Microfluidic paper-based aptasensor devices for multiplexed detection of pathogenic bacteria.

Foodborne pathogens are major public health concerns worldwide. Paper-based microfluidic devices are versatile, user friendly and low cost. We report a novel paper-based single input channel microfluidic device that can detect more than one whole-cell foodborne bacteria at the same time, and comes with quantitative reading via image analysis. This microfluidic paper-based multiplexed aptasensor simultaneously detects E. coli O157:H7 and S. Typhimurium. Custom designed particles provide colorimetric signal enhancement and false results prevention. Several aptamers were screened and the highest-affinity aptamers were optimized and employed for detection of these bacteria in solution, both in a buffer as well as pear juice. Image analysis was used to read and quantify the colorimetric signal and measure bacteria concentration, thus rendering this paper based microfluidic device quantitative. The colorimetric results show linearity over a wide concentration range (102CFU/mL to 108CFU/mL) and a limit of detection (LOD) of 103CFU/mL and 102CFU/mL for E. coli O157:H7 and S. Typhimurium, respectively. An insignificant change in colorimetric response for non-target bacteria indicates the aptasesnors are specific. The reported multiplexed colorimetric paper-based microfluidic devices is likely to perform well for on-site rapid screening of pathogenic bacteria in water and food products.

Nonlinear Optical Limiting and Radiation Shielding Characteristics of Sm2O3 Doped Cadmium Sodium Lithium Borate Glasses.

Strong nonlinear absorption (NLA), reduced optical limiting (OL) thresholds, and high radiation shielding parameters are required for the effective use of glasses in the laser radiation and nuclear radiation protecting materials. In view of this, the efficacy of Sm2O3 on the nonlinear optical (NLO) and OL properties were ascertained (at 532 nm) along with radiation shielding characteristics. The open and closed aperture Z-scan profiles revealed the presence of positive NLA and nonlinear refraction (NLR) phenomena respectively. OL measurements showed the existence of limiting behavior in the studied glasses. The NLA and NLR coefficients were improved while the OL thresholds were decreased as the doping of Sm2O3 elevated to a higher doping level. These improvements in NLA, NLR coefficients and OL efficiencies were attributed to the non-bridging oxygens and high polarizable Sm3+ ions. The NLA and OL results clearly suggest the high (5 mol %) Sm2O3 doped glass (Sm5CNLB) glass is beneficial to protect the delicate devices and human eye by suppressing the high energy laser light. The theoretical linear attenuation coefficients (LAC) values of the presented SmxCNLB glasses were obtained with the help of Phy-X software between 0.284 and 1.333 MeV. At 0.284 MeV, the maximum values occur and take values between 0.302 (for Sm0CNLB) and 0.409 cm-1 (for Sm5CNLB). We found that the LAC for the presented SmxCNLB glasses is a function of Sm2O3 content, where the LAC tends to increase, corresponding to the high probabilities of interaction, as the content of Sm2O3 changes from 0 to 5 mol %. The effective atomic number (Zeff) for the presented SmxCNLB glasses was examined between 0.284 and 1.333 MeV. As the amount of Sm2O3 is added, the Zeff increases, and this was observed at any energy.

Induction Heating Analysis of Surface-Functionalized Nanoscale CoFe2O4 for Magnetic Fluid Hyperthermia toward Noninvasive Cancer Treatment.

Oleic acid-coated cobalt ferrite nanoparticles were synthesized using the chemical co-precipitation route and characterized by standard techniques for structure, morphology, and magnetic properties analysis. The Rietveld refined X-ray diffraction (XRD) pattern of CoFe2O4 nanoparticles indicated the formation of a cubic-spinel single-phase structure with the Fd3̅m space group. The average crystallite size (∼12 nm) confirmed the nanocrystalline appearance of the prepared CoFe2O4 nanoparticles. Transmission electron microscopy (TEM) images revealed the spherical nature of both (CoFe2O4) and (OA-CoFe2O4) samples. The absorption bands in the Fourier transform infrared (FT-IR) spectrum at ∼3418, 3026, 1628, 1404, 1068, 845, 544, and 363 cm-1 affirmed the spinel ferrite formation and OA attachment. The M-H curve recorded at room temperature showed the superparamagnetic nature of the CoFe2O4 nanoparticles with moderate saturation magnetization (∼78 emu/gm). The blocking temperature of the prepared CoFe2O4 nanoparticles obtained from the field-cooled and zero-field-cooled (FC-ZFC) curve was estimated to be 144 K. Further, the characterized surface-modified CoFe2O4 was then added in ethylene glycol/water with various concentrations and characterized by the induction heating technique for the evaluation of their self-heating characteristics. A series of temperature versus time measurements were made by varying the ethylene glycol/water proportion for better understanding of the self-heating characteristics of the prepared CoFe2O4 nanoparticles. All of the findings display the applicability of the surface-modified CoFe2O4 nanoparticles in magnetic fluid hyperthermia toward noninvasive cancer treatment and other bio-applications.

Influence of trivalent Cr ion substitution on the physicochemical, optical, electrical, and dielectric properties of sprayed NiFe2O4 spinel-magnetic thin films.

In this study, we mainly investigated the effects of trivalent Cr ion substitution on the properties of nickel ferrite (NCF) spinel-thin films. The as-prepared spinel thin films were characterized by thermogravimetry-differential thermal analysis (TGA-DTA) to comprehensively examine their phase transition. X-ray diffraction (XRD) analysis revealed that the prepared films have a single-phase face-centered cubic crystal structure. A Raman study confirmed the arrangement of the inverse-cubic spinel structure of these spinel-thin films. Field-emission scanning electron microscopy (FE-SEM) images verified the slight agglomeration of particles. Similarly, transmission electron microscopy (TEM) images together with selected area electron diffraction (SAED) patterns supported the XRD results. PL spectra showed enhanced near band emission (NBE) intensity due to the passivation of oxygen vacancies by Cr3+ substitution. The DC electrical resistivity (ρ) increases from 1.4 × 10-6 Ω cm to 4.42 × 10-6 Ω cm at room temperature. Dielectric parameters were studied as a function of frequency in the range of 1-10 MHz at 300 K, and these parameters decreased with the increasing Cr3+ ion concentration in the spinel-thin films. The obtained results indicate the applicability of the fabricated thin films in high-frequency electronic devices.

Epizootiological observations on canine microfilaremia in Gujarat state, India.

AIM: The present investigation was conducted to study the prevalence of microfilaremia in dogs in Gujarat. MATERIALS AND METHODS: A total of 418 adult dogs aged between 2 and 14 years with signs of weakness and non-specified complaints, presented at TVCC, Deesa (North Gujarat), Nandini Veterinary Hospital, Surat (South Gujarat), and Private Clinics, Ahmedabad (Central Gujarat), were included in the present investigation for studying the prevalence of microfilaremia from July 2016 to May 2017. RESULTS: A total of 418 dogs were screened, of which 33 were found positive for circulating microfilariae with the prevalence rate of 7.89% in the population. Among microfilaremic dogs, the finding of microfilariae of Dipetalonema (Acanthocheilonema) reconditum was more common (23 cases; 69.69%) than Dirofilaria immitis (10 cases; 30.30%) making their prevalence in the population of 418 dogs as 5.50% and 2.39%, respectively. Breed-wise distribution of microfilaremic dogs revealed that 12 (36.36%), 8 (24.24%), 5 (15.15%), 4 (12.12%), 2 (6.06%), 1 (3.03%), and 1 (3.03%) cases were observed in Pomeranian, non-descript, German Shepherd, Labrador, Great Dane, Lhasa Apso, and Pug dogs, respectively. Of 10 cases of D. immitis, 5, 2, 2, and 1 were observed in Pomeranian, Labrador, non-descript, and Great Dane dogs, respectively. Cases of Dipetalonema reconditum were highest in Pomeranian (7), followed by non-descript (6), German Shepherd (5), Labrador (2), Great Dane (1), Lhasa Apso (1), and Pug (1). Age-wise distribution recorded significantly (p≤0.01) higher number of cases in adult dogs (4-14 years) for D. immitis (30.30%) and D. reconditum (39.39%). Sex-wise distribution of microfilaremic dogs showed that male (22/33, 66.66%) was more predisposed to microfilaremia rather than females (11/33, 33.34%). It is apparent from the study that the number of dogs with microfilaremia due to D. reconditum was significantly (p≤0.01) higher than that of D. immitis. CONCLUSION: The present study revealed that microfilaremia due to D. immitis and D. reconditum is prevalent in the state of Gujarat. The infection with D. immitis was associated with severe lung and cardiac pathological manifestations.