Shell Dimensions Research Articles

Morphological variations in blood cockle Tegillarca granosa (L, 1758) populations collected from the south-east and south-west coasts of Bangladesh

Morphology helps in studying the external features of an individual, including the size, shape, structure of the animals and in determining the evolutionary relationships among organisms. Current study was undertaken to investigate the morphological variations between the two populations of blood cockle, Tegillarca granosa collected from the south-east (west coast of Maheshkhali Island, Cox’s Bazar; S1) and south-west (Jamuna River Estuary near Ishawrypur, Shemnagar, Shatkhira; S2) coasts of Bangladesh. Samples were drawn from the intertidal region during low-tide by hand-picking with the aid of local people in March 2020 from both sites. Fifteen primary parameters, and 27 secondary parameters obtained from the ratios of different primary parameters were studied to compare the values between the two populations. Out of 15 primary morphological parameters, there was no significant difference (p>0.05) between the populations. Among the 27 secondary morphological parameters, only 4 parameters were significantly different (p<0.05) between the two populations. The statistically different parameters were shell length (SL)/wet tissue weight (TWW), shell height (SH)/wet tissue weight (TWW), shell thickness (ST)/wet tissue weight (TWW) and condition index (CI). The ratios of shell dimensions and wet tissue weight were significantly higher (p<0.05) in S2 when compared with S1 indicated that S1 population could be more economically viable due to their relatively higher edible meat content. The CIs were significantly higher (p<0.05) in S1 population than the CIs of S2 population. The values of CIs reflected that S1 population had better health condition than S2 population. The ratios of different shell measurements did not vary significantly implied that both populations were homogenous in size, shape and structure. Morphological analyses of different populations of T. granosa revealed that habitat could play a vital role in morphological variations.

Broad-Spectrum Virus Trapping with Heparan Sulfate-Modified DNA Origami Shells.

Effective broadband antiviral platforms that can act on existing viruses and viruses yet to emerge are not available, creating a need to explore treatment strategies beyond the trodden paths. Here, we report virus-encapsulating DNA origami shells that achieve broadband virus trapping properties by exploiting avidity and a widespread background affinity of viruses to heparan sulfate proteoglycans (HSPG). With a calibrated density of heparin and heparan sulfate (HS) derivatives crafted to the interior of DNA origami shells, we could encapsulate adeno, adeno-associated, chikungunya, dengue, human papilloma, noro, polio, rubella, and SARS-CoV-2 viruses or virus-like particles, in one and the same HS-functionalized shell system. Additional virus-type-specific binders were not needed for the trapping. Depending on the relative dimensions of shell to virus particles, multiple virus particles may be trapped per shell, and multiple shells can cover the surface of clusters of virus particles. The steric occlusion provided by the heparan sulfate-coated DNA origami shells can prevent viruses from further interactions with receptors, possibly including those found on cell surfaces.

Improving external shell volume estimation in snails using landmark-based size measurements

ABSTRACTShell images in digital collections and publications enable taxonomically, geographically and morphologically broad approaches to studying gastropod body size. Because traditional linear size measurements are not directly comparable across morphologically disparate taxa, we propose a transition to landmark-based size measurements, which are less sensitive to shape differences. Traditional and landmark-based size measurements were compared using two study systems: 36 specimens of diplommatinid micromolluscs from the Belau archipelago and 66 marine, freshwater and terrestrial gastropod shells from the Roosevelt Wild Life Collections (RWLC; housed at the State University of New York College of Environmental Science and Forestry, Syracuse, NY, USA). Belau diplommatinids were used to assess the effectiveness of size measurements when comparing confamilial specimens. This study system was most sensitive to methodologically introduced variance. RWLC shells were used to assess measurement effectiveness when comparing morphologically disparate taxa. A total of seven size variables measured from 2D images were compared, three variables based on interlandmark distances and four based on linear shell dimensions. Landmark-based size measurements were centroid size, a proposed new measurement dubbed size adjusted mean (SAM) and its rescaled version, SAM1/3. The linear dimension-based measurements were maximum, mean and geometric mean of shell height and width, as well as conical volume (volume of a cone with similar dimensions to specimen). Measurement accuracy was assessed by regressing external shell volume against each size measurement. For Belau diplommatinids, centroid size and maximum shell dimension most accurately predicted external shell volume. For RWLC shells, conical volume followed by SAM1/3 and geometric mean shell dimension were the most accurate predictors. Repeatability was assessed by computing % measurement error (%ME). Maximum shell dimension was most repeatable (%ME = 4.19%) for Belau diplommatinids, followed by centroid size (7.76%). Conical volume (%ME = 0.0039%) and maximum shell dimension (0.0073%) were most repeatable for RWLC shells. In both study systems, SAM1/3 was the land-mark-based size measurement most robust to missing landmarks, followed by centroid size. Based on these findings, we recommend using centroid size to compare congeneric or confamilial specimens and using conical volume to compare morphologically or taxonomically disparate specimens. However, conical volume could not be calculated when shell height or width data are unavailable. In such cases, we recommend comparing morphologically disparate shells using SAM1/3.

Modeling of core-shell magneto-electric nanoparticles for biomedical applications: Effect of composition, dimension, and magnetic field features on magnetoelectric response.

The recent development of core-shell nanoparticles which combine strain coupled magnetostrictive and piezoelectric phases, has attracted a lot of attention due to their ability to yield strong magnetoelectric effect even at room temperature, thus making them a promising tool to enable biomedical applications. To fully exploit their potentialities and to adapt their use to in vivo applications, this study analyzes, through a numerical approach, their magnetoelectric behavior, shortly quantified by the magnetoelectric coupling coefficient (αME), thus providing an important milestone for the characterization of the magnetoelectric effect at the nanoscale. In view of recent evidence showing that αME is strongly affected by both the applied magnetic field DC bias and AC frequency, this study implements a nonlinear model, based on magnetic hysteresis, to describe the responses of two different core-shell nanoparticles to various magnetic field excitation stimuli. The proposed model is also used to evaluate to which extent realistic variables such as core diameter and shell thickness affect the electric output. Results prove that αME of 80 nm cobalt ferrite-barium titanate (CFO-BTO) nanoparticles with a 60:40 ratio is equal to about 0.28 V/cm∙Oe corresponding to electric fields up to about 1000 V/cm when a strong DC bias is applied. However, the same electric output can be obtained even in absence of DC field with very low AC fields, by exploiting the hysteretic characteristics of the same composites. The analysis of core and shell dimension is as such to indicate that, to maximize αME, larger core diameter and thinner shell nanoparticles should be preferred. These results, taken together, suggest that it is possible to tune magnetoelectric nanoparticles electric responses by controlling their composition and their size, thus opening the opportunity to adapt their structure on the specific application to pursue.

Plasmonic heating of protected silver nanowires for anti-frosting superhydrophobic coating

Atmospheric frosting and icing pose significant problems for critical and common-use infrastructures. Passive anti-frosting and anti-icing strategies that require no energy input have been actively sought, with no viable and permanent solutions known yet. Bioinspired superhydrophobic (SH) materials have been considered promising path to explore; however, the outcome has been less than compelling because of their low resistance to atmospheric humidity. In most cases, condensing water on an SH surface eventually leads to mechanical locking of ice instead of ice removal. Hybrid strategies involving some form of limited energy input are being increasingly considered, each with its own challenges. Here, we propose the application of plasmonic heating of silver nanowires (AgNWs) for remote frost removal, utilizing an SH hybrid passive-active system. This novel system comprises a durable nanocomposite covered with a hydrophobized mesh of AgNWs, protected against environmental degradation by a tin oxide (SnO2) shell. We demonstrate the frost removal ability at −10 °C and 30% RH, achieved by a combination of plasmonic heating of AgNWs with a non-sticking behavior of submicrometric droplets of molten frost on the SH surface. Heating was realized by illuminating the mesh with low-power blue laser light. Adjustment of the nanowire (NW) and shell dimensions allows the generation of surface plasmon resonance in illuminated NWs at a wavelength overlapping the emission maximum of the light used. In environmental stability tests, the nanostructures exhibited high atmospheric, mechanical, and thermal stability. The narrow-wavelength absorption of the structure in the blue light range and the reflective properties in the infrared range were designed to prevent protected surfaces from overheating in direct sunlight.

Trojan pH-Sensitive Polymer Particles Produced in a Continuous-Flow Capillary Microfluidic Device Using Water-in-Oil-in-Water Double-Emulsion Droplets.

A facile and robust microfluidic method to produce nanoparticle-in-microparticle systems (Trojan systems) is reported as a delivery vector for the oral administration of active pharmaceutical ingredients. The microfluidic system is based on two coaxial capillaries that produce monodisperse water-in-oil-in-water (W/O/W) double emulsions in a highly controlled fashion with precise control over the resulting particle structure, including the core and shell dimensions. The influence of the three phase flow rates, pH and drying process on the formation and overall size is evaluated. These droplets are then used as templates for the production of pH-sensitive Trojan microparticles after solvent evaporation. The shell of Trojan microparticles is made of Eudragit®, a methacrylic acid-ethyl acrylate copolymer that would enable the Trojan microparticle payload to first pass through the stomach without being degraded and then dissolve in the intestinal fluid, releasing the inner payload. The synthesis of the pH-sensitive Trojan microparticles was also compared with a conventional batch production method. The payloads considered in this work were different in nature: (1) fluorescein, to validate the feasibility of the polymeric shell to protect the payload under gastric pH; (2) poly(D,L-lactic acid/glycolic acid)-PLGA nanoparticles loaded with the antibiotic rifampicin. These PLGA nanoparticles were produced also using a microfluidic continuous process and (3) PLGA nanoparticles loaded with Au nanoparticles to trace the PLGA formulation under different environments (gastric and intestinal), and to assess whether active pharmaceutical ingredient (API) encapsulation in PLGA is due efficiently. We further showed that Trojan microparticles released the embedded PLGA nanoparticles in contact with suitable media, as confirmed by electron microscopy. Finally, the results show the possibility of developing Trojan microparticles in a continuous manner with the ability to deliver therapeutic nanoparticles in the gastrointestinal tract.

Shell features and anatomy of the springsnail genus Radomaniola (Caenogastropoda: Hydrobiidae) show a different pace and mode of evolution over five million years

Abstract Shell features are key factors for systematics and evolutionary biology studies of freshwater gastropods. Based mostly on shell morphology, 19 species of the springsnail genus Radomaniola (family Hydrobiidae) have been described. Although the scarce differentiation of various shell dimensions suggests morphological stasis, the evolutionary dynamics of shell and other anatomical structures have not yet been explored fully. By inferring a phylogeny and a time-calibrated species tree from mitochondrial (COI and 16S) and nuclear (28S) sequences of 15 recognized species, we initially examine the species diversity of the Radomaniola dataset and then, through phylogenetic comparative methods, assess the evolutionary correlation, pace and mode of 40 continuous shell and anatomical characters. By synthesizing the results of four species delimitation methods and through morphological examinations, we recognize 21 groups, for which taxonomy is discussed here. Seven new species are described. We reveal a high degree of correlated evolution between characters of the shell, which are constrained by a single morphological optimum, consistent with the morphological stasis model. Anatomical traits diverged rapidly in an unconstrained manner or toward multiple optima. These findings indicate that in order to understand the morphological evolution of springsnails, it is essential to examine different organs in detail.

Parasitic manipulation or by-product of infection: an experimental approach using trematode-infected snails.

Natural selection should favour parasite genotypes that manipulate hosts in ways that enhance parasite fitness. However, it is also possible that the effects of infection are not adaptive. Here we experimentally examined the phenotypic effects of infection in a snail-trematode system. These trematodes (Atriophallophorus winterbourni) produce larval cysts within the snail's shell (Potamopyrgus antipodarum); hence the internal shell volume determines the total number of parasite cysts produced. Infected snails in the field tend to be larger than uninfected snails, suggesting the hypothesis that parasites manipulate host growth so as to increase the space available for trematode reproduction. To test the hypothesis, we exposed juvenile snails to trematode eggs. Snails were then left to grow for about one year in 800-l outdoor mesocosms. We found that uninfected males were smaller than uninfected females (sexual dimorphism). We also found that infection did not affect the shell dimensions of males. However, infected females were smaller than uninfected females. Hence, infection stunts the growth of females, and (contrary to the hypothesis) it results in a smaller internal volume for larval cysts. Finally, infected females resembled males in size and shape, suggesting the possibility that parasitic castration prevents the normal development of females. These results thus indicate that the parasite is not manipulating the growth of infected hosts so as to increase the number of larval cysts, although alternative adaptive explanations are possible.

Population structure and relative growth of rock snails Reishia bitubercularis (Gastropoda: Muricidae) from Ambon Island, Eastern Indonesia

The present study reports and discusses population structure and morphometric relationships of muricid <em>Reishia bitubercularis</em> in two populations from Ambon Island, Maluku. Field sampling was conducted at two locations with typical hard substrate i.e. Ambon Bay and Central Maluku, where each location comprises three different stations. Morphometric relationships were analyzed for shell dimensions i.e., shell length (SL), shell width (SW), shell height (SH) and total weight (TW). A total of 496 individuals of <em>R. bitubercularis </em>were collected in both locations. SL ranged from 7.07 to 42.38 mm in Ambon Bay, and 12.45 to 42.69 mm in Central Maluku. The highest number of individuals in Ambon Bay and Central Maluku was in size 26-28 mm and 30-32 mm, respectively. The mean SW/SL ratio ranged from 0.67 mm to 0.73 mm. Sex ratio was significantly different from 1:1, with females outnumbered males in both locations. Morphometric relationships indicated SL grows faster than SW in both locations and faster than SH and TW in Central Maluku. While the growth rate between SL vs SH; and TW vs SL are relatively similar in Ambon Bay. Overall, both Ambon Bay and Central Maluku have a similar variation of abiotic factors which also play an important role in shell morphometrics and relative growth of muricids, especially related to the exposed area in the rocky intertidal zone where sampling was conducted.

ZIF-Mediated Gold Nanorod Assembly for Surface-Enhanced Raman Scattering Detection of 4-Nitrobenzenethiol

Nanoparticle assemblies exhibit unique properties compared to single entities due to interactions between their building blocks. Although the development of large-area assemblies has been extensively studied, finite nanoparticle assemblies with tens of building blocks have not been adequately explored. Here, we prepared a finite assembly of anisotropic gold nanorods through encapsulation by a zeolitic imidazolate framework-8 (ZIF). The three-dimensional reconstruction of the ZIF-encapsulated nanorod assembly indicated that the assembled nanorods are separate bundles aligned side-by-side, each of which serves as a nucleation center for a cube-shaped ZIF domain. Further experiments showed that the assembly pattern and the shell dimension can be controlled by the cysteamine and surfactant concentrations. Moreover, the ZIF-encapsulated nanorod assembly had twice the surface-enhanced Raman scattering signal of a single nanorod and showed higher selectivity for 4-nitrobenzenethiol versus rhodamine 6G. Our model system will significantly contribute to the development of finite anisotropic nanoparticle assemblies with microporous metal–organic framework shells and extend their applicability.

Design assessment of a horizontal shell and tube latent heat storage system: Alternative to fin designs

In the present study, the charging and discharging performances of a horizontal shell and tube latent heat storage (LHS) system are analysed. The effective heat capacity approach is adopted to develop a numerical model using sodium nitrate as the phase change material (PCM) and air as the heat transfer fluid (HTF). The study proposes design alternatives to conventional shell and tube LHS systems by varying the PCM volume distribution and the surface area of heat transfer along the length. A novel design methodology is proposed, wherein, the outer shell of the LHS system is optimized into a cone and the cross-section of the HTF tube is varied. Based on the optimal shell dimensions, seven different designs having cylindrical/converging conical/diverging conical shells and cylindrical/converging/diverging cross-sections of the inner HTF tube are developed for a fixed PCM volume and heat transfer surface area. The LHS system with converging shell and converging cross-section HTF tube is found to have optimal performance with 37% and 47.3% reduction in charging and discharging times over the conventional cylindrical shell and tube system. The system is also compared with a fin and non-finned cylindrical shell and tube system at different inlet charging and discharging temperatures. The melting and solidification contours and melt fraction plots show a more uniform rate of natural convection and conduction heat transfer along the length of the proposed optimal design which is projected as an alternative to longitudinal fin design due to similar charging/discharging performances.

Heterostructural tailoring of blue ZnSeTe quantum dots toward high-color purity and high-efficiency electroluminescence

Ternary ZnSeTe quantum dots (QDs) are regarded as the most promising non-Cd blue emitters, which can be exploited for the fabrication of self-emissive QD display device or QD-light-emitting diode (QLED). We report extensive synthesis of high-quality blue ZnSeTe QDs with a double shell scheme of ZnSe inner and ZnS outer shell in a unique two-step approach. In such ZnSeTe/ZnSe/ZnS heterostructure, the thickness modulation of ZnSe inner shell leads to the variations in not only the thickness of ZnS outer shell but Photoluminescence (PL) characteristics such as peak wavelength, color purity-associated bandwidth, and Quantum yield (QY). The Te/Se ratio in ZnSeTe core is precisely tailored to demonstrate moderate PL tunability in deep-blue territory and the thickness of ZnS outer shell is further independently varied to examine its effects on the performance of QLED. All the QDs that possess outstanding PL QYs up to near-unity (96%) along with an appropriate deep-blue emissivity are individually employed for solution-processed QLED fabrication. The resulting blue QLEDs produce high electroluminescence performances in the ranges of 6107–12654 cd/m2 in luminance and 5.3–18.6% in external quantum efficiency, depending on ZnSe inner, ZnS outer shell dimensions and ZnSeTe core composition.

Solvent-Mediated Shell Dimension Reconstruction of Core@Shell PdAu@Pd Nanocrystals for Robust C1 and C2 Alcohol Electrocatalysis.

The core@shell structure dimension of the Pd-based nanocrystals deeply impacts their catalytic properties for C1 and C2 alcohol oxidation reactions. However, the precise simultaneous control on the synthesis of core@shell nanocrystals with different shell dimensions is difficult, and most synthesis on Pd-based core@shell nanocatalysts involves the surfactants participation by multiple steps, thus leads to limited catalytic properties. Herein, for the first time, a facile one-step surfactant-free strategy is developed for shell dimension reconstruction of PdAu@Pd core@shell nanocrystals by altering volume ratios of mixed solvents. The Pd-based sunflower-like (SL) and coral grass-like (CGL) nanocrystals are obtained with different 2D hexagonal nanosheet assembles and 3D network shells, respectively. Benefitting from the clean surface shell of 2D ultrathin nanosheets structure, high atom utilization efficiency, and robust electronic effect. The PdAu@Pd SL achieves the ascendant methanol/ethanol/ethylene glycol oxidation reaction (MOR/EOR/EGOR) activities, much higher than Pd/C catalysts, as well as the improved antipoisoning ability. Notably, this one-step construction shell dimension of PdAu@Pd core@shell catalysts not only provide a significant reference for the improvement of surfactant-free synthetic routes, but also shed light on the advanced engineering on shell dimensions in core@shell nanostructures for electrocatalysis and so forth.

Site-Specifically-Labeled Antibodies for Super-Resolution Microscopy Reveal In Situ Linkage Errors.

The precise spatial localization of proteins in situ by super-resolution microscopy (SRM) demands their targeted labeling. Positioning reporter molecules as close as possible to the target remains a challenge in primary cells or tissues from patients that cannot be easily genetically modified. Indirect immunolabeling introduces relatively large linkage errors, whereas site-specific and stoichiometric labeling of primary antibodies relies on elaborate chemistries. In this study, we developed a simple two-step protocol to site-specifically attach reporters such as fluorophores or DNA handles to several immunoglobulin G (IgG) antibodies from different animal species and benchmarked the performance of these conjugates for 3D STORM (stochastic optical reconstruction microscopy) and DNA-PAINT (point accumulation in nanoscale topography). Glutamine labeling was restricted to two sites per IgG and saturable by exploiting microbial transglutaminase after removal of N-linked glycans. Precision measurements of 3D microtubule labeling shell dimensions in cell lines and human platelets showed that linkage errors from primary and secondary antibodies did not add up. Monte Carlo simulations of a geometric microtubule-IgG model were in quantitative agreement with STORM results. The simulations revealed that the flexible hinge between Fab and Fc segments effectively randomized the direction of the secondary antibody, while the restricted binding orientation of the primary antibody’s Fab fragment accounted for most of the systematic offset between the reporter and α-tubulin. DNA-PAINT surprisingly yielded larger linkage errors than STORM, indicating unphysiological conformations of DNA-labeled IgGs. In summary, our cost-effective protocol for generating well-characterized primary IgG conjugates offers an easy route to precise SRM measurements in arbitrary fixed samples.

Population structure and shell dimension of the invasive veined whelk (Rapana venosa)

The veined whelk (Rapana venosa) is a widely known invasive species in the Black Sea. This species exerts negative impacts on the Black Sea ecosystem including destruction of bivalve, mussel and oyster populations. This study aimed to examine population structure using the length-frequency distribution and shell dimensions of R. venosa, collected from the Black Sea. A total of 506 specimens were collected from the Trabzon Coast and classified into 6 age groups using the Bhattacharya method. The Von-Bertalanffy growth parameters were calculated as L∞ = 10.29 cm, k = 0.09, t0 = 1.25 yr–1. The mortality and exploitation rates were estimated as total mortality Z = 0.51 yr–1, fishing mortality F = 0.31 yr–1, annual mortality M = 0.20 yr–1 and exploitation rate E = 0.60 yr–1. This study will help understanding the growth of R. venosa and its management.

Biology of the common cockle Cerastoderma edule (Linnaeus, 1758) in Ria de Aveiro (NW Portugal): Implications for fisheries management

This study reports the reproductive cycle, condition index, size at first maturity, growth and the morphometric relationships of the common cockle Cerastoderma edule in Ria de Aveiro (NW Portugal), fundamental knowledge in fisheries management planning and ecosystem conservation. The reproductive cycle was monitored for a period of two years, from January 2013 to December 2014. Spawning extended from June to October, with a peak in the summer months (July to September). The condition index showed a seasonal pattern which appear related to food availability and gametogenic cycle. Sexual maturity was attained at a shell length of 18.6 mm during the first year of life, which stands below the minimum landing size currently in force (25 mm). The von Bertalanffy growth equation was based on size-at-age data obtained from the microscopic analysis of growth rings in sectioned shells: Lt = 40.7[1-e −0.74(t-0.30)]. The morphometric relationships between shell dimensions (length, height and width) were studied in order to understand the effects of ontogenetic changes in cockles` shell morphology, an information that is useful to improve the selectivity of the fishing gears and the size-sorting devices. Some management strategies for the Ria de Aveiro cockle fishery were proposed.

Population growth model of Anadara granosa based on correlation between dimension of shell with the weight at the water environment of Sunda Strait

Exploitation of shellfish resources can affect its growth which can be seen from changes in the size of the shell dimensions including length, width and height. The study was conducted to determine the relationship between the dimensions of the shell with its total weight as a description of growth patterns, and to determine the environmental factors that affect shell growth. Descriptive method with direct observation technique was carried out at 3 observation stations in the Sunda Strait waters. Data were analyzed using power regression, while the correlation of environmental parameters were analyzed using PCA. The results show that the correlation between the dimensions of the shell and the total weight of the shell is allometric negative (b <3), which is an unbalanced growth between the dimensions of the shell and the weight of the shell, so that the shell growth pattern is indicated by the increase in width, length and height that was faster than the body weight. The parameters that affects the dimensions of the shell and weight are NH3-N, NO2-N, BOD, salinity, depth, TOM, brightness, Pb, Cd, Hg and temperature.

Analysis of the modal frequency of a functionally graded cylindrical shell

The modal frequencies of a functionally graded material (FGM) cylindrical shell with different geometry dimensions and material constituents are studied under eight boundary conditions. The main goal is to reveal the influencing mechanism of different factors on the modal frequencies of the FGM shell. Firstly, the Voigt model is used to describe the properties of FGM. Secondly, the motion equation of the FGM shell is derived using Hamilton’s principle. Thirdly, the modal frequency equation of the FGM shell is obtained based on a trigonometric function for the eight boundary conditions. Lastly, the effects of geometry dimension, material constituents, and boundary conditions on the modal frequencies of the FGM shell are analyzed through case studies. Results indicate that the modal frequencies obtained are good agreement with those from previous literature and the finite element method. The geometry dimensions of the FGM shell, the material constituents of the FGM, and the boundary conditions are crucial to the modal frequencies. This work can serve as a reference for the design of FGM and optimization of the structure of FGM shells.

Effect of the compaction parameters on the final structure and properties of a press-coated tablet (Tab-in-Tab): Experimental and numerical study of the influence of core and shell dimensions

With increasing interest in chronopharmaceutics, press-coated tablets have become a key technology in the field of modified release drug delivery systems. Although their benefits in terms of drug release have been largely studied, the comprehension of the compaction process of press-coated tablets is yet to complete. Particularly, the effects of geometrical parameters like the ratios between the thickness/diameter of the core and the thickness/diameter of the whole tablet were so far not much considered. Moreover, there is only few studies in the literature about the effect of the press-coating compression on the final structure and properties of the core. The present work consists in a joint experimental and numerical study that aims to assess these points. The study revealed high stress concentrations on the core during compression, causing high permanent deformations of the core, especially when the ratio between the core thickness and the total tablet thickness was high. The mechanical properties of the core tablet were also shown to be impacted: its density and strength were found to decrease before increasing again along the coating-compression. This effect was highlighted to be dependent on the triaxiality of the stress state (i.e. the ratio between the stresses in the different directions), itself depending on the two studied geometrical parameters. As the properties of the core affect the release attributes, ratios between the dimensions of the core and the dimensions of the whole tablet (thickness, diameter) should be taken into account as critical parameters for the manufacture of press-coated tablets.

Effect of magnetic field on energy states and optical properties of quantum dots and quantum antidots

In this study, the effect of magnetic field on electronic spectra and optical properties of spherical quantum dot (QD) and quantum anti-dot (QAD) are investigated. The energies and corresponding wave functions are calculated by using the finite difference method and oscillator strengths are obtained based on the dipole approximation approach. Based on perturbation theory, our theoretical results are presented and it will be shown clearly how the magnetic field affects energy levels and intersubband transitions. In the following, our numerical results based on a comparative perspective for both QD and QAD models are given. Our results indicate that in the presence of magnetic field, changes on energy levels and optical properties of QD and QAD are considerably different. In addition, we study the effect of change in core and shell dimensions in the presence of magnetic field on the energy states and oscillator strengths of both nanostructures.