Cation Mass Research Articles

Acriflavine Is More than It Seems: Resolving Optical Properties of Multiple Isomeric Constituents at 5 K.

Ion mobility spectrometry at room temperature was combined with vibrationally resolved electronic spectroscopy of mass-selected ions at 5 K to study the well-known cationic fluorophore acriflavine. One- and two-color photodepletion action spectra recorded in gas-phase (by helium tagging) as well as dispersed fluorescence spectra obtained in neon matrix (after soft-landing deposition) indicate that the primary cation mass electrosprayed from solution comprises two isomers with different optical properties. Theory at the TD-DFT level allowed full spectral assignment. The results have implications for the preparation of novel thin film photonic materials by low-energy ion beam deposition.

The influence of nitrogen fertilizer treated with low-temperature, low-pressure glow plasma on the growth and quality of selected species

Water treated with low-pressure glow plasma of low frequency takes unique properties which might be utilized as a novel, benefi”cial nitrogen fertilizer. Th™at assumption is tested in this report. ™Thus, plantations of dill (Anethum graveolens) var. Moravan, grass Universal (5% westerwold ryegrass (Lolium multiWorum), 20% tall fescue (Festuca arundinacea), 40% perennial ryegrass (Lolium perenne), 35% red festuce (Festuca rubra) and strawberry ((Fragaria) var. Senga Sengana were watered with that nitrogen fertilizer (LPGPAm) prepared of 1% ammonia solution in tap water treated for 30 min with plasma generated at 38oC at 5x10-3 mbar, 800 V, 50 mA and 10 kHz frequency. Watering lasted from August 1th (sowing) till September 30th (harvesting) 2023 in a greenhouse.Th™e eff˜ect of the use of watering plants with LPGPAm was checked involving the following parameters: plant height, mass of stems, total mass of crops, content of fat, proteins, carotenoids, ascorbic acid, sulphur content chlorophyll, content of dry mass, and ash and bioaccumulation of cations and anions.

Laboratory characterization of hydrothermally processed oligopeptides in ice grains emitted by Enceladus and Europa.

The Cassini mission provided evidence for a global subsurface ocean and ongoing hydrothermal activity on Enceladus, based on results from Cassini's mass spectrometers. Laboratory simulations of hydrothermal conditions on icy moons are needed to further constrain the composition of ejected ice grains containing hydrothermally altered organic material. Here, we present results from our newly established facility to simulate the processing of ocean material within the temperature range 80-150°C and the pressure range 80-130 bar, representing conditions suggested for the water-rock interface on Enceladus. With this new facility, we investigate the hydrothermal processing of triglycine (GGG) peptide and, for the first time, analyse the extracted samples using laser-induced liquid beam ion desorption (LILBID) mass spectrometry, a laboratory analogue for impact ionization mass spectrometry of ice grains in space. We outline an approach to elucidate hydrothermally processed GGG in ice grains ejected from icy moons based on characteristic differences between GGG anion and cation mass spectra. These differences are linked to hydrothermal processing and thus provide a fingerprint of hydrothermal activity on extraterrestrial bodies. These results will serve as important guidelines for biosignatures potentially obtained by a future Enceladus mission and the SUrface Dust Analyzer (SUDA) instrument onboard Europa Clipper. This article is part of the theme issue 'Dust in the Solar System and beyond'.

Effect of Relative Mass on Ion Velocity Cross-Correlations in Ionic Liquids and Molten Salts: Different Perspectives in Different Reference Frames.

In electrolytes, the self- and interdiffusion coefficients, transport numbers, and electrical conductivity can be used to determine velocity cross-correlation coefficients (VCC) that are also accessible through molecular dynamics simulations. In an ionic liquid or molten salt, there are only three, corresponding to correlations between the velocities of distinct ion pairs (cation-anion, cation-cation, and anion-anion) averaged over both the ensemble and time, calculable from experimental ion self-diffusion coefficients and the electrolyte conductivity. Most usually, the mass-fixed frame of reference (with velocities relative to that of the center of mass of the system) is used to discuss the VCC and the distinct diffusion coefficients (DDC) derived from them. Recent work in the literature has suggested a dependence of the DDC on the ratio of the anion to cation mass. Here, we demonstrate, using our own and literature transport property data for a large number of ionic liquids and molten salts, that the trends observed depend on the particular choice of velocity reference frame, mass-, number-, or volume-fixed. The perception of ion-ion interactions may be distorted in the mass- and volume fixed frames when the co-ions have very different masses or volumes, particularly for systems containing light lithium ions.

Yb0.5Ca0.75Si7.5Al4.5O1.5N14.5 α-SiAlON ceramics: A hard material with low thermal conductivity

High hardness is desirable for thermal insulation materials in various applications to improve wear resistance. However, hard materials like diamond, Si3N4, and SiC are often accompanied by high thermal conductivity, due to their strong covalent bonds and high Young’s modulus, which increase sound velocity and benefit heat transportation. How to achieve concurrent high hardness and low thermal conductivity remains a challenge in thermal insulation materials. In this work, we report (Yb+Ca) co-doped α-SiAlON (Yb0.5Ca0.75Si7.5Al4.5O1.5N14.5, a solid solution of α-Si3N4) with a low thermal conductivity of 3.4 W/(m·K) and a hardness of 18.1 GPa at 25℃. The thermal conductivity of α-SiAlONs co-doped by (Yb+Nd/Lu) were also studied, and we found that phonon scattering could be significantly increased only when there was a remarkable difference in cation mass and radius between the co-doping cations, like that between Yb3+ and Ca2+. Additionally, high-entropy α-SiAlONs co-doped by five kinds of cations were studied (e.g., Nd0.1Gd0.1Dy0.1Er0.1Yb0.1Si9.5Al2.5ON15), and we found that the high-entropy strategy is not so effective in pursuing low thermal conductivity in α-SiAlONs. The contribution of different phonon scattering mechanisms in the α-SiAlONs was discussed based on inverse thermal diffusivity. Compared with most other ceramics (e.g., 8YSZ and rare-metal zirconates) with low thermal conductivity, (Yb+Ca) co-doped α-SiAlON has a lower bulk density, higher hardness, and higher toughness, which makes it a potential candidate material for applications requiring both thermal insulation and good mechanical properties.

Cationic effect in the formation of toxic and antiviral properties of Keggon heteropoly compounds

The Cytotoxicity indices (IC50) of Keggin’s phosphorus-molybdenum heteropoly acids (HPCAs) and their sodium and potassium salts on dog kidney cells (MDSC) were determined. The antiviral activity of these compounds against topical strains of influenza A (H3N2 and H1N1) was revealed. The dependence of the biological properties of polyoxometalates (POMs) on the elemental composition of their molecules has been confirmed. It has been shown that when some of the molybdenum atoms are replaced by vanadium atoms, HPCA and their salts acquire higher cytotoxicities, which increase monotonically as the number of substitutions increases. For the first time, the dependence of the biological activity of HPCA and their salts on the mass of cations has been established and interpreted. In vivo (on white outbred mice) the values of semi-lethal doses (DL50) of these compounds were established. For aqueous solutions of sodium and potassium salts of GPCA in a wide range of concentrations (from 0.05 μM to 15 μM), the values of the toxicity index (It) were determined on the model of motile cells. It has been established that GPCA and their salts are classified as moderately dangerous toxic substances and have selective antiviral activity, which at low concentrations (less than 15 μM) for influenza A strains is manifested mainly by a decrease in hemagglutination activity (HA).

Dehydrogenation in Electron-Induced Dissociative Ionization of Pyridine Molecule

"The electron-impact dissociative ionization of pyridine has been investigated using mass spectrometry. Thirty-two well-resolved mass peaks have been identified in the cation mass spectra and assigned to the most likely ionic molecular fragments. The new sixteen ionic fragments' appearance energies have been determined, and sixteen others remeasured. The total cross-section for electron-impact ionization of pyridine has been measured at 100 eV. Thorough analysis indicates that at least three peaks' groups in the mass spectra occur via the shake-off dehydrogenation mechanism, i.e., by sequential hydrogen atoms elimination from the pyridine parent cation or its fragmentation products. The nature of this process is deciphered. "

Linking meteorites to their asteroid parent bodies: The capabilities of dust analyzer instruments during asteroid flybys

AbstractLinking meteorites to their asteroid parent bodies remains an outstanding issue. Space‐based dust characterization using impact ionization mass spectrometry is a proven technique for the compositional analysis of individual cosmic dust grains. Here we investigate the feasibility of determining asteroid compositions via cation mass spectrometric analyses of their dust ejecta clouds during low (7–9 km s−1) velocity spacecraft flybys. At these speeds, the dust grain mass spectra are dominated by easily ionized elements and molecular species. Using known bulk mineral volume abundances, we show that it is feasible to discriminate the common meteorite classes of carbonaceous chondrites, ordinary chondrites, and howardite–eucrite–diogenite achondrites, as well as their subtypes, relying solely on the detection of elements with ionization efficiencies of ≤700 or ≤800 kJ mol−1, applicable to low (~7 km s−1) and intermediate (~9 km s−1) flyby speed scenarios, respectively. Including the detection of water ion groups enables greater discrimination between certain meteorite types, and flyby speeds ≥10 km s−1 enhance the diagnostic capabilities of this technique still further. Although additional terrestrial calibration is required, this technique may allow more unequivocal asteroid‐meteorite connections to be determined by spacecraft flybys, emphasizing the utility of dust instruments on future asteroid missions.

Polyimides as Promising Cathodes for Metal-Organic Batteries: A Comparison between Divalent (Ca2+, Mg2+) and Monovalent (Li+, Na+) Cations.

Ca- and Mg-based batteries represent a more sustainable alternative to Li-ion batteries. However, multivalent cation technologies suffer from poor cation mass transport. In addition, the development of positive electrodes enabling reversible charge storage currently represents one of the major challenges. Organic positive electrodes, in addition to being the most sustainable and potentially low-cost candidates, compared with their inorganic counterparts, currently present the best electrochemical performances in Ca and Mg cells. Unfortunately, organic positive electrodes suffer from relatively low capacity retention upon cycling, the origin of which is not yet fully understood. Here, 1,4,5,8-naphthalenetetracarboxylic dianhydride-derived polyimide was tested in Li, Na, Mg, and Ca cells for the sake of comparison in terms of redox potential, gravimetric capacities, capacity retention, and rate capability. The redox mechanisms were also investigated by means of operando IR experiments, and a parameter affecting most figures of merit has been identified: the presence of contact ion-pairs in the electrolyte.

Equilibrium hydrogen isotope fractionation between portlandite/brucite and water: Implication from the vibrational spectra at elevated temperature and pressure

Minerals in brucite-type structure, including brucite (Mg(OH)2) and portlandite (Ca(OH)2), have been studied as important analogs of hydrous silicate minerals for their thermodynamic properties, including equilibrium hydrogen and oxygen isotope fractionations between minerals and water at elevated temperatures and pressures. In this study, Raman and Fourier transform infrared (FTIR) spectra were collected at high-temperature (T) and high-pressure (P) conditions on synthetic hydrogenated and deuterated portlandite samples (i.e., Ca(OH)2 and Ca(OD)2), and their isobaric and isothermal mode Grüneisen parameters, as well as anharmonic parameters, were then evaluated. These high-precision vibrational spectra enable the evaluation of thermodynamic properties of portlandite (ΔU, CV, CP and ΔS) up to 427 °C, to which anharmonicity has positive contributions. More importantly, they help to determine the isobaric (at P = 1 bar) β factors of brucite and portlandite for equilibrium D/H fractionation considering anharmonic effects, and the D/H fractionation factor (103∙lnα) between brucite/portlandite and water at high-P,T conditions. The calculated equilibrium fractionation factor (lnαbrucite-water) agrees with experimental results in the temperature range from 300 to 647 K (∼27 to ∼374 °C, the critical point of water) within analytical uncertainties estimated using Monte Carlo method. The Ab initio calculation using DFT theory and VASP program was also carried out to obtain phonon spectra for brucite and portlandite with three-split hydrogen sites and to evaluate the dispersion effect, which is found to be smaller than the statistical uncertainty at high temperatures. Our results show that the internal OH-stretching modes in brucite/portlandite play a dominant role in determining the β values, and the anharmonic OH-stretching potential (xi parameter) contributes significantly to the D/H fractionation factor. Because previous studies show that OH-stretching frequencies generally decrease with increasing mass of cation in the metallic hydroxide having similar crystal structure, our results imply that the deuterium isotope may be preferentially enriched in the hydroxide phase with the light cation bonded to the hydroxyl group, which is also consistent with the observed D/H fractionations among hydrous silicates.

The phononic and charge density wave behavior of entire rare-earth tritelluride series with chemical pressure and temperature

Here, we present comprehensive phononic and charge density wave properties (CDW) of rare-earth van der Waals tritellurides through temperature dependent angle-resolved Raman spectroscopy measurements. All the possible rare-earth tritellurides (RTe3) ranging from R = La–Nd, Sm, Gd–Tm were synthesized through a chemical vapor transport technique to achieve high quality crystals with excellent CDW characteristics. Raman spectroscopy studies successfully identify the emergence of the CDW state and transition temperature (TCDW), which offers a non-destructive method to identify their CDW response with micron spatial resolution. Temperature dependent Raman measurements further correlate how the atomic mass of metal cations and the resulting chemical pressure influence its CDW properties and offer detailed insight into the strength of CDW amplitude mode-phonon coupling during the CDW transition. Angle-resolved Raman measurements offer the first insights into the CDW-phonon symmetry interplay by monitoring the change in the symmetry of phonon mode across the CDW transition. Overall results introduce the library of RTe3 CDW materials and establish their characteristics through the non-destructive angle-resolved Raman spectroscopy technique.

Hydrogeochemical evolution of Taiyuan Formation limestone water under the disturbance of water inrush from karst collapse column in Taoyuan Coal Mine, China

Abstract The project implementation of water inrush and its treatment ensures the safe mining of coal mines, but also causes certain disturbance to the hydrogeochemistry of primary limestone water. Based on the water inrush event in Taoyuan Coal Mine of Huaibei coalfield in 2013, the water rock interaction mechanism of Taiyuan Formation limestone water (namely, ‘Taihui water’) was discussed. The results showed that: (1) the relationship of cation mass concentration before and after water inrush was Na+ + K+ > Ca2+ > Mg2+; the correlation of anionic mass concentration before water inrush was SO42− > HCO3− > Cl−, while it was HCO3− > SO42− > Cl− after the event. Before the event, the main water quality types were SO4•Cl-Ca and SO4•Cl-Na; after the event, they mainly included HCO3-Na and SO4•Cl-Na; (2) There is a strong positive correlation between mineral saturation index and pH value, that is, minerals are easy to dissolve under acidic conditions, while alkaline conditions will inhibit the dissolution and transformation of minerals; (3) The hydrogeochemical processes of limestone aquifer mainly included cation exchange, carbonate dissolution, pyrite oxidation, sulfate and silicate dissolution.

Developing a Laser Induced Liquid Beam Ion Desorption Spectral Database as Reference for Spaceborne Mass Spectrometers

AbstractSpaceborne impact ionization mass spectrometers, such as the Cosmic Dust Analyzer on board the past Cassini spacecraft or the SUrface Dust Analyzer being built for NASA's upcoming Europa Clipper mission, are of crucial importance for the exploration of icy moons in the Solar System, such as Saturn's moon Enceladus or Jupiter's moon Europa. For the interpretation of data produced by these instruments, analogue experiments on Earth are essential. To date, thousands of laboratory mass spectra have been recorded with an analogue experiment for impact ionization mass spectrometers. Simulation of mass spectra of ice grains in space is achieved by a Laser Induced Liquid Beam Ion Desorption (LILBID) approach. The desorbed cations or anions are analyzed in a time‐of‐flight mass spectrometer. The amount of unstructured raw data is increasingly challenging to sort, process, interpret and compare with data from space. Thus far this has been achieved manually for individual mass spectra because no database containing the recorded reference spectra was available. Here we describe the development of a comprehensive, extendable database containing cation and anion mass spectra from the laboratory LILBID facility. The database is based on a Relational Database Management System with a web server interface and enables filtering of the laboratory data using a wide range of parameters. The mass spectra can be compared not only with data from past and future space missions but also mass spectral data generated by other, terrestrial, techniques. The validated and approved subset of the database is available for general public (https://lilbid-db.planet.fu-berlin.de).

RETRACTED: Development of hybrid machine learning model for simulation of chemical reactors in water treatment applications: Absorption in amino acid

Separation and capture of CO2 from gas mixtures is of great importance from environmental point of view which can be effectively achieved using amino acids as new class of chemical absorbents. However, screening the proper absorbent with desired separation properties using experimental measurements is tedious and costly. The predictive computational techniques can be employed to overcome this problem. In this study, for estimating and analyzing CO2 solubility in chemical solvents based on amino acid salt solutions, we created two regression models from different classes of machine learning methods. The main aim is to analyze the effect of physico-chemical parameters on the CO2 dissolution in solvent which can be carried out in chemical reactors for separation/conversion of CO2 for environmental applications. A number of CO2 solubility data are collected from resources and used for training and validation of machine learning computations. Several inputs were considered for the developed machine learning models. Inputs in this regression task are T (temperature), weight% (overall mass percentage of solvent), PCO2 (partial pressure of CO2 in the gas), MW-am (molecular weight of amino acid salt), MPC (melting point of amino acid salt), MWC (molecular mass of cation). In this task, we must predict alpha (CO2 loading in the amino acid solution) as the only output of the developed models. The models studied in this research are the Gaussian process and the decision tree boosted with Gradient boosting. With the R2 criterion, the scores of the two Gradient boosting and Gaussian process models were obtained 0.985 and 0.993, respectively. As the third efficiency metric of the models, the Gradient boosting and regression of the Gaussian process with the RMSE criterion is the error rates of 1.10E−01 and 1.44E−01. The models developed in this work indicated to be reliable and robust enough for screening the solvents for a particular application and to save time and cost of experimental measurements.

Impact of CaCl2 concentration and in situ rheometric setup configuration on fast alginate–Ca2+ reaction

Recording kinetics during a reaction is a challenging effort that provides significant insight into gelation. We recently published our work based on a novel custom-made rheometric setup for in situ cross-linking reaction [Besiri et al., Carbohydr. Polym., 2020, 246, 116615]. It facilitates the instant injection of CaCl2 solution into alginate via micro-holes of the lower plate configuration to initiate the process. Considering that the time evolution of the viscoelastic parameters is related to the developed structure, we can obtain the reaction kinetics. This study aims to improve the setup by increasing the number of micro-holes from 2 to 4, investigating the mass ratio effects, and considering the proposed design as a batch reactor. As the volume and concentration of the reactants can be controlled during the initiation of the process, we investigate the molarity effect on the gelation. The long-term behavior of rheological oscillatory shear experiments indicates that the reaction is based on the mass of cations. The stoichiometry of reactants affects the diffusion of ions to alginate since, at high concentration and low volume of CaCl2, the mechanical properties are increased compared to lower concentration and higher volume of the cationic solution. Systematic time sweep experiments prove that at low angular frequencies, ω, the driving force of the reaction is the distribution of ions to the polymer. For higher values of ω, the force acting on the oscillating geometry of the rheometer is possibly the factor causing an enhanced mixing of the reactants, with a corresponding increase in moduli.

Thermal conductivity of rare-earth titanate pyrochlores

Pyrochlore oxides with the chemical formula ${R}_{2}{B}_{2}{\mathrm{O}}_{7}$ ($R=$ rare earth and $B=$ tetravalent metal) exhibit very low thermal conductivities (\ensuremath{\kappa}) and are considered as promising materials for thermal barrier coatings. To achieve better understanding of their intrinsic thermal properties, this study reports \ensuremath{\kappa} for single crystalline ${\mathrm{Gd}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$ and ${\mathrm{Dy}}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$, and for a series of polycrystalline ${R}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$, in the temperature range from 300 to 773 K. For the single crystals, \ensuremath{\kappa} values are evaluated in comparison to spinel ${\mathrm{MgAl}}_{2}{\mathrm{O}}_{4}$ and garnet ${\mathrm{Y}}_{3}{\mathrm{Al}}_{5}{\mathrm{O}}_{12}$ using the Slack equation. It is more difficult to obtain satisfactory analysis for the pyrochlores, and this is attributed to the strong involvement of low-lying optic phonons and very low energies of zone-boundary acoustic phonons. For polycrystalline ${R}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7}$, \ensuremath{\kappa} values similar to single crystals are obtained. Comparison with published data shows a systematic trend of $\ensuremath{\kappa}({R}_{2}{\mathrm{Sn}}_{2}{\mathrm{O}}_{7})>\ensuremath{\kappa}({R}_{2}{\mathrm{Ti}}_{2}{\mathrm{O}}_{7})>\ensuremath{\kappa}({R}_{2}{\mathrm{Zr}}_{2}{\mathrm{O}}_{7})$ at 300 K, which reflects the increasing ionicity from ${\mathrm{Sn}}^{4+}$ to ${\mathrm{Ti}}^{4+}$ to ${\mathrm{Zr}}^{4+}$. For the three ${R}_{2}{B}_{2}{\mathrm{O}}_{7}$ systems, \ensuremath{\kappa} appears to decrease with either decreasing ionic radius or increasing cation mass of $R$.

A novel asymmetric CDI device for targeted removal of cation in water desalination

A novel asymmetric CDI device was home-made for the removal of cations from aqueous solution through the structural innovation in this experiment. The adsorbent materials were characterized by SEM and BET as well as performing CV curve tests. The results showed that the materials exhibited excellent performance（the Specific surface area is 321.14 m²/g） and the maximum specific capacitance of the adsorbent material can reach 60F/g at the 5mV/s. The optimal operating conditions of the asymmetric CDI device were obtained using an orthogonal test method analysis and response surface methodology (RSM): the best desalination efficiency of CDI was obtained at concentration is 455.82 mg/L, potential is 1.18 V and flow rate is 46.54 mL/min. After the analysis of first-order kinetic model，it can be obtained that the fastest adsorption efficiency for Ca2+, followed by Mg2+, and the slowest for Na+, and the CDI device had better adsorption effect on divalent cations. Simulation by Comsol software showed that the adsorption efficiency was better at high flow rate. In addition, the CDI device has good stability, and the mechanism of targeted cation removal and mass transfer process of the CDI were discussed in detail.

Liming legacy effects associated with the world's largest soil liming and regreening program in Sudbury, Ontario, Canada

Limestone is a common amendment used to counteract soil acidity and metal pollution. Understanding the legacy effects of a one-time soil limestone application and subsequent afforestation is needed to evaluate the long-term success of remediation efforts. In this study, soil and tree chemistry were measured across 15 limed sites that were treated and planted 14 to 37 years ago in Sudbury, Ontario, along with two untreated sites. Soil pH and exchangeable base cation (calcium (Ca) and magnesium (Mg)) concentrations were generally elevated especially in surface organic [FH] horizons up to 37-years post limestone treatment. High site-to-site variation however, obscured clear patterns over time and base cation mass budgets were generally unable to account for the mass of added Ca and Mg. Metal partitioning (Kd) in soil was most influenced by soil pH rather than organic matter (OM) showing that metal availability increases as liming effects fade. This study shows that the legacy effects of soil liming can persist for several decades and are most apparent in the forest floor (FH), but legacy effects are quite modest, and it is likely that a considerable amount of limestone has been lost through erosion.

Hydrochemical characteristics and ion sources of river water in the upstream of the Shiyang River, China

As the largest tributary of the Shiyang River, with the average annual inflow of total runoff accounting for 23%, the Xiying River has representative of mountain runoff of inland rivers in the Northwest of China. Using samples collected in this basin from September 2016 to October 2017, the water chemical composition and ion source characteristics of river were studied. The results show that the river is weakly alkaline, the average pH is 8.0 and the TDS is 179.29 mg·L−1. With the elevation decreasing along the river, the TDS of main stream tend to increase first and then decrease, but those of TDS of each tributary decrease, and the latter is lower than the former. Affected significantly by the flow, the lowest value of ion concentration in river occurs in summer, and the highest occurs in autumn and winter. The hydrochemical type of river is CaMg–HCO3. In the river, the order of cation mass concentration is NH4+ < K+ < Na+ < Mg2+ < Ca2+, and that of anion is F− < NO3− < Cl− < SO42− < HCO3−. The sources of ions in river are mainly from the weathering of silicates and carbonates. With the elevation decreasing along the river, the influence of silicates on the inflowing tributaries is gradually strengthened.

CLASSIFICATION OF MAMMOGRAMS HAVING ARCHITECTURAL DISTORTION AND SPICULATED MASSES USING TEXTURE FEATURES

Architectural distortion is the third most common mammographic appearance of nonpalpable breast cancer, representing nearly 6% of abnormalities detected on screening mammography. Although its prevalence on mammography is small compared with calcication or visible mass, architectural distortion is also more difcult to diagnose because it can be subtle and variable in presentation. Early detection of breast cancer is possible by nding architectural distortion in monographic images. Spiculated masses account for about 14% of biopsied lesions and about 81% of these are malignant. Current CAD systems are dramatically better at detecting microcalcications than masses. The sensitivity is considerably lower for Spiculated Masses that are rated as "subtle" by radiologists Moreover, since current systems were devised with masses and calcications in mind, they don’t perform as well on other, less prevalent but still clinically signicant lesion types. In this paper, we propose a computer aided diagnosis system for distinguishing abnormal mammograms with architectural distortion or spiculated masses from normal mammograms. Five types of texture features GLCM, GLRLM, fractal texture, spectral texture and HOG features for the regions of suspicion are extracted. Support vector machine has been used as classier in this work. The proposed system yielded an overall accuracy of 97.29% for mammogram images collected from mini-MIAS database which is better as compared to existing methods.