First Measurement of Hard Exclusive π^{-}Δ^{++} Electroproduction Beam-Spin Asymmetries off the Proton

The polarized cross-section ratio σ_{LT^{'}}/σ_{0} from hard exclusive π^{-}Δ^{++} electroproduction off an unpolarized hydrogen target has been extracted based on beam-spin asymmetry measurements using a 10.2  GeV/10.6  GeV incident electron beam and the CLAS12 spectrometer at Jefferson Lab. The study, which provides the first observation of this channel in the deep-inelastic regime, focuses on very forward-pion kinematics in the valence regime, and photon virtualities ranging from 1.5  GeV^{2} up to 7  GeV^{2}. The reaction provides a novel access to the d-quark content of the nucleon and to p→Δ^{++} transition generalized parton distributions. A comparison to existing results for hard exclusive π^{+}n and π^{0}p electroproduction is provided, which shows a clear impact of the excitation mechanism, encoded in transition generalized parton distributions, on the asymmetry.

Nanoarchitectonics of Three-Dimensional Carbon Nanofiber-Supported Hollow Copper Sulfide Spheres for Asymmetric Supercapacitor Applications

Three-dimensional carbon nanofiber (3D-CNF)-supported hollow copper sulfide (HCuS) spheres were synthesized by the facile hydrothermal method. The morphology of the as-synthesized HCuS@3D-CNF composite clearly revealed that the 3D-CNFs act as a basement for HCuS spheres. The electrochemical performance of as-synthesized HCuS@3D-CNFs was evaluated by cyclic voltammetry (CV) tests, gravimetric charge-discharge (GCD) tests, and Nyquist plots. The obtained results revealed that the HCuS@3D-CNFs exhibited greater areal capacitance (4.6 F/cm²) compared to bare HCuS (0.64 F/cm²) at a current density of 2 mA/cm². Furthermore, HCuS@3D-CNFs retained excellent cyclic stability of 83.2% after 5000 cycles. The assembled asymmetric device (HCuS@3D-CNFs//BAC) exhibits an energy density of 0.15 mWh/cm² with a working potential window of 1.5 V in KOH electrolyte. The obtained results demonstrate that HZnS@3D-CNF nanoarchitectonics is a potential electrode material for supercapacitor applications.

First CLAS12 Measurement of Deeply Virtual Compton Scattering Beam-Spin Asymmetries in the Extended Valence Region

Deeply virtual Compton scattering (DVCS) allows one to probe generalized parton distributions describing the 3D structure of the nucleon. We report the first measurement of the DVCS beam-spin asymmetry using the CLAS12 spectrometer with a 10.2 and 10.6 GeV electron beam scattering from unpolarized protons. The results greatly extend the Q^{2} and Bjorken-x phase space beyond the existing data in the valence region and provide 1600 new data points measured with unprecedented statistical uncertainty, setting new, tight constraints for future phenomenological studies.

First Measurement of Λ Electroproduction off Nuclei in the Current and Target Fragmentation Regions

We report results of Λ hyperon production in semi-inclusive deep-inelastic scattering off deuterium, carbon, iron, and lead targets obtained with the CLAS detector and the Continuous Electron Beam Accelerator Facility 5.014 GeV electron beam. These results represent the first measurements of the Λ multiplicity ratio and transverse momentum broadening as a function of the energy fraction (z) in the current and target fragmentation regions. The multiplicity ratio exhibits a strong suppression at high z and an enhancement at low z. The measured transverse momentum broadening is an order of magnitude greater than that seen for light mesons. This indicates that the propagating entity interacts very strongly with the nuclear medium, which suggests that propagation of diquark configurations in the nuclear medium takes place at least part of the time, even at high z. The trends of these results are qualitatively described by the Giessen Boltzmann-Uehling-Uhlenbeck transport model, particularly for the multiplicity ratios. These observations will potentially open a new era of studies of the structure of the nucleon as well as of strange baryons.

Observation of Correlations between Spin and Transverse Momenta in Back-to-Back Dihadron Production at CLAS12

We report the first measurements of deep inelastic scattering spin-dependent azimuthal asymmetries in back-to-back dihadron electroproduction in the deep inelastic scattering process. In this reaction, two hadrons are produced in opposite hemispheres along the z axis in the virtual photon-target nucleon center-of-mass frame, with the first hadron produced in the current-fragmentation region and the second in the target-fragmentation region. The data were taken with longitudinally polarized electron beams of 10.2 and 10.6 GeV incident on an unpolarized liquid-hydrogen target using the CLAS12 spectrometer at Jefferson Lab. Observed nonzero sinΔϕ modulations in ep→e^{'}pπ^{+}X events, where Δϕ is the difference of the azimuthal angles of the proton and pion in the virtual photon and target nucleon center-of-mass frame, indicate that correlations between the spin and transverse momenta of hadrons produced in the target- and current-fragmentation regions may be significant. The measured beam-spin asymmetries provide a first access in dihadron production to a previously unexplored leading-twist spin- and transverse-momentum-dependent fracture function. The fracture functions describe the hadronization of the target remnant after the hard scattering of a virtual photon off a quark in the target particle and provide a new avenue for studying nucleonic structure and hadronization.

Observation of Azimuth-Dependent Suppression of Hadron Pairs in Electron Scattering off Nuclei

We present the first measurement of dihadron angular correlations in electron-nucleus scattering. The data were taken with the CLAS detector and a 5.0 GeV electron beam incident on deuterium, carbon, iron, and lead targets. Relative to deuterium, the nuclear yields of charged-pion pairs show a strong suppression for azimuthally opposite pairs, no suppression for azimuthally nearby pairs, and an enhancement of pairs with large invariant mass. These effects grow with increased nuclear size. The data are qualitatively described by the gibuu model, which suggests that hadrons form near the nuclear surface and undergo multiple scattering in nuclei.These results show that angular correlation studies can open a new way to elucidate how hadrons form and interact inside nuclei.

Free-roaming dog population dynamics in Ranchi, India

Rabies causes approximately 20,000 human deaths in India each year. Nearly all of these occur following dog bites. Large-scale, high-coverage dog rabies vaccination campaigns are the cornerstone of rabies elimination strategies in both human and dog populations, although this is particularly challenging to achieve in India as a large proportion of the dog population are free-roaming and unowned. Further, little is known about free-roaming dog ecology in India which makes defining optimum vaccination strategies difficult. In this study, data collected using a mobile phone application during three annual mass vaccination and neutering (surgical sterilisation of both males and females) campaigns of free-roaming dogs in Ranchi, India (during which a total of 43,847 vaccinations, 26,213 neuter surgeries and 28,172 re-sight observations were made) were interrogated, using two novel approaches to estimate the proportion of neutered dogs that were lost from the city (assumed due to mortality or migration) between campaign years. Analysis revealed high losses of neutered dogs each year, ranging from 25.3% (28.2-22.8) to 55.8% (57.0-54.6). We also estimated that the total population declined by 12.58% (9.89-15.03) over the three-year period. This demonstrates that there is a high turnover of free-roaming dogs and that despite neutering a large number of dogs in an annual sterilisation campaign, the decline in population size was modest over a three-year time period. These findings have significant implications for the planning of rabies vaccination campaigns and population management programmes as well as highlighting the need for further research into the demographics of free-roaming, unowned dogs in India.

Improved Λp Elastic Scattering Cross Sections between 0.9 and 2.0 GeV/c as a Main Ingredient of the Neutron Star Equation of State

Strange matter is believed to exist in the cores of neutron stars based on simple kinematics. If this is true, then hyperon-nucleon interactions will play a significant part in the neutron star equation of state. Yet, compared to other elastic scattering processes, there is very little data on Λ-N scattering. This experiment utilized the CEBAF Large Acceptance Spectrometer (CLAS) detector to study the Λp→Λp elastic scattering cross section in the incident Λ momentum range 0.9-2.0  GeV/c. These are the first data on this reaction since the 1970s. The new cross sections have significantly better accuracy and precision than the existing world data, and the techniques developed here can also be used in future experiments.

First Measurement of Timelike Compton Scattering

We present the first measurement of the timelike Compton scattering process, γp→p^{'}γ^{*}(γ^{*}→e^{+}e^{-}), obtained with the CLAS12 detector at Jefferson Lab. The photon beam polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities 2.25<Q^{'2}<9  GeV^{2}, squared momentum transferred 0.1<-t<0.8  GeV^{2}, and average total center-of-mass energy squared s=14.5  GeV^{2}. The photon beam polarization asymmetry, similar to the beam-spin asymmetry in deep virtual Compton scattering, is sensitive to the imaginary part of the Compton form factors and provides a way to test the universality of the generalized parton distributions. The angular asymmetry of the decay leptons accesses the real part of the Compton form factors and thus the D-term in the parametrization of the generalized parton distributions.

Plasmonic Core-Shell-Satellites with Abundant Electromagnetic Hotspots for Highly Sensitive and Reproducible SERS Detection

In this work, we develop a Ag@Al2O3@Ag plasmonic core-shell-satellite (PCSS) to achieve highly sensitive and reproducible surface-enhanced Raman spectroscopy (SERS) detection of probe molecules. To fabricate PCSS nanostructures, we employ a simple hierarchical dewetting process of Ag films coupled with an atomic layer deposition (ALD) method for the Al2O3 shell. Compared to bare Ag nanoparticles, several advantages of fabricating PCSS nanostructures are discovered, including high surface roughness, high density of nanogaps between Ag core and Ag satellites, and nanogaps between adjacent Ag satellites. Finite-difference time-domain (FDTD) simulations of the PCSS nanostructure confirm an enhancement in the electromagnetic field intensity (hotspots) in the nanogap between the Ag core and the satellite generated by the Al2O3 shell, due to the strong core-satellite plasmonic coupling. The as-prepared PCSS-based SERS substrate demonstrates an enhancement factor (EF) of 1.7 × 107 and relative standard deviation (RSD) of ~7%, endowing our SERS platform with highly sensitive and reproducible detection of R6G molecules. We think that this method provides a simple approach for the fabrication of PCSS by a solid-state technique and a basis for developing a highly SERS-active substrate for practical applications.

Ballistic Graphene Cooper Pair Splitter

We report an experimental study of a Cooper pair splitter based on ballistic graphene multiterminal junctions. In a two transverse junction geometry, namely the superconductor-graphene-superconductor and the normal metal-graphene-normal metal, we observe clear signatures of Cooper pair splitting in the local as well as nonlocal electronic transport measurements. Our experimental data can be very well described by our beam splitter model. These results open up possibilities to design new entangled state detection experiments using ballistic Cooper pair splitters.

Comparative evaluation of DTT treated ABO isoagglutinin titres performed by two methods with solid phase red cell adhesion (SPRCA) titres

BACKGROUND AND AIMS

Measurement of actual concentration of IgG requires methods like treatment of serum with dithiothreitol (DTT). This study was aimed at comparing of DTT treated ABO titres performed by conventional test tube technique (CTT) and column agglutination technique (CAT) with HA/SPRCA.

MATERIALS AND METHODS

This was a prospective, observational study conducted from October 2019 to March 2020. All consecutive A, B and O group donors who gave consent for participation were included. All samples were tested by CTT and CAT before and after DTT treatment (pCTT, pCAT) and with HA/SPRCA.

RESULTS

A total of 300 donors were included; 100 each from A, B and O blood group donors. Group O titres were higher than group A/B titres. Group O titres were highest when performed by pCAT, followed by pCTT and lowest by HA/SPRCA. Group A/B titres were highest when performed by HA/SPRCA, followed by pCAT and pCTT for anti-A and highest when performed by pCAT, followed by HA/SPRCA and lowest by pCTT for anti-B.

CONCLUSION

Results obtained by pCAT were closer to results obtained by pCTT, whereas those obtained by HA/SPRCA were variable. SPRCA offers the advantage of automation, no inter-observer variation and less time consumption because IgM interference is not observed with SPRCA, thus providing an alternative to pCTT. However, these methods cannot be used interchangeably and to discern the most suitable method, a clinical impact of these results needs to be studied.

Neurosurgery in paediatric strokes

Paediatric strokes are a different entity owing to the difference in pathological entity causing the stroke as well as difficulty in treatment and management due to the presence of a growing brain and small vascular volume making surgery and endovascular intervention dangerous. Yet, the high neuronal plasticity coupled with unique surgical and endovascular procedures makes surgery in these conditions rewarding with improving morbidity and mortality statistics. The field is young and dynamic leading to constant change and updating. We attempt to review the current recommendations with our own experience in paediatric neurosurgery for paediatric strokes and present an overview of common conditions causing paediatric strokes. A brief review of the literature is also supplied for reference.

Improved Morphological and Localized Surface Plasmon Resonance (LSPR) Properties of Fully Alloyed Bimetallic AgPt and Monometallic Pt NPs Via the One-Step Solid-State Dewetting (SSD) of the Ag/Pt Bilayers

Multi-metallic alloy nanoparticles (NPs) can offer a promising route for the integration of multi-functional elements by the adaptation of advantageous individual NP properties and thus can exhibit the multi-functional dynamic properties arisen from the electronic heterogeneity as well as configurational diversity. The integration of Pt-based metallic alloy NPs are imperative in the catalytic, sensing, and energy applications; however, it usually suffers from the difficulty in the fabrication of morphologically well-structured and elementally well-alloyed NPs, which yields poor plasmonic responses. In this work, the improved morphological and localized surface plasmon resonance (LSPR) properties of fully alloyed bimetallic AgPt and monometallic Pt NPs are demonstrated on sapphire (0001) via the one-step solid-state dewetting (SSD) of the Ag/Pt bilayers. In a sharp contrast to the previous studies of pure Pt NPs, the surface morphology of the resulting AgPt and Pt NPs in this work are significantly improved such that they possess larger size, increased interparticle gaps, and improved uniformity. The intermixing of Ag and Pt atoms, AgPt alloy formation, and concurrent sublimation of Ag atoms plays the major roles in the fabrication of bimetallic AgPt and monometallic Pt NPs along with the enhanced global diffusion and energy minimization of NP system. The fabricated AgPt and Pt NPs show much-enhanced LSPR responses as compared to the pure Pt NPs in the previous studies, and the excitation of dipolar, quadrupolar, multipolar and higher-order resonance modes is realized depending upon the size, configuration, and elemental compositions. The LSPR peaks demonstrate drastic alteration along with the evolution of AgPt and Pt NPs, i.e., the resonance peaks are shifted and enhanced by the variation of size and Ag content.

Enhanced Localized Surface Plasmon Resonance of Fully Alloyed AgAuPdPt, AgAuPt, AuPt, AgPt, and Pt Nanocrystals: Systematical Investigation on the Morphological and LSPR Properties of Mono Bi-, Tri-, and Quad-Metallic Nanoparticles

Multi-metallic alloy nanoparticles (NPs) can offer tunable or modifiable localized surface plasmon resonance (LSPR) properties depending upon their configurational and elemental alterations, which can be utilized in various applications, that is, in photon energy harvesting, optical sensing, biomedical imaging, photocatalysis, and spectroscopy. In this work, a systematic investigation on the morphological and LSPR properties of multi-metallic alloy NPs incorporating Ag, Au, Pd, and Pt is presented on c-plane sapphire (0001). The resulting NPs exhibit much enhanced and tunable LSPR bands in the UV-VIS wavelength as compared to the previously reported mono-metallic NPs based on the considerable improvement in size and shape of nanostructures along with the electronic heterogeneity. Solid-state dewetting of sputtered bilayers (Ag/Pt), tri-layers (Ag/Au/Pt), and quad-layers (Ag/Au/Pd/Pt) is employed to demonstrate a wide variety of configurations, sizes, densities, and elemental compositions of Pt, AgPt, AuPt, AgAuPt, AgAuPt, and AgAuPdPt NPs by the systematic control of annealing temperature and deposition schemes. The distinct morphology and elemental composition of surface nanostructures are obtained by means of surface diffusion, intermixing, and surface/interface energy minimization along with the applied thermal energy. In addition, the sublimation of Ag atoms from the alloy nanostructure matrix significantly influences the structural, elemental, and thus optical properties of NPs by reducing the average size and Ag percentage in the alloy NPs. Based on the specific size, shape, and elemental composition of NPs, the excitation of LSPR is correlated to the dipolar, quadrupolar, multi-polar, and higher order (HO) modes along with the finite difference time domain simulation of local electric-field. The LSPR intensity is generally stronger with a higher percentage of Ag atoms in the alloy NPs and gradually diminished by the sublimation loss. However, even the mono-metallic and alloy NPs without Ag exhibited significantly improved and dynamic nature of plasmonic bands in the UV and VIS wavelength.

Systematic investigation on quad-metallic AgAuPdPt and tri-metallic AuPdPt NPs through the solid-state dewetting of quad-layer Ag/Au/Pd/Pt thin films on c-plane sapphire

Multi-metallic alloy nanoparticles (MNPs) can offer valuable opportunities to meet the various demands of applications. MNPs consist of various noble metallic elements can combine diverse electronic, optical and catalytic properties in a single NP configuration, thus taking the advantage of each element. In this paper, the fabrication of tri- and quad- metallic alloy NPs with noble elements (Ag, Au, Pd and Pt) and the corresponding localized surface plasmon resonance (LPSR) properties are systematically demonstrated. Tri- and quad-metallic alloy NPs come in various size and configurations by the solid-state dewetting of Ag/Au/Pd/Pt quad-layers on sapphire (0001). Tri-metallic AuPdPt NPs are demonstrated by the systematic control of growth temperature along with the significant Ag atom sublimation. Strongly enhanced and tunable LPSR is exerted in the UV-VIS regions depending upon the size, configuration, spacing and elemental composition of the MNPs. The size dependent LSPR response of MNPs is discussed based on the absorption and scattering along with the excitation of dipolar, quadrupolar, high order and multipolar resonance modes. The MNPs exhibit much stronger and dynamic LSPR bands as compared with the monometallic Pt and Pd NPs with the comparable size and configurations.

P5385Development and preclinical testing of upscaled engineered heart tissue for use in translational studies

Introduction

The lack of efficacy of stem cell therapy for the treatment of heart failure may be related to the poor retention rates offered by existing delivery methods (intra-coronary/ intramyocardial). Tissue engineering strategies improve cell retention in small animal models but data regarding engineered heart tissue (EHT) patches large enough for human studies are lacking.

Purpose

To upscale EHT to a clinically relevant size and mature the patch in-vitro. Once matured to undergo preclinical testing in a rabbit model of myocardial infarction.

Methods

We developed an upscaled EHT patch (3cm x 2cm x 1.5mm) able to contain up to 50 million human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CM; Fig A/B). Myocardial infarction model was performed by permanent ligation.

Results

The patches began to beat spontaneously within 3 days of fabrication and after 28 days of dynamic culture (Late EHTs) showed the development of several mature characteristics when compared to early patches (<14 days from fabrication). For example, late EHTs contained hiPSC-CMs which were more aligned (hiPSC-CM accumulative angle change: early 2702±778 degrees [n=4] vs late 922±186 [n=5], p=0.042); showed better contraction kinetics (early peak contraction amplitude 87.9±5.8a.u. versus late 952±304a.u.; p<0.001) and faster calcium transients (time to peak: early 200.8±8.8ms [n=5] vs late 147.7±10.2ms [n=6], p=0.004; time to 75% decay: early 274±9.7ms vs late 219.9±2.7ms, p=0.0003).

We then tested the EHT patch in-vivo using a rabbit model (Fig C). Patches were applied to normal (n=5) or infarcted hearts (n=8). Sham operations used non-cellular fibrin patches (n=5). The mean fraction of troponin positive cells in the graft was 27.8±10.3% at 25.2±1.7 days relative to day 0 [n=5] and KU80 (human specific marker) staining confirmed that this was of human origin. CD31 (Fig D) and KU80 staining revealed that the grafts were well vascularized and that the vasculature was not human in origin (therefore were originating from the host). Ex-vivo optical mapping revealed evidence of electrical coupling between the graft and host at 2 weeks and preliminary experiments indicated that the patch improved left ventricular function when grafted onto infarcted hearts. Telemetry recordings in vivo and arrhythmia provocation protocols (ex vivo) indicated that the patch was not proarrhythmic.

Figure 1. A/B) EHT Images; C) 20x troponin T (brown) of rabbit myocardium/EHT (2 weeks after grafting), blue counterstain = haematoxylin, red lines = EHT borders; D) 63x CD31 staining (brown) rabbit/EHT border zone (2 weeks after grafting), blue stain = haematoxylin, red lines = graft/host border zones.

Conclusion

We successfully upscaled hiPSC-CM derived EHT to a clinically relevant size and demonstrated feasibility and integration using a rabbit model of myocardial infarction. Tissue engineering strategies may be the preferred modality of cell delivery for future cardiac regenerative medicine studies.

Improved Configuration and LSPR Response of Platinum Nanoparticles via Enhanced Solid State Dewetting of In-Pt Bilayers

Noble metallic nanoparticles (NPs) can exhibit valuable properties such as localized surface plasmon resonance (LSPR) and large surface to volume ratio, which can find various optoelectronic and catalytic applications. In this work, the improved configuration and uniformity of platinum (Pt) NPs are demonstrated by using a sacrificial indium (In) layer via the enhanced solid state dewetting of In-Pt bilayers on sapphire (0001). In a sharp contrast to the conventional dewetting of intrinsic Pt film, the introduction of In component can significantly enhance the global dewetting process and thus can result in the fabrication of well-defined Pt NPs with the improved uniformity. This can be due to the fact that In possess high diffusivity, low surface energy and low sublimation temperature. Upon annealing, the intermixing of In and Pt atoms can occur at the interface due to the inter-diffusion, which forms In-Pt alloy system. As a result, the overall diffusivity and dewetting degree of system can be significantly improved and this can produce more isolated, uniform and semispherical Pt NPs at much lower temperatures as compared to the pure Pt film dewetting. Conveniently, the In atoms preferentially can be removed from the NP matrix by the sublimation even at relatively low temperatures. These Pt NPs exhibit dynamic LSPR band in the UV-visible wavelength based on the excitation of dipolar, quadrupolar and higher order resonance modes. Specifically, the LSPR wavelength can be tuned between ~480 and 580 nm by the fabrication of small to large size Pt NPs with the distinct configuration and interparticle spacing. Furthermore, at a constant Pt thickness, the size, spacing and density of Pt NPs can be readily tuned by the control of In layer thickness. The introduction of sacrificial In component can enable an additional flexibility for the control of surface morphologies of metallic NPs with the low diffusivity materials.

Improved control on the morphology and LSPR properties of plasmonic Pt NPs through enhanced solid state dewetting by using a sacrificial indium layer

Platinum (Pt) nanoparticles (NPs) are important nano-material components in various catalytic, photonic and electronic applications, yet face challenges in the fabrication of desired morphology and uniformity with the conventional solid-state dewetting approach. Specifically, the necessity of high annealing temperatures, typically above 800 °C due to the low diffusivity of Pt atoms, limits the morphological and functional tunability of Pt NPs. In this work, the fabrication of Pt NPs with an improved configuration, spacing and uniformity is demonstrated through the enhancement of solid state dewetting by using a sacrificial indium (In) layer on sapphire (0001). The well-defined Pt NPs demonstrate the dynamic localized surface plasmon (LSPR) bands in the visible range between ∼400 and 700 nm depending on the size and spacing of NPs. The LSPR peak intensity and width are also varied depending on the uniformity of Pt NPs. The overall dewetting magnitude is significantly enhanced through the inter-mixing of In and Pt atoms at the In/Pt interface that eventually results in the formation of an In–Pt alloy. During the dewetting process the In atoms desorb from the NP matrix by atomic sublimation, which gives rise to pure Pt NP fabrication. In sharp contrast to the pure Pt film dewetting, the Pt NPs in this approach demonstrate significantly improved spatial arrangement with well-defined configuration and uniformity. In addition, the ratio of In can be readily controlled along with the thickness of the Pt layer to alter the dewetting kinetics and thereby the surface morphology of Pt NPs. Specifically, large hexagonal, semi-spherical and small hexagonal Pt NPs are obtained through the dewetting of In_{75 nm}/Pt_{25 nm}, In_{20 nm}/Pt_{20 nm} and In_{2.5 nm}/Pt_{7.5 nm} bilayers respectively.

Fabrication of Pt NPs with the improved configuration, spacing, uniformity and localized surface plasmon resonance (LSPR) response is demonstrated.

Modification of dewetting characteristics for the improved morphology and optical properties of platinum nanostructures using a sacrificial indium layer

Metal nanoparticles (NPs) fabricated by means of the solid state dewetting (SSD) approach are applicable in many optoelectronic, biomedical and catalytical applications. However, the fabrication of metallic NPs with the low diffusivity elements such as platinum (Pt) has been challenging for the well-defined configuration and uniformity due to the low diffusivity of Pt atoms and thus the optical properties suffer. In this paper, the evolution of well-defined configuration and improved uniformity of Pt NPs are demonstrated by the altered solid state dewetting (ASSD) approach using a sacrificial indium (In) layer. Upon annealing, the high diffusivity In atoms can lead to the formation of In-Pt alloy due to the inter-mixing at the interface and the dewetting process advances along with the enhanced diffusion of In-Pt alloy atoms. Eventually, well-defined Pt NPs are formed by means of complete desorption of In atoms by sublimation. By the control of In and Pt ratio in the bilayers with the fixed total thickness such as In4.5 nm/Pt1.5 nm, In3 nm/Pt3 nm, In1.5 nm/Pt4.5 nm, the isolated dome shaped Pt NPs of various size are demonstrated, which reflects the significant impact of In component in the dewetting process. The optical characterization of Pt NPs exhibits the formation of quadrupolar resonance and strong dipolar resonance bands in the UV and VIS regions respectively, which are tunable based on the morphology of Pt NPs. In specific, the dipolar resonance peaks demonstrate a red shifting behavior with the increment of size of Pt NPs and gradually become narrower along with the improvement of uniformity of Pt NPs.

Long-term follow-up of hepatic adenoma and adenomatosis: analysis of size change on imaging with histopathological correlation

AIM

To analyse the change in size on follow-up of hepatic adenomas (HAs) and adenomatosis, and to investigate the relationship of imaging features with size change.

MATERIALS AND METHODS

The study included 44 patients (142 lesions) who underwent magnetic resonance imaging (MRI) or computed tomography (CT) for diagnosis and follow-up of HA. The imaging features and percentage change in maximum tumour dimension were observed over a follow-up duration of up to 139 months.

RESULTS

With an average follow-up of 43 months, 37% lesions decreased in size, 58% were stable, 4% increased; one lesion regressed completely. Adenomas were stratified into size groups (<3, 3-5, and ≥5 cm). Size change among the three groups was similar (p>0.05). Percent size change was different for lesions followed for ≤12 months (-7.2%) compared with lesions followed for 13-60 months (-20.5%), and those followed for ≥60 months (-23.5%; p<0.05); there was no difference between lesions followed for 13-60 months and ≥60 months (p=0.523). Baseline size and percent size change was similar between the hepatocyte nuclear factor 1α-inactivated HA (HA-H) and inflammatory HA (HA-I) subtype (p>0.05).

CONCLUSION

Most adenomas were either stable or regressed on follow-up. Size change was independent of baseline size. After an initial size decrease within 5 years, no further size reduction was noted on extended follow-up. The percent size change in the HA-H and HA-I subtype was similar.

Standardization of a two-step real-time polymerase chain reaction based method for species-specific detection of medically important Aspergillus species

PURPOSE

Standardization of Aspergillus polymerase chain reaction (PCR) poses two technical challenges (a) standardization of DNA extraction, (b) optimization of PCR against various medically important Aspergillus species. Many cases of aspergillosis go undiagnosed because of relative insensitivity of conventional diagnostic methods such as microscopy, culture or antigen detection. The present study is an attempt to standardize real-time PCR assay for rapid sensitive and specific detection of Aspergillus DNA in EDTA whole blood.

MATERIALS AND METHODS

Three nucleic acid extraction protocols were compared and a two-step real-time PCR assay was developed and validated following the recommendations of the European Aspergillus PCR Initiative in our setup. In the first PCR step (pan-Aspergillus PCR), the target was 28S rDNA gene, whereas in the second step, species specific PCR the targets were beta-tubulin (for Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus), gene and calmodulin gene (for Aspergillus niger).

RESULTS

Species specific identification of four medically important Aspergillus species, namely, A. fumigatus, A. flavus, A. niger and A. terreus were achieved by this PCR. Specificity of the PCR was tested against 34 different DNA source including bacteria, virus, yeast, other Aspergillus sp., other fungal species and for human DNA and had no false-positive reactions. The analytical sensitivity of the PCR was found to be 102 CFU/ml.

CONCLUSION

The present protocol of two-step real-time PCR assays for genus- and species-specific identification for commonly isolated species in whole blood for diagnosis of invasive Aspergillus infections offers a rapid, sensitive and specific assay option and requires clinical validation at multiple centers.

Modulation of Morphology and Optical Property of Multi-Metallic PdAuAg and PdAg Alloy Nanostructures

In this work, the evolution of PdAg and PdAuAg alloy nanostructures is demonstrated on sapphire (0001) via the solid-state dewetting of multi-metallic thin films. Various surface configurations, size, and arrangements of bi- and tri-metallic alloy nanostructures are fabricated as a function of annealing temperature, annealing duration, film thickness, and deposition arrangements such as bi-layers (Pd/Ag), tri-layers (Pd/Au/Ag), and multi-layers (Pd/Au/Ag × 5). Specifically, the tri-layers film shows the gradual evolution of over-grown NPs, voids, wiggly nanostructures, and isolated PdAuAg alloy nanoparticles (NPs) along with the increased annealing temperature. In contrast, the multi-layers film with same thickness show the enhanced dewetting rate, which results in the formation of voids at relatively lower temperature, wider spacing, and structural regularity of alloy NPs at higher temperature. The dewetting enhancement is attributed to the increased number of interfaces and reduced individual layer thickness, which aid the inter-diffusion process at the initial stage. In addition, the time evolution of the Pd_{150 nm}/Ag_{80 nm} bi-layer films at constant temperature show the wiggly-connected and isolated PdAg alloy NPs. The overall evolution of alloy NPs is discussed based on the solid-state dewetting mechanism in conjunction with the diffusion, inter-diffusion, alloying, sublimation, Rayleigh instability, and surface energy minimization. Depending upon their surface morphologies, the bi- and tri-metallic alloy nanostructures exhibit the dynamic reflectance spectra, which show the formation of dipolar (above 700 nm) and quadrupolar resonance peaks (~ 380 nm) and wide dips in the visible region as correlated to the localized surface plasmon resonance (LSPR) effect. An absorption dip is readily shifted from ~ 510 to ~ 475 nm along with the decreased average size of alloy nanostructures.

Effect of Annealing Temperature on Morphological and Optical Transition of Silver Nanoparticles on c-Plane Sapphire

As a promising candidate for the improved performance, silver nanoparticles (Ag NPs) have been successfully adapted in various applications such as photovoltaics, light emitting diodes (LEDs), sensors and catalysis by taking the advantage of their controllable plasmonic properties. In this paper, the control on the morphologies and optical properties of Ag NPs on c-plane sapphire (0001) is demonstrated by the systematic control of annealing temperature (between 200 and 950 °C) with 20 and 6 nm thick Ag films through the solid state dewetting. With the relatively thicker film of 20 nm, various configuration and size of Ag NPs are fabricated such as irregular, round dome-shaped and tiny Ag NPs depending on the annealing temperature. In a shrill contrast, the 6 nm Ag set exhibits a sharp distinction with the formation of densely packed small NPs and ultra-highly dense tiny Ag NPs due to the higher dewetting rate. While, the surface diffusion assumes the main driving force in the evolution process of Ag NP morphologies up to 550 °C, the sublimation of Ag atoms has played a significant role on top on the surface diffusion between 600 and 950 °C. The reflectance spectra of Ag NPs exhibit the quadrupolar resonance and dipolar resonance peaks, and the evolution of peaks, shift and average reflectance were discussed based on the Ag NPs size and surface coverage. In particular, the dipolar resonance peak in the reflectance spectra red shifts from ~475 to ~570 nm due to the size increment of Ag NPs (38.31 to 74.68 nm). The wide surface coverage of Ag NPs exhibits the highest average reflectance (~27%) and the lowest Raman intensity.

Morphological and optical properties of PdxAg1-x alloy nanoparticles

Alloy nanoparticles (NPs) can offer a wide range of opportunities for various applications due to their composition and structure dependent properties such as multifunctionality, electronic heterogeneity, site-specific response, and multiple plasmon resonance bands. In this work, the fabrication of self-assembled PdxAg1-x NPs alloy nanostructures with distinct size, density, shape, and composition is demonstrated via the solid-state dewetting of sputtered Pd/Ag thin films on c-plane sapphire. The initial stage of bilayer dewetting exhibits the nucleation of voids, followed by the expansion of voids and cluster breakdown and finally shape transformation along with the temperature control. Bilayer composition shows a substantial influence on the dewetting such that the overall dewetting is enhanced along with the increased Ag composition, i.e. Pd0.25Ag0.75 > Pd0.5Ag0.5 > Pd0.75Ag0.25. On the other hand, the size and density of NPs can be efficiently controlled by varying the initial thickness of bilayers. Reflectance peaks in UV and near-infrared (NIR) regions and a wide absorption band in the visible region arisen from the surface plasmon resonance are observed in reflectance spectra. The peak intensity depends on the composition of PdxAg1-x NPs and the NIR peaks gradually blue-shift with the size decrement.

Correction: Compositional effect on the fabrication of AgxPd1−x alloy nanoparticles on c-plane sapphire at distinctive stages of the solid-state-dewetting of bimetallic thin films

Correction for ‘Compositional effect on the fabrication of Ag_xPd_1−x alloy nanoparticles on c-plane sapphire at distinctive stages of the solid-state-dewetting of bimetallic thin films’ by Puran Pandey et al., RSC Adv., 2017, 7, 55471–55481.

Effect of Dairy Manure Storage Conditions on the Survival of E. coli O157:H7 and Listeria

Dairy manure is regularly applied to crop fields as a solid or liquid to improve the soil nutrient status. However, pathogens may survive during manure storage and enter the environment during application. In this study, three storage practices were evaluated to understand the survival patterns of O157:H7 and spp. in dairy manure using a culture-based approach. To replicate common farm manure storage techniques, solid manure was stacked as piles with periodic turning or as static piles without turning, whereas liquid manure (feces, urine, and water) was stored as a slurry in small tanks to simulate lagoon conditions. The and levels in the manure samples were determined for 29 wk. Results showed that there was an initial reduction in bacteria levels in the first month; however, both and managed to survive in the solid manure piles for the full study period. In slurry samples, was not detected after 14 wk, but survived until the end of the experiment at relatively lower levels than in the solid manure piles. Ambient weather and pile size were identified as the main reasons for bacteria survival during the course of the experiment. The outcome of this study is important in terms of understanding pathogen survival in manure piles and slurries prior to their application to crop fields.

p-Hexafluoroisopropanol phenyl functionalized graphene for QCM based detection of dimethyl methylphosphonate, a simulant of the nerve agent sarin

The hexafluoroisopropanol moiety was grafted onto graphene and used as a sensing layer for the detection of a nerve agent simulant using QCM.

Investigation on the morphological and optical evolution of bimetallic Pd-Ag nanoparticles on sapphire (0001) by the systematic control of composition, annealing temperature and time

Multi-metallic alloy nanoparticles (NPs) can offer additional opportunities for modifying the electronic, optical and catalytic properties by the control of composition, configuration and size of individual nanostructures that are consisted of more than single element. In this paper, the fabrication of bimetallic Pd-Ag NPs is systematically demonstrated via the solid state dewetting of bilayer thin films on c-plane sapphire by governing the temperature, time as well as composition. The composition of Pd-Ag bilayer remarkably affects the morphology of alloy nanostructures, in which the higher Ag composition, i.e. Pd_0.25Ag_0.75, leads to the enhanced dewetting of bilayers whereas the higher Pd composition (Pd_0.75Ag_0.25) hinders the dewetting. Depending on the annealing temperature, Pd-Ag alloy nanostructures evolve with a series of configurations, i.e. nucleation of voids, porous network, elongated nanoclusters and round alloy NPs. In addition, with the annealing time set, the gradual configuration transformation from the elongated to round alloy NPs as well as size reduction is demonstrated due to the enhanced diffusion and sublimation of Ag atoms. The evolution of various morphology of Pd-Ag nanostructures is described based on the surface diffusion and inter-diffusion of Pd and Ag adatoms along with the Ag sublimation, Rayleigh instability and energy minimization mechanism. The reflectance spectra of bimetallic Pd-Ag nanostructures exhibit various quadrupolar and dipolar resonance peaks, peak shifts and absorption dips owing to the surface plasmon resonance of nanostructures depending on the surface morphology. The intensity of reflectance spectra is gradually decreased along with the surface coverage and NP size evolution. The absorption dips are red-shifted towards the longer wavelength for the larger alloy NPs and vice-versa.

Effect of Systematic Control of Pd Thickness and Annealing Temperature on the Fabrication and Evolution of Palladium Nanostructures on Si (111) via the Solid State Dewetting

Si-based optoelectronic devices embedded with metallic nanoparticles (NPs) have demonstrated the NP shape, size, spacing, and crystallinity dependent on light absorption and emission induced by the localized surface plasmon resonance. In this work, we demonstrate various sizes and configurations of palladium (Pd) nanostructures on Si (111) by the systematic thermal annealing with the variation of Pd thickness and annealing temperature. The evolution of Pd nanostructures are systematically controlled by the dewetting of thin film by means of the surface diffusion in conjunction with the surface and interface energy minimization and Volmer-Weber growth model. Depending on the control of deposition amount ranging between 0.5 and 100 nm at various annealing temperatures, four distinctive regimes of Pd nanostructures are demonstrated: (i) small pits and grain formation, (ii) nucleation and growth of NPs, (iii) lateral evolution of NPs, and (iv) merged nanostructures. In addition, by the control of annealing between 300 and 800 °C, the Pd nanostructures show the evolution of small pits and grains, isolated NPs, and finally, Pd NP-assisted nanohole formation along with the Si decomposition and Pd-Si inter-diffusion. The Raman analysis showed the discrepancies on phonon modes of Si (111) such that the decreased peak intensity with left shift after the fabrication of Pd nanostructures. Furthermore, the UV-VIS-NIR reflectance spectra revealed the existence of surface morphology dependent on absorption, scattering, and reflectance properties.

Determination of growth regimes of Pd nanostructures on c-plane sapphire by the control of deposition amount at different annealing temperatures

Metallic nanoparticles (NPs) with tunable physical, optical and catalytic properties have a wide range of applications including various optoelectronics, sensors and fuel cells. In this paper, we demonstrate the evolution of various physical properties, configurations, size and density of palladium (Pd) nanostructures on sapphire(Al₂O₃) (0001) by the systematic control of deposition amount (DA) at distinct annealing temperatures. The transformation of the deposited thin films into various Pd NPs is achieved by the dewetting of the thin film by means of surface diffusion, nucleation, Volmer-Weber growth and surface energy minimization mechanism. Depending on the evolution of size, density and configuration, five distinctive regimes of Pd nanostructures are demonstrated: (i) nucleation and evolution of small NPs between 1 and 3 nm, (ii) medium NPs with the dominating vertical growth between 5 and 20 nm, (iii) laterally expanded large NPs between 30 and 40 nm, (iv) irregular coalesced Pd NPs between 50 and 80 nm and (v) voids evolution between 100 and 200 nm. Initial film thickness and annealing temperature play major roles on the dewetting process and the resulting Pd nanostructures are notably distinguished. The fabricated Pd nanostructures influence the lattice vibration modes of sapphire(0001) such as gradual decrement in the intensity and left-shift of the peak position with increased surface coverage. In addition, the optical properties are studied by UV-VIS-NIR (300-1100 nm) reflectance spectra, which shows the reflectance, absorption and scattering over the wavelength and are closely related to the morphology evolution of Pd nanostructures.

Measurement of the Neutrino Mixing Angle θ_{23} in NOvA

This Letter reports new results on muon neutrino disappearance from NOvA, using a 14 kton detector equivalent exposure of 6.05×10^{20} protons on target from the NuMI beam at the Fermi National Accelerator Laboratory. The measurement probes the muon-tau symmetry hypothesis that requires maximal θ_{23} mixing (θ_{23}=π/4). Assuming the normal mass hierarchy, we find Δm_{32}^{2}=(2.67±0.11)×10^{-3}  eV^{2} and sin^{2}θ_{23} at the two statistically degenerate values 0.404_{-0.022}^{+0.030} and 0.624_{-0.030}^{+0.022}, both at the 68% confidence level. Our data disfavor the maximal mixing scenario with 2.6σ significance.

Data collection using open access technology in multicentre operational research involving patient interviews

Conducting multicentre operational research is challenging due to issues related to the logistics of travel, training, supervision, monitoring and troubleshooting support. This is even more burdensome in resource-constrained settings and if the research includes patient interviews. In this article, we describe an innovative model that uses open access tools such as Dropbox, TeamViewer and CamScanner for efficient, quality-assured data collection in an ongoing multicentre operational research study involving record review and patient interviews. The tools used for data collection have been shared for adaptation and use by other researchers.

Free radicals hasten head and neck cancer risk: A study of total oxidant, total antioxidant, DNA damage, and histological grade

Background:

Free radicals such as reactive oxygen species (ROS), which induce oxidative stress, are the main contributors to head and neck carcinogenesis (HNC). The present study was conducted with the aim to assess the oxidant/antioxidant status and DNA damage analysis in head and neck cancer/control patients.

Materials and Methods:

This prospective study was conducted on 60 patients with biopsy-proven HNC and 17 patients of head and neck disease (HND). The total antioxidant status (TAS), total oxidant status (TOS), and oxidative stress index (OSI) were determined by novel automatic colorimetric methods from tissue homogenate. DNA damage analysis was determined by single cell gel electrophoresis (SCGE).

Results:

The mean age of the study cohort was 46.65 ± 14.84 years for HNC patients, while it was 49.41 ± 13.00 years for HND patients. There were no significant differences found between the two groups with respect to demographic presentation except tobacco addiction. The association between oxidative stress parameters and DNA damage analysis with study group revealed the following. (A) DNA damage - tissue homogenate TOS and OSI were significantly higher in HNC subjects than in HND (16.06 ± 1.78 AU vs 7.86 ± 5.97 AU, P < 0.001; 53.00 ± 40.61 vs 19.67 ± 21.90, P < 0.01; 7.221 ± 5.80 vs 2.40 ± 2.54, P < 0.01, respectively), while TAS was significantly decreased. (B) Aggressive histological features were identified, more commonly with higher TOS and lower TAS [probability (P) = 0.002, relative risk (RR) = 11.838, 95% confidence interval CI = 2.514-55.730 and P = 0.043, RR = 0.271, 95% CI = 0.077-0.960, respectively].

Conclusion:

The increase in free radicals may be the event that led to the reduction of antioxidant status in HNC, thus explaining the oxidative damage of DNA and the severity of disease. Increased OSI represents a general mechanism in its pathogenesis.

Various Silver Nanostructures on Sapphire Using Plasmon Self-Assembly and Dewetting of Thin Films

Silver (Ag) nanostructures demonstrate outstanding optical, electrical, magnetic, and catalytic properties and are utilized in photonic, energy, sensors, and biomedical devices. The target application and the performance can be inherently tuned by control of configuration, shape, and size of Ag nanostructures. In this work, we demonstrate the systematical fabrication of various configurations of Ag nanostructures on sapphire (0001) by controlling the Ag deposition thickness at different annealing environments in a plasma ion coater. In particular, the evolution of Ag particles (between 2 and 20 nm), irregular nanoclusters (between 30 and 60 nm), and nanocluster networks (between 80 and 200 nm) are found be depended on the thickness of Ag thin film. The results were systematically analyzed and explained based on the solid-state dewetting, surface diffusion, Volmer-Weber growth model, coalescence, and surface energy minimization mechanism. The growth behavior of Ag nanostructures is remarkably differentiated at higher annealing temperature (750 °C) due to the sublimation and temperature-dependent characteristic of dewetting process. In addition, Raman and reflectance spectra analyses reveal that optical properties of Ag nanostructures depend on their morphology.

Compositional effect on the fabrication of AgxPd1−x alloy nanoparticles on c-plane sapphire at distinctive stages of the solid-state-dewetting of bimetallic thin films

The bilayer composition effect on the evolution of AgxPd_1–x nanoparticles is thoroughly investigated by the thermal activation, diffusion and inter-mixing of Ag–Pd adatoms with respect to the growth conditions on c-plane sapphire.

A high yield DNA extraction method for medically important Candida species: A comparison of manual versus QIAcube-based automated system

The prognosis of infected individuals with candidemia depends on rapid and precise diagnosis which enables optimising treatment. Three fungal DNA extraction protocols have been compared in this study for medically important Candida species. The quality and quantity of the DNA extracted by physical, chemical and automated protocols was compared using NanoDrop ND-2000 spectrophotometer. It was found that the yield and purity (260/230) ratio of extracted DNA was significantly high in the physical treatment-based protocol as compared to chemical based or automated protocol. Extracted DNA-based real time-polymerase chain reaction showed an analytical sensitivity of 103 cfu/mL. The result of this study suggests physical treatment is the most successful extraction technique compared to other two protocols.

Linitis plastica like primary signet ring cell carcinoma of the gallbladder - an extremely rare variant

Signet ring carcinoma (SRCC) of gallbladder is an extremely rare tumor accounting for approximately 3% of all gallbladder carcinomas, with a handful of case reports in the literature. We report a case of signet ring cell carcinoma of the gallbladder in a 70 year-old female who was operated upon after the preoperative diagnosis of cholecystitis with cholelithiasis, based on ultrasonographic findings and subsequently diagnosed as signet ring cell carcinoma of the gallbladder on histopathological examination. Grossly there was no discrete growth, instead tumor presented as linitis plastica like diffuse thickening of the gallbladder wall. Microscopic examination revealed a diffusely infiltrative carcinoma comprised exclusively of signet ring cells and confirmed by periodic acid-Schiff (PAS), Alcian blue & Cytokeratin 7 stains. Post -operative clinico-radiological workup was done to exclude secondary. This highly aggressive signet ring cell carcinoma of gallbladder is being reported because of its rarity, its unique histomorphological features and diagnostic inadequacy of the routinely performed ultrasonography as well as highlighting the use of special stains and immunohistochemistry to exclude other possibilities. Our case highlights that routine histopathological examination of all the cholecystectomy specimens is a must to facilitate the early diagnosis of aggressive signet ring cell carcinoma gallbladder.