Circularly Polarized Dielectric‐Loaded Antennas: Current Technology and Future Challenges

In the last few years, dielectric loaded antennas (DLAs) have emerged as a viable solution for high‐gain reception at microwave frequencies for handheld devices such as satellite phones, radios, and global positioning systems. This article compares the performance, cost, and volumetric efficiencies of the two dominant designs, namely the dielectrically loaded quadrifilar‐helix and microstrip patch antennas. The current and future material requirements for DLAs are discussed and an example is given of a recently developed castable glass ceramic based on BiNbO₄, which is suitable in terms of properties and glass formability for the single‐step fabrication of net‐shape antenna cores.

     

Degrees of Antioxidant Protection: A 2‐Year Study of the Bioactive Properties of Organic Milk in Poland

The aim of this study was to determine the nutritional value of organic milk in Poland, investigate the influence of diet on antioxidant capacity and degree of antioxidant protection (DAP), and to examine the effect of season on the bioactive properties of milk from organic farms. From 2014 to 2015, 820 milk samples were collected from 6 organic farms during indoor feeding season (IDS) and pasture feeding season (PS). Pasture feeding season + corn grain (PSCG) cows’ daily ration during pasture feeding season was enriched with 4 kg a day of corn to improve dietary energy balance. Milk obtained during PS was found to have a higher fat content, slight but significantly lower protein content compared with milk from IDS. The study showed that the content of monounsaturated fatty acids (MUFA) in milk fat was strongly linked to the concentration of polyunsaturated fatty acids (PUFA) and, to a lesser extent, on the supply of MUFA. The IDS data (concentration of vitamin E, A, and β‐carotene) showed the lowest values compared with the PS and PSCG groups. Total antioxidant status (TAS) and DAP showed an increasing trend in organic milk. PSCG was associated with highest level of DAP (9% higher than PS and 79% higher than IDS) and TAS (37% higher than PS and 79% higher than IDS). The results obtained show that supplementation of the basic ration with corn grain improved both TAS and DAP. The higher DAP and TAS value is responsible for product stability, considering the risk factor related to levels of cholesterol‐oxide intake in humans.     

Styrylquinolinium borates as donor–acceptor initiators for sensitized photopolymerization of TMPTA

Several photoredox pairs containing mono- and bicationic hemicyanine dyes have been evaluated as photoinitiators for free radical polymerization induced with an argon-ion laser irradiation. The tested photoredox couples are the pairs composed of the hemicyanine dye cations acting as electron acceptors and n-butyltriphenyl borate anions being the electron donors. The photoinitiating abilities of the series of monochromophoric stilbazolium borates, 4-(p-N,N-dialkylaminostyryl)quinolinium n-butyltriphenylborate, were compared to the photochemistry of structurally related, bicationic styrylquinolinium borates. The obtained results clearly documented that the dicationic photoinitiators exhibit a marked increase in the photoinitiation ability compared to the initiators consisting of a single charged hemicyanine dye.Our studies revealed also that the rate of photopolymerization depends on ΔG_el of electron transfer between borate anion and styrylquinolinium cation. The relationship between the rate of polymerization and the free energy of activation shows the dependence predicted by the classical theory of electron transfer.     

Do the levels of selected metals differ significantly between the roots of carious and non-carious teeth?

Since the metals deposited in teeth during formation and mineralization processes are to a large extent retained, human teeth receive a considerable attention as the indicators of the heavy metal exposure. The use of permanent teeth is limited because the extraction of healthy permanent teeth just for this purpose is hardly acceptable. As the issue of the loss of elements from a carious lesion in the coronal part of a tooth remains controversial, the valuable material could only be the root of carious and fractured permanent teeth. However, to ensure the validity of the results, it should be ascertained that the levels of certain toxic and essential elements do not differ significantly between the roots of non-carious and carious teeth, and therefore this is the aim of this project. The levels of cadmium, chromium, copper, iron, manganese, lead, zinc, potassium, sodium, calcium and magnesium were determined in the roots of 344 permanent teeth (189 carious and 155 caries-free teeth) from the residents of Ruda Slaska, Poland, aged 18 to 34. No statistically significant difference between the concentration of these metals in the roots of non-carious and carious teeth was found. This finding applies to both the general population and after the grouping by donor's gender and tooth type. The concentration of lead, iron, calcium and manganese in the roots of non-carious and carious teeth exhibited dependence upon tooth type, as well as the concentration of potassium in the roots of carious teeth. Since the mineral composition of the roots of permanent teeth is similar for the non-carious, as well as the carious teeth, they can be indiscriminately selected for the tests required by a research project, as they will produce the comparable results. However, in the case of lead, iron, calcium, potassium and manganese, the comparison should be made after grouping by tooth type.     

A study of cements formed by aqueous lactic acid and aluminosilicate glass

A study is reported of the formation of cements from aqueous lactic acid and aluminosilicate glass of the type used in dental glass–ionomer cements. These cements were found to set quickly, and were shown by infrared spectroscopy to have undergone a neutralization reaction to yield mainly calcium lactate. They were very soluble in water at 1 h, but became progressively less so over time; when matured for 6 h before being placed in water, they had become almost insoluble. No spectroscopic differences could be detected between the cements at 1 h or 6 h, indicating that insolubilization arises from a reaction that does not alter the part of the infrared spectrum examined. This suggested that a wholly inorganic reaction between the ion-depleted glass fragments is responsible for the formation of the insoluble structure. After 24 h, the cements were found to have compressive strengths in the range 9–35 MPa, the actual value varying with concentration of lactic acid used to form the cement, and there was no statistically significant increase in strength for the strongest of these after one month.     

When Greta Garbo is easier to remember than Stefan Edberg: Influences of prior knowledge on recognition memory in Alzheimer's disease.

Investigated the effects of prior knowledge on recognition memory in patients with a mild Alzheimer's disease. Normal older adults and mildly demented patients were presented with dated and contemporary famous faces with name tags and were asked to generate unique statements about each person. Results indicate that both groups generated more statements about the dated than about the contemporary figures. Most important, both groups performed better with the dated than with the contemporary faces in an unexpected episodic face recognition task. This pattern of results suggests that both groups (1) possess more knowledge of dated than of contemporary famous individuals and (2) are able to utilize prior knowledge to enhance episodic remembering. Viewing these results in light of other recent work, it is concluded that differences between normal old and mildly demented individuals in the ability to utilize cognitive support for remembering may be differences in degree. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Mode of SN38 Derivatives Interacting with Nicked DNA Mimics Biological Targeting of Topo I Poisons

The compounds 7-ethyl-9-(N-methylamino)methyl-10-hydroxycamptothecin (2) and 7-ethyl-9-(N-morpholino)methyl-10-hydroxycamptothecin (3) are potential topoisomerase I poisons. Moreover, they were shown to have favorable anti-neoplastic effects on several tumor cell lines. Due to these properties, the compounds are being considered for advancement to the preclinical development stage. To gain better insights into the molecular mechanism with the biological target, here, we conducted an investigation into their interactions with model nicked DNA (1) using different techniques. In this work, we observed the complexity of the mechanism of action of the compounds 2 and 3, in addition to their decomposition products: compound 4 and SN38. Using DOSY experiments, evidence of the formation of strongly bonded molecular complexes of SN38 derivatives with DNA duplexes was provided. The molecular modeling based on cross-peaks from the NOESY spectrum also allowed us to assign the geometry of a molecular complex of DNA with compound 2. Confirmation of the alkylation reaction of both compounds was obtained using MALDI–MS. Additionally, in the case of 3, alkylation was confirmed in the recording of cross-peaks in the ¹H/¹³C HSQC spectrum of ¹³C-enriched compound 3. In this work, we showed that the studied compounds—parent compounds 2 and 3, and their potential metabolite 4 and SN38—interact inside the nick of 1, either forming the molecular complex or alkylating the DNA nitrogen bases. In order to confirm the influence of the studied compounds on the topoisomerase I relaxation activity of supercoiled DNA, the test was performed based upon the measurement of the fluorescence of DNA stain which can differentiate between supercoiled and relaxed DNA. The presented results confirmed that studied SN38 derivatives effectively block DNA relaxation mediated by Topo I, which means that they stop the machinery of Topo I activity.     

Major histocompatibility complex (MHC) markers in conservation biology

Human impacts through habitat destruction, introduction of invasive species and climate change are increasing the number of species threatened with extinction. Decreases in population size simultaneously lead to reductions in genetic diversity, ultimately reducing the ability of populations to adapt to a changing environment. In this way, loss of genetic polymorphism is linked with extinction risk. Recent advances in sequencing technologies mean that obtaining measures of genetic diversity at functionally important genes is within reach for conservation programs. A key region of the genome that should be targeted for population genetic studies is the Major Histocompatibility Complex (MHC). MHC genes, found in all jawed vertebrates, are the most polymorphic genes in vertebrate genomes. They play key roles in immune function via immune-recognition and -surveillance and host-parasite interaction. Therefore, measuring levels of polymorphism at these genes can provide indirect measures of the immunological fitness of populations. The MHC has also been linked with mate-choice and pregnancy outcomes and has application for improving mating success in captive breeding programs. The recent discovery that genetic diversity at MHC genes may protect against the spread of contagious cancers provides an added impetus for managing and protecting MHC diversity in wild populations. Here we review the field and focus on the successful applications of MHC-typing for conservation management. We emphasize the importance of using MHC markers when planning and executing wildlife rescue and conservation programs but stress that this should not be done to the detriment of genome-wide diversity.