Central neurocytoma: proton MR spectroscopy and diffusion weighted MR imaging findings

Purpose

To present proton magnetic resonance spectroscopy and diffusion-weighted imaging (DWI) findings of central neurocytoma (CN).

Methods and Materials

Imaging findings of seven patients with the histopathological diagnosis of CN (five male and two female; age range, 21–28 years of age) were evaluated retrospectively. In addition to conventional magnetic resonance imaging features, we also assessed the metabolite ratios and tumor normalized apparent diffusion coefficient (NADC), which was calculated by dividing the tumor apparent diffusion coefficient (ADC) values by normal ADC. Approval from our institutional review board was obtained for this review.

Results

The tumor choline/creatine ratios were 5.17±2.38, while N-acetyl aspartate/choline and N-acetyl aspartate/creatine ratios were 0.33±0.15 and 1.84±1.38, respectively. On DWI, tumors had heterogeneous hyperintense appearances when compared with the contralateral parietal lobe white matter and tumor NADC values were 0.63±0.05.

Conclusion

Significantly increased choline/creatine and decreased N-acetyl aspartate/choline ratios with lower NADC values in CN resemble high-grade gliomas and complicate the diagnosis. Familarity its physiologic features would help to presurgical diagnosis of ventricular and exraventricular CNs.     

Axially Symmetric Bianchi Type-I Model with Massless Scalar Field and Cosmic Strings in Barber’s Self-Creation Cosmology

Axially symmetric Bianchi type-I space time is considered in the presence of massless scalar field and cosmic strings in Barber’s (Gen. Relativ. Gravit. 14:117, 1982) self-creation theory with two conditions (i) A=B ⁿ and (ii) ε+λ=0. Some physical and kinematical properties of the model, thus obtained, are also discussed.     

Role of diet and trace elements in lithogenesis of renal calculi

Twenty eight stones were characterized for chemical composition and structure. The concentrations of trace elements were determined using INAA while EDXRF was used for determining the calcium contents of the stones. Twenty stones were found to be mainly composed of calcium, six were mixed type and the remaining two were of uric acid type. The concentrations of trace elements namely Zn, Sr, Fe and Cr were lower in uric acid stones as compared to calcium based stones. Diet analysis of 310 patients who were treated for renal stones showed a diet rich in calcium and oxalate and decreased water consumption.

     

Neural network study of hidden-charm pentaquark resonances

Recently,the LHCb experiment announced the observation of hidden-charm pentaquark states P,(4312),P_c(4440),and P_c(4457)near Σ_cD and Σ_cD~* thresholds.In this present work,we studied these pentaquarks in the framework of the nonrelativistic quark model with four types of potential.We solved five-body Schrodinger equation by using the artificial neural network method and made predictions of parities for these states,which are not yet determined by experiment.The mass of another possible pentaquark state near the D~*Σ_c~* with J~P=5/2~-is also calculated.     

AgNOR increase in buccal epithelial cells of trisomy 21 infants

The aim of this study is to compare the Argilophilic Nucleolus Organizer Regions (AgNORs) level between Down syndrome (DS) patients and controls in a tissue sharing the same embryonic origin with the central nervous system and compare the results with those obtained recently by us from DS's lymphocytes. For this, buccal desquamating epithelial cells well known as the ectodermic origin were used. Since the AgNOR staining intensity is an indicator of the ribosomes biosynthesis rate, comparison of the image analysis values of the AgNOR area/total nuclear area (NORa/TNa) in buccal desquamating epithelial cells of DS patients and controls provided a plausible conclusion about the regulation/deregulation of the rRNA genes (rDNA) in these cells of DS babies/infants. The (NORa/TNa) proportion was calculated using an in-house computer program. Fifty buccal desquamating cells were analysed for each individual to determine the average NORa/TNa value per individual. In contrast to healthy controls, NORa/TNa proportion value of buccal epithelial cells from DS patients found significantly higher than that of the controls: (4.08 ± 1.16)% and (2.13 ± 0.55)%, respectively. This 92% increase is far higher than the expected value due to the extra rRNA genes on the extra-chromosome 21. Finally DS babies/infants exhibit very higher AgNOR expression increase in their buccal epithelial cells compared to controls. This is the first study that is available on the comparison of AgNOR expression levels in buccal epithelial cells between DS infants and their controls.     

Strong electron-hole exchange in coherently coupled quantum dots

We have investigated few-body states in vertically stacked quantum dots. Because of a small interdot tunneling rate, the coupling in our system is in a previously unexplored regime where electron-hole exchange plays a prominent role. By tuning the gate bias, we are able to turn this coupling off and study a complementary regime where total electron spin is a good quantum number. The use of differential transmission allows us to obtain unambiguous signatures of the interplay between electron and hole-spin interactions. Small tunnel coupling also enables us to demonstrate all-optical charge sensing, where a conditional exciton energy shift in one dot identifies the charging state of the coupled partner.     

Evolution of the degree of polarization of an electromagnetic Gaussian Schell-model beam in a Gaussian cavity

The interaction of an electromagnetic Gaussian Schell-model (EGSM) beam with a Gaussian cavity is analyzed. In particular, the evolution of the degree of polarization of the EGSM beam is investigated. The results show that the behavior of the degree of polarization depends on both the statistical properties of the source that generates the EGSM beam and the parameters of the cavity.     

Straightforward access to chiral diol bidentate ligands: their efficient enantioselective induction in the addition of diethylzinc to aromatic aldehydes

Enantiopure C₂‐symmetric diol bidentate ligands have been synthesized in a straightforward manner through a three‐step reaction with good yields. The synthesized C₂‐symmetric diol bidentate ligands were used in the addition of diethylzinc to various aromatic aldehydes, a general catalytic benchmark reaction, in order to assess their enantioselective induction properties. The enantioselective addition of diethylzinc to 1‐naphthaldehyde and 3‐chlorobenzaldehyde was achieved with an enantiomeric excess (ee) of up to 98%. All synthesized ligands were also evaluated in the addition of diethyzinc to aromatic aldehydes including an extra metal such as Ti(IV) (up to 99% ee). Copyright © 2014 John Wiley & Sons, Ltd.