Proučavanje optičkih vlakana sa skokovitim indeksima loma interferometrijskom metodom s dva snopa

The Pluta polarizing interference microscope is used to measure the refractive index profile and material dispersion of step index optical fibers. The refractive index profile of the fiber has been determined experimentally at different wavelengths using two-beam interference technique. Measuring these values at different wavelengths gives useful information about the structural behavior of highly oriented fibers. Also, the theoretical consideration for determining the refractive index is given. Some optical parameters which characterize the optical fiber such as the numerical aperture NA, normalized frequency ν, the acceptance angle θa and the number of modes MN propagating in the fiber with wavelength have been calculated. Also, the constants of the Cauchy’s dispersion formula were determined.Primijenili smo Plutinov polarizacijski interferometrijski mikroskop u mjerenjima profila indeksa loma i disperzije materijala optičkih vlakana sa skokovitim indeksima loma. Mjerili smo profil indeksa vlakna za više valnih duljina primjenom interferentne metode s dva snopa. Ta mjerenja na više valnih duljina dala su važne podatke o strukturnim svojstvima jako usmjerenih vlakana. Opisuju se također osnove teorije za određivanje indeksa loma u vlaknima. Izračunali smo niz optičkih parametara koji su značajke optičkih vlakana: brojnog otvora, normalizirane frekvencije, ν, kuta prihvaćanja, θa, i broja modova, MN , kojima se na nekoj frekvenciji šire valovi. Također smo odredili konstante Cauchyjeve disperzijske formule

COLORECTAL CANCER: AN UPDATE ON THE EFFECTS OF LYCOPENE ON TUMOR PROGRESSION AND CELL PROLIFERATION

Colorectal cancer (CRC) is one of the most common cancers worldwide. Various factors, including oxidative stress, where excessive productions of reactive oxygen species (ROS) and reactive nitrogen species (RNS) occur, contribute to its pathogenesis. Numerous studies have investigated the effect of antioxidant substances derived from food such fruits and vegetables; however, data on Lycopene are still rare. Stidies on HT-29 colorectal cancer cells and on animal models have shown that Lycopene has effects on cell proliferation and on the progression of the CRC by interacting with variuos cellular signaling pathways. this analysis of the literature focused on the antioxidant effect of Lycopene, a substance that is found in the tomato

COLORECTAL CARCINOGENESIS; ROLE OF OXIDATIVE STRESS AND ANTIOXIDANTS

One of the contributory causes of colon cancer is the negative effect of reactive oxygen species on DNA repair mechanism. Currently, there is a growing support for the concept that oxidative stress may be an important etiological factor for carcinogenesis. The purpose of this review is to elucidate the role of oxidative stress in promoting colorectal carcinogenesis and to highlight the potential protective role of antioxidants. Several studies have documentes the importance of antioxidants in countering oxidative stress and preventing colorectal carcinogenesis. However, there are conflicting data in the literature concerning its proper use in humans, since these studies did not yeld definitive results and were performed mostly in vitro on cell population, or in vivo in experimental animal models

The long-term effects of probiotics in the therapy of ulcerative colitis: a clinical study

Aim. Intestinal dysbiosis seems to be the leading cause of inflammatory bowel diseases, and probiotics seems to represent the proper support against their occurrence. Actually, probiotic blends and anti-inflammatory drugs represent a weapon against inflammatory bowel diseases. The present study evaluates the long-term (2 years) effects of combination therapy (mesalazine plus a probiotic blend of Lactobacillus salivarius, Lactobacillus acidophilus and Bifidobacterium bifidus strain BGN4) on ulcerative colitis activity. Method. Sixty patients with moderate-to-severe ulcerative colitis were enrolled: 30 of them were treated with a single daily oral administration of mesalazine 1200 mg; 30 patients received a single daily oral administration of mesalazine 1200 mg and a double daily administration of a probiotic blend of Lactobacillus salivarius, Lactobacillus acidophilus and Bifidobacterium bifidus strain BGN4. The treatment was carried out for two years and the clinical response evaluated according to the Modified Mayo Disease Activity Index. Results. All patients treated with combination therapy showed better improvement compared to the controls. In particular, the beneficial effects of probiotics were evident even after two years of treatment. Conclusions. A long-term treatment modality of anti-inflammatory drugs and probiotics is viable and could be an alternative to corticosteroids in mild-to moderate ulcerative colitis

Expanding the host range of hepatitis C virus through viral adaptation

Hepatitis C virus (HCV) species tropism is incompletely understood. We have previously shown that at the level of entry, human CD81 and occludin (OCLN) comprise the minimal set of human factors needed for viral uptake into murine cells. As an alternative approach to genetic humanization, species barriers can be overcome by adapting HCV to use the murine orthologues of these entry factors. We previously generated a murine tropic HCV (mtHCV or Jc1/mCD81) strain harboring three mutations within the viral envelope proteins that allowed productive entry into mouse cell lines. In this study, we aimed to characterize the ability of mtHCV to enter and infect mouse hepatocytes in vivo and in vitro Using a highly sensitive, Cre-activatable reporter, we demonstrate that mtHCV can enter mouse hepatocytes in vivo in the absence of any human cofactors. Viral entry still relied on expression of mouse CD81 and SCARB1 and was more efficient when mouse CD81 and OCLN were overexpressed. HCV entry could be significantly reduced in the presence of anti-HCV E2 specific antibodies, suggesting that uptake of mtHCV is dependent on viral glycoproteins. Despite mtHCV's ability to enter murine hepatocytes in vivo, we did not observe persistent infection, even in animals with severely blunted type I and III interferon signaling and impaired adaptive immune responses. Altogether, these results establish proof of concept that the barriers limiting HCV species tropism can be overcome by viral adaptation. However, additional viral adaptations will likely be needed to increase the robustness of a murine model system for hepatitis C. IMPORTANCE: At least 150 million individuals are chronically infected with HCV and are at risk of developing serious liver disease. Despite the advent of effective antiviral therapy, the frequency of chronic carriers has only marginally decreased. A major roadblock in developing a vaccine that would prevent transmission is the scarcity of animal models that are susceptible to HCV infection. It is poorly understood why HCV infects only humans and chimpanzees. To develop an animal model for hepatitis C, previous efforts focused on modifying the host environment of mice, for example, to render them more susceptible to HCV infection. Here, we attempted a complementary approach in which a laboratory-derived HCV variant was tested for its ability to infect mice. We demonstrate that this engineered HCV strain can enter mouse liver cells but does not replicate efficiently. Thus, additional adaptations are likely needed to construct a robust animal model for HCV

Dual role of the exocyst in AMPA receptor targeting and insertion into the postsynaptic membrane

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102104/1/emboj7601065.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102104/2/emboj7601065-sup-0001.pd

Understanding Russia's return to the Middle East

Over recent years, there has been a significant resurgence of Russian power and influence in the Middle East, which has been evident in the diplomatic and military intervention into Syria. This article identifies the principal factors behind Russia’s return to the region. First, there are domestic political influences with the coincidence of the uprisings in the Middle East, the so-called ‘Arab Spring,’ with large-scale domestic opposition protests within Russia during the elections in 2011–2012. Second, there is the role of ideas, most notably the growing anti-Westernism in Putin’s third presidential term, along with Russia’s own struggle against Islamist terrorism. These ideational factors contributed to Russia’s resolve to support the Assad government against both Western intervention and its domestic Islamist opposition. Third, Russia has benefited from a pragmatic and flexible approach in its engagement with the region. Moscow seeks to ensure that it is a critical actor for all the various states and political movements in the Middle East