Finite element study on the influence of pore size and structure on stress shielding effect of additive manufactured spinal cage.

The stress shielding effect occurs when the orthopedic implant reduces the load delivered to the bone, causing inefficient stress transfer to the host bone. The usage of porous additive manufactured (AM) cages reduces the stress shielding effect and promotes bone ingrowth also. The purpose of this work is to study the stress and deformation on porous hybrid spinal cages under different loading conditions using Finite Element Analysis (FEA).

High-efficient photoacoustic generation with an ultrathin metallic multilayer broadband absorber.

Metal nanomaterials have been widely used to generate photoacoustic (PA) signals because of their high optical absorption characteristics. However, the PA conversion efficiency of metal nanomaterials is limited by the single-wavelength absorption at the resonant peak. To mitigate this issue, a three-layer ultrathin film containing a thin PDMS layer sandwiched between two ultrathin chromium films is proposed.

GAPS-megacities: A new global platform for investigating persistent organic pollutants and chemicals of emerging concern in urban air.

A pilot study was initiated in 2018 under the Global Atmospheric Passive Sampling (GAPS) Network named GAPS-Megacities. This study included 20 megacities/major cities across the globe with the goal of better understanding and comparing ambient air levels of persistent organic pollutants and other chemicals of emerging concern, to which humans residing in large cities are exposed. The first results from the initial period of sampling are reported for 19 cities for several classes of flame retardants (FRs) including organophosphate esters (OPEs), polybrominated diphenyl ethers (PBDEs), and halogenated flame retardants (HFRs) including new flame retardants (NFRs), tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCDD).

Soil concentrations and soil-air exchange of polycyclic aromatic hydrocarbons in five Asian countries.

The Asia Soil and Air Monitoring Program (Asia-SAMP) is a large-scale monitoring program spanning China, Japan, South Korea, Vietnam and India. 47 polycyclic aromatic hydrocarbons (PAHs) were analyzed in 169 concurrently collected surface soil samples across the five study regions. Total PAH concentrations (∑PAHs) ranged from 13.

Organophosphate esters in indoor dust from 12 countries: Concentrations, composition profiles, and human exposure.

A total of 20 organophosphate triesters (OPEs), including seven alkyl-OPEs, three chlorinated (Cl)-OPEs, seven aryl-OPEs, and three oligomeric-OPEs were measured in 341 house dust samples collected from 12 countries during the period 2010-2014. OPEs were ubiquitous in indoor dust, and the total concentrations of OPEs (∑OPEs; sum of 20 OPEs) ranged from 49.4 to 249,000 ng/g dry weight (dw).

Tumor blood perfusion-based requirement of nanoparticle dose-loadings for plasmonic photothermal therapy.

Blood perfusion-based requirement of nanoparticle dose-loadings is computed for plasmonic photothermal therapy of a tumor. Thermal damage is quantified through coupled multiphysics approach to specify nanoparticle loadings. For low blood perfusion, the nanoparticle loading of 1 mm at 0.

Two-dimensional transition metal dichalcogenides assisted biofunctionalized optical fiber SPR biosensor for efficient and rapid detection of bovine serum albumin.

The present study reports an alternative method of functionalizing the optical fiber Surface Plasmon Resonance (SPR) sensing probe with antibodies for label-free detection of bovine serum albumin (BSA) protein. In this novel approach, the gold coated fiber was first modified with Molybdenum disulfide (MoS) nanosheets followed by its bio-functionalization with Anti-BSA antibodies. The developed technique not only allowed the amplification of the SPR signals by synergic effects of MoS and gold metallic thin film but also enabled a direct and chemical-free attachment of representative antibodies through hydrophobic interactions.

Negative axicon tip-based fiber optic interferometer cavity sensor for volatile gas sensing.

In this research work we demonstrated negative axicon optical fiber tip filled with Polydimethylsiloxane (PDMS) as a sensor platform for volatile organic gases detection at room temperature. The response of the sensor was measured with various Volatile Organic Compounds (VOCs) such as Chloroform, Hexane, Isopropanol, Acetone, Toluene and Methanol in the concentration ranging from 5 to 200 ppm. The corresponding sensitivity and limit of detection (LOD) of the developed sensor for the measured VOCs were observed between the order of around 23.

Label-free detection of Escherichia coli bacteria by cascaded chirped long period gratings immunosensor.

An optical fiber based immunosensing platform formed by two identical chirped long period gratings (CLPGs) for sensitive and label-free detection of Escherichia coli (E. coli) is presented. The proposed immunosensor having two CLPGs with an inter-grating space (IGS) works like a Mach-Zehnder interferometer.

Rapid detection of Escherichia coli using fiber optic surface plasmon resonance immunosensor based on biofunctionalized Molybdenum disulfide (MoS) nanosheets.

The molybdenum disulfide (MoS) nanosheets functionalized fiber optic surface plasmon resonance (SPR) immunosensor has been reported for the sensitive detection of Escherichia coli (E. coli). The MoS nanosheets were prepared by chemical exfoliation method.

Occurrence and Source Effect of Novel Brominated Flame Retardants (NBFRs) in Soils from Five Asian Countries and Their Relationship with PBDEs.

This paper presents the first comprehensive survey of 19 novel brominated flame retardants (NBFRs) in soil samples collected among five Asian countries. High variability in concentrations of all NBFRs was found in soils with the geometric mean (GM) values ranging from 0.50 ng/g dry weight (dw) in Vietnam to 540 ng/g dw in the vicinity of a BFR manufacturer in China.

Occurrence and fate of parabens and their metabolites in five sewage treatment plants in India.

Parabens (p-hydroxy benzoic acid esters) are antimicrobial agents, used widely as preservatives in personal care products (PCPs), pharmaceuticals, foods, and beverages. PCPs that contain parabens are a major source of these chemicals in sewage treatment plants (STPs). Very few studies have demonstrated the occurrence of parabens in wastewater.

Experimental and theoretical study of hydroxyquinolines: hydroxyl group position dependent dipole moment and charge-separation in the photoexcited state leading to fluorescence.

Optical absorption and fluorescence (FL) spectra of 2-, 6-, 7-, 8-hydroxyquinolines (2-,6-,7- and 8-HQs) have been measured at room temperature in the wide range of solvents of different polarities, dielectric constant and refractive index. The ground state dipole moment (µ ) and excited state dipole moment (µ ) of 2-, 6-, 7- and 8-HQs were obtained using solvatochromic shift (SS) methods and microscopic solvent polarity parameters (MSPP). Change in the dipole moment (Δµ) between the ground and photo-excited states was estimated from SS and MSPP methods.

Ultra broadband mid-IR supercontinuum generation in GeAsSe based chalcogenide graded-index photonic crystal fiber: design and analysis.

In this paper, we report design and numerical analysis of a GeAsSe based chalcogenide glass graded-index photonic crystal fiber structure for mid-IR ultra broadband supercontinuum generation. The proposed dispersion engineered photonic crystal fiber offers a zero dispersion wavelength at a pump wavelength of 2.8 μm.

Design and analysis of single-mode tellurite photonic crystal fibers for stimulated Brillouin scattering based slow-light generation.

We theoretically examine two designs of single-mode (i) Er-doped tellurite and (ii) undoped tellurite photonic crystal fiber (PCF) for generation of slow light with tunable features based on stimulated Brillouin scattering. We obtained (i) Brillouin gain up to 91 dB and time delay of ∼145  ns at maximum allowable pump power of ∼775  mW in a 2 m Er-doped tellurite PCF and (ii) Brillouin gain up to ∼88  dB and time delay of ∼154  ns at maximum allowable pump power ∼21  mW in a 100 m undoped tellurite photonic crystal fiber. Simulated results clearly indicate that the doped tellurite PCF with Er enhances the maximum allowable pump power and comparable time delay can be obtained even with reduced photonic crystal fiber length.

Design and analysis of a highly nonlinear composite photonic crystal fiber for supercontinuum generation: visible to mid-infrared.

A composite photonic crystal fiber structure has been designed with tellurite as the cladding and chalcogenide as a core material. To increase nonlinearity, rods of the chalcogenide glass material have been inserted around the core region. The reported structure offers very high nonlinearity of 1042  W Km at 2800 nm pump wavelength with low and flattened dispersion of approximately -11  ps·nm Km.

Large-mode-area single-polarization single-mode photonic crystal fiber: design and analysis.

A rectangular core photonic crystal fiber structure has been presented and analyzed for single-polarization single-mode operation. Single-polarization is obtained with asymmetric design and by introducing different loss for x-polarization and y-polarization of fundamental modes. Single-polarization single-mode operation of the proposed photonic crystal fiber is investigated in detail by using a full vector finite element method with an anisotropic perfectly matched layer.

Asymmetric large-mode-area photonic crystal fiber structure with effective single-mode operation: design and analysis.

The asymmetrical structure of photonic crystal fiber has been reported for a large mode area with the single-mode operation. The design works on the principle of bend-induced mode filtering. The proposed structure can be designed (i) by introducing down-doped material rods in place of nine air holes of the inner ring near the core of the structure and (ii) by increasing the diameter of the rest of the three air holes of the same ring in the direction of bending.

Musculoskeletal-based finite element analysis of femur after total hip replacement.

This article evaluates the effect of stress variation on adult femur following total hip replacement using musculoskeletal-based finite element analysis. The aim was to study the changes in stress distribution in the femur after total hip replacement by providing simulated in vivo loading and boundary conditions. The loading and boundary conditions were generated using a musculoskeletal modelling software 'AnyBody' and were applied on femur model, generated from the computed tomography (CT) scan data for standing posture of male patient.

Distribution and Relationships of Antimicrobial Resistance Determinants among Extended-Spectrum-Cephalosporin-Resistant or Carbapenem-Resistant Escherichia coli Isolates from Rivers and Sewage Treatment Plants in India.

To determine the distribution and relationship of antimicrobial resistance determinants among extended-spectrum-cephalosporin (ESC)-resistant or carbapenem-resistant Escherichia coli isolates from the aquatic environment in India, water samples were collected from rivers or sewage treatment plants in five Indian states. A total of 446 E. coli isolates were randomly obtained.

Synthetic Phenolic Antioxidants and Their Metabolites in Indoor Dust from Homes and Microenvironments.

Synthetic phenolic antioxidants (SPAs), including 2,6-di-tert-butyl-4-hydroxytoluene (BHT), are extensively used in food, cosmetic and plastic industries. Nevertheless, limited information is available on human exposures, other than the dietary sources, to SPAs. In this study, occurrence of 9 SPAs and their metabolites/degradation products was determined in 339 indoor dust collected from 12 countries.

Design and analysis of large-core multitrench channel waveguide for high-power applications.

We present a multitrench leaky channel waveguide design that supports effective single-mode operation even with large-core size. The proposed waveguide structure has a uniform rectangular core and a geometrically shaped trench-assisted cladding in such a way that all the confined modes become leaky. The effective single-mode operation is achieved by choosing the appropriate geometrical parameters that introduce very large leakage losses for higher-order modes with very low leakage losses for fundamental mode.

A comparative assessment of human exposure to tetrabromobisphenol A and eight bisphenols including bisphenol A via indoor dust ingestion in twelve countries.

Tetrabromobisphenol A (TBBPA) and eight bisphenol analogues (BPs) including bisphenol A (BPA) were determined in 388 indoor (including homes and microenvironments) dust samples collected from 12 countries (China, Colombia, Greece, India, Japan, Kuwait, Pakistan, Romania, Saudi Arabia, South Korea, U.S., and Vietnam).