Mineral matrix deposition of MC3T3-E1 pre-osteoblastic cells exposed to silicocarnotite and nagelschmidtite bioceramics: In vitro comparison to hydroxyapatite.

This work presents the effect of the silicocarnotite (SC) and nagelschmidtite (Nagel) phases on in vitro osteogenesis. The known hydroxyapatite of biological origin (BHAp) was used as a standard of osteoconductive characteristics. The evaluation was carried out in conventional and osteogenic media for comparative purposes to assess the osteogenic ability of the bioceramics. First, the effect of the material on cell viability at 24 h, 7 and 14 days of incubation was evaluated. In addition, cell morphology and attachment on dense bioceramic surfaces were observed by fluorescence microscopy. Specifically, alkaline phosphatase (ALP) activity was evaluated as an osteogenic marker of the early stages of bone cell differentiation. Mineralized extracellular matrix was observed by calcium phosphate deposits and extracellular vesicle formation. Furthermore, cell phenotype determination was confirmed by scanning electron microscope. The results provided relevant information on the cell attachment, proliferation, and osteogenic differentiation processes after 7 and 14 days of incubation. Finally, it was demonstrated that SC and Nagel phases promote cell proliferation and differentiation, while the Nagel phase exhibited a superior osteoconductive behavior and could promote MC3T3-E1 cell differentiation to a higher extent than SC and BHAp, which was reflected in a higher number of deposits in a shorter period for both conventional and osteogenic media.

Interlayer charge transfer in supported and suspended MoS2/Graphene/MoS2 vertical heterostructures.

In this letter, we report on the optical and structural properties of supported and suspended MoS2/Graphene/MoS2 vertical heterostructures using Raman and photoluminescence (PL) spectroscopies. Vertical heterostructures (VH) are formed by multiple wet transfers on micro-sized holes in SiO2/Si substrates, resulting in VH with different configurations. The strong interlayer coupling is confirmed by Raman spectroscopy. Additionally, we observe an enhancement of the PL emission in the three-layer VH (either support or suspended) compared with bare MoS2 or MoS2/Graphene. This suggests the formation of a spatial type-II band alignment assisted by the graphene layer and thus, the operation of the VH as a n++/metal/n junction.

Ligninolytic activity of the Penicillium chrysogenum and Pleurotus ostreatus fungi involved in the biotransformation of synthetic multi-walled carbon nanotubes modify its toxicity.

Multi-walled carbon nanotubes (MWCNTs) are of multidisciplinary scientific interest due to their exceptional physicochemical properties and a broad range of applications. However, they are considered potentially toxic nanoparticles when they accumulate in the environment. Given their ability to oxidize resistant polymers, mycorremediation with lignocellulolytic fungi are suggested as biological alternatives to the mineralization of MWCNTs. Hence, this study involves the ability of two fungi specie to MWCNTs biotransformation by laccase and peroxidases induction and evaluation in vivo of its toxicity using Caenorhabditis elegans worms as a model. Results showed that the fungi Penicillium chrysogenum and Pleurotus ostreatus were capable to grow on media with MWCNTs supplemented with glucose or lignin. Activities of lignin-peroxidase, manganese-peroxidase, and laccase in cultures of both fungi were induced by MWCNTs. Raman, FTIR spectroscopy, HR-TEM, and TGA analyses of the residue from the cultures of both fungi revealed structural modifications on the surface of MWCNTs and its amount diminished, correlating the MWCNTs structural modifications with the laccase-peroxidase activities in the fungal cultures. Results indicate that the degree of toxicity of MWCNTs on the C. elegans model was enhanced by the structure modification associated with the fungal ligninolytic activity. The toxic effect of MWCNTs on the in vivo model of worms reveals the increment of reactive oxygen species as a mechanism of toxicity. Findings indicate that the MWCNTs can be subject in nature to biotransformation processes such as the fungal metabolism, which contribute to modify their toxicity properties on susceptible organisms and contributing to environmental elimination.

Comment on "Investigation on the structure and thermoelectric properties of CuxTe binary compounds" by Shriparna Mukherjee et al., Dalton Trans., 2019, 48, 1040.

The Raman spectra of copper tellurides are nearly unknown. This is due not only to the difficulty in obtaining single-phase specimens, but also to the low inelastic light scattering efficiency of Cu2-xTe. To date, only the Raman spectrum of the vulcanite phase, CuTe, has been both measured and calculated by density functional theory. The authors of the commented work reported the Raman spectra of Cu2Te, Cu1.6Te and Cu1.25Te samples. However, the assignment of the measured modes has been defective and their Raman spectra lack some of the features usually found for copper tellurides.

Dual-doped CdSe:Cu:O films grown by sputtering using CdSe-CuO composite targets.

The effects of the simultaneous incorporation of Cu and O in CdSe films grown by sputtering are presented. The Cu and O contents varied between 1 and 5 at.% in films deposited at 150, 200, 250 and 300 °C. Concentrations of 2, 3, 4 and 5 at.% of CuO in the target promoted the formation of copper selenide clusters immersed within the CdSe:Cu:O host. Energy considerations (enthalpy of formation and bond dissociation energy) were used to discuss the absence of copper oxide and the formation of copper selenide aggregates, as well as the film thickness dependence on the concentration of CuO in the target. The band gap of the films ranged from 1.21 to 2.07 eV, depending upon growth conditions. Significant below-band-gap absorption was observed which was ascribed to the copper selenide micro and nano clusters. Good crystalline quality of the films, for high substrate temperatures, was evidenced through the appearance of overtones of the vibrational longitudinal optic modes detected by Raman micro spectroscopy. It was determined that the electronic properties, optical transmission and electrical conductivity depended on the chemical composition and crystalline structure. This characteristic is relevant because through copper and oxygen co-doping is possible to control these technologically important physical properties of CdSe in a simple and reliable manner.

Food Security and Obesity among Mexican Agricultural Migrant Workers.

Mexican migrant farm workers are one of the poorest and most marginalized social groups within the country. They face the double burden of malnutrition, food insecurity, as well as harsh living and labor conditions. Objective: To examine the relationship between household food insecurity (HFI) and obesity in a population of migrant farm workers in highly modernized agribusiness areas of Northwest Mexico. Methods: This was a cross-sectional study with a concentric (site) (n = 146 households) and systematic selection of participants (adult men and women). Methods included questionnaires regarding socio-demographic characteristics, food security, diet (two non-consecutive 24-h recalls), and physical activity (PA). Anthropometric data included height, weight, and waist circumference. Data analysis covered descriptive statistics, multivariate linear and logistic regression. Results: Sample showed 75% prevalence of overweight and obesity, while 87% of households reported some level of HFI. Mild HFI resulted in five times more probability of farm workers' obesity (OR = 5.18, 95% CI: 1.37-19.58). However, there was a protective effect of HFI for obesity among men (OR 0.089, 95% CI: 0.01-0.58) in a context of intense labor-related PA. Conclusion: There is a difference by gender in the relationship of HFI with obesity prevalence related perhaps to the energy expenditure of male agricultural migrant workers.

Crystalline structure, electronic and lattice-dynamics properties of NbTe2.

Layered-structure materials are currently relevant given their quasi-2D nature. Knowledge of their physical properties is currently of major interest. Niobium ditelluride possesses a monoclinic layered-structure with a distortion in the tellurium planes. This structural complexity has hindered the determination of its fundamental physical properties. In this work, NbTe2 crystals were used to elucidate its structural, compositional, electronic and vibrational properties. These findings have been compared with calculations based on density functional theory. The chemical composition and elemental distribution at the nanoscale were obtained through atom probe tomography. Ultraviolet photoelectron spectroscopy allowed the first determination of the work function of NbTe2. Its high value, 5.32 eV, and chemical stability allow foreseeing applications such as contact in optoelectronics. Raman spectra were obtained using different excitation laser lines: 488, 633, and 785 nm. The vibrational frequencies were in agreement with those determined through density functional theory. It was possible to detect a theoretically-predicted, low-frequency, low-intensity Raman active mode not previously observed. The dispersion curves and electronic band structure were calculated, along with their corresponding density of states. The electrical properties, as well as a pseudo-gap in the density of states around the Fermi energy are characteristics proper of a semi metal.

Biological effects of carbon nanotubes generated in forest wildfire ecosystems rich in resinous trees on native plants.

Carbon nanotubes (CNTs) have a broad range of applications and are generally considered human-engineered nanomaterials. However, carbon nanostructures have been found in ice cores and oil wells, suggesting that nature may provide appropriate conditions for CNT synthesis. During forest wildfires, materials such as turpentine and conifer tissues containing iron under high temperatures may create chemical conditions favorable for CNT generation, similar to those in synthetic methods. Here, we show evidence of naturally occurring multiwalled carbon nanotubes (MWCNTs) produced from Pinus oocarpa and Pinus pseudostrobus, following a forest wildfire. The MWCNTs showed an average of 10 walls, with internal diameters of ∼2.5 nm and outer diameters of ∼14.5 nm. To verify whether MWCNT generation during forest wildfires has a biological effect on some characteristic plant species of these ecosystems, germination and development of seedlings were conducted. Results show that the utilization of comparable synthetic MWCNTs increased seed germination rates and the development of Lupinus elegans and Eysenhardtia polystachya, two plants species found in the burned forest ecosystem. The finding provides evidence that supports the generation and possible ecological functions of MWCNTs in nature.

Solid State Sensor for Simultaneous Measurement of Total Alkalinity and pH of Seawater.

A novel design is demonstrated for a solid state, reagent-less sensor capable of rapid and simultaneous measurement of pH and Total Alkalinity (AT) using ion sensitive field effect transistor (ISFET) technology to provide a simplified means of characterization of the aqueous carbon dioxide system through measurement of two "master variables": pH and AT. ISFET-based pH sensors that achieve 0.001 precision are widely used in various oceanographic applications. A modified ISFET is demonstrated to perform a nanoliter-scale acid-base titration of AT in under 40 s. This method of measuring AT, a Coulometric Diffusion Titration, involves electrolytic generation of titrant, H+, through the electrolysis of water on the surface of the chip via a microfabricated electrode eliminating the requirement of external reagents. Characterization has been performed in seawater as well as titrating individual components (i.e., OH-, HCO3-, CO32-, B(OH)4-, PO43-) of seawater AT. The seawater measurements are consistent with the design in reaching the benchmark goal of 0.5% precision in AT over the range of seawater AT of ∼2200-2500 µmol kg-1 which demonstrates great potential for autonomous sensing.

Phylogeography and spatial structure of the lowland tapir (Tapirus terrestris, Perissodactyla: Tapiridae) in South America.

We sequenced the mitochondrial cytochrome b gene of 141 lowland tapirs (Tapirus terrestris) - representing the largest geographical distribution sample of this species studied across of South America to date. We compare our new data regard to two previous works on population structure and molecular systematics of T. terrestris. Our data agree with the Thoisy et al.'s work in (1) the Northern Western Amazon basin was the area with the highest gene diversity levels in T. terrestris, being probably the area of initial diversification; (2) there was no clear association between haplogroups and specific geographical areas; (3) there were clear population decreases during the last glacial maximum for the different haplogroups detected, followed by population expansions during the Holocene; and (4) our temporal splits among different T. terrestris haplogroups coincided with the first molecular clock approach carried out by these authors (fossil calibration). Nevertheless, our study disagreed regard to other aspects of the Thoisy et al.'s claims: (1) meanwhile, they detected four relevant clades in their data, we put forward six different relevant clades; (2) the Amazon River was not a strong barrier for haplotype dispersion in T. terrestris; and (3) we found reciprocal monophyly between T. terrestris and T. pinchaque. Additionally, we sequenced 42 individuals (T. terrestris, T. pinchaque, T. bairdii, and the alleged "new species", T. kabomani) for three concatenated mitochondrial genes (Cyt-b, COI, and COII) agreeing quite well with the view of Voss et al., and against of the claims of Cozzuol et al. Tapirus kabomani should be not considered as a full species with the results obtained throughout the mitochondrial sequences.

Quantification of endocytosis using a folate functionalized silica hollow nanoshell platform.

A quantification method to measure endocytosis was designed to assess cellular uptake and specificity of a targeting nanoparticle platform. A simple N -hydroxysuccinimide ester conjugation technique to functionalize 100-nm hollow silica nanoshell particles with fluorescent reporter fluorescein isothiocyanate and folate or polyethylene glycol (PEG) was developed. Functionalized nanoshells were characterized using scanning electron microscopy and transmission electron microscopy and the maximum amount of folate functionalized on nanoshell surfaces was quantified with UV-Vis spectroscopy. The extent of endocytosis by HeLa cervical cancer cells and human foreskin fibroblast (HFF-1) cells was investigated in vitro using fluorescence and confocal microscopy. A simple fluorescence ratio analysis was developed to quantify endocytosis versus surface adhesion. Nanoshells functionalized with folate showed enhanced endocytosis by cancer cells when compared to PEG functionalized nanoshells. Fluorescence ratio analyses showed that 95% of folate functionalized silica nanoshells which adhered to cancer cells were endocytosed, while only 27% of PEG functionalized nanoshells adhered to the cell surface and underwent endocytosis when functionalized with 200 and 900 µg , respectively. Additionally, the endocytosis of folate functionalized nanoshells proved to be cancer cell selective while sparing normal cells. The developed fluorescence ratio analysis is a simple and rapid verification/validation method to quantify cellular uptake between datasets by using an internal control for normalization.

Malfunctioning of the iron-sulfur cluster assembly machinery in Saccharomyces cerevisiae produces oxidative stress via an iron-dependent mechanism, causing dysfunction in respiratory complexes.

Biogenesis and recycling of iron-sulfur (Fe-S) clusters play important roles in the iron homeostasis mechanisms involved in mitochondrial function. In Saccharomyces cerevisiae, the Fe-S clusters are assembled into apoproteins by the iron-sulfur cluster machinery (ISC). The aim of the present study was to determine the effects of ISC gene deletion and consequent iron release under oxidative stress conditions on mitochondrial functionality in S. cerevisiae. Reactive oxygen species (ROS) generation, caused by H2O2, menadione, or ethanol, was associated with a loss of iron homeostasis and exacerbated by ISC system dysfunction. ISC mutants showed increased free Fe2+ content, exacerbated by ROS-inducers, causing an increase in ROS, which was decreased by the addition of an iron chelator. Our study suggests that the increment in free Fe2+ associated with ROS generation may have originated from mitochondria, probably Fe-S cluster proteins, under both normal and oxidative stress conditions, suggesting that Fe-S cluster anabolism is affected. Raman spectroscopy analysis and immunoblotting indicated that in mitochondria from SSQ1 and ISA1 mutants, the content of [Fe-S] centers was decreased, as was formation of Rieske protein-dependent supercomplex III2IV2, but this was not observed in the iron-deficient ATX1 and MRS4 mutants. In addition, the activity of complexes II and IV from the electron transport chain (ETC) was impaired or totally abolished in SSQ1 and ISA1 mutants. These results confirm that the ISC system plays important roles in iron homeostasis, ROS stress, and in assembly of supercomplexes III2IV2 and III2IV1, thus affecting the functionality of the respiratory chain.

Europium Doped TiO(2) Hollow Nanoshells: Two-Photon Imaging of Cell Binding.

A simple scalable method to fabricate luminescent monodisperse 200 nm europium doped hollow TiO(2) nanoshell particles is reported. Fluorophore reporter, Eu(3+) ions, are incorporated directly in the NS matrix, leaving the surface free for functionalization and the core free for payload encapsulation. Amine functionalized polystyrene beads were used as templates, and the porous walls of europium doped titania nanoshells were synthesized using titanium(IV) t-butoxide and europium(III) nitrate as reactants. X-ray diffraction analysis identified anatase as the predominant titania phase of the rigid nanoshell wall structure, and photoluminescence spectra showed that the Eu(III) doped TiO(2) nanoshells exhibited a red emission at 617 nm due to an atomic f-f transition. Nanoshell interactions with HeLa cervical cancer cells in vitro were visualized using two-photon microscopy of the Eu(III) emission, and studied using a luminescence ratio analysis to assess nanoshell adhesion and endocytosis.

Red-luminescent europium (III) doped silica nanoshells: synthesis, characterization, and their interaction with HeLa cells.

A simple method to fabricate Eu(3+) doped silica nanoshells particles with 100 and 200 nm diameters is reported. Amino polystyrene beads were used as templates, and an 8 to 10 nm thick silica gel coating was formed by the sol-gel reaction. After removing the template by calcination, porous dehydrated silica gel nanoshells of uniform size were obtained. The Eu(3+) doped silica nanoshells exhibited a red emission at 615 nm on UV excitation. The porous structure of the silica shell wall was characterized by transmission electron microscopy measurements, while particle size and zeta potentials of the particles suspended in aqueous solution were characterized by dynamic light scattering. Two-photon microscopy was used to image the nanoshells after assimilation by HeLa cancer cells.

Quantitative comparison of surgical margin histology following excision with traditional electrosurgery and a low-thermal-injury dissection device.

BACKGROUND: This study is the first to examine in vivo the effect of thermal injury in breast conservation pathology in a direct comparison of traditional electrosurgery and an alternative low-thermal-injury device. METHODS: A prospective study of 20 consecutive subjects with biopsy-proven invasive ductal carcinoma (IDC) tumors 1 cm was conducted. Following excision, incisions were made into the tumor with the two devices. Thermal injury depth, margin distance, tissue type, and histological effect were compared on the same breast tissue cut with each excision instrument. A probability evaluation of close and positive margin cases for the true tumor margins was conducted. RESULTS: Compared to traditional electrosurgery, the low-thermal-injury instrument reduced collagen denaturation depth from 435 to 102 µm (77%), fused tissue depth from 262 to 87 µm (67%), and distortion depth from 1,132 to 774 µm (30%). CONCLUSIONS: Based on analysis of the close subset of the true margins, using the traditional electrosurgical device in place of the low-thermal-injury device would have resulted in 48% of the close margin samples being negatively converted to false-positive, and in 11% converting from close to false-negative. The methodology of this work may be readily applied to larger, more definitive studies.

Quantitative automated image analysis system with automated debris filtering for the detection of breast carcinoma cells.

OBJECTIVE: To develop an intraoperative method for margin status evaluation during breast conservation therapy (BCT) using an automated analysis of imprint cytology specimens. STUDY DESIGN: Imprint cytology samples were prospectively taken from 47 patients undergoing either BCT or breast reduction surgery. Touch preparations from BCT patients were taken on cut sections through the tumor to generate positive margin controls. For breast reduction patients, slide imprints were taken at cuts through the center of excised tissue. Analysis results from the presented technique were compared against standard pathologic diagnosis. Slides were stained with cytokeratin and Hoechst, imaged with an automated fluorescent microscope, and analyzed with a fast algorithm to automate discrimination between epithelial cells and noncellular debris. RESULTS: The accuracy of the automated analysis was 95% for identifying invasive cancers compared against final pathologic diagnosis. The overall sensitivity was 87% while specificity was 100% (no false positives). This is comparable to the best reported results from manual examination of intraoperative imprint cytology slides while reducing the need for direct input from a cytopathologist. CONCLUSION: This work demonstrates a proof of concept for developing a highly accurate and automated system for the intraoperative evaluation of margin status to guide surgical decisions and lower positive margin rates.

Lanthanide(III) complexes with 4,5-bis(diphenylphosphinoyl)-1,2,3-triazolate and the use of 1,10-phenanthroline as auxiliary ligand.

New lanthanide complexes with 4,5-bis(diphenyl)phosphoranyl-1,2,3-triazolate (L(-)), LnL(3).nH(2)O (1-8) and LnL(3)(phen).nH(2)O (9-16) (Ln = La, Ce, Nd, Sm, Eu, Gd, Tb, Er), have been prepared and spectroscopically characterized. The structures of LnL(3).nH(2)O (Ln = La, Ce, Nd, Sm and Gd) were determined by X-ray crystallography. The metal centers exhibit a distorted trigonal dodecahedron coordination environment with two symmetrically O,O-bidentate ligands and one unsymmetrically O,N- ligand attached to the metal; two oxygen atoms from neighboring dimethyl sulfoxide (DMSO) molecules complete the coordination sphere. This unsymmetrical ligand coordination behavior was also identified in solution through (31)P{(1)H} NMR studies. Photoluminescence spectroscopy experiments in CH(2)Cl(2) for both types of complexes containing Eu(III) (6, 14) and Tb(III) (7, 15) exhibit strong characteristic red and green emission bands for Eu(III) and Tb(III), respectively. Furthermore, NdL(3) (phen).5H (2)O (11) displays emission in the near-infrared spectral region ((4)F(3/2) --> (4)F(9/2) at 872 nm and (4)F(3/2) --> (4)F(11/2) at 1073 nm). The complexes containing 1,10-phenantroline exhibit higher quantum yields upon excitation at 267 nm, indicating that this auxiliary ligand promotes the luminescence of the complexes; however, luminescence lifetimes (tau) in this case are shorter than those of the LnL(3).nH(2)O series.

Hard shell gas-filled contrast enhancement particles for colour Doppler ultrasound imaging of tumors.

Hollow hard shell particles of 200 nm and 2 micron diameter with a 10 nm thick porous silica shell have been synthesized using polystyrene templates and a sol-gel process. The template ensures than the hollow particles are monodispersed, while the charged silica surface ensures that they remain suspended in solution for weeks. When filled with perfluorocarbon gas, the particles behave as an efficient contrast agent for colour Doppler ultrasound imaging in human breast tissue. The silica shell provides unique properties compared to conventional soft shell particles employed as ultrasound contrast agents: uniform size control, strong adsorption to tissue and cells immobilizing particles at the tissue injection site, a long imaging lifetime, and a silica surface that can be easily modified with biotargeting ligands or small molecules to adjust the surface charge and polarity.

Automated microscopy to evaluate surgical specimens via touch prep in breast cancer.

BACKGROUND: Breast conservation therapy is the standard treatment for breast cancer; however, 20-50% of operations have a positive margin leading to secondary procedures. The standard of care to evaluate surgical margins is based on permanent section. Imprint cytology (touch prep) has been used to evaluate surgical samples, but conventional techniques require an experienced cytopathologist for correct interpretation. An automated image screening process has been developed to discern cancer cells from normal epithelial cells. This technique is based on cellularity of the imprint specimen and does not require expertise in cytopathology. METHODS: A rapid immunofluorescent staining technique coupled with automated microscopy was used to classify specimens as cancer vs. noncancer based on the density of epithelial cells captured on touch prep of tumor cross-sections. The results of the automated analysis vs. a manual screen of ten 20x fields were compared to the pathology interpretation on permanent section. RESULTS: A total of 34 consecutive cases were analyzed: 10 normal cases, and 24 cancer cases. The cross-section specimens for invasive cancer were correctly classified in at least 65% of the cases by using manual microscopy and at least 83% by using automated microscopy. The manual and automated microscopy correlated well for measurements of epithelial cell density (R(2)=0.64); however, the automated microscopy was more accurate. CONCLUSIONS: This preliminary study using an automated system for intraoperative interpretation does not require a cytopathologist and shows that rapid, low-resolution imaging can correctly identify cancer cells for invasive carcinoma in surgical specimens. Therefore, automated determination of cellularity in touch prep is a promising technique for future margin interpretation of breast conservation therapy.

Enhanced touch preps improve the ease of interpretation of intraoperative breast cancer margins.

Positive margins and the resulting multiple operations are a major problem for breast conservation therapy. Accurate assessment of intraoperative tumor margins can limit multiple re-excision procedures. Intraoperative touch preparations have been used in the past but can be difficult to interpret without an experienced cytopathologist. The objective of this study is to examine the reliability of enhanced intraoperative touch preps (EIOTP) compared with final pathologic margins. We prospectively performed EIOTP on 20 tumors in women undergoing breast conservation therapy. Six margins and the main tumor were touched onto poly-L-lysine coated slides. The slides were stained with anti MUC1 and anti-E-cadherin antibodies, and Hoechst nuclear stain. A parallel set of slides were stained with hematoxylin and eosin for comparison. The EIOTP results were compared with pathologic interpretation of paraffin embedded permanent sections. A total of 120 margins underwent EIOTP in 20 patients. We found a sensitivity equal to 80 per cent, specificity 100 per cent, positive predictive value 100 per cent, and negative predictive value 99 per cent. EIOTP in conjunction with MUC-1 and E-cadherin by immunofluorescence is a sensitive and highly specific mechanism to identify cancer cells at breast tissue margins. The immunofluorescence stains may help the pathologist to identify cancer cells in fresh breast tissue and limit breast re-excisions in the future.