Significant Increase In Density Research Articles

Digitized assessment of mammographic breast density – Effects of continuous combined hormone therapy, tibolone and black cohosh compared to placebo

ObjectivesTo determine the effects of continuous combined hormone therapy, tibolone, black cohosh, and placebo on digitized mammographic breast density in postmenopausal women. Study designA prospective, double-blind, placebo-controlled study of 154 postmenopausal women randomized to estradiol 2mg/norethisterone acetate 1mg (E2/NETA), tibolone 2.5mg or placebo and a prospective, open, uncontrolled drug safety study, of which 65 postmenopausal women were treated with black cohosh. Mammograms, at baseline and after six months of treatment, were previously classified according to visual quantification scales. Main outcome measuresReanalysis of assessable mammograms by digitized quantification of breast density. ResultsTreatment groups were comparable at baseline. During treatment, both E2/NETA and tibolone significantly increased breast density (mean increase 14.3%, p<0.001 and 2.3%, p<0.001, respectively), while black cohosh and placebo did not. Twenty-four out of the 43 women on E2/NETA had an increase in density exceeding 10% and 6 women had an increase of 30% or more. In the tibolone group, only one woman had an increase in density of more than 10%. The difference in increase in breast density between E2/NETA on the one hand and tibolone, black cohosh and placebo on the other was highly significant (p<0.0001). ConclusionsDigitized mammographic breast density is a highly sensitive method confirming significant increase in density by standard E2/NETA treatment and to a lesser extent by tibolone, whereas black cohosh does not influence mammographic breast density during six months treatment. Digitized assessment also yields data on individual variation and small increases left undetectable by visual classification.

High-Precision Absolute (True) Density Measurements on Hygroscopic Powders by Gas Pycnometry: Application to Determining Effects of Formulation and Process on Free Volume of Lyophilized Products

As density (free volume) of the amorphous solids should be related to mobility and stability, an attempt was made to develop a simple, sensitive, and reproducible method to evaluate free volume via high-precision gas pycnometry density measurements, and to apply this methodology to study the variation of free volume with formulation and thermal history (i.e., annealing). Annealed samples were prepared either by heating the product after freeze drying (postannealing) or drying at higher temperature in secondary drying than normal (in-process annealing). Density was measured using a gas pycnometer. We find that the key to high-precision density measurements is isolation of the instrument from atmospheric moisture; accordingly, all operations were carried out in a dry box. With suitable care, densities of amorphous freeze-dried products can be measured with a precision of better than 0.5% in a series of independent but nominally identical samples. Density decreased with increasing molecular weight of dextran, but density of proteins was independent of molecular weight. Small but significant increases in density upon annealing were observed for several formulations. Thus, we conclude that accurate density measurements may be made by carefully controlling residual moisture. Density may be a useful parameter to predict long-term stability.

Effects of Powder Synthesis Method on the Sinterability of Hydroxyapatite

The sinterability of hydroxyapatite (HA) powder synthesized through a novel wet chemical method (HAp) and a wet mechanochemical method (HAwm) was investigated over a temperature range of 1000oC to 1400oC in terms of phase stability, bulk density, hardness and fracture toughness. The results indicated that the sinterability of HAp powder were significantly better than HAwm powder. Moreover, the XRD traces of HAwm sintered samples showed signs of decomposition into TTCP when sintered at 1300oC and above. Densification of ~98% of theoretical density was attained by HAp compacts at 1100oC while the HAwm compacts exhibited only ~96% of theoretical density even at 1350oC with no significant increase of density at 1400oC. The Vickers hardness of HAp showed increasing trend for temperature range of 1000oC to 1100oC with the compacts attaining HV of ~7 GPa at 1100oC. Subsequently, the hardness decreased with increasing sintering temperature though the value does not dropped below ~5 GPa. Similarly, HAwm compacts showed an increasing trend from 1000oC to 1300oC with the largest HV attained was ~4.57 GPa. Further increased in sintering temperature resulted in the decreased of Vicker’s hardness. Moreover, the HAp samples reached a maximum fracture toughness of ~0.9 MPam1/2 at 1050oC while the HAwm attained maximum KIc of only ~0.7 MPam1/2 at 1300oC.

Modulating ZnO Nanostructure Arrays on Any Substrates by Nanolevel Structure Control

A uniform high-aspect-ratio nanotextured surface with a very dense forest of vertically aligned nanowires that was produced by surface chemical postfabrication of ZnO was induced by a structural transformation at the nanolevel. X-ray photoelectron spectroscopy verified the formation of the heterogeneous surface structures (GaOx on GaN and AuOx on Au) at the nanolevel as well as the modification of surface stoichiometry by UV/ozone treatment. The structural transformation contributes to generating a surface charge, acting as nucleation sites for nanotip growth. This led to a significant increase in density and improvement in diameter of the nanotips for various substrates, such as ZnO, Au, GaN, and graphene. However, the surface oxygen by O2 plasma treatment reduced the activity as activation sites of the exposed surface, resulting in the decrease of the density of the nanotips. This rational engineering of substrates by a structural transformation at the nanolevel may provide a promising method for producing highly dense one-dimensional nanomaterials.

Protective effect of Morinda officinalis polysaccharides on bone degeneration in theaged rats

In the current study, we examined the effect of Morinda officinalis polysaccharides (MOP) on bone quality in aged rats. Rats were given orally by daily gavage at 200 and 400 mg/kg/day for 3 months, respectively. The results showed that there was a significant decrease in serum alkaline phosphatase (ALP), Interleukin 6 (IL-6) content and a significant increase in density and strength of femur and lumbar vertebrae in aged rats 3 months afterMorinda officinalis polysaccharides treatment. In conclusion, these data suggest thatMorinda officinalis polysaccharides can protect the age-induced bone degeneration. Key words: Morinda officinalis polysaccharides, bone, osteoporosis, ALP.

Studies of monomer impregnation and polymerised in situ in wood using dynamic mechanical thermal analyser

Ten tropical hardwoods are impregnated with methyl methacrylate and polymerised in-situ by use of catalysts and heat techniques. Treatability of the wood, as determined from the fractional volumetric retentions of monomers that are a fraction of voids filled by the impregnant, showed that the mean retention range from 15·03% (Acacia Mangium) to 56·59% (Cratoxylum Arborescens). The penetration of the monomer evaluated using ultrasonic waves showed that the treated wood had higher velocities which indicated significant increase in density. The present paper deals with the viscoelastic relaxation of polymerised treated wood. The efficiency of the monomer as a plasticiser is studied through the temperature dependence of the storage modulus (E′) and loss tangent (tan δ) of treated and untreated wood by dynamic mechanical thermal analysis (DMTA) over a temperature in the range from −100 to 200°C. The storage modulus E′ decreased with temperature and as the maximum mechanical damping developed, the glass transition temperature (Tg) of the plasticised wood decreased with the plasticiser content.

Thermophysical and Electrical Properties of Nanocomposites Based on Ethylene–Vinylacetate Copolymer (EVA) Filled with Expanded and Unexpanded Graphite

Over the last few years, conducting polymer/graphite nanocomposites have attracted considerable interest because of their exceptional electrical, thermal, and mechanical properties. Polymeric nanocomposites prepared from high aspect ratio layered graphite nanofillers achieve significant improvements in thermophysical and electrical properties at low filler concentrations, compared to conventional composites, without a significant increase in density. In this work, various aspects of the electrical and thermophysical behavior of nanocomposites are presented based on the ethylene–vinylacetate matrix filled with nanostructured expanded graphite and standard, (nano)/micro-sized graphite.

Influence of shelter availability on interactions between Caribbean spiny lobsters and moray eels: implications for artificial lobster enhancement

The Caribbean spiny lobster Panulirus argus is a valuable fishing resource, but local populations may be limited by availability of crevice shelter on juvenile (seagrass) habitats. This has prompted research into the potential density enhancement of juvenile lobsters with 'casitas', large (1.1 m 2 surface area) but low-lying (3.8 cm entrance height) artificial shelters that exclude large predators. Moray eels (Muraenidae), however, fit into casitas and could therefore pose a threat to lob- ster enhancement. In a shelter-poor reef lagoon, we examined potential interactions between juve- nile lobsters and the locally dominant morays Gymnothorax vicinus and G. moringa in the absence (four 1 ha control sites) and presence of casitas (five 1 ha 'casita sites', each with 10 casitas), before (6 surveys) and after (22 surveys) deployment. Morays and lobsters did not interact as predator-prey, as morays neither consumed nor intimidated co-occurring lobsters. Rather, the 2 taxa appeared to compete for limited shelter on the reef lagoon, as suggested by a significant increase in density and mean size of both taxa on casita sites after deployment. Casitas significantly increased cohabitation of morays and lobsters, yet they tended to co-occur less often than expected by chance, but this result likely reflects behavioral differences between the highly gregarious, more numerous lobsters and the typically solitary, cannibalistic morays. Our study exemplifies the influence of habitat complexity on the nature of interspecific interactions and shows that G. vicinus and G. moringa would not pose a threat to lobster enhancement with casitas.

Experiments on Settlement of Coral Polyps and Coral Growth Promotion Using a Feeble Electrochemical Method

This study aims to investigate experimentally the effects of an electrochemical method on growth promotion and settlement of corals. Naturally growing colonies of the pier in Taketomi Higashi port showed significant increase in density of corals corresponding with electricity of the cathodic protection. To know the reason of these effects on settlement and growth promotion, field experiments and laboratory experiments were carried out. As a result, the settlement rate of electrochemically deposited bases was 5 times larger than that of ceramic bases. The growth rate of the treated nubbins was relatively high in the field and its effect depended on species. The laboratory experiment results indicated that positive effects on the growth of corals by the feeble electric current densities in the range from 50mA/m2 to 100mA/m2.

Phenotyping of Sympathetic Chain Ganglia (SChG) Neurons in Porcine Colitis

Colonic inflammation involves the changes in chemical coding of not only sensory but also enteric and sympathetic prevertebral neurons innervating inflamed target tissue. Since the sympathetic chain ganglia neurons (SChG) affect colonic function, the purpose of our study was to determine the precise location of the SChG neurons innervating the porcine descending colon, define their chemical coding and answer the question of whether paraformaldehyde-induced colitis in female pigs is able to change the chemical phenotype of the perikarya. Using the Fast Blue (FB) retrograde tracing, the greatest concentration of the (FB+) perikarya was revealed in L₃ ganglia. Applying double immunohistochemistry, we detected a strongly catecholaminergic character and in majority neuropeptide Y (NPY)-positive staining of the colon-projecting FB+ neurons both in the control and the inflamed animals. Furthermore, colonic inflammation caused the significant increase in density of galanin- (P<0.001), somatostatin- (P<0.005), leu5-enkephalin- (P<0.05), substance P- (P<0.005), and calcitonin gene-related peptide- (P<0.005) immunoreactive (-IR) nerve fibers surrounding the FB+ perikarya, while the density of nitric oxide synthase-IR and NPY-IR fibers remained unaffected compared to the control animals. The increase in visible immunofluorescent detection of neuropeptide-containing fibers could possibly be caused by enhanced demand and release of neuropeptides that modulate intestinal immune response and regulate the gastrointestinal activity through inflammatory mediators.

Physical properties and MAS-NMR studies of titanium phosphate-based glasses

In this study, for a series phosphate-based glasses ((P2O5)0.45(CaO)0.3(Na2O)0.25−x(TiO2)x, 0 ≤ x ≤ 0.15), their degradation, ion release, surface and thermal properties have been determined. The results show that adding TiO2 was associated with a significant increase in density and glass transition temperature, but a decrease in degradation rate and ion release. 31P solid-state magic-angle-spinning nuclear magnetic resonance (MAS-NMR) showed that the local structure of the glasses changes with increasing TiO2 content. As TiO2 is incorporated into the glass, the phosphate connectivity increases as Q1 units transform to Q2, confirming that an increase in the nominal TiO2 content correlates unequivocally with an increase in glass stability. As reported for titania–silica gels, Ti4+ is clearly adopting a network former role in these phosphate-based glasses. 23Na MAS-NMR results corroborate this phenomenon with a marked upfield trend of the 23Na isotropic chemical shift suggesting that the local Na–O bond distances are decreasing within a more condensed glass network upon increased incorporation of TiO2.

Construction of supported lipid membrane modified piezoelectric biosensor for sensitive assay of cholera toxin based on surface-agglutination of ganglioside-bearing liposomes

A novel piezoelelctric biosensor has been developed for cholera toxin (CT) detection based on the analyte-mediated surface-agglutination of ganglioside (GM1)-functionalized liposomes. To achieve a CT-specific agglutination at the surface, the gold electrode is modified by a GM1-functionalized supported lipid membrane via spontaneous spread of the liposomes on a self-assembled monolayer of a long-chain alkanethiol. In the presence of CT, the GM1-incorporated liposomes in assay medium will rapidly specifically agglutinate at the electrode surface through the binding of CT to GM1 on the electrode surface and the liposome interface. This results in an enormous mass loading on the piezoelelctric crystal as well as a significant increase of density and viscosity at the interface, thereby generating a decrease in frequency of the piezoelelctric crystal. The combination of mass loading with interfacial change in the surface-agglutination reaction allows the developed piezoelelctric biosensor to show substantial signal amplification in response to the analyte CT. The detection limit can be achieved as low as 25 ng mL(-1) CT. This is the first demonstration on CT detection based on specific surface-agglutination of GM1-modified liposomes. The supported lipid layer based sensing interface can be prepared readily and renewably, making the developed technique especially useful for simple, reusable and sensitive determination of proteins.

Glial Damage After Transient Focal Cerebral Ischemia in Rats

We investigated the immunohistochemical changes of 8-hydroxy-2'-deoxyguanosine (8-OHdG) immunoreactivity as a marker of DNA damage and single-strand DNA (ssDNA) immunoreactivity as a marker of apoptosis in the striatum from 1 up to 15 days after 90 min of focal cerebral ischemia caused by middle cerebral artery occlusion in rats. In the present study, marked loss of MAP2 immunostaining was observed in the ipsilateral striatum 3 days after focal cerebral ischemia. A significant increase in the number of ssDNA-immunoreactive apoptotic neurons was observed in the ipsilateral striatum 1 and 3 days after focal cerebral ischemia. In contrast, a significant increase in densities of 8-OHdG-immunopositive cells was observed in the ipsilateral striatum from 3 up to 15 days after focal cerebral ischemia. Our double-labeled immunochemical study showed that 8-OHdG immunoreactivity was observed in both isolectin B(4)-positive microglia and glial fibrillary acidic protein-immunopositive astrocytes in the ipsilateral striatum 7 days after focal cerebral ischemia. These results suggest that focal cerebral ischemia can cause a marked increase in the number of microglia and astrocytes with oxidative DNA damage in the ipsilateral striatum. Furthermore, our results show that most microglia and astrocytes in the ipsilateral striatum after focal cerebral ischemia may not die by apoptosis. Thus, our findings provide novel evidence that focal cerebral ischemia can cause oxidative DNA damage in most microglia and astrocytes.

Temperature–density relationship of hot-mix asphalt pavement after completed rolling

This study investigates the relationship between the density and temperature of newly placed hot-mix asphalt pavement, and attempts, using both field and laboratory-based data, to validate the theory that as asphalt cools it becomes denser. Hence, if a nuclear gauge is used to measure asphalt density, it should record a higher reading after the asphalt has been allowed to cool overnight than when the asphalt density was first measured just after cold rolling the previous day. This research investigation has found a model that does not reinforce this theory. Research has shown that testing a road for density the morning after paving, as opposed to the same day, does not result in a significant increase in density. In addition, this study found significant factors that impact pavement density, and developed an explanatory model to estimate pavement density.

Dendritic Cells in Barrett’s Esophagus and Esophageal Adenocarcinoma

BackgroundLike other premalignant conditions that develop in the presence of chronic inflammation, the development and progression of Barrett’s esophagus is associated with the development of an immune response, but how this immune response is regulated is poorly understood. A comprehensive literature search failed to find any report of the presence of dendritic cells in Barrett’s intestinal metaplasia and esophageal adenocarcinoma and this prompted our study. Material and MethodsWe used immunohistochemical staining and electron microscopy to examine whether dendritic cells are present in Barrett’s esophagus and esophageal adenocarcinoma. Immunohistochemical staining with CD83, a specific marker for dendritic cells, was performed on paraffin-embedded sections of Barrett’s intestinal metaplasia (IM, n = 12), dysplasia (n = 11) and adenocarcinoma (n = 14). ResultsCD83+ cells were identified in the lamina propria surrounding intestinal type glands in Barrett’s IM, dysplasia, and cancer tissues. Computerized quantitative analysis showed that the numbers of dendritic cells were significantly higher in cancer tissues. Double immunostaining with CD83, CD20, and CD3, and electron microscopy demonstrated that dendritic cells are present in Barrett’s esophagus and form clusters with T cells and B cells directly within the lamina propria. ConclusionsThese findings demonstrate that dendritic cells are present in Barrett’s tissues, with a significant increase in density in adenocarcinoma compared to benign Barrett’s esophagus. Dendritic cells may have a role in the pathogenesis and immunotherapy treatment of Barrett’s esophagus and adenocarcinoma.

Sintering behavior and dielectric properties of polycrystalline CaCu3Ti4O12

Sintering behavior and dielectric properties of CaCu3Ti4O12 (CCTO) have been studied. CCTO phase was formed at 950 °C. A two-step sintering method was employed. The pressed green body of CaCu3Ti4O12 was first heated to 1,080 °C to achieve an intermediate density (>75% of theoretical density), then cooled down and held at 950 °C for 0–20 h until it was fairly dense. A slight grain growth was observed for 20 h holding time with a significant increase in density from 81% to 92% of theoretical density. The average grain size of dense ceramics was ~6 μm and the bulk density was 4.7 g/cm3. The normally sintered specimen at 1,070 °C exhibited slightly higher density (4.8 g/cm3, 95%) with bimodal grain size. Normal sintering also yielded higher dielectric constants than the specimens processed by the two-step sintering.

Degradation of Hubble Space Telescope Aluminized-Teflon Bi-Stem Thermal Shields

A section of retrieved Hubble Space Telescope (HST) bi-stem thermal shields (BSTS), which experienced 8.25 years of space exposure, was analyzed for space environmental durability. The shields were comprised of 2 mil (0.051 mm) aluminized-Teflon® fluorinated ethylene propylene (Al-FEP) rings fused together into a circular bellows shape. As the circular thermal shields had solar, anti-solar and solar-grazing surfaces and were exposed to the space environment for a long duration, it provided a unique opportunity to study solar effects on the environmental degradation of Al-FEP, a commonly used spacecraft thermal control material. Therefore, the objective of this research was to characterize the degradation of retrieved HST BSTS Al-FEP with particular emphasis on solar effects. Data obtained included tensile properties, density (as-retrieved and after 200 3C heating), solar absorptance, and surface morphology and chemistry. The solar-facing surfaces of the thermal shields were found to be extremely embrittled and contained numerous through-thickness cracks. Tensile testing verified that near solar-facing surfaces lost their mechanical strength and elasticity, whereas the anti-solar-facing surfaces maintained their ductility. The density of the as-retrieved BSTS insulation was similar to pristine FEP. Heating at 200 3C resulted in significant increases in density for the solar-facing BSTS indicating chain scission damage, consistent with the loss of mechanical strength and elongation. The solar absorptance of the solar-grazing and the anti-solar-facing surfaces were found to be similar to pristine BSTS, whereas the solar-facing surfaces were found to have significantly increased solar absorptance. Both solar- and anti-solar-facing surfaces were microscopically textured from sweeping atomic oxygen erosion with the solar-facing surface appearing to have a more pronounced texture in spite of being exposed to a lower atomic oxygen fluence indicating a possible solar/atomic oxygen synergistic effect. These results provide valuable information on space environmental degradation of Al-FEP, particularly with respect to solar radiation effects on embrittlement.

Densification, magnetic and dielectric behaviour of Cu-substituted Mg–Zn ferrites

The physical, magnetic and dielectric properties of Cu-substituted Mg–Zn ferrites having the general formula of Mg 0.55− x Cu x Zn 0.45O(Fe 2O 3) 0.97 prepared by standard double sintering ceramic technique have been studied. X-ray diffraction (XRD) patterns of the samples indicate the formation of single-phase cubic spinel structure. The lattice parameter ‘ a’ is increased with increasing Cu 2+ ion substitution. A significant increase in density is observed with increasing Cu content. The beneficial effect of copper ions on the densification of Mg–Zn ferrite can be reasonably explained by possible bimodal diffusion mechanism. The initial permeability μ′ shows a good stability with frequency for x = 0.0–0.25 while μ′ shows the constant value up to 200 kHz for x = 0.30 and 0.35 beyond which it falls rapidly. The permeability is found to increase as copper content increases which is consistent with the variation of density with copper ions. Saturation magnetization ( M s) increases with copper content up to x = 0.30 and then it decreases. The observed variation in M s can be explained in terms of the cation redistribution between A and B sublattices. Dielectric constant ( ɛ′) decreases with increase in frequency which is rapid at lower frequencies and slower at higher frequencies which may be due to the Maxwell-Wagner interfacial polarization. Dielectric relaxation peaks were observed for the frequency dependence of dielectric loss tangent curves. ɛ′ increases as the temperature increases which is attributed to the fact that the hoping of electrons between Fe 2+ and Fe 3+ ions is thermally activated on increasing the temperature.

Low velocity impact properties of nanoparticulate syntactic foams

The low velocity impact response of nanoparticulate syntactic foams is studied. Nanoparticulate syntactic foams are prepared by mixing nanoclay in low density syntactic foams composed of glass microballoons and epoxy matrix. The volume percentage of microballoons is maintained at 60% while the nanoclay concentrations in the composite are set at 1%, 2% and 5% so that the density of the composite does not increase significantly. The impact test results show that the maximum load bearing capacity and initiation energy is obtained when 1% nanoclay volume fraction is incorporated. The SEM images also reveal the effect of incorporation of nanoclay on the fracture behavior of syntactic foam. Two types of microballoons are used to investigate the effect of radius ratio on the impact resistance of fabricated syntactic foams. The syntactic foam having higher wall thickness microballoons has shown more impact resistance. This work has demonstrated the possibility of achieving higher impact properties in syntactic foam without significant increase in density.

Abundance of Predaceous Arthropods and Lygus spp. (Hemiptera: Miridae) in Response to Different Nitrogen Fertilizer Rates in Acala 1517-99 Cotton

A three-year study evaluated the density of predaceous arthropods and Lygus spp. in response to different nitrogen fertilizer rates in Acala 1517-99 cotton [Gossypium hirsutum (L)]. The most abundant predator genera in the samples were Nabis spp., Chrysoperla spp., and Hippodamia spp. There were no significant increases in densities of predaceous arthropods with increased nitrogen rates. There were, however, significant increases in densities of adult Lygus spp. as nitrogen fertilizer rates were increased. Densities of Lygus spp. nymphs were much lower among years and treatments than adult densities. The highest Lygus spp./predator ratio (41.5:1) occurred at the lowest nitrogen rate (50.6 kg/ha) with no insecticide treatments.