Green synthesis of nanostructured silver particles and their catalytic application in dye degradation

Today, discharge of hazardous dyes from textile industries in water bodies like lakes, rivers and groundwater has become a serious problem, which contributes to increase their pollution levels significantly. These pollutants are difficult to remove by traditional water treatment procedures. Thus, there is a need to develop more suitable methods of effluent treatment. Here, we describe use of green-synthesized nanostructured silver particles in degradation of hazardous dyes like Safranine O, Methyl red, Methyl orange and Methylene blue etc. The silver nanoparticles (AgNPs) used as nanocatalysts were synthesized using Zanthoxylum armatum leaves. The reduction of silver ions and the formation of AgNPs have been assessed by UV–Vis spectroscopy. DLS, SEM–EDX, TEM, SAED and XRD studies revealed that the AgNPs were crystalline in nature with size range from 15 to 50 nm. The report emphasizes that the AgNPs are observed to be an excellent catalyst on reduction of hazardous dyes, which is confirmed by a decrease in absorbance maximum values.

Nanoscale analysis of clustered DNA damage after high-LET irradiation by quantitative electron microscopy--the heavy burden to repair

Low- and high-linear energy transfer (LET) ionising radiation are effective cancer therapies, but produce structurally different forms of DNA damage. Isolated DNA damage is repaired efficiently; however, clustered lesions may be more difficult to repair, and are considered as significant biological endpoints. We investigated the formation and repair of DNA double-strand breaks (DSBs) and clustered lesions in human fibroblasts after exposure to sparsely (low-LET; delivered by photons) and densely (high-LET; delivered by carbon ions) ionising radiation. DNA repair factors (pKu70, 53BP1, γH2AX, and pXRCC1) were detected using immunogold-labelling and electron microscopy, and spatiotemporal DNA damage patterns were analysed within the nuclear ultrastructure at the nanoscale level. By labelling activated Ku-heterodimers (pKu70) the number of DSBs was determined in electron-lucent euchromatin and electron-dense heterochromatin. Directly after low-LET exposure (5 min post-irradiation), single pKu70 dimers, which reflect isolated DSBs, were randomly distributed throughout the entire nucleus with a linear dose correlation up to 30 Gy. Most euchromatic DSBs were sensed and repaired within 40 min, whereas heterochromatic DSBs were processed with slower kinetics. Essentially all DNA lesions induced by low-LET irradiation were efficiently rejoined within 24h post-irradiation. High-LET irradiation caused localised energy deposition within the particle tracks, and generated highly clustered DNA lesions with multiple DSBs in close proximity. The dimensions of these clustered lesions along the particle trajectories depended on the chromatin packing density, with huge DSB clusters predominantly localised in condensed heterochromatin. High-LET irradiation-induced clearly higher DSB yields than low-LET irradiation, with up to ∼ 500 DSBs per μm(3) track volume, and large fractions of these heterochromatic DSBs remained unrepaired. Hence, the spacing and quantity of DSBs in clustered lesions influence DNA repair efficiency, and may determine the radiobiological outcome.

Scanning electron microscope measurement of width and shape of 10nm patterned lines using a JMONSEL-modeled library

The width and shape of 10nm to 12 nm wide lithographically patterned SiO2 lines were measured in the scanning electron microscope by fitting the measured intensity vs. position to a physics-based model in which the lines' widths and shapes are parameters. The approximately 32 nm pitch sample was patterned at Intel using a state-of-the-art pitch quartering process. Their narrow widths and asymmetrical shapes are representative of near-future generation transistor gates. These pose a challenge: the narrowness because electrons landing near one edge may scatter out of the other, so that the intensity profile at each edge becomes width-dependent, and the asymmetry because the shape requires more parameters to describe and measure. Modeling was performed by JMONSEL (Java Monte Carlo Simulation of Secondary Electrons), which produces a predicted yield vs. position for a given sample shape and composition. The simulator produces a library of predicted profiles for varying sample geometry. Shape parameter values are adjusted until interpolation of the library with those values best matches the measured image. Profiles thereby determined agreed with those determined by transmission electron microscopy and critical dimension small-angle x-ray scattering to better than 1 nm.

Two major cuticular proteins are required for assembly of horizontal laminae and vertical pore canals in rigid cuticle of Tribolium castaneum

The insect exoskeleton is composed of cuticle primarily formed from structural cuticular proteins (CPs) and the polysaccharide chitin. Two CPs, TcCPR27 and TcCPR18, are major proteins present in the elytron (highly sclerotized and pigmented modified forewing) as well as the pronotum (dorsal sclerite of the prothorax) and ventral abdominal cuticle of the red flour beetle, Tribolium castaneum. Both CPs belong to the CPR family, which includes proteins that have an amino acid sequence motif known as the Rebers & Riddiford (R&R) consensus sequence. Injection of double-stranded RNA (dsRNA) for TcCPR27 and TcCPR18 resulted in insects with shorter, wrinkled, warped and less rigid elytra than those from control insects. To gain a more comprehensive understanding of the roles of CPs in cuticle assembly, we analyzed for the precise localization of TcCPR27 and the ultrastructural architecture of cuticle in TcCPR27- and TcCPR18-deficient elytra. Transmission electron microscopic analysis combined with immunodetection using gold-labeled secondary antibody revealed that TcCPR27 is present in dorsal elytral procuticle both in the horizontal laminae and in vertical pore canals. dsRNA-mediated RNA interference (RNAi) of TcCPR27 resulted in abnormal electron-lucent laminae and pore canals in elytra except for the boundary between these two structures in which electron-dense molecule(s) apparently accumulated. Insects subjected to RNAi for TcCPR18 also had disorganized laminae and pore canals in the procuticle of elytra. Similar ultrastructural defects were also observed in other body wall regions with rigid cuticle such as the thorax and legs of adult T. castaneum. TcCPR27 and TcCPR18 are required for proper formation of the horizontal chitinous laminae and vertical pore canals that are critical for formation and stabilization of rigid adult cuticle.

Antibacterial, antibiofilm and cytotoxic effects of Nigella sativa essential oil coated gold nanoparticles

This study reports the biological synthesis of gold nanoparticles using essential oil of Nigella sativa (NsEO-AuNPs). The synthesized NsEO-AuNPs were characterized by UV-visible spectra, X-ray diffraction (XRD), FTIR and Transmission electron microscopy (TEM). UV-vis spectra of NsEO-AuNPs showed strong absorption peak at 540 nm. The X-ray diffraction analysis revealed crystalline nature of nanoparticle with distinctive facets (111, 200, 220 and 311 planes) of NsEO-AuNPs. The FTIR spectra recorded peaks at 3388, 2842, 1685, 1607, 1391 and 1018 cm(-1). TEM studies showed the spherical shape of nanoparticles and the particle size ranges between 15.6 and 28.4 nm. The antibacterial activity of NsEO-AuNPs was greater against Gram positive Staphylococcus aureus MTCC 9542 (16 mm) than Gram negative Vibrio harveyi MTCC 7771 (5 mm) at the concentration of 10 μg ml(-1). NsEO-AuNPs effectively inhibited the biofilm formation of S. aureus and V. harveyi by decreasing the hydrophobicity index (78% and 46% respectively). The in-vitro anti-lung cancer activity confirmed by MTT assay on the cell line of A549 carcinoma cells showed IC50 values of bulk Au at 87.2 μg ml(-1), N. sativa essential oil at 64.15 μg ml(-1) and NsEO-AuNPs at 28.37 μg ml(-1). The IC50 value showed that NsEO-AuNPs was highly effective in inhibiting the A549 lung cancer cells compared to bulk Au and N. sativa essential oil.

Imaging and Quantification of Extracellular Vesicles by Transmission Electron Microscopy

Extracellular vesicles (EVs) are cell-derived vesicles that are present in blood and other body fluids. EVs raise major interest for their diverse physiopathological roles and their potential biomedical applications. However, the characterization and quantification of EVs constitute major challenges, mainly due to their small size and the lack of methods adapted for their study. Electron microscopy has made significant contributions to the EV field since their initial discovery. Here, we describe the use of two transmission electron microscopy (TEM) techniques for imaging and quantifying EVs. Cryo-TEM combined with receptor-specific gold labeling is applied to reveal the morphology, size, and phenotype of EVs, while their enumeration is achieved after high-speed sedimentation on EM grids.

Local strain evolution due to athermal γ→ε martensitic transformation in biomedical CoCrMo alloys

Locally developed strains caused by athermal γ face-centered cubic (fcc)→ε hexagonal close-packed (hcp) martensitic transformation were investigated for the γ matrix of Ni-free Co-29Cr-6Mo (wt%) alloys prepared with or without added nitrogen. Electron-backscatter-diffraction-(EBSD)-based strain analysis revealed that in addition to ε-martensite interiors, the N-free alloy that had a duplex microstructure consisting of the γ matrix and athermal ε-martensite plates showed larger magnitudes of both elastic and plastic strains in the γ phase matrix than the N-doped counterpart that did not have a ε-martensite phase. Transmission electron microscopy (TEM) results indicated that the ε-martensite microplates were aggregates of thin ε-layers, which were formed by three different {111}γ〈112¯〉γ Shockley partial dislocations in accordance with a previously proposed mechanism (Putaux and Chevalier, 1996) that canceled the shear strains of the individual variants. The plastic strains are believed to have originated from the martensitic transformation itself, and the activity of dislocations is believed to be the origin of the transformation. We have revealed that the elastic strains in the γ matrix originate from interactions among the ε-martensite phase, extended dislocations, and/or thin ε-layers. The dislocations highly dissociated into stacking faults, making stress relaxation at intersections difficult and further introducing local strain evolution.

Bacterial-mediated synthesis of silver nanoparticles and their significant effect against pathogens

Silver nanoparticles are potent antimicrobials and could be used as a promising alternative of conventional antibiotics. The aim of this study was to isolate bacteria from soil that have ability to produce AgNPs by secondary metabolite activity and their elucidation against human pathogens. These strains Escherichia coli, Exiguobacterium aurantiacumm, and Brevundimonas diminuta with NCBI accession number MF754138, MF754139, and MF754140 respectively were grown for secondary metabolite production. The nanoparticles were confirmed and characterized by UV-Vis spectroscopy and transmission electron microscopy. The optimization study was also carried out to obtain the maximum production of silver nanoparticles. Three parameters, temperature, pH, and AgNO3 concentration, were used to optimize the production of silver nanoparticles. Antimicrobial potential of these nanoparticles was addressed on the Muller-Hinton Agar, and their zones of inhibitions were measured. TEM analysis revealed the size and shape of the silver nanoparticles. All types of AgNPs were spherical in shape; their size range is from 5 to 50 nm. The findings of optimization study showed the maximum production of silver nanoparticles at the pH 9, temperature 37 °C, and 1 mM AgNO3 concentration. All the strains exhibited the great potential as antimicrobial agents against MRSA and several other MDR bacteria with minimum 10 mm to maximum 28 mm zone of inhibition. It was concluded that the present study is an eco-friendly approach for the synthesis of AgNPs that will be beneficial to control the nosocomial infections triggered by MRSA and other human pathogens.

Poly-3-hydroxybutyrate (PHB) production from alkylphenols, mono and poly-aromatic hydrocarbons using Bacillus sp. CYR1: A new strategy for wealth from waste

In the present study five different types of alkylphenols, each of the two different types of mono and poly-aromatic hydrocarbons were selected for degradation, and conversion into poly-3-hydroxybutyrate (PHB) using the Bacillus sp. CYR1. Strain CYR1 showed growth with various toxic organic compounds. Degradation pattern of all the organic compounds at 100 mg/l concentration with or without addition of tween-80 were analyzed using high pressure liquid chromatography (HPLC). Strain CYR1 showed good removal of compounds in the presence of tween-80 within 3 days, but it took 6 days without addition of tween-80. Strain CYR1 showed highest PHB production with phenol (51 ± 5%), naphthalene (42 ± 4%), 4-chlorophenol (32 ± 3%) and 4-nonylphenol (29 ± 3%). The functional groups, structure, and thermal properties of the produced PHB were analyzed. These results denoted that the strain Bacillus sp. CYR1 can be used for conversion of different toxic compounds persistent in wastewaters into useable biological polyesters.

Extraordinary high strength Ti-Zr-Ta alloys through nanoscaled, dual-cubic spinodal reinforcement

While titanium alloys represent the current state-of-the-art for orthopedic biomaterials, concerns still remain over their modulus. Circumventing this via increased porosity requires high elastic admissible strains, yet also limits traditional thermomechanical strengthening techniques. To this end, a novel β-type Ti-Zr-Ta alloy system, comprised of Ti-45Zr-10Ta, Ti-40Zr-14Ta, Ti-35Zr-18Ta and Ti-30Zr-22Ta, was designed and characterized mechanically and microstructurally. As-cast, this system displayed extremely high yield strengths and elastic admissible strains, up to 1.4GPa and potentially 1.48%, respectively. This strength was attributed to a nanoscaled, cuboidal structure of semi-coherent, dual body-centered cubic (BCC) phases, arising from the thermodynamics of interaction between Ta and Zr; this morphology occurring with dual BCC-phases is heretofore unreported in Ti-based alloys. Further, cell proliferation investigated by MTS assay suggests this was achieved without sacrificing biocompatibility, with no significant difference to either empty-well or commercially-pure Ti controls noted.

STATEMENT OF SIGNIFICANCE

The current research details microstructural, mechanical, and biological investigations into four novel biomedical alloys in a hitherto uninvestigated region of the Ti-Zr-Ta alloy system; Ti-45Zr-10Ta, Ti-40Zr-14Ta, Ti-35Zr-18Ta and Ti-30Zr-22Ta. We find that the investigated alloys display 0.2% yield strengths of up to 1.40GPa and elastic admissible strains of up to 1.48%, along with biological properties comparable to that seen in the conventional metallic biomaterial ASTM Grade-2 CP-Ti, achieved in the complete absence of traditional thermomechanical processing techniques. This is attributed to the presence of a dual-BCC cuboidal nanostructure, achieved via spinodal decomposition; while similar structures have been reported in e.g. Ni-based superalloys, we believe this is the first such structure investigated in a Ti-based material. As such, this work is felt to be of great interest in aiding the design and manufacture of highly-biocompatible, porous, metallic biomaterials for orthopedic application.

Clustered DNA damage concentrated in particle trajectories causes persistent large-scale rearrangements in chromatin architecture

BACKGROUND AND PURPOSE

High linear-energy-transfer (LET) irradiation (IR) is characterized by unique depth-dose distribution and advantageous biologic effectiveness compared to low-LET-IR, offering promising alternatives for radio-resistant tumors in clinical oncology. While low-LET-IR induces single DNA lesions such as double-strand breaks (DSBs), localized energy deposition along high-LET particle trajectories induces clustered DNA lesions that are more challenging to repair. During DNA damage response (DDR) 53BP1 and ATM are required for Kap1-dependent chromatin relaxation, thereby sustaining heterochromatic DSB repair. Here, spatiotemporal dynamics of chromatin restructuring were visualized during DDR after high-LET and low-LET-IR.

MATERIAL AND METHODS

Human fibroblasts were irradiated with high-LET carbon/calcium ions or low-LET photons. At 0.1 h, 0.5 h, 5 h and 24 h post-IR fluorophore- and gold-labeled repair factors (53BP1, pATM, pKAP-1, pKu70) were visualized by immunofluorescence and transmission electron microscopy, to monitor formation and repair of DNA damage in chromatin ultrastructure. To track chromatin remodeling at damage sites, decondensed regions (DCR) were delineated based on local chromatin concentration densities.

RESULTS

Low-LET-IR induced single DNA lesions throughout the nucleus, but nearly all DSBs were efficiently rejoined without visible chromatin decompaction. High-LET-IR induced clustered DNA damage and triggered profound changes in chromatin structure along particle trajectories. In DCR multiple heterochromatic DSBs exhibited delayed repair despite cooperative activity of 53BP1, pATM, pKap-1. These closely localized DSBs may disturb efficient repair and subsequent chromatin restoration, thereby affecting large-scale genome organization.

CONCLUSION

Clustered damage concentrated in particle trajectories causes persistent rearrangements in chromatin architecture, which may affect structural and functional organization of cell nuclei.

Ultrastructural Characteristics of DHA-Induced Pyroptosis

Microglial cells are resident macrophages of the central nervous system (CNS) that respond to bioactive lipids such as docosahexaenoic acid (DHA). Low micromolar concentrations of DHA typically promote anti-inflammatory functions of microglia, but higher concentrations result in a form of pro-inflammatory programmed cell death known as pyroptosis. This study used scanning electron microscopy (SEM) and transmission electron microscopy (TEM) to investigate the morphological characteristics of pyroptosis in BV-2 microglial cells following exposure to 200 µM DHA. Vehicle-treated cells are characterized by extended processes, spine-like projections or 0.4 to 5.2 µm in length, and numerous extracellular vesicles (EVs) tethered to the surface of the plasma membrane. In contrast to vehicle-treated cells, gross abnormalities are observed after treating cells with 200 µM DHA for 4 h. These include the appearance of numerous pits or pores of varying sizes across the cell surface, structural collapse and flattening of the cell shape. Moreover, EVs and spines were lost following DHA treatment, possibly due to release from the cell surface. The membrane pores appear after DHA treatment initially measured ~ 30 nm, consistent with the previously reported gasdermin D (GSDMD) pore complexes. Complete collapse of cytoplasmic organization and loss of nuclear envelope integrity were also observed in DHA-treated cells. These processes are morphologically distinct from the changes that occur during cisplatin-induced apoptosis, such as the appearance of apoptotic bodies and tightly packed organelles, and the maintenance of EVs and nuclear envelope integrity. Cumulatively, this study provides a systematic description of the ultrastructural characteristics of DHA-induced pyroptosis, including distinguishing features that differentiate this process from apoptosis.

Development and ultrastructure of the rigid dorsal and flexible ventral cuticles of the elytron of the red flour beetle, Tribolium castaneum

Insect exoskeletons are composed of the cuticle, a biomaterial primarily formed from the linear and relatively rigid polysaccharide, chitin, and structural proteins. This extracellular material serves both as a skin and skeleton, protecting insects from environmental stresses and mechanical damage. Despite its rather limited compositional palette, cuticles in different anatomical regions or developmental stages exhibit remarkably diverse physicochemical and mechanical properties because of differences in chemical composition, molecular interactions and morphological architecture of the various layers and sublayers throughout the cuticle including the envelope, epicuticle and procuticle (exocuticle and endocuticle). Even though the ultrastructure of the arthropod cuticle has been studied rather extensively, its temporal developmental pattern, in particular, the synchronous development of the functional layers in different cuticles during a molt, is not well understood. The beetle elytron, which is a highly modified and sclerotized forewing, offers excellent advantages for such a study because it can be easily isolated at precise time points during development. In this study, we describe the morphogenesis of the dorsal and ventral cuticles of the elytron of the red flour beetle, Tribolium castaneum, during the period from the 0 d-old pupa to the 9 d-old adult. The deposition of exocuticle and mesocuticle is substantially different in the two cuticles. The dorsal cuticle is four-fold thicker than the ventral. Unlike the ventral cuticle, the dorsal contains a thicker exocuticle consisting of a large number of horizontal laminae and vertical pore canals with pore canal fibers and rib-like veins and bristles as well as a mesocuticle, lying right above the enodcuticle. The degree of sclerotization appears to be much greater in the dorsal cuticle. All of these differences result in a relatively thick and tanned rigid dorsal cuticle and a much thinner and less pigmented membrane-like ventral cuticle.

Synthesis, characterization and evaluation cytotoxic activity of silver nanoparticles synthesized by Chinese herbal Cornus officinalis via environment friendly approach

Cornus officinalis has been widely used as a precious herb and as the tonic food to improve kidney function in China. Its fruits have been used in many traditional Chinese medicine prescriptions to treat kidney diseases, diabetes, cancer and shock. In this study, a new eco-friendly approach for green synthesis of silver nanoparticles (AgNPs) by using the fruits of Cornus officinalis aqueous extract as a reducing and stabilizing agent. The so-synthesized AgNPs showed quasi-spherical in shape with uniform dispersal and an average mean size of 11.7nm. Water soluble biomolecules such as flavonoids and/or anthocyanins from the extract played important roles in the nanoparticles formation. The AgNPs displayed distinctive cytotoxicity activities against human prostate cancer (PC-3) and human liver cancer (HepG2) cell lines. The results provided a low cost, nontoxic and eco-friendly approach for synthesizing metal nanoparticles to explore alternative anticancer agents on the way fighting against cancer in future.

Investigating mitochondrial autophagy by routine transmission electron microscopy: Seeing is believing?

Mitochondrial autophagy is affected in many diseases. In the past few years, the multiple-steps process of selective degradation of mitochondria has been dissected in details by combining outcomes from different approaches. Perhaps one of the most rigorous methods to clearly visualise mitochondria undergoing autophagic engulfment and degradation, is transmission electron microscopy (TEM). In this opinion paper, we want to give a brief summary of the mitophagic process, and by which means mitophagy can be addressed, including TEM analysis. We will report examples of autophagy and mitophagy-related TEM images, and discuss how to decipher the different steps of the mitophagic process by routine TEM. In our opinion, this technique can be used as a powerful confirmatory approach for mitochondrial autophagy and can provide details of the organelle fate throughout the course of mitophagy with no substantial sample manipulation.

Rapid separation of blood plasma exosomes from low-density lipoproteins via a hydrophobic interaction chromatography method on a polyester capillary-channeled polymer fiber phase

Exosomes are membrane-bound, cell-secreted vesicles, with sizes ranging from 30 to 150 nm. Exosomes in blood plasma have become proposed targets as measurable indicators of disease conditions. Current methods for plasma-based exosome isolation are time-consuming, complex, and have high operational costs. One of the most commonly reported shortcomings of current isolation protocols is the co-extraction of lipoproteins (e.g. low-density lipoproteins, LDLs) with the target exosomes. This report describes the use of a rapid, single-operation hydrophobic interaction chromatography (HIC) procedure on a polyester (PET) capillary-channeled polymer (C-CP) fiber column, demonstrating the ability to efficiently purify exosomes. The method has previously been demonstrated for isolation of exosomes from diverse biological matrices, but questions were raised about the potential co-elution of LDLs. In the method described herein, a step-gradient procedure sequentially elutes spiked lipoproteins and blood plasma-originating exosomes in 10 min, with the LDLs excluded from the desired exosome fraction. Mass spectrometry (MS) was used to characterize an impurity in the primary LDL material, identifying the presence of exosomal material. Transmission electron microscopy (TEM) and an enzyme-linked immunosorbent assay (ELISA) were used to identify the various elution components. The method serves both as a rapid means of high purity exosome isolation as well as a screening tool for the purity of LDL samples with respect to extracellular vesicles.

Experimental modulation and computational model of nano-hydrophobicity

We demonstrate that nano-hydrophobicity, which governs the biological aggressiveness of nanoparticles, is determined by the outermost regions of surface ligands. We have also successfully modulated nano-hydrophobicity using systematic surface ligand modifications and built the first computational model of nano-hydrophobicity.

Diethyldithiocarbamate enhanced chemical generation of volatile palladium species, their characterization by AAS, ICP-MS, TEM and DART-MS and proposed mechanism of action

Comprehensive investigation of chemical generation of volatile species (VSG) of palladium for detection by analytical atomic and mass spectrometry and, specifically, the mechanistic aspects of their formation and tentative identification are presented. VSG was achieved in a flow injection mode using a generator that permitted rapid mixing of acidified sample with NaBH₄ reductant. Atomization in a diffusion flame with detection by atomic absorption spectrometry was exclusively used for optimization of generation conditions while inductively coupled plasma mass spectrometry was utilized to investigate overall system efficiency and analytical metrics of the VSG system for potential ultratrace analysis. Sodium diethyldithiocarbamate (DDTC) served as a crucial reaction modifier, enhancing overall system efficiency 9-fold. Combinations of modifiers, Triton X-100 and Antifoam B surfactants provided a synergistic effect to yield a further 2-fold enhancement of VSG. The overall system efficiency was in the range 16-22%, with higher efficiencies correlating with higher Pd concentrations. The contribution of co-generated aerosol to the overall system efficiency, determined by means of concurrent measurement of added Cs, was negligible - less than 0.1%. The nature of the volatile species was investigated using several approaches, but principally by transmission electron microscopy (TEM) after their collection on a grid, and by direct analysis in real time (DART) using high resolution orbitrap mass spectrometry. These experiments suggest a parallel but dual-route mechanism of VSG of Pd, one attributed to generation of a volatile DDTC chelate of Pd and a second to nanoparticle formation.

Synthesis, characterization and antitumoral activity of new cobalt(II)complexes: Effect of the ligand isomerism on the biological activity of the complexes

The synthesis, physico-chemical characterization and cytotoxicity against five human tumoral cell lines (THP-1, U937, Molt-4, Colo205 and H460) of three new cobalt(II) coordination compounds are reported (i.e. Co(HL1)Cl (1), Co(HL2)Cl (2) and [Co(HL3)Cl]0.0.5 (CH3)2CHOH (3)). H2L2 (2-{[[2-hydroxy-3-(1-naphthyloxy)propyl](pyridin-2-ylmethyl)amino]methyl}phenol) and H2L3 (2-{[[2-hydroxy-3-(2-naphthyloxy)propyl](pyridin-2-ylmethyl)amino]methyl}phenol) present α and β-naphthyl groups respectively, which is absent in H2L1 (N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)[(3-chloro)(2-hydroxy)]propylamine. These compounds were characterized by a range of physico-chemical methods. X-ray diffraction studies were performed for complex (3), indicating the formation of a mononuclear complex. Complexes (2) and (3), which contain α and β-naphthyl groups respectively, have presented lower IC50 values than those exhibited by complex (1). Complex (3) presents IC50 values lower than cisplatin against Colo205 (90 and 196μmolL(-1), respectively) and H460 (147 and 197μmolL(-1), respectively). These human neoplastic cells under investigation were also more susceptible toward complex (3) than peripheral blood mononuclear cells. Transmission electron microscopy investigations are in agreement with the loss of mitochondrial membrane potential (ΔΨm) observed by JC-1 mitochondrial potential sensor and indicate that the activity of complex (3) against leukemic cell line (U937) is mediated by an apoptotic mechanism associated with mitochondrial dysfunction (intrinsic pathway).

Effects of activated carbon ageing in three PCB contaminated sediments: Sorption efficiency and secondary effects on Lumbriculus variegatus

The sorption efficiency and possible secondary effects of activated carbon (AC) (ø 63-200 μm) was studied with Lumbriculus variegatus in three PCB contaminated sediments applying long AC-sediment contact time (3 years). AC amendment efficiently reduced PCB bioavailability as determined with both, L. variegatus bioaccumulation test and passive samplers. However, dose related secondary effects of AC on egestion rate and biomass were observed (applied doses 0.25% and 2.5% sediment dry weight). The sorption capacity and secondary effects remained similar when the experiments were repeated after three years of AC-sediment contact time. Further, transmission electron microscopy (TEM) samples revealed morphological changes in the L. variegatus gut wall microvilli layer. Sediment properties affected both sorption efficiency and secondary effects, but 2.5% AC addition had significant effects regardless of the sediment. In, conclusion, AC is an efficient and stable sorbent to decrease the bioavailability of PCBs. However, sediment dwelling organisms, such as Oligochaete worms in this study, may be sensitive to the carbon amendments. The secondary effects and possible morphological changes in benthic organisms should not be overlooked as in many cases they form the basis of the aquatic food webs.

Assessment of nanoscopic dynamic mechanical properties and B-C-N triad effect on MWCNT/h-BNNP nanofillers reinforced HDPE hybrid composite using oscillatory nanoindentation: An insight into medical applications

A thrust on improvement of different properties of polymer has taken a contemporary route with advent of nanofillers. Although several nanofillers are existent; MultiWalled Carbon Nanotubes- (MWCNTs) and h-Boron Nitride nanoplatelets-(h-BNNPs) unique combination of 1D and 2D dimensional geometry aids an advantage of B-C-N triad elemental effects on properties of tested samples. The current study aims to investigate the effects of MWCNT and h-BNNP reinforcement in High Density Polyethylene (HDPE) for high load bearing areas of medical applications requiring both elastic and viscous behavior. The results were analyzed keeping a view of its application in areas like HDPE based fracture fixation plates, acetabular cups and others. The composite and hybrid samples with different loadings were prepared after surface modification of nanofillers by mechanical mixing and molding technique. The dynamic nano-mechanical properties like storage modulus, loss modulus and tan delta were assessed for each sample during frequency swept from 10 to 220 Hz. The viscoelastic properties like h_c/h_m, H/E, elastic-plastic deformation were investigated and evaluated. At a frequency of 10 Hz, the storage and loss modulus of 0.1 CNT increased by 37.56% and decreased by 23.52% respectively on comparison with pure HDPE. This infers a good elastic as well as viscous behavior. Overall elastic behavior of 0.1 CNT was confirmed from tan delta evaluation. The interaction between B-C-N elemental triad had significant effect on creep strength, visco-damping property (h_c/h_m and H/E), elastic plastic displacement and pile-up and sink-in behavior. Highest creep strength and visco-damping property was exhibited by 0.25 CNT/0.15 BNNP hybrid. The elastic-plastic displacement of hybrid composite was noted as least, which decreased by 30% on comparison with pure HDPE. It can be inferred that presence of 1D-MWCNT and 2D-h-BNNP had significant effect on important dynamic viscoelastic and creep properties of HDPE based hybrid composites.

Characterizing the structure of styrene-maleic acid copolymer-lipid nanoparticles (SMALPs) using RAFT polymerization for membrane protein spectroscopic studies

Membrane proteins play an important role in maintaining the structure and physiology of an organism. Despite their significance, spectroscopic studies involving membrane proteins remain challenging due to the difficulties in mimicking their native lipid bilayer environment. Membrane mimetic systems such as detergent micelles, liposomes, bicelles, nanodiscs, lipodisqs have improved the solubility and folding properties of the membrane proteins for structural studies, however, each mimetic system suffers from its own limitations. In this study, using three different lipid environments, vesicles were titrated with styrene-maleic acid (StMA) copolymer leading to a homogeneous SMALP system (∼10 nm) at a weight ratio of 1:1.5 (vesicle: StMA solution). A combination of Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM) was used to characterize these SMALPs. We used a controlled synthesis mechanism to synthesize StMA based block copolymers called reversible addition-fragmentation chain transfer polymerization (RAFT) SMALPs. Incorporation of the Voltage Sensor Domain of KCNQ1 (Q1-VSD) into RAFT SMALPs indicates that this is a promising application of this system to study membrane proteins using different biophysical techniques. V165C in Q1-VSD corresponding to the hydrophobic region was incorporated into the SMALP system. Continuous Wave-Electron Paramagnetic Resonance (CW-EPR) line shape analysis showed line shape broadening, exposing a lower rigid component and a faster component of the spin label.

A correlative approach to segmenting phases and ferrite morphologies in transformation-induced plasticity steel using electron back-scattering diffraction and energy dispersive X-ray spectroscopy

Using a combination of electron back-scattering diffraction and energy dispersive X-ray spectroscopy data, a segmentation procedure was developed to comprehensively distinguish austenite, martensite, polygonal ferrite, ferrite in granular bainite and bainitic ferrite laths in a thermo-mechanically processed low-Si, high-Al transformation-induced plasticity steel. The efficacy of the ferrite morphologies segmentation procedure was verified by transmission electron microscopy. The variation in carbon content between the ferrite in granular bainite and bainitic ferrite laths was explained on the basis of carbon partitioning during their growth.

Single particle aerosol mass spectrometry of coal combustion particles associated with high lung cancer rates in Xuanwei and Fuyuan, China

Coal combustion particles (CCPs) are linked to the high incidence of lung cancer in Xuanwei and in Fuyuan, China, but studies on the chemical composition of the CCPs are still limited. Single particle aerosol mass spectrometry (SPAMS) was recently developed to measure the chemical composition and size of single particles in real-time. In this study, SPAMS was used to measure individual combustion particles emitted from Xuanwei and Fuyuan coal samples and the results were compared with those by ICP-MS and transmission electron microscopy (TEM). The total of 38,372 particles mass-analyzed by SPAMS can be divided into 9 groups based on their chemical composition and their number percentages: carbonaceous, Na-rich, K-rich, Al-rich, Fe-rich, Si-rich, Ca-rich, heavy metal-bearing, and PAH-bearing particles. The carbonaceous and PAH-bearing particles are enriched in the size range below 0.56 μm, Fe-bearing particles range from 0.56 to 1.0 μm in size, and heavy metals such as Ti, V, Cr, Cu, Zn, and Pb have diameters below 1 μm. The TEM results show that the particles from Xuanwei and Fuyuan coal combustion can be classified into soot aggregates, Fe-rich particles, heavy metal containing particles, and mineral particles. Non-volatile particles detected by SPAMS could also be observed with TEM. The number percentages by SPAMS also correlate with the mass concentrations measured by ICP-MS. Our results could provide valuable insight for understanding high lung cancer incidence in the area.

Decorin regulates collagen fibrillogenesis during corneal wound healing in mouse in vivo

A characteristic rigid spatial arrangement of collagen fibrils in the stroma is critical for corneal transparency. This unique organization of collagen fibrils in corneal stroma can be impacted by the presence and interactions of proteoglycans and extracellular matrix (ECM) proteins in a corneal microenvironment. Earlier studies revealed that decorin, a leucine-rich proteoglycan in stroma, regulates keratocyte-collagen matrix assembly and wound healing in the cornea. This study investigated the role of decorin in the regulation of stromal fibrillogenesis and corneal transparency in vivo employing a loss-of-function genetic approach using decorin null (dcn^-/-) and wild type (dcn^+/+) mice and a standard alkali-injury model. A time-dependent ocular examinations with Slit lamp microscope in live animals assessed corneal clarity, haze, and neovascularization levels in normal and injured eyes. Morphometric changes in normal and injured dcn^+/+ and dcn^-/- corneas, post-euthanasia, were analyzed with Masson's Trichrome and Periodic Acid-Schiff (PAS) histology evaluations. The ultrastructure changes in all corneas were investigated with transmission electron microscopy (TEM). Injury to eye produced clinically relevant corneal haze and neovascularization in dcn^-/- and dcn^+/+ mice while corneas of uninjured eyes remained clear and avascular. A clinically significant haze and neovascularization appeared in injured dcn^-/- corneas compared to the dcn^+/+ corneas at day 21 post-injury and not at early tested times. Histological examinations revealed noticeably abnormal morphology and compromised collagen levels in injured dcn^-/- corneas compared to the injured/normal dcn^+/+ and uninjured dcn^-/- corneas. TEM analysis exhibited remarkably uneven collagen fibrils size and distribution in the stroma with asymmetrical organization and loose packing in injured dcn^-/- corneas than injured/normal dcn^+/+ and uninjured dcn^-/- corneas. The minimum and maximum inter-fibril distances were markedly irregular in injured dcn^-/- corneas compared to all other corneas. Together, results of clinical, histological, and ultrastructural investigations in a genetic knockout model suggested that decorin influenced stromal fibrillogenesis and transparency in healing cornea.