In the present study, a series of p-hydroxy benzoic acid derivatives (1-29) was synthesized and tested for its antimicrobial potential. Results of antimicrobial studies indicated that in general, ...Schiff bases were found to be more active as compared to esters and compound 14 was found to be most potent antimicrobial agent (pMICam=1.50 µM/ml). QSAR study was performed in order to understand the relationship between antimicrobial activity and changes in the molecular structures which indicated that antimicrobial activity of the synthesized compounds was governed by valence first order molecular connectivity index (1χv), Kier's alpha first order shape index (κα1), Kier's first order shape index (κ1) and Balaban topological index (J).
The study describes the in situ formation of magnetite nanoparticles within a swollen polyacrylamide hydrogel. The average diameter of nanoparticles, as determined by TEM analysis, was found to be ...nearly 12.5 nm. In XRD analysis the characteristic peaks, observed at d
= 3.07, 2.78, 2.64, 2.53, 2.32 and 2.03, also confirmed the formation of magnetite within the polymer network. The percent swelling of magnetite-loaded gel in physiological fluid was observed to decrease with increasing amount of magnetite in the gel. Moreover, the percent swelling increased
from 140 to 254% as the strength of the applied magnetic field increased from 500 to 2500 Oe. Finally, the model drug, vitamin B
2
, loaded magnetic gels showed relatively slower release in the presence of an applied magnetic field.
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BFBNIB, DOBA, GIS, IJS, IZUM, KILJ, KISLJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Abstract With more than 1 million new cases each year, female breast cancer is the second most common cancer in the world and the most common cancer among women. Breast cancer involves a ...multimodality treatment and a co-ordinated approach from various specialties. Breast-conserving therapy (BCT) is increasingly being integrated into the management of breast cancer. The obvious advantages of BCT are equivalent local and distant control rates as compared with mastectomy and the preservation of the breast. However, the key to a successful BCT is achieving a cosmetic outcome that is acceptable to the patient and the physician. Cosmesis in breast cancer is the end result of a range of factors that fall under the broad heads of surgery, radiotherapy, chemotherapy and hormonal treatment. All of these modalities can play a role in compromising breast cosmesis. This overview discusses the factors that are critical in affecting the final cosmetic outcome in patients with BCT.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Mapping axon diameters within the central and peripheral nervous system could play an important role in our understanding of nerve pathways, and help diagnose and monitor an array of neurological ...disorders. Numerous diffusion MRI methods have been proposed for imaging axon diameters, most of which use conventional single diffusion encoding (SDE) spin echo sequences. However, a growing number of studies show that oscillating gradient spin echo (OGSE) sequences can provide additional advantages over conventional SDE sequences. Recent theoretical results suggest that this is especially the case in realistic scenarios, such as when fibres have unknown or dispersed orientation. In the present study, we adopt the ActiveAx approach to experimentally investigate the extent of these advantages by comparing the performances of SDE and trapezoidal OGSE in viable nerve tissue. We optimise SDE and OGSE ActiveAx protocols for a rat peripheral nerve tissue and test their performance using Monte Carlo simulations and a 800 mT/m gradient strength pre-clinical imaging experiment. The imaging experiment uses excised sciatic nerve from a rat's leg placed in a MRI compatible viable isolated tissue (VIT) maintenance chamber, which keeps the tissue in a viable physiological state that preserves the structural complexity of the nerve and enables lengthy scan times. We compare model estimates to histology, which we perform on the nerve post scanning. Optimisation produces a three-shell SDE and OGSE ActiveAx protocol, with the OGSE protocol consisting of one SDE sequence and two low-frequency oscillating gradient waveform sequences. Both simulation and imaging results show that the OGSE ActiveAx estimates of the axon diameter index have a higher accuracy and a higher precision compared to those from SDE. Histology estimates of the axon diameter index in our nerve tissue samples are 4–5.8 μm and these are excellently matched with the OGSE estimates 4.2–6.5 μm, while SDE overestimates at 5.2–8 μm for the same sample. We found OGSE estimates to be more precise with on average a 0.5 μm standard deviation compared to the SDE estimates which have a 2 μm standard deviation. When testing the robustness of the estimates when the number of the diffusion gradient directions reduces, we found that both OGSE and SDE estimates are affected, however OGSE is more robust to these changes than the SDE. Overall, these results suggest, quantitatively and in in vivo conditions, that low-frequency OGSE sequences may provide improved accuracy of axon diameter mapping compared to standard SDE sequences.
•Performance of SDE and OGSE ActiveAx are compared for axon diameter imaging.•A viable rat sciatic nerve and Monte Carlo simulations are used as samples.•OGSE outperforms SDE in accuracy, precision and robustness of diameter estimates.•Optimal OGSE has low frequency with results matching histology at 800 mT/m.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Purpose:
We investigate the feasibility of data-driven, model-free quantitative MRI (qMRI) protocol design on
in vivo
brain and prostate diffusion-relaxation imaging (DRI).
Methods:
We select subsets ...of measurements within lengthy pilot scans, without identifying tissue parameters for which to optimise for. We use the “
select and retrieve via direct upsampling
” (SARDU-Net) algorithm, made of a
selector
, identifying measurement subsets, and a
predictor
, estimating fully-sampled signals from the subsets. We implement both using artificial neural networks, which are trained jointly end-to-end. We deploy the algorithm on brain (32 diffusion-/T1-weightings) and prostate (16 diffusion-/T2-weightings) DRI scans acquired on three healthy volunteers on two separate 3T Philips systems each. We used SARDU-Net to identify sub-protocols of fixed size, assessing reproducibility and testing sub-protocols for their potential to inform multi-contrast analyses via the
T1-weighted spherical mean diffusion tensor
(T1-SMDT, brain) and
hybrid multi-dimensional
MRI (HM-MRI, prostate) models, for which sub-protocol selection was not optimised explicitly.
Results:
In both brain and prostate, SARDU-Net identifies sub-protocols that maximise information content in a reproducible manner across training instantiations using a small number of pilot scans. The sub-protocols support T1-SMDT and HM-MRI multi-contrast modelling for which they were not optimised explicitly, providing signal quality-of-fit in the top 5% against extensive sub-protocol comparisons.
Conclusions:
Identifying economical but informative qMRI protocols from subsets of rich pilot scans is feasible and potentially useful in acquisition-time-sensitive applications in which there is not a qMRI model of choice. SARDU-Net is demonstrated to be a robust algorithm for data-driven, model-free protocol design.
Low-molecular-weight heparin (LMWH) is effective in the prevention of postoperative venous thromboembolism but does it have the safety advantages over standard heparin (SH) that have been claimed? In ...a multicentre randomised trial in 3809 patients undergoing major abdominal surgery (1894 LMWH, 1915 SH) heparin was given preoperatively and continued for at least 5 postoperative days. Patients were assessed in the postoperative period and were followed up for at least 4 weeks, the emphasis being on safety. Major bleeding events occurred in 69 (3·6%) patients in the LMWH group and 91 (4·8%) patients in the SH group (relative risk 0·77, 95% confidence interval 0·56-1·04; p=0·10). 93 indices of major bleeding were observed in the 69 LMWH patients and 141 in the SH patients. (p=0·058). Severe bleeding was less frequent in the LMWH group (1 0% vs 1·9%; p=0·02), as was wound haematoma (1·4% vs 2·7%; p=0·007). Bleeding episodes with LMWH were less likely to lead to further surgery to evacuate a haematoma or to control bleeding, and injection site bruising was also less common in the LMWH group. No significant differences were found in the efficacy of the two agents. Perioperative death rates were 3·3% in the LMWH group and 2·5% in the SH group; pulmonary emboli were detected in 0·7% and 0·7%; and deep-vein thrombosis was diagnosed in 0·6% of patients in each group. Follow-up was done on 91% of 3699 evaluable patients. There were 19 further deaths (10 LMWH, 9 SH group) and 25 patients with thromboembolic complications (15 and 10). Of the 3 patients with fatal pulmonary emboli during follow-up 2 had received LMWH and 1 SH. The two drugs were of similar efficacy. The primary end point, the frequency of major bleeding, showed a 23% reduction in the LMWH group, but this difference was not significant. The secondary safety end points revealed that LMWH was significantly better than SH. Fatal pulmonary embolism occurs rarely (0·09%) following discharge from hospital so the cost benefit ratio would not justify prolonged prophylaxis in this setting.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SBJE, SIK, UILJ, UKNU, UL, UM, UPUK, VSZLJ
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