Environmentally benign and cost-effective synthesis of water soluble red light emissive gold nanoclusters: selective and ultra-sensitive detection of mercuric ions

A green approach to synthesize red emissive gold nanoclusters for nano-molar detection of mercuric ions.

Design and assessment of stimulation parameters for a novel peripheral nerve interface

Bi-directional interfaces for peripheral nerve stimulation and recording aim to improve control and acceptance of sensorized prosthetic limbs. The implantable multimodal peripheral recording and stimulation system (IMPRESS) is an intraneural interface technology supporting a high-density transverse intrafascicular multichannel electrode (hd-TIME). Herein we report on in vivo selectivity studies using a passive hd-TIME, and computational modeling towards optimal stimulation parameters for fiber recruitment.

Effect of Asymmetric, Charge Balanced Stimuli on Elicited Compound Neural Action Potentials

Whether via cuff or intrafascicular electrode, peripheral neural stimulations often rely on symmetric, charge balanced paradigms. To date, few investigations have been carried out which systematically decompose the features of a stimulus waveform. Factors such as pulse-width, amplitude, and the timing with which they are presented may have significant effects on the quality of the stimuli. This work seeks to fill this gap in knowledge and share insight into how selection of electrical stimuli may affect the resultant neural activation in peripheral nerves. In particular, we found that, although there is some variance, over the parameter range tested there was not a significant effect on neural fiber recruitment percent due to waveform selection.

Honeycomb-Like Interconnected Network of Nickel Phosphide Heteronanoparticles with Superior Electrochemical Performance for Supercapacitors

Transition-metal-based heteronanoparticles are attracting extensive attention in electrode material design for supercapacitors owing to their large surface-to-volume ratios and inherent synergies of individual components; however, they still suffer from limited interior capacity and cycling stability due to simple geometric configurations, low electrochemical activity of the surface, and poor structural integrity. Developing an elaborate architecture that endows a larger surface area, high conductivity, and mechanically robust structure is a pressing need to tackle the existing challenges of electrode materials. This work presents a supercapacitor electrode consisting of honeycomb-like biphasic Ni₅P₄-Ni₂P (Ni_xP_y) nanosheets, which are interleaved by large quantities of nanoparticles. The optimized Ni_xP_y delivers an ultrahigh specific capacity of 1272 C g^-1 at a current density of 2 A g^-1, high rate capability, and stability. An asymmetric supercapacitor employing as-synthesized Ni_xP_y as the positive electrode and activated carbon as the negative electrode exhibits significantly high power and energy densities (67.2 W h kg^-1 at 0.75 kW kg^-1; 20.4 W h kg^-1 at 15 kW kg^-1). These results demonstrate that the novel nanostructured Ni_xP_y can be potentially applied in high-performance supercapacitors.

Generation and application of LET calibration curve for neutron dosimetry using CR-39 detector and microwave induced chemical etching

Microwave induced chemical etching (MICE) has been established as a faster and improved technique compared to other contemporary etching techniques for the development of tracks in a CR-39 detector. However, the methodology could not be applied for LET (linear energy transfer) spectrometry due to lack of a calibration curve using this method. For this purpose, a new LET calibration curve in the range of 12 keV/μm-799 keV/μm was generated considering different ions such as H, Li, C, O, and F on CR-39 having different LETs in water. An empirical relation was established from the obtained calibration curve for determining the value of LET (in water) from the value of V, the ratio of track etch rate to bulk etch rate. For application of this calibration curve in neutron dosimetry, CR-39 detectors were irradiated to neutrons generated from 120 and 142 MeV ¹⁶O+²⁷Al systems followed by a similar MICE procedure. The absorbed dose (D_LET) and the dose equivalent (H_LET) were obtained from the LET spectra and were found to be 13% and 10% higher for 142 MeV ¹⁶O+²⁷Al system than those for 120 MeV ¹⁶O+²⁷Al system, respectively. The outcome of the study demonstrates the possibility of using the MICE technique for neutron dose estimation by CR-39 via LET spectrometry.

Use of transcutaneous ultrasonography to characterize ovarian status, size distribution, and hierarchical status of follicles in Japanese quail (Coturnix coturnix japonica)

The present study was undertaken to evaluate the ovarian status of matured breeding female Japanese quail by means of B Mode portable ultrasound scanning. Active ovaries in various stages of hierarchical development and different morphological structure were observed. The large yellow follicles appeared as a cluster of dark circles with various intensity of hyperechoic concentric ring. Sonographically, these follicles were classified into F1, F2, and F3 measuring 16.20 ± 0.06 mm, 12.48 ± 0.09 mm, and 7.95 ± 0.16 mm, respectively. A comparative study on preslaughter and postslaughter ovarian follicular status revealed accuracy of follicles less than 10 mm, 10-15 mm, 15-18 mm, and greater than 18 mm as 26.31%, 78.9%, 93.75%, and 100%, respectively, with an overall accuracy of 71%. This is the first report on the application of transcutaneous ultrasonographic technique to monitor ovarian status on Japanese quail reporting that the ovarian follicular activity and morphological structure can be monitored nonintrusively throughout quail life which can used as model for reproductive and biomedical research.

Caudal anesthesia in a patient with peritonitis: Is it safe??

Neuraxial anesthesia combined with general anesthesia has become a widely accepted method of providing effective postoperative analgesia and decreasing intraoperative anesthetic needs in the pediatric population. In clinical practice, there still appears to be hesitancy for the use of a neuraxial technique (spinal or epidural) in patients at risk for bacteremia or with an on-going systemic infection. However, evidence-based medicine lacks any data to support an increase in the risk of infectious complications following neuraxial anesthesia. We present two pediatric patients with intra-abdominal infectious processes who received caudal epidural blockade for postoperative operative analgesia. The use of neuraxial techniques in patients at risk for bacteremia is reviewed, evidence-based medicine regarding the risks of infection discussed, and the potential favorable effects of neuraxial blockade on the neurohumoral response to sepsis and the systemic inflammatory responses presented.

Fluorescent graphene oxide via polymer grafting: an efficient nanocarrier for both hydrophilic and hydrophobic drugs

Functionalized graphene-based drug delivery vehicles have conquered a significant position because functionalization improves its biocompatibility and stability in cell medium, leaving sufficient graphitic basal plane for drug loading through π-π stacking. In this study, poly(N-isopropylacrylamide) (PNIPAM) is covalently grafted from the surface of graphene oxide (GO) via a facile, eco-friendly and an easy procedure of free radical polymerization (FRP) using ammonium persulfate initiator. Various spectroscopic and microscopic studies confirm the successful grafting of PNIPAM from GO surface. PNIPAM-grafted GO (GPNM) exhibits enhanced thermal stability, improved dispersibility both in aqueous and cell medium, and better biocompatibility and cell viability compared to GO. Interestingly, GPNM displays an exciting fluorescence property in aqueous medium, which is a hike of intensity at 36 °C due to the lower critical solution temperature (LCST) of PNIPAM chains (32 °C). Moreover both hydrophilic (doxorubicin (DOX)) and hydrophobic (indomethacin (IMC)) drugs loaded on the surface of GPNM hybrid exhibits its efficacy as an efficient carrier for both types of drugs. Cellular uptakes of free DOX and DOX-loaded GPNM (GPNM-DOX) are evidenced both from optical and fluorescence imaging of live cells, and the efficiency of drug is significantly improved in the loaded system. The release of DOX from GPNM-DOX was achieved at pH 4, relevant to the environment of cancer cells. The pH-triggered release of hydrophobic drug was also studied using UV-vis spectroscopy via alginate encapsulation, showing a great enhancement at pH = 7.4. The IMC is also found to be released by human serum albumin using dialysis technique. The GPNM nanomaterial shows the property of simultaneous loading of DOX and IMC as well as pH-triggered simultaneous release of both of the drugs.

Energy versus information based estimations of dissipation using a pair of magnetic colloidal particles

Using the framework of stochastic thermodynamics, we present an experimental study of a doublet of magnetic colloidal particles that is manipulated by a time-dependent magnetic field. Because of hydrodynamic interactions, each bead experiences a state-dependent friction, which we characterize using a hydrodynamic model. In this work, we compare two estimates of the dissipation in this system: the first one is energy based since it relies on the measured interaction potential, while the second one is information based since it uses only the information content of the trajectories. While the latter only offers a lower bound of the former, we find it to be simple to implement and of general applicability to more complex systems.

Simultaneous HPLC determination of 22 components of essential oils; method robustness with experimental design

The aim of the present study was the development and validation of a simple, precise and specific reversed phase HPLC method for the simultaneous determination of 22 components present in different essential oils namely cinnamon bark oil, caraway oil and cardamom fruit oil. The chromatographic separation of all the components was achieved on Wakosil-II C18 column with mixture of 30 mM ammonium acetate buffer (pH 4.7), methanol and acetonitrile in different ratio as mobile phase in a ternary linear gradient mode. The calibration graphs plotted with five different concentrations of each component were linear with a regression coefficient R(2) >0.999. The limit of detection and limit of quantitation were estimated for all the components. Effect on analytical responses by small and deliberate variation of critical factors was examined by robustness testing with Design of Experiment employing Central Composite Design and established that this method was robust. The method was then validated for linearity, precision, accuracy, specificity and demonstrated to be applicable to the determination of the ingredients in commercial sample of essential oil.

Fluorescence resonance energy transfer from sulfonated graphene to riboflavin: a simple way to detect vitamin B2

We have prepared sulfonated graphene (SG) by diazonium coupling technique and it has been characterized by UV-vis absorption spectroscopy, Raman spectroscopy, electron microscopy, energy-dispersive spectroscopy (EDS), EDS elemental mapping, X-ray photoelectron spectroscopy (XPS), and FTIR spectroscopy. The photoluminescence (PL) property of SG at different pH (pH 4, 7, and 9.2) has been investigated and SG shows highest PL-intensity and quantum yield at pH 4 compared to those at higher pH and that of GO at pH 4. Due to the strong overlap between the emission spectrum of SG and absorption spectrum of riboflavin (RF, vitamin B2) at pH 4, it has been tactfully used as donor for the fluorescence resonance energy transfer (FRET) process. However, graphene oxide (GO) does not exhibit any FRET with RF at an identical condition due to its much lower quantum yield. We have demonstrated a selective detection of vitamin B2 in presence of nucleic acid (DNA, RNA), protein (BSA), amino acid (Lysine) and other water-soluble vitamins (Becosules, Zevit capsules) based on the spontaneous FRET from PL-active SG (donor) to RF (acceptor). The calibration curve indicates excellent affirmation to detect vitamin B2 using FRET and it is superior to the ordinary fluorescence method of detecting RF in presence of different biomolecules.