Amplification of the index of refraction of aqueous immersion fluids with crown ethers

There is a current need for high refractive index (RI) materials that can be used in aqueous systems for improving 193-nm immersion photolithography. Although heavy metal salts such as Ca2+ and Ba2+ have the potential to substantially increase the RI of aqueous solutions, the water solubility of these salts with common anions is often too low to achieve concentrations that significantly increase the RI to the desired values. We therefore investigate the use of crown ethers to enhance the solubility of these cations. Most of crown ethers are soluble in water, are inexpensive materials, and are available commercially. 15-crown-5-ether and 12-crown-4-ether are liquids at room temperature and therefore can be used as neat immersion fluids without dilution in water. Saturation of crown ethers with inorganic salts do not lead to any increase in the refractive index due to their low solubility in such an apolar medium. Thus, the use of inorganic salts as refractive index enhancement agents does not seem to be a desirable proposition in the present case. Instead, the use of crown ethers or their derivatives can be an alternative system, since these compounds have properties such as density, viscosity, and boiling point similar to aqueous media

Medium-to-high prevalence of screening-detected parkinsonism in the urban area of Tehran, Iran: Data from a community-based door-to-door study

Introduction: Parkinsonism occurs in all ethnic groups worldwide; however, there are wide variations in the prevalence rates reported from different countries, even for neighboring regions. The huge socioeconomic burden of parkinsonism necessitates the need for prevalence studies in each country. So far, there is neither data registry nor prevalence information on parkinsonism in the Iranian population. The aim of our study was to estimate the prevalence rate of probable parkinsonism in a huge urban area in Iran, Tehran using a community-based door-to-door survey. Materials and methods: We used a random multistage sampling of the households within the network of health centers consisting of 374 subunits in all 22 districts throughout the entire urban area of Tehran. Overall, 20,621 individuals answered the baseline checklist and screening questionnaire and data from 19,500 persons aged �30 years were entered in the fnal analysis. Health care professionals used a new six-item screening questionnaire for parkinsonism, which has been previously shown to have a high validity and diagnostic value in the same population. Results: A total of 157 cases were screened for parkinsonism using the validated six-item questionnaire. After age and sex adjustment based on the Tehran population, the prevalence of parkinsonism was calculated as 222.9 per 100,000. Using the World Health Organization�s World Standard Population, the standardized prevalence rate of parkinsonism was 285 per 100,000 (95 confdence interval 240-329). The male:female ratio of probable parkinsonism was calculated as 1.62, and there was a signifcant increase in the screening rate by advancing age. Conclusion: The calculated rates for the prevalence of parkinsonism in our study are closer to reports from some European and Middle Eastern countries, higher than reports from Eastern Asian and African populations, and lower than Australia. The prevalence rate of >200 in 100,000 for parkinsonism in Tehran, Iran could be considered a medium-to-high rate. © 2015 Fereshtehnejad et al

Mortality in Iranian patients with Parkinson's disease: Cumulative impact of cardiovascular comorbidities as one major risk factor

Mortality rate, life expectancy, survival, and the impact of comorbidities on them in people with Parkinson's disease (PD) need to be assessed in settings with different sociodemographic backgrounds. We investigated mortality features in Iranian PD patients focusing on the role of cardiovascular multimorbidity on their survival. Data on mortality and comorbidity profile was gathered in a cohort of 190 individuals with idiopathic PD referred to a Movement Disorders Clinic. Standardized mortality ratio (SMR) compared to the Tehran general population was 3.44 and the life expectancy at birth was 67.4 (95 CI: 59.1-75.8) yr. Patients with at least one cardiovascular comorbidity had a shorter survival time after PD onset (14.0 versus 29.2 yr, p = 0.012). The hazard ratio for death increased 2.8 times (95 CI: 1.5-5.2, p = 0.002) with one additional cardiovascular comorbidity. Among all comorbid conditions, stroke showed the strongest independent effect on mortality in PD patients HR = 13.1 (95% CI: 2.4-71.7), p = 0.003 . Conclusively, life expectancy was slightly lower in Iranian PD patients compared to the general population, while the SMR was high. Cardiometabolic multimorbidity substantially decreased survival in people with PD. Our study highlights the need for assessment, prevention, and treatment of cardiovascular morbidities in parkinsonian patients, given their effect on survival. © 2015 Seyed-Mohammad Fereshtehnejad et al

Outlook for potential third-generation immersion fluids

In a search for alkane candidates for 193 nm immersion fluids, several alkanes and cycloalkanes were synthesized, purified and screened to ascertain their absorption at 193 nm, refractive index and temperature dispersion coefficient in the context of the actual application. In general, cycloalkanes, and more specifically polycycloalkanes, possess a higher refractive index than do linear alkanes. Decalin, cyclodecane, perhydrophenanthreme (PHP), perhydrofluorene (PHF) and perhydropyrene (PHPY) are examined as potential second and third generation immersion fluids. The use of perhydropyrene, which possesses a high refractive index of 1.7014 at 193 nm, may be limited as an immersion fluid because of high absorption at 193 nm. Mixtures of cycloalkanes can lead to a higher enhancement of the refractive index together with a decrease on the viscosity. Exhaustive purification of the fluids is a critical step in determining the real absorption of the different fluids at 193 nm. Two simple purification processes of these cycloalkanes were developed that led to low absorption fluids in the VUV region. The possibility of forming the oxygen complex in aerated fluids was reduced by purging samples with argon or nitrogen. This easy elimination of the oxygen complex shows the weak bonding nature of this complex

Engineering a vascularised 3D in vitro model of cancer progression.

The hallmark of tumours is the ability of cancerous cells to promote vascular growth, to disseminate and invade to distant organs. The metastatic process is heavily influenced by the extracellular matrix (ECM) density and composition of the surrounding tumour microenvironment. These microenvironmental cues, which include hypoxia, also regulate the angiogenic processes within a tumour, facilitating the spread of cancer cells. We engineered compartmentalized biomimetic colorectal tumouroids with stromal surrounds that comprised a range of ECM densities, composition and stromal cell populations. Recapitulating tissue ECM composition and stromal cell composition enhanced cancer cell invasion. Manipulation of ECM density was associated with an altered migration pattern from glandular buds (cellular aggregates) to epithelial cell sheets. Laminin appeared to be a critical component in regulating endothelial cell morphology and vascular network formation. Interestingly, the disruption of vascular networks by cancer cells was driven by changes in expression of several anti-angiogenic genes. Cancer cells cultured in our biomimetic tumouroids exhibited intratumoural heterogeneity that was associated with increased tumour invasion into the stroma. These findings demonstrate that our 3D in vitro tumour model exhibits biomimetic attributes that may permit their use in studying microenvironment clues of tumour progression and angiogenesis

The rapidly pulsating sdO star, SDSS J160043.6+074802.9

A spectroscopic analysis of SDSS J160043.6+074802.9, a binary system containing a pulsating subdwarf-O (sdO) star with a late-type companion, yields Teff = 70 000 +/- 5000 K and log g = 5.25 +/- 0.30, together with a most likely type of K3V for the secondary star. We compare our results with atmospheric parameters derived by Fontaine et al. (2008) and in the context of existing evolution models for sdO stars. New and more extensive photometry is also presented which recovers most, but not all, frequencies found in an earlier paper. It therefore seems probable that some pulsation modes have variable amplitudes. A non-adiabatic pulsation analysis of uniform metallicity sdO models show those having log g > 5.3 to be more likely to be unstable and capable of driving pulsation in the observed frequency range.Comment: 14 pages, 12 figures, accepted for publication in MNRAS, 2009 September

Prognostic Value of CEA and CA 19.9 in Gastric Cancer

Introduction: Gastric cancer (GC) is still a major health problem due to the majority of patients present with advanced disease. This considerably reduces the possibility of curative treatment. A critical decision in the treatment of GC is related to staging, which is mainly assessed by the use of the TNM classification. There are other factors that can influence in the prognosis during the preoperative period: pathological type, degree of differentiation or tumor markers level. The most commonly used tumor markers (TM) in GC are CEA and CA 19.9. The aim of the present study is to analyze the relationship between CEA and CA 19.9 markers with certain characteristics of the patients and tumors and to evaluate the utility of these TM determined at the time of diagnosis as prognostic factors.Material and methods: A prospective collection of the data of all pacients operated by GC at our centre. A total of 501 cases were diagnosed. Mean age was 68.2 years. We analyzed age, sex, tumor location, clinical stage, tumor markers determined in the preoperative period, the use of perioperative chemotherapy and response to chemotherapy, the pathological characteristics and disease follow-up.Results: At the time of diagnosis 23,3 % of the patients presented high values of CEA, 32,6 % presented high values of CA 19.9 and 14,1% presented with both elevated markers. Patients who were diagnosed at an advanced stage and presented high levels of CEA or CA 19.9 or both TM had worse survival compared to those with normal values.Conclusion: the presence of an elevated serum level of tumor markers is related to advanced tumor stage and worse prognosis in terms of overall survival