respectively, were observed relative to creatine in the ipsilateral brain. Postmortem histology confirmed these white matter degradations as well as glial fibrillary acidic protein and glutamine synthetase immunoreactivity increase in the ipsilateral brain.

Conclusion

The microstructural and metabolic changes in late radiation‐induced brain injuries were documented in vivo. These multiparametric MRI measurements may help understand the white matter changes and neurotoxicity upon radiation treatment in a single setting. J. Magn. Reson. Imaging 2009;29:1013–1020. © 2009 Wiley‐Liss, Inc.
Microperfusion‐induced elevation of ADC is suppressed after contrast in breast carcinoma
Authors: Yuen Sachiko , Yamada Kei , Goto Mariko , Nishida Kaori , Takahata Akiko , Nishimura Tsunehiko
Published: April 2009

Purpose

To investigate the effect of gadolinium (Gd)‐DTPA on the apparent diffusion coefficient (ADC) of breast carcinoma and to analyze the relationship between pre/postcontrast ADC and the degree of contrast enhancement.

Materials and Methods

Nineteen histopathologically confirmed breast carcinomas (mean size = 22 mm) were analyzed. Their ADCs before and after contrast administration were measured. The contrast‐to‐noise ratios (CNRs) of the tumors were measured on fat‐suppressed 3D T1‐weighted images in precontrast, early, and late postcontrast phases. These results were correlated with the measured ADC values.

Results

A significant decrease in the measured ADC was noted after contrast administration (−23%, P = 0.01). Lesions with relatively high ADC before contrast (>1.3 × 10−3 mm2/sec; n = 12) demonstrated a larger degree of ADC reduction (mean 34%) than lesions with low ADC (≤1.3 × 10−3 mm2/sec; n = 7) (mean 4.5%). When an early postcontrast image was used as a surrogate marker of malignant potential, we found a significant inverse correlation with postcontrast ADC (γ = −0.57, P = 0.02).

Conclusion

Postcontrast ADC exhibited lower values than precontrast ADC, which is thought to reflect suppression of the microperfusion‐induced effect on diffusion‐weighted imaging. Postcontrast ADC may be a better indicator than precontrast ADC to reflect malignant potential of tumors. J. Magn. Reson. Imaging 2009;29:1080–1084. © 2009 Wiley‐Liss, Inc.
Fast dixon‐based multisequence and multiplanar MRI for whole‐body detection of cancer metastases
Authors: Ma Jingfei , Costelloe Colleen M. , Madewell John E. , Hortobagyi Gabriel N. , Green Marjorie C. , Cao Guang , Sun Fei , Kundra Vikas
Published: April 2009

Purpose

To develop and demonstrate the feasibility of multisequence and multiplanar MRI for whole‐body cancer detection.

Materials and Methods

Two fast Dixon‐based sequences and a diffusion‐weighted sequence were used on a commercially available 1.5 T scanner for whole‐body cancer detection. The study enrolled 19 breast cancer patients with known metastases and in multistations acquired whole‐body axial diffusion‐weighted, coronal T2‐weighted, axial/sagittal pre‐ and postcontrast T1‐weighted, as well as triphasic abdomen images. Three radiologists subjectively scored Dixon images of each series for overall image quality and fat suppression uniformity on a 4‐point scale (1 = poor, 2 = fair, 3 = good, and 4 = excellent).

Results

Eighteen of the 19 patients completed the whole‐body MRI successfully. The mean acquisition time and overall patient table time were 46 ± 3 and 69 ± 5 minutes, respectively. The average radiologists' scores for overall image quality and fat suppression uniformity were both 3.4 ± 0.5. The image quality was consistent between patients and all completed whole‐body examinations were diagnostically adequate.

Conclusion

Whole‐body MRI offering essentially all the most optimal tumor‐imaging sequences in a typical 1‐hour time slot can potentially become an appealing “one‐stop‐shop” for whole‐body cancer imaging. J. Magn. Reson. Imaging 2009;29:1154–1162. © 2009 Wiley‐Liss, Inc.
MRI features of cellular angiomyofibroma with pathologic correlation
Authors: Koo Phillip J. , Goykhman Igor , Lembert Larissa , Nunes Linda W.
Published: April 2009

Within the spectrum of extratesticular mesenchymal tumors in the scrotum and perineum lies cellular angiofibroma, also known as angiomyofibroblastoma‐like tumor, a rare lesion originally described to almost exclusively occur in the vulva, perineum, and pelvis of women. We report a case of this tumor, with an adjacent scrotal lipoma, occurring in a 60‐year‐old male who presented to our department with a firm palpable scrotal mass. To our knowledge, the MRI findings of this entity have yet to be described in the radiological literature. We present the MRI features of cellular angiofibroma that are consistent with the pathological characteristics of this entity—a benign cellular and fibrous tumor with prominent vascularity. J. Magn. Reson. Imaging 2009;29:1195–1198. © 2009 Wiley‐Liss, Inc.
Image artifacts in concurrent transcranial magnetic stimulation (TMS) and fMRI caused by leakage currents: Modeling and compensation
Authors: Weiskopf Nikolaus , Josephs Oliver , Ruff Christian C. , Blankenburg Felix , Featherstone Eric , Thomas Anthony , Bestmann Sven , Driver Jon , Deichmann Ralf
Published: April 2009

Purpose

To characterize and eliminate a new type of image artifact in concurrent transcranial magnetic stimulation and functional MRI (TMS‐fMRI) caused by small leakage currents originating from the high‐voltage capacitors in the TMS stimulator system.

Materials and Methods

The artifacts in echo‐planar images (EPI) caused by leakage currents were characterized and quantified in numerical simulations and phantom studies with different phantom‐coil geometries. A relay‐diode combination was devised and inserted in the TMS circuit that shorts the leakage current. Its effectiveness for artifact reduction was assessed in a phantom scan resembling a realistic TMS‐fMRI experiment.

Results

The leakage‐current‐induced signal changes exhibited a multipolar spatial pattern and the maxima exceeded 1% at realistic coil‐cortex distances. The relay‐diode combination effectively reduced the artifact to a negligible level.

Conclusion

The leakage‐current artifacts potentially obscure effects of interest or lead to false‐positives. Since the artifact depends on the experimental setup and design (eg, amplitude of the leakage current, coil orientation, paradigm, EPI parameters), we recommend its assessment for each experiment. The relay‐diode combination can eliminate the artifacts if necessary. J. Magn. Reson. Imaging 2009;29:1211–1217. © 2009 Wiley‐Liss, Inc.
Non‐contrast‐enhanced MR portography with time‐spatial labeling inversion pulses: Comparison of imaging with three‐dimensional half‐fourier fast spin‐echo and true steady‐state free‐precession sequences
Authors: Shimada Kotaro , Isoda Hiroyoshi , Okada Tomohisa , Kamae Toshikazu , Arizono Shigeki , Hirokawa Yuusuke , Shibata Toshiya , Togashi Kaori
Published: April 2009

Purpose

To compare and evaluate images acquired with two different MR angiography (MRA) sequences, three‐dimensional (3D) half‐Fourier fast spin‐echo (FSE) and 3D true steady‐state free‐precession (SSFP) combined with two time‐spatial labeling inversion pulses (T‐SLIPs), for selective and non‐contrast‐enhanced (non‐CE) visualization of the portal vein.

Materials and Methods

Twenty healthy volunteers were examined using half‐Fourier FSE and true SSFP sequences on a 1.5T MRI system with two T‐SLIPs, one placed on the liver and thorax, and the other on the lower abdomen. For quantitative analysis, vessel‐to‐liver contrast (Cv‐l) ratios of the main portal vein (MPV), right portal vein (RPV), and left portal vein (LPV) were measured. The quality of visualization was also evaluated.

Results

In both pulse sequences, selective visualization of the portal vein was successfully conducted in all 20 volunteers. Quantitative evaluation showed significantly better Cv‐l at the RPVs and LPVs in half‐Fourier FSE (P < 0.0001). At the MPV, Cv‐l was better in true SSFP, but was not statistically different. Visualization scores were significantly better only at branches of segments four and eight for half‐Fourier FSE (P = 0.001 and 0.03, respectively).

Conclusion

Both 3D half‐Fourier FSE and true SSFP scans with T‐SLIPs enabled selective non‐CE visualization of the portal vein. Half‐Fourier FSE was considered appropriate for intrahepatic portal vein visualization, and true SSFP may be preferable when visualization of the MPV is required. J. Magn. Reson. Imaging 2009;29:1140–1146. © 2009 Wiley‐Liss, Inc.
Diminished visibility of cerebral venous vasculature in multiple sclerosis by susceptibility‐weighted imaging at 3.0 Tesla
Authors: Ge Yulin , Zohrabian Vahe M. , Osa Etin‐Osa , Xu Jian , Jaggi Hina , Herbert Joseph , Haacke E. Mark , Grossman Robert I.
Published: April 2009

Multiple sclerosis (MS) is a disease of the central nervous system characterized by widespread demyelination, axonal loss and gliosis, and neurodegeneration; susceptibility‐weighted imaging (SWI), through the use of phase information to enhance local susceptibility or T2* contrast, is a relatively new and simple MRI application that can directly image cerebral veins by exploiting venous blood oxygenation. Here, we use high‐field SWI at 3.0 Tesla to image 15 patients with clinically definite relapsing‐remitting MS and to assess cerebral venous oxygen level changes. We demonstrate significantly reduced visibility of periventricular white matter venous vasculature in patients as compared to control subjects, supporting the concept of a widespread hypometabolic MS disease process. SWI may afford a noninvasive and relatively simple method to assess venous oxygen saturation so as to closely monitor disease severity, progression, and response to therapy. J. Magn. Reson. Imaging 2009;29:1190–1194. © 2009 Wiley‐Liss, Inc.
Improved vessel delineation in keyhole time‐resolved contrast‐enhanced MR angiography using a gadolinium doped flush
Authors: Beranek‐Chiu Jan , Froehlich John M. , Wentz Klaus U. , Doert Alexis N. , Zollikofer Christoph L. , Eckhardt Boris P.
Published: April 2009

Purpose

To prospectively assess the influence of a gadolinium doped saline flush compared with a pure saline flush on the image quality of the supra‐aortic vessels using time‐resolved contrast‐enhanced MR angiography (4D CE‐MRA) in a randomized double blind clinical trial.

Materials and Methods

Twenty‐two patients scheduled for contrast‐enhanced craniocerebral MRI underwent a supplemental 4D CE‐MRA covering the carotids to the superior sinus consisting of 30 dynamics of a T1‐weighted 3D gradient‐echo sequence (FFE) in sagittal direction. The temporal resolution of 1.1 s per dataset was achieved using the keyhole technique with the reference scan acquired at the end. Immediately after the intravenous (IV) injection of 0.1 mmol Gd/kg body weight of gadoterate, our patients received a 50‐mL flush consisting either of a 0.9% saline solution (n = 11) or doped with 50 mM gadolinium (n = 11; total Gd: 0.11 mmol/kg) at a flow‐rate of 2 mL/s. Vessel delineation, image quality, signal‐to‐noise‐ (SNR) and contrast‐to‐noise (CNR) ratios over time were compared.

Results

Both vessel delineation (internal carotid artery [ICA]: slopesaline = 308.5; slopeGd = 528.9; P = 0.006; superior sagittal sinus [SSS]: slopesaline = 505.3; slopeGd = 674.9; P = 0.007) and CNR (ICA: CNRsaline = 57.3; CNRGd = 80.55; P = 0.0417; SSS: CNRsaline = 74.15; CNRGd = 117.4; P = 0.0331) of the ICA and SSS were significantly increased using the gadolinium doped flush.

Conclusion

A low concentrated gadolinium flush in comparison to a pure saline flush improves significantly vessel contrast and their delineation in time‐resolved CE‐MRA using the keyhole technique. J. Magn. Reson. Imaging 2009;29:1147–1153. © 2009 Wiley‐Liss, Inc.
Climate and weather factors modulating river flows in southern Angola
Authors: Jury Mark
Published: April 2009

The large‐scale circulation and thermodynamic fields that modulate the flow of the Kavango River in southern Angola during austral summer are studied. According to composite patterns constructed from National Center for Environmental Prediction (NCEP) data, enhanced river flow is associated with an anomalous wave train of upper level winds that emanate from the North Atlantic. Sea‐surface temperatures (SST) show a warm‐north/cool‐south Atlantic dipole condition as the Kavango River rises. Correlations are analysed with respect to the Kavango River flow and a 0 lag value of − 0.41 is found for the upper zonal wind over the North Atlantic. Rainfall over the African Sahel region is positively linked with Kavango River flow at 6 month lead time (r = + 0.34). The work is extended to the event scale and it is found that winds draw tropical moisture over southern Angola in response to an anomalous low‐high pair and bifurcated subtropical jet stream. A continental scale sea breeze circulation amplifies the convection during afternoons. Knowledge of run‐off into Namibia is critical to the management and planning of water resources in the northern Kalahari savanna. Copyright © 2009 Royal Meteorological Society
Real‐time molecular assessment on oxidative injury of single cells using Raman spectroscopy
Authors: Chang Wei‐Tien , Lin Hung‐Lung , Chen Hung‐Che , Wu Yao‐Ming , Chen Wen‐Jone , Lee Yuan‐Teh , Liau Ian
Published: April 2009

Oxidative stress is encountered in many biological systems; the resultant oxidative injury plays a significant role in the pathogenesis of diverse diseases. Conventional measurements on oxidative injury are employed almost exclusively on a large population of cells either by counting the fraction of cell death or by observing the fluorometric change resulting from exogenous reagents, thereby lacking in molecular detail and temporal specificity. In this work we combine laser tweezers and Raman spectroscopy to observe the response of single cells to oxidative stress. By measuring the temporal changes of vibrational spectra of single optically trapped cells, we demonstrate a molecular‐level assessment of cellular oxidative injury in real time, both qualitatively and quantitatively, without the introduction of exogenous reagents. The main experimental findings are supported by the observation of Raman spectra of intermediates and downstream products. The abrogation of the above changes by ascorbic acid further illustrates the therapeutic effect of antioxidants against cellular oxidative injury. This approach is extensible to studies exploring the biochemical transformation of single cells or intracellular organelles in response to various chemical or physical stimuli. With the aid of ‘molecular fingerprints’, single‐cell Raman spectroscopy exhibits a great potential for accessing the chemical aspects of cellular bioactivity, yielding insight into pathophysiological processes and assisting the development of novel therapeutic interventions against diseases. Copyright © 2009 John Wiley & Sons, Ltd.
Combined use of HMF and furosine to assess fresh honey quality
Authors: Morales Valle , Sanz María Luz , Martín‐Álvarez Pedro J , Corzo Nieves
Published: April 2009

BACKGROUND: The quality of honey can be affected by practices such as adulteration, inadequate storage or the application of severe heat treatments. Because hydroxymehylfurfural (HMF) is an indicator of honey freshness and furosine (ε‐2‐furoylmethyl lysine) has proved to be a useful chemical indicator of the progress of the Maillard reaction in foods, the aim of this work was to assess their usefulness as indicators of fresh honey quality. The effect of heat treatment, storage and adulteration with different types of syrups on HMF and furosine content has been studied.

RESULTS: In fresh honey, HMF and furosine values ranged from 0.9 to 14.6 mg kg−1 of product and from 3.06 to 12.06 g kg−1 of protein, respectively. Heating of honey samples with different pH (3.76 and 5.14) produced slight increases in HMF content and negligible changes were detected in furosine values. The storage of fresh honey for 2 years caused a high increase in the HMF level, reaching values above EU limits. However, furosine showed a different behavior depending on the type of honey sample. Adulteration assays using different syrups produced an increase in HMF and a decrease of furosine values by dilution effect. HMF content of adulterated honey samples with syrup of known origin did not exceed EU limits.

CONCLUSION: These results show the influence of long periods of storage or adulteration, using different percentages of corn or invert sugar syrups, on HMF and furosine content of fresh honey. This seems to indicate that the combination of HMF and furosine may be useful for evaluating the quality of fresh honey. Copyright © 2009 Society of Chemical Industry
Theoretical study of the O + HSO reaction
Authors: Ballester M. Y. , Varandas A. J. C.
Published: April 2009

A quasi‐classical trajectory study of the title reaction is reported using a global, double, many‐body expansion potential energy surface for HSO2. Calculations are presented for specific translational energies and rovibrational states of the reactants, showing that formations of H + SO2 and HS + O2 are the most favored processes, although other products are also formed. The reaction is predicted to be barrier free and its mechanism is discussed, with reaction rate constants also being reported. © 2009 Wiley Periodicals, Inc. Int J Chem Kinet 41: 455–462, 2009
Self‐organized colloidal crystals for photonics and laser applications
Authors: Furumi S. , Fudouzi H. , Sawada T.
Published: April 2009

We present an overview of recent developments in the fabrication and uses of colloidal crystals (CCs) for photonics and laser applications. Microparticles with a diameter in the range from 10 nm to 10 μm often have an intrinsic capability to spontaneously organize themselves from a colloidal suspension into 3D lattice structures. Such highly ordered 3D architectures of microparticles are called colloidal crystals (CCs). The CC structures have received tremendous attention as one of the facile and high‐throughput fabrication techniques of photonic crystals (PCs). We introduce here interesting precedents not only of diverse techniques of high‐quality CC structures, but also of their versatile applications in optical sensors responding to various external stimuli. This review also highlights a new potential use of the CCs as low‐threshold laser devices. We believe that a wide variety of CC architectures will play leading roles in the next generation of optoelectronic devices.
Synthesis of PVP‐coated silver nanoparticles and their biological activity towards human mesenchymal stem cells
Authors: Kittler S. , Greulich C. , Köller M. , Epple M.
Published: April 2009

Silver nanoparticles were prepared by the polyol process, i.e. by the reduction of silver nitrate with ethylene glycol in the presence of polyvinylpyrrolidone, PVP. Thereby, the silver nanoparticles were colloidally stabilized by the polymer. The synthesis of nanoparticles of different size and shape (cubes, rods and spheres) was possible by changing the reaction conditions such as reagent ratio and temperature. The silver nanoparticles were characterized by dynamic light scattering (DLS), zeta‐potential measurements, UV‐spectroscopy, and scanning electron microscopy (SEM). The biological activity of spherical PVP‐coated silver nanoparticles (about 100 nm diameter) was tested on human mesenchymal stem cells (hMSC) in comparison with equivalent amounts of silver ions (silver acetate). hMSC were treated with silver concentrations in the range of 50 ng mL‐1 to 50 μg mL‐1 for 7 days under cell culture conditions. Cytotoxic cell reactions occurred at ≥2.5 μg Ag mL‐1 for nanoparticles and ≥1 μg Ag mL‐1 for silver acetate, indicating a critical role of the silver ions for toxic reactions.
Oxidation of barium on the surface of nanothick chromium oxide films grown on the (110) molybdenum substrate
Authors: Klimenko E.V. , Starovojtova L.N. , Zasimovich I.N. , Naumovets A.G.
Published: April 2009

Auger electron spectroscopy and work function measurements were used to investigate adsorption of barium onto the surface of nanothick chromium oxide films grown on the (110) molybdenum substrate. We prepared smooth 3‐monolayers (ML) thick pseudomorphic chromium oxide films and rough 2–3 ML chromium oxide films carrying three‐dimensional oxide nanoparticles (the Stranski‐Krastanov (SK) surface morphology). The interaction of barium with chromium oxide films of both types was found to lead to barium oxide formation and partial reduction of chromium oxide to chromium. When barium was deposited onto a 3 ML pseudomorphic chromium oxide film, the barium oxidation at room temperature was restricted to formation of only one monolayer of barium oxide. However, in the case of barium adsorption on chromium oxide film with the SK type surface morphology, the oxidation encompassed 3 monolayers of barium. A strong effect of metal substrate‐oxide film interface on the oxidation ability of nanothick oxide films was revealed. These results showed possibilities of tailoring surface properties of the barium oxide films by variation of their thickness and by substrate‐film interface modification.
Photoluminescence effects on gold nano‐ particles modified by short single stranded DNA molecules
Authors: Kysil O. , Simonova K. , Frolov V. , Buzaneva E. , Köhler M. , Gobsch G. , Ritter U. , Scharff P.
Published: April 2009

The concept for a function of gold nanoparticle photosensor based on gold nanoparticle optical properties, depending on the size and architecture of their self – assemblies, is revised from the studies of modified by short ssDNA (5.4 nm length) selected gold nanoparticle (8.6 nm diameter) assembling in biosuspensions. Biosensing effect, collective photoluminescence in visible range of different size 2D, 3D assemblies from these nanoparticles, is revealed due to their controlled assembling in biosuspesions, dependent on ssDNA conformation, that changes gold core capping and therefore a force of interparticle interaction. Nanophotosensor is characterized by intensive photoluminescence maxima in two regions of visible range for tested biosuspensions due to detected difference in the self ‐ assemblies’ architecture of gold nanoparticles with different gold core capping by the ssDNA molecules. The emission maxima are 4.2x103pps and 4.1x104pps in (525–780) nm and (780–920) nm regions mainly for 2D assemblies as nanowires and 3D assemblies as circle holms, correspondently, in DNA buffer suspensions with different biomolecules. The results are explained addressing photoluminescence of gold nanoparticle assemblies to system of discrete electron states in valence and conductivity bands for gold nanoparticle model.
SQUID‐imaging technology to study magnetic nanocarriers for targeted magnetic transport
Authors: Budnyk M.M. , Dudchenko N.O. , Stavynska O.M. , Alekseytsev Y.O. , Dudchenko O.K. , Chaikovsky I.A. , Minov Y.D. , Sutkovyi P.G. , Shpylyovy P.B. , Ryzhenko T.M. , Budnyk V.M. , Voytovych I.D.
Published: April 2009

The aim of the study was to develop SQUID‐magnetometer system and to reveal the ability of above system to monitor the dynamics of injected magnetic nanoparticles (MNP) into rabbit’s body. MNP were prepared by first precipitation of ferrous hydroxide which was then crystallized into magnetite in the presence of potassium nitrate as mild oxidizing agent and further the MNP surface was modified with oxidized hidroxyethylstarch. The dynamics of the MNP distribution into the rabbit tissues according to the electron‐spin resonance (ESR) data shows that after 60 min of nanomaterial preparation circulation into the rabbit’s body the preparation redistribution occurs in favor of liver and spleen. The magnetic field applying to the kidneys area leads to the considerable increase of iron concentration in kidneys. As a result of magnetic fields measurements over the rabbit with injected MNP using developed SQUID‐magnetometry system, the maps of MNP spatial distribution into the rabbit’s body were obtained.
Interaction of carbon nanotubes containing iron catalysts and iron‐based powders with human blood plasma
Authors: Ivashchenko O. , Boshytska N. , Uvarova I. , Prylutskyi E.
Published: April 2009

When nanotubes containing a metallic catalyst enter a living organism through the respiratory apparatus, they may interact with tissue fluid and blood. We describe the estimation of the activity of the catalyst nanoparticles in the interaction with such biomedia in comparison to iron‐based powders. The interaction of iron‐carbon nanotubes, carbonyl iron and iron (III) oxide with human blood and tissue fluid was modelled. The amount of iron released into the biomedia was determined using a spectral photometric method. The nanotubes released almost the same amount of iron into the plasma‐containing media as the carbonyl iron (34.67 mg/0.5 g and 38.92 mg/0.5 g, respectively), despite the fact that the carbonyl iron contained 99.3 wt % iron whereas the nanotubes contained only 33.5 wt %. Carbonyl iron powder interacted with blood plasma 180 times more compared to iron (III) oxide powder. This suggests that α‐iron is assimilated (i.e. it dissolves and gets biotransformed) by blood plasma easier and faster than iron (III) oxide. We conclude that the dominant contribution in the iron released from nanotubes into blood plasma is made by iron (III) oxide. The high concentration of iron (close to that of carbonyl iron) in blood plasma may be ascribed to the nanoscale nature of iron (III) oxide particles.
Effect of exogenous carbon nanoparticles on structure and reinforcement of aluminum matrix composite
Authors: Demchenko I.I. , Stovpchenko G.P.
Published: April 2009

The possibility of carbon nanotubes (CNT) using as strengthening phase in aluminum‐matrix composite is represented in the present work both theoretically and practically. The hardness which was determined in obtained samples using Vickers method is reduced in one graph. This graph quantitively represents the increasing hardness. The mechanism of the obtained composites hardening was explained using the classical laws of hardening theory. The maximal concentration of CNT in metal matrix under the highest composite hardening was calculated.
Investigation of the improvement of the physical and mechanical properties of polymer composite materials with nano‐sized powders
Authors: Bilogurova L. , Shevtsova M.
Published: April 2009

Polymer composites are widely applied in modern aviation. However, their shortcomings force scientists to look for material enhancing methods. Therefore experimental research of the influence of nanoparticles on the polymer strength and the electromagnetic properties was conducted. The polymer modification was realized by two kinds of nano‐sized powders: iron and diamond. The addition of 0.67 % nanodiamonds mass content in polymer increases its strength (about 2 times). This can be explained by electrical interaction of nanoparticles with high specific surface energy and monomer molecules having dipole moments. The samples for dielectric permittivity measuring were made from pure resin and from resin reinforced with 0.67 % nanodiamonds and 1 % nano‐iron mass content. The results show that the addition of nanodiamonds decreases the resin dielectric permittivity but nano‐iron addition increases it. The electrical conductivity σ and the magnetic permeability μ were measured on samples with 1 %, 3 %, 10 % and 25 % weight content of nanoscale iron. The electrical conductivity did not uniformly increase according to the percolation theory. This percolation transition (by 5 orders of magnitude) corresponds to nano‐iron mass content 3 %.
Detection of dying cells using lectin‐conjugated fluorescent and luminescent nanoparticles
Authors: Bilyy R. , Tomyn A. , Kit Y. , Podhorodecki A. , Misiewicz J. , Nyk M. , Strek W. , Stoika R.
Published: April 2009

Constantly increasing sector of industry of biomedical diagnostics requires photosensitive and stable nanomaterials which can be specifically bio‐labeled for targeting selected cells in the body. Here we describe two types of novel nanomaterials conjugated with specific proteins recognized by dying (apoptotic and necrotic) cells. They are luminescent GaN:Eu3+‐doped nanoparticles with wide green emission and very narrow red emission and fluorescent green‐emitting fluorescein‐containing polystyrene nanoparticles. These nanoparticles were conjugated with carbohydrate recognizing proteins – the lectins – that are targeting specific cell surface glycoproteins which were recently shown to be novel markers of dying cells (Bilyy et al., 2003, Bilyy et al., 2007). Both luminescent and fluorescent nanoparticles possessed high brightness and low level of photobleaching and efficiently interacted with dying cells, thus discriminating them from the intact ones.
Comparative study of biological action of fullerenes C60 and carbon nanotubes in thymus cells
Authors: Prylutska S.V. , Grynyuk I.I. , Grebinyk S.M. , Matyshevska O.P. , Prylutskyy Y.I. , Ritter U. , Siegmund C. , Scharff P.
Published: April 2009

In a model experiment on T‐cells isolated from Wistar rat thymus the biological activity of nonmodified fullerenes (C60) and multi‐walled carbon nanotubes (MWCNT) is studied. It is demonstrated that C60 at a concentration of 14.4 μg/ml in the cell incubation medium inhibit the activity of plasma membrane Ca2+‐stimulated ecto‐ATPase. Both, the initial rate of the extracellular ATP hydrolysis and the time of reaching the half‐maximum level of the enzyme activity are decreased, while MWCNT (12.5 and 25 μg/ml) have no effect on the kinetic parameters of the ecto‐ATPase reaction. It is shown that both C60 and MWCNT demonstrate a protective effect against H2O2‐induced injury of thymic T‐cells.
Mechanism of thermal and electrical conductivity in polymer‐nanocarbon composites
Authors: Lazarenko A. , Vovchenko L. , Prylutskyy Y. , Matzuy L. , Ritter U. , Scharff P.
Published: April 2009

The electrical and thermal conductivity of nanocarbon filled polymers were studied by adding nanocarbon fillers (thermoexfoliated graphite (TEG) and dispersed TEG (nanoTEG)) to epoxy resin (ED) or polyethylene oxide (PEO). The content of filler in composite materials (CM) was (0.5–10) wt%. The temperature range of the investigations was (77–300) K for electrical conductivity and (150–423) K for thermal conductivity, respectively. It was found that electrical conductivity of CM obeys percolation dependence with low critical concentration cr∼(1–2) wt% (φcr∼(0.56–1.1) vol%) and characterised by a positive temperature coefficient. The thermal conductivity is approximately linear on nanocarbon content. The model describing the mechanisms of electrical and thermal conductivity of CM had been proposed. The basic parameters of this model are following: content of nanocarbon anisotropic particles and their distribution in polymer matrix; the contact thermal (electrical) resistance both between the filler particles and on the interface of two phases – polymer‐carbon filler.
Sources of highly charged ions as a platform technology for applications in nanotechnology and medicine
Authors: Zschornack G. , Grossmann F. , Ovsyannikov V.P. , Heller R. , Kentsch U. , Kreller M. , Schmidt M. , Schwan A. , Silze A. , Ullmann F.
Published: April 2009

Highly charged ions significantly differ in their physical properties compared to “classical” low charged ions. With the Dresden EBIT/EBIS family (EBIT: Electron Beam Ion Trap, EBIS: Electron Beam Ion Source) a compact, economic and long‐term stable source setup for highly charged ions is available providing the platform technology for various applications. Beside the use in basic as well as in applied research this technology is also suitable for nanotechnology and medical applications. Potential applications and first proof‐of‐principle experiments are discussed. The integration of an EBIT in a FIB setup is exemplified.