Laser Patterning of Aligned Carbon Nanotubes Arrays: Morphology,Surface Structure,and Interaction with Terahertz Radiation

The patterning of arrays of aligned multi-walled carbon nanotubes (MWCNTs) allows creating metastructures for terahertz (THz) applications. Here, the strips and columns from MWCNTs vertically grown on silicon substrates are prepared using CO₂ laser treatment. The tops of the patterned arrays are flat when the laser power is between 15 and 22 W, and craters appear there with increasing power. Laser treatment does not destroy the alignment of MWCNTs while removing their poorly ordered external layers. The products of oxidative destruction of these layers deposit on the surfaces of newly produced arrays. The oxygen groups resulting from the CO₂ laser treatment improve the wettability of nanotube arrays with an epoxy resin. We show that the patterned MWCNT arrays absorb the THz radiation more strongly than the as-synthesized arrays. Moreover, the pattern influences the frequency behavior of the absorbance.     

In-vitro subsurface remineralisation of artificial enamel white spot lesions pre-treated with chitosan

Objective

To test the null hypothesis that chitosan application has no impact on the remineralisation of artificial incipient enamel white spot lesions (WSLs).

Nanostructured transdermal hormone replacement therapy for relieving menopausal symptoms: a confocal Raman spectroscopy study

OBJECTIVE:

To determine the safety and efficacy of a transdermal nanostructured formulation of progesterone (10%) combined with estriol (0.1%) + estradiol (0.25%) for relieving postmenopausal symptoms.

METHODS:

A total of 66 postmenopausal Brazilian women with climacteric symptoms of natural menopause received transdermal nanostructured formulations of progesterone and estrogens in the forearm daily for 60 months to mimic the normal ovarian secretory pattern. Confocal Raman spectroscopy of hormones in skin layers was performed. Clinical parameters, serum concentrations of estradiol and follicle-stimulating hormone, blood pressure, BI-RADS classification from bilateral mammography, and symptomatic relief were compared between baseline and 60 months post-treatment. Clinicaltrials.gov: {"type":"clinical-trial","attrs":{"text":"NCT02033512","term_id":"NCT02033512"}}NCT02033512.

RESULTS:

An improvement in climacteric symptoms was reported in 92.5% of women evaluated before and after 60 months of treatment. The serum concentrations of estradiol and follicle-stimulating hormone changed significantly (p<0.05) after treatment; the values of serum follicle-stimulating hormone decreased after 60 months from 82.04±4.9 to 57.12±4.1 IU/mL. A bilateral mammography assessment of the breasts revealed normal results in all women. No adverse health-related events were attributed to this hormone replacement therapy protocol.

CONCLUSION:

The nanostructured formulation is safe and effective in re-establishing optimal serum levels of estradiol and follicle-stimulating hormone and relieving the symptoms of menopause. This transdermal hormone replacement therapy may alleviate climacteric symptoms in postmenopausal women.     

Influence of composition on setting kinetics of new injectable and/or fast setting tricalcium silicate cements

ObjectivesNew commercial tricalcium silicate based cements were elaborated to improve handling properties and setting time. The goals of the present work were: (i) to determine the composition of the new injectable and/or fast setting calcium silicate based cements, and (ii) to investigate the impact of the differences in composition on their setting kinetics.MethodsThe materials considered were Angelus MTA™, Biodentine™, MM-MTA™, MTA-Caps™, and ProRoot MTA™ as control.Elemental composition of materials was studied by Inductively Coupled Plasma-Atomic Emission Spectroscopy and X-ray Energy Dispersive analysis, whereas phases in presence were analyzed by Micro-Raman spectroscopy and X-ray Diffraction analysis and cement surface by Scanning Electron Microscope. Setting kinetics was evaluated using rheometry.ResultsElemental analysis revealed, for all cements, the presence of three major components: calcium, silicon and oxygen. Chlorine was detected in MM-MTA, MTA-Caps and Biodentine. Different radio-opacifiers were identified: bismuth oxide in ProRoot MTA, Angelus MTA and MM-MTA, zirconium oxide in Biodentine and calcium tungstate (CaWO₄) in MTA-Caps. All cements were composed of di- and tri-calcium silicate, except Biodentine for which only the latter was detected. Major differences in setting kinetics were observed: a modulus of 8 × 10⁸ Pa is reached after 12 min for Biodentine, 150 min for MM-MTA, 230 min for Angelus MTA and 320 min for ProRoot MTA. The maximum modulus reached by MTA-Caps was 7 × 10⁸ Pa after 150 min.SignificanceEven if these cements possess some common compounds, major differences in their composition were observed between them, which directly influence their setting kinetics.     

湿度及摩擦涂布对粘结剂渗入牙本质深度的激光拉曼光谱分析

目的：采用显微激光拉曼光谱仪观测不同湿度及摩擦涂布对粘结剂渗入牙本质深度的研究。方法：选用24颗新鲜第三磨牙,随机均分为6组,去除胎面釉质,在干燥和再湿润脱矿牙本质上分别进行非摩擦涂布（norub－bingaction,NRA）、轻轻摩擦涂布（slightrubbingaction,SRA）、加力摩擦涂布（vigorousrubbingaction,VRA）各10s,光照10S后粘结Chrisma树脂。平行牙本质小管方向片切厚1mm的试件,并将其置于显微激光拉曼光谱仪中,在界面处,每5tzm测量一个点,计算机自动记录拉曼光谱,根据所记录的谱线进行对比、分析。结果：湿润组SRA渗透深度最高,干燥组VRA渗透深度与其相当。结论：显微激光拉曼光谱仪是研究修复粘接界面的有效手段。干燥条件下,粘结剂加力摩擦涂布渗入牙本质的深度与湿润组轻轻、加力摩擦涂布相似。     

Nanosensing protein allostery using a bivalent mouse double minute two (MDM2) assay

The tumor suppressor protein, p53, is either mutated or absent in >50% of cancers and is negatively regulated by the mouse double minute (MDM2) protein. Understanding and inhibition of the MDM2-p53 interaction are, therefore, critical for developing novel chemotherapeutics, which are currently limited because of a lack of appropriate study tools. We present a nanosensing approach to investigate full-length MDM2 interactions with p53, thus providing an allosteric assay for identifying binding ligands. Surface-enhanced Raman scattering (SERS)-active nanoparticles, functionalized with a p53 peptide mimic (peptide 12.1), display biologically specific aggregation following addition of MDM2. Nanoparticle assembly is competitively inhibited by the N-terminal MDM2-binding ligands peptide 12.1 and Nutlin-3. This study reports nanoparticle assembly through specific protein-peptide interactions that can be followed by SERS. We demonstrate solution-based MDM2 allosteric interaction studies that use the full-length protein.     

Comparing the mechanism of water condensation and evaporation in glassy aerosol

Atmospheric models generally assume that aerosol particles are in equilibrium with the surrounding gas phase. However, recent observations that secondary organic aerosols can exist in a glassy state have highlighted the need to more fully understand the kinetic limitations that may control water partitioning in ambient particles. Here, we explore the influence of slow water diffusion in the condensed aerosol phase on the rates of both condensation and evaporation, demonstrating that significant inhibition in mass transfer occurs for ultraviscous aerosol, not just for glassy aerosol. Using coarse mode (3–4 um radius) ternary sucrose/sodium chloride/aqueous droplets as a proxy for multicomponent ambient aerosol, we demonstrate that the timescale for particle equilibration correlates with bulk viscosity and can be ≫10³ s. Extrapolation of these timescales to particle sizes in the accumulation mode (e.g., approximately 100 nm) by applying the Stokes-Einstein equation suggests that the kinetic limitations imposed on mass transfer of water by slow bulk phase diffusion must be more fully investigated for atmospheric aerosol. Measurements have been made on particles covering a range in dynamic viscosity from < 0.1 to > 10¹³ Pa s. We also retrieve the radial inhomogeneities apparent in particle composition during condensation and evaporation and contrast the dynamics of slow dissolution of a viscous core into a labile shell during condensation with the slow percolation of water during evaporation through a more homogeneous viscous particle bulk.     

Detecting anthrax in the mail by coherent Raman microspectroscopy

In this report, we show the collection of spatial information through a turbid medium by coherent Raman microspectroscopic imaging. In particular, the technique is capable of identifying anthrax endospores inside a sealed paper envelope.