Evaluation of Moderate-Resolution Imaging Spectroradiometer (MODIS) collection 004 (C004) aerosol retrievals at Kanpur, Indo-Gangetic basin

[1] We have compared the spectral aerosol optical depth (AOD, tau lambda) and aerosol fine mode fraction (AFMF) of Collection 004 (C004) derived from Moderate-Resolution Imaging Spectroradiometer (MODIS) on board National Aeronautics and Space Administration's (NASA) Terra and Aqua platforms with that obtained from Aerosol Robotic Network (AERONET) at Kanpur (26.45 degrees N, 80.35 degrees E), India for the period 2001-2005. The spatially-averaged (0.5 degrees x 0.5 degrees centered at AERONET sunphotometer) MODIS Level-2 aerosol parameters (10 km at nadir) were compared with the temporally averaged AERONET-measured AOD (within +/- 30 minutes of MODIS overpass). We found that MODIS systematically overestimated AOD during the pre-monsoon season (March to June, known to be influenced by dust aerosols). The errors in AOD at 0.66 mu m were correlated with the apparent reflectance at 2.1 mu m (rho*(2.1)) which MODIS C004 uses to estimate the surface reflectance in the visible channels (rho(0.47) = rho*(2.1)/ 4, rho(0.66) = rho*(2.1)/ 2). The large errors in AOD (Delta tau(0.66) > 0.3) are found to be associated with the higher values of rho*(2.1) (0.18 to 0.25), where the uncertainty in the ratios of reflectance is large (Delta rho(0.66) +/- 0.04, Delta rho(0.47) +/- 0.02). This could have resulted in lower surface reflectance, higher aerosol path radiance and thus lead to overestimation in AOD. While MODIS-derived AFMF has binary distribution (1 or 0) with too low (AFMF < 0.2) during dust-loading period, and similar to 1 for the rest of the retrievals, AERONET showed range of values (0.4 to 0.9). The errors in tau(0.66) were also high in the scattering angle range 110 degrees - 140 degrees, where the optical effects of nonspherical dust particles are different from that of spherical particles.

CHEK2 in Breast and Colorectal Cancer

Breast and colorectal cancers, are common types of cancer, with over two million newly diagnosed cases annually worldwide. Cancer is a genetic disease and defects in DNA integrity restoring functions make a significant contribution to cancer risk. CHEK2 is a checkpoint kinase functioning as a regulator of cell cycle checkpoints, apoptosis, and DNA repair in response to DNA double-strand breaks. The aim of this study was to evaluate the role of CHEK2 in breast cancer predisposition in Finnish breast cancer families and in breast cancer risk at the population level. We were interested in the clinical and biological characteristics of the breast tumors associated with the CHEK2 germline mutations or aberrant CHEK2 protein expression and the effect on survival of patients with these CHEK2 defects. We also assessed the role of CHEK2 mutations, namely 1100delC and I157T, in colorectal cancer susceptibility in Finland. CHEK2 I157T was found to be a low-penetrance breast cancer susceptibility allele, conferring a 1.4-fold risk for carriers. Reduced or absent CHEK2 protein expression was observed in one-fifth of breast tumors from patients unselected for family history, implying that defective CHEK2 signaling contributes to tumorigenesis. Reduction in CHEK2 expression was more common in tumors with larger diameter and ER expression, but with regard to other tumor characteristics and prognosis of a patient no association was observed. Results from comparison of CHEK2 1100delC carrier tumors with noncarrier tumors were in line with the findings from the CHEK2 expression study. Tumors from CHEK2 1100delC carriers were more often of higher grade than tumors from noncarriers, and they also tended to be ER-positive more often, although generally 1100delC status does not seem to radically affect the tumor characteristics. Our results suggest that CHEK2 1100delC may not be a susceptibility allele for CRC, although a very small effect cannot be excluded. Furthermore, CHEK2 1100delC is equally frequent in HBCC (hereditary breast and colorectal cancer) phenotype families and in breast cancer families. Over 1000 CRC cases were screened for CHEK2 I157T, and a significantly higher frequency of I157T was observed among both familial and sporadic CRC cases. The relation of CHEK2 I157T with familial CRC has not been studied previously. CHEK2 I157T seems to be a susceptibility allele for both familial and sporadic CRC, conferring a 1.5-fold risk for carriers of this variant. CHEK2 I157T has been proposed to have a role as a multiple cancer susceptibility allele, which is supported by our results since we observed a trend towards higher frequency of the variant among cases with multiple primary tumors or those with a family history of cancer. During the last five years CHEK2 has established its role as an important cancer susceptibility gene. It has become apparent that CHEK2 is a low-penetrance susceptibility gene for several cancer types, significantly contributing to familial cancer risk as well as to cancer risk at the population level.

Multiphase porous media model for Intermittent Microwave Convective Drying (IMCD) of food

Intermittent microwave convective (IMCD) drying is an advanced drying technology that improves both energy efficiency and food quality during the drying of food materials. Despite numerous experimental studies available for IMCD, there is no complete multiphase porous media model available to describe the process. A multiphase porous media model considering liquid water, gases and the solid matrix inside the food during drying can provide in depth understanding of IMCD. In this article, firstly a multiphase porous media model was developed for IMCD. Then the model is validated against experimental data by comparing moisture content and temperature distributions after each heating and tempering periods. The profile of vapour pressures and evaporation during IMCD are presented and discussed. The relative contribution of water and vapour fluxes due to gas pressure and diffusion demonstrated that the fluxes due are relatively higher in IMCD compared to convection drying and this makes the IMCD faster.

Correlative fluorescence and transmission electron microscopy: An elegant tool to study the actin cytoskeleton of whole-mount (breast) cancer cells

Elucidating the structure and dynamics of lamellipodia and filopodia in response to different stimuli is a topic of continuing interest in cancer cells as these structures may be attractive targets for therapeutic purposes. Interestingly, a close functional relationship between these actin-rich protrusions and specialized membrane domains has been recently demonstrated. The aim of this study was therefore to investigate the fine organization of these actin-rich structures and examine how they structurally may relate to detergent-resistant membrane (DRM) domains in the MTLn3 EGF/serum starvation model. For this reason, we designed a straightforward and alternative method to study cytoskeleton arrays and their associated structures by means of correlative fluorescence (/laser)- and electron microscopy (CFEM). CFEM on whole mounted breast cancer cells revealed that a lamellipodium is composed of an intricate filamentous actin web organized in various patterns after different treatments. Both actin dots and DRM's were resolved, and were closely interconnected with the surrounding cytoskeleton. Long actin filaments were repeatedly observed extending beyond the leading edge and their density and length varied after different treatments. Furthermore, CFEM also allowed us to demonstrate the close structural association of DRMs with the cytoskeleton in general and the filamentous/dot-like structural complexes in particular, suggesting that they are all functionally linked and consequently may regulate the cell's fingertip dynamics. Finally, electron tomographic modelling on the same CFEM samples confirmed that these extensions are clearly embedded within the cytoskeletal matrix of the lamellipodium.

A Nationwide Study on Breast Cancer Risk in Postmenopausal Women Using Hormone Therapy in Finland

Since national differences exist in genes, environment, diet and life habits and also in the use of postmenopausal hormone therapy (HT), the associations between different hormone therapies and the risk for breast cancer were studied among Finnish postmenopausal women. All Finnish women over 50 years of age who used HT were identified from the national medical reimbursement register, established in 1994, and followed up for breast cancer incidence (n= 8,382 cases) until 2005 with the aid of the Finnish Cancer Registry. The risk for breast cancer in HT users was compared to that in the general female population of the same age. Among women using oral or transdermal estradiol alone (ET) (n = 110,984) during the study period 1994-2002 the standardized incidence ratio (SIR) for breast cancer in users for < 5 years was 0.93 (95% confidence interval (CI) 0.80–1.04), and in users for ≥ 5 years 1.44 (1.29–1.59). This therapy was associated with similar rises in ductal and lobular types of breast cancer. Both localized stage (1.45; 1.26–1.66) and cancers spread to regional nodes (1.35; 1.09–1.65) were associated with the use of systemic ET. Oral estriol or vaginal estrogens were not accompanied with a risk for breast cancer. The use of estrogen-progestagen therapy (EPT) in the study period 1994-2005 (n= 221,551) was accompanied with an increased incidence of breast cancer (1.31;1.20-1.42) among women using oral or transdermal EPT for 3-5 years, and the incidence increased along with the increasing duration of exposure (≥10 years, 2.07;1.84-2.30). Continuous EPT entailed a significantly higher (2.44; 2.17-2.72) breast cancer incidence compared to sequential EPT (1.78; 1.64-1.90) after 5 years of use. The use of norethisterone acetate (NETA) as a supplement to estradiol was accompanied with a higher incidence of breast cancer after 5 years of use (2.03; 1.88-2.18) than that of medroxyprogesterone acetate (MPA) (1.64; 1.49-1.79). The SIR for the lobular type of breast cancer was increased within 3 years of EPT exposure (1.35; 1.18-1.53), and the incidence of the lobular type of breast cancer (2.93; 2.33-3.64) was significantly higher than that of the ductal type (1.92; 1.67-2.18) after 10 years of exposure. To control for some confounding factors, two case control studies were performed. All Finnish women between the ages of 50-62 in 1995-2007 and diagnosed with a first invasive breast cancer (n= 9,956) were identified from the Finnish Cancer Registry, and 3 controls of similar age (n=29,868) without breast cancer were retrieved from the Finnish national population registry. Subjects were linked to the medical reimbursement register for defining the HT use. The use of ET was not associated with an increased risk for breast cancer (1.00; 0.92-1.08). Neither was progestagen-only therapy used less than 3 years. However, the use of tibolone was associated with an elevated risk for breast cancer (1.39; 1.07-1.81). The case-control study confirmed the results of EPT regarding sequential vs. continuous use of progestagen, including progestagen released continuously by an intrauterine device; the increased risk was seen already within 3 years of use (1.65;1.32-2.07). The dose of NETA was not a determinant as regards the breast cancer risk. Both systemic ET, and EPT are associated with an elevation in the risk for breast cancer. These risks resemble to a large extent those seen in several other countries. The use of an intrauterine system alone or as a complement to systemic estradiol is also associated with a breast cancer risk. These data emphasize the need for detailed information to women who are considering starting the use of HT.

Brain imaging of chronic pain

Acute pain has substantial survival value because of its protective function in the everyday environment. Instead, chronic pain lacks survival and adaptive function, causes great amount of individual suffering, and consumes the resources of the society due to the treatment costs and loss of production. The treatment of chronic pain has remained challenging because of inadequate understanding of mechanisms working at different levels of the nervous system in the development, modulation, and maintenance of chronic pain. Especially in unclear chronic pain conditions the treatment may be suboptimal because it can not be targeted to the underlying mechanisms. Noninvasive neuroimaging techniques have greatly contributed to our understanding of brain activity associated with pain in healthy individuals. Many previous studies, focusing on brain activations to acute experimental pain in healthy individuals, have consistently demonstrated a widely-distributed network of brain regions that participate in the processing of acute pain. The aim of the present thesis was to employ non-invasive brain imaging to better understand the brain mechanisms in patients suffering from chronic pain. In Study I, we used magnetoencephalography (MEG) to measure cortical responses to painful laser stimulation in healthy individuals for optimization of the stimulus parameters for patient studies. In Studies II and III, we monitored with MEG the cortical processing of touch and acute pain in patients with complex regional pain syndrome (CRPS). We found persisting plastic changes in the hand representation area of the primary somatosensory (SI) cortex, suggesting that chronic pain causes cortical reorganization. Responses in the posterior parietal cortex to both tactile and painful laser stimulation were attenuated, which could be associated with neglect-like symptoms of the patients. The primary motor cortex reactivity to acute pain was reduced in patients who had stronger spontaneous pain and weaker grip strength in the painful hand. The tight coupling between spontaneous pain and motor dysfunction supports the idea that motor rehabilitation is important in CRPS. In Studies IV and V we used MEG and functional magnetic resonance imaging (fMRI) to investigate the central processing of touch and acute pain in patients who suffered from recurrent herpes simplex virus infections and from chronic widespread pain in one side of the body. With MEG, we found plastic changes in the SI cortex, suggesting that many different types of chronic pain may be associated with similar cortical reorganization. With fMRI, we found functional and morphological changes in the central pain circuitry, as an indication of central contribution for the pain. These results show that chronic pain is associated with morphological and functional changes in the brain, and that such changes can be measured with functional imaging.

Magnetic Resonance Imaging of Atherosclerotic Manifestations in Familial Hypercholesterolemia

Cardiovascular diseases (CVD) are, in developed countries, the leading cause of mortality. The majority of premature deaths and disability caused by CVD are due to atherosclerosis, a degenerating inflammatory disease affecting arterial walls. Early identification of lesions and initiation of treatment is crucial because the first manifestations quite often are major disabling cardiovascular events. Methods of finding individuals at high risk for these events are under development. Because magnetic resonance imaging (MRI) is an excellent non-invasive tool to study the structure and function of vascular system, we sought to discover whether existing MRI methods are able to show any difference in aortic and intracranial atherosclerotic lesions between patients at high risk for atherosclerosis and healthy controls. Our younger group (age 6-48) comprised 39 symptomless familial hypercholesterolemia (FH) patients and 25 healthy controls. Our older group (age 48-64) comprised 19 FH patients and 18 type 2 diabetes mellitus (DM) patients with coronary heart disease (CHD) and 29 healthy controls. Intracranial and aortic MRI was compared with carotid and femoral ultrasound (US). In neither age-group did MRI reveal any difference in the number of ischemic brain lesions or white matter hyperintensities (WMHIs) - possible signs of intracranial atherosclerosis - between patients and controls. Furthermore, MRI showed no difference in the structure or function of the aorta between FH patients and controls in either group. DM patients had lower compliance of the aorta than did controls, while no difference appeared between DM and FH patients. However, ultrasound showed greater plaque burden and increased thickness of carotid arterial walls in FH and DM patients in both age-groups, suggesting a more advanced atherosclerosis. The mortality of FH patients has decreased substantially after the late 1980´s when statin treatment became available. With statins, the progression of atherosclerotic lesions slows. We think that this, in concert with improvements in treatment of other risk factors, is one reason for the lack of differences between FH patients and controls in MRI measurements of the aorta and brain despite the more advanced disease of the carotid arteries assessed with US. Furthermore, whereas atherosclerotic lesions between different vascular territories correlate, differences might still exist in the extent and location of these lesions among different diseases. Small (<5 mm in diameter) WMHIs are more likely a phenomenon related to aging, but the larger ones may be the ones related to CVD and may be intermediate surrogates of stroke. The image quality in aortic imaging, although constantly improving, is not yet optimal and thus is a source of bias.

Microwave-Assisted Synthesis of NiO Nanoparticles

NiO has been synthesized by microwave-induced chemical synthesis route using metalorganic complex of nickel in a domestic-type microwave oven (2.45 GHz). A novel metalorganic complex of nickel, viz., a beta-ketoester of nickel, synthesized and characterized as apart of this work, was employed as the precursor material. We varied the experimental parameters, such as the choice of solvent and microwave power, to obtain nanoparticles of NiO. The NiO nanoparticles were characterized by XRD, SEM, and TEM. The particle size of the NiO was found to vary from 7-40 nm. The magnetic behavior of the nanoparticles of NiO was examined with a vibrating sample magnetometer, revealing that as the particle size diminishes, the magnetic ordering in NiO changes, leading to a small, measurable coercivity.

Imaging of knee injuries with special focus on tibial plateau fractures

Acute knee injury is a common event throughout life, and it is usually the result of a traffic accident, simple fall, or twisting injury. Over 90% of patients with acute knee injury undergo radiography. An overlooked fracture or delayed diagnosis can lead to poor patient outcome. The major aim of this thesis was retrospectively to study imaging of knee injury with a special focus on tibial plateau fractures in patients referred to a level-one trauma center. Multi-detector computed tomography (MDCT) findings of acute knee trauma were studied and compared to radiography, as well as whether non-contrast MDCT can detect cruciate ligaments with reasonable accuracy. The prevalence, type, and location of meniscal injuries in magnetic resonance imaging (MRI) were evaluated, particularly in order to assess the prevalence of unstable meniscal tears in acute knee trauma with tibial plateau fractures. The possibility to analyze with conventional MRI the signal appearance of menisci repaired with bioabsorbable arrows was also studied. The postoperative use of MDCT was studied in surgically treated tibial plateau fractures: to establish the frequency and indications of MDCT and to assess the common findings and their clinical impact in a level-one trauma hospital. This thesis focused on MDCT and MRI of knee injuries, and radiographs were analyzed when applica-ble. Radiography constitutes the basis for imaging acute knee injury, but MDCT can yield information beyond the capabilities of radiography. Especially in severely injured patients , sufficient radiographs are often difficult to obtain, and in those patients, radiography is unreliable to rule out fractures. MDCT detected intact cruciate ligaments with good specificity, accuracy, and negative predictive value, but the assessment of torn ligaments was unreliable. A total of 36% (14/39) patients with tibial plateau fracture had an unstable meniscal tear in MRI. When a meniscal tear is properly detected preoperatively, treatment can be combined with primary fracture fixation, thus avoiding another operation. The number of meniscal contusions was high. Awareness of the imaging features of this meniscal abnormality can help radiologists increase specificity by avoiding false-positive findings in meniscal tears. Postoperative menisci treated with bioabsorbable arrows showed no difference, among different signal intensities in MRI, among menisci between patients with operated or intact ACL. The highest incidence of menisci with an increased signal intensity extending to the meniscal surface was in patients whose surgery was within the previous 18 months. The results may indicate that a rather long time is necessary for menisci to heal completely after arrow repair. Whether the menisci with an increased signal intensity extending to the meniscal surface represent improper healing or re-tear, or whether this is just the earlier healing feature in the natural process remains unclear, and further prospective studies are needed to clarify this. Postoperative use of MDCT in tibial plateau fractures was rather infrequent even in this large trauma center, but when performed, it revealed clinically significant information, thus benefitting patients in regard to treatment.