First Measurement of η Meson Production in Neutrino Interactions on Argon with MicroBooNE

We present a measurement of η production from neutrino interactions on argon with the MicroBooNE detector. The modeling of resonant neutrino interactions on argon is a critical aspect of the neutrino oscillation physics program being carried out by the DUNE and Short Baseline Neutrino programs. η production in neutrino interactions provides a powerful new probe of resonant interactions, complementary to pion channels, and is particularly suited to the study of higher-order resonances beyond the Δ(1232). We measure a flux-integrated cross section for neutrino-induced η production on argon of 3.22±0.84(stat)±0.86(syst) 10^{-41}  cm^{2}/nucleon. By demonstrating the successful reconstruction of the two photons resulting from η production, this analysis enables a novel calibration technique for electromagnetic showers in GeV accelerator neutrino experiments.

Search for Heavy Neutral Leptons in Electron-Positron and Neutral-Pion Final States with the MicroBooNE Detector

We present the first search for heavy neutral leptons (HNLs) decaying into νe^{+}e^{-} or νπ^{0} final states in a liquid-argon time projection chamber using data collected with the MicroBooNE detector. The data were recorded synchronously with the NuMI neutrino beam from Fermilab's main injector corresponding to a total exposure of 7.01×10^{20} protons on target. We set upper limits at the 90% confidence level on the mixing parameter |U_{μ4}|^{2} in the mass ranges 10≤m_{HNL}≤150  MeV for the νe^{+}e^{-} channel and 150≤m_{HNL}≤245  MeV for the νπ^{0} channel, assuming |U_{e4}|^{2}=|U_{τ4}|^{2}=0. These limits represent the most stringent constraints in the mass range 35 Collapse

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Affiliation(s)

P Abratenko Tufts University, Medford, Massachusetts 02155, USA
O Alterkait Tufts University, Medford, Massachusetts 02155, USA
D Andrade Aldana Illinois Institute of Technology (IIT), Chicago, Illinois 60616, USA
L Arellano The University of Manchester, Manchester M13 9PL, United Kingdom
J Asaadi University of Texas, Arlington, Texas 76019, USA
A Ashkenazi Tel Aviv University, Tel Aviv, Israel, 69978
S Balasubramanian Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
B Baller Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
G Barr University of Oxford, Oxford OX1 3RH, United Kingdom
D Barrow University of Oxford, Oxford OX1 3RH, United Kingdom
J Barrow Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA Tel Aviv University, Tel Aviv, Israel, 69978
V Basque Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
O Benevides Rodrigues Illinois Institute of Technology (IIT), Chicago, Illinois 60616, USA
S Berkman Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA Michigan State University, East Lansing, Michigan 48824, USA
A Bhanderi The University of Manchester, Manchester M13 9PL, United Kingdom
A Bhat University of Chicago, Chicago, Illinois 60637, USA
M Bhattacharya Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
M Bishai Brookhaven National Laboratory (BNL), Upton, New York 11973, USA
A Blake Lancaster University, Lancaster LA1 4YW, United Kingdom
B Bogart University of Michigan, Ann Arbor, Michigan 48109, USA
T Bolton Kansas State University (KSU), Manhattan, Kansas 66506, USA
J Y Book Harvard University, Cambridge, Massachusetts 02138, USA
M B Brunetti University of Warwick, Coventry CV4 7AL, United Kingdom
L Camilleri Columbia University, New York, New York 10027, USA
Y Cao The University of Manchester, Manchester M13 9PL, United Kingdom
D Caratelli University of California, Santa Barbara, California 93106, USA
F Cavanna Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
G Cerati Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
A Chappell University of Warwick, Coventry CV4 7AL, United Kingdom
Y Chen SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
J M Conrad Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA
M Convery SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
L Cooper-Troendle University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
J I Crespo-Anadón Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), Madrid E-28040, Spain
R Cross University of Warwick, Coventry CV4 7AL, United Kingdom
M Del Tutto Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
S R Dennis University of Cambridge, Cambridge CB3 0HE, United Kingdom
P Detje University of Cambridge, Cambridge CB3 0HE, United Kingdom
A Devitt Lancaster University, Lancaster LA1 4YW, United Kingdom
R Diurba Universität Bern, Bern CH-3012, Switzerland
Z Djurcic Argonne National Laboratory (ANL), Lemont, Illinois 60439, USA
R Dorrill Illinois Institute of Technology (IIT), Chicago, Illinois 60616, USA
K Duffy University of Oxford, Oxford OX1 3RH, United Kingdom
S Dytman University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
B Eberly University of Southern Maine, Portland, Maine 04104, USA
P Englezos Rutgers University, Piscataway, New Jersey 08854, USA
A Ereditato University of Chicago, Chicago, Illinois 60637, USA Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
J J Evans The University of Manchester, Manchester M13 9PL, United Kingdom
R Fine Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, USA
O G Finnerud The University of Manchester, Manchester M13 9PL, United Kingdom
W Foreman Illinois Institute of Technology (IIT), Chicago, Illinois 60616, USA
B T Fleming University of Chicago, Chicago, Illinois 60637, USA
D Franco University of Chicago, Chicago, Illinois 60637, USA
A P Furmanski University of Minnesota, Minneapolis, Minnesota 55455, USA
F Gao University of California, Santa Barbara, California 93106, USA
D Garcia-Gamez Universidad de Granada, Granada E-18071, Spain
S Gardiner Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
G Ge Columbia University, New York, New York 10027, USA
S Gollapinni Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, USA
E Gramellini The University of Manchester, Manchester M13 9PL, United Kingdom
P Green University of Oxford, Oxford OX1 3RH, United Kingdom
H Greenlee Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
L Gu Lancaster University, Lancaster LA1 4YW, United Kingdom
W Gu Brookhaven National Laboratory (BNL), Upton, New York 11973, USA
R Guenette The University of Manchester, Manchester M13 9PL, United Kingdom
P Guzowski The University of Manchester, Manchester M13 9PL, United Kingdom
L Hagaman University of Chicago, Chicago, Illinois 60637, USA
O Hen Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA
C Hilgenberg University of Minnesota, Minneapolis, Minnesota 55455, USA
G A Horton-Smith Kansas State University (KSU), Manhattan, Kansas 66506, USA
Z Imani Tufts University, Medford, Massachusetts 02155, USA
B Irwin University of Minnesota, Minneapolis, Minnesota 55455, USA
M Ismail University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
C James Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
X Ji Nankai University, Nankai District, Tianjin 300071, China
J H Jo Brookhaven National Laboratory (BNL), Upton, New York 11973, USA
R A Johnson University of Cincinnati, Cincinnati, Ohio 45221, USA
Y-J Jwa Columbia University, New York, New York 10027, USA
D Kalra Columbia University, New York, New York 10027, USA
N Kamp Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA
G Karagiorgi Columbia University, New York, New York 10027, USA
W Ketchum Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
M Kirby Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
T Kobilarcik Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
I Kreslo Universität Bern, Bern CH-3012, Switzerland
M B Leibovitch University of California, Santa Barbara, California 93106, USA
I Lepetic Rutgers University, Piscataway, New Jersey 08854, USA
J-Y Li University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
K Li Wright Laboratory, Department of Physics, Yale University, New Haven, Connecticut 06520, USA
Y Li Brookhaven National Laboratory (BNL), Upton, New York 11973, USA
K Lin Rutgers University, Piscataway, New Jersey 08854, USA
B R Littlejohn Illinois Institute of Technology (IIT), Chicago, Illinois 60616, USA
H Liu Brookhaven National Laboratory (BNL), Upton, New York 11973, USA
W C Louis Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, USA
X Luo University of California, Santa Barbara, California 93106, USA
C Mariani Center for Neutrino Physics, Virginia Tech, Blacksburg, Viriginia 24061, USA
D Marsden The University of Manchester, Manchester M13 9PL, United Kingdom
J Marshall University of Warwick, Coventry CV4 7AL, United Kingdom
N Martinez Kansas State University (KSU), Manhattan, Kansas 66506, USA
D A Martinez Caicedo South Dakota School of Mines and Technology (SDSMT), Rapid City, South Dakota 57701, USA
S Martynenko Brookhaven National Laboratory (BNL), Upton, New York 11973, USA
A Mastbaum Rutgers University, Piscataway, New Jersey 08854, USA
I Mawby University of Warwick, Coventry CV4 7AL, United Kingdom
N McConkey University College London, London WC1E 6BT, United Kingdom
V Meddage Kansas State University (KSU), Manhattan, Kansas 66506, USA
J Micallef Massachusetts Institute of Technology (MIT), Cambridge, Massachusetts 02139, USA Tufts University, Medford, Massachusetts 02155, USA
K Miller University of Chicago, Chicago, Illinois 60637, USA
A Mogan Colorado State University, Fort Collins, Colorado 80523, USA
T Mohayai Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA Indiana University, Bloomington, Indiana 47405, USA
M Mooney Colorado State University, Fort Collins, Colorado 80523, USA
A F Moor University of Cambridge, Cambridge CB3 0HE, United Kingdom
C D Moore Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
L Mora Lepin The University of Manchester, Manchester M13 9PL, United Kingdom
M M Moudgalya The University of Manchester, Manchester M13 9PL, United Kingdom
S Mulleriababu Universität Bern, Bern CH-3012, Switzerland
D Naples University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
A Navrer-Agasson The University of Manchester, Manchester M13 9PL, United Kingdom
N Nayak Brookhaven National Laboratory (BNL), Upton, New York 11973, USA
M Nebot-Guinot University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
J Nowak Lancaster University, Lancaster LA1 4YW, United Kingdom
N Oza Columbia University, New York, New York 10027, USA
O Palamara Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
N Pallat University of Minnesota, Minneapolis, Minnesota 55455, USA
V Paolone University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
A Papadopoulou Argonne National Laboratory (ANL), Lemont, Illinois 60439, USA
V Papavassiliou New Mexico State University (NMSU), Las Cruces, New Mexico 88003, USA
H B Parkinson University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
S F Pate New Mexico State University (NMSU), Las Cruces, New Mexico 88003, USA
N Patel Lancaster University, Lancaster LA1 4YW, United Kingdom
Z Pavlovic Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
E Piasetzky Tel Aviv University, Tel Aviv, Israel, 69978
I Pophale Lancaster University, Lancaster LA1 4YW, United Kingdom
X Qian Brookhaven National Laboratory (BNL), Upton, New York 11973, USA
J L Raaf Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
V Radeka Brookhaven National Laboratory (BNL), Upton, New York 11973, USA
A Rafique Argonne National Laboratory (ANL), Lemont, Illinois 60439, USA
M Reggiani-Guzzo University of Edinburgh, Edinburgh EH9 3FD, United Kingdom The University of Manchester, Manchester M13 9PL, United Kingdom
L Ren New Mexico State University (NMSU), Las Cruces, New Mexico 88003, USA
L Rochester SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
J Rodriguez Rondon South Dakota School of Mines and Technology (SDSMT), Rapid City, South Dakota 57701, USA
M Rosenberg Tufts University, Medford, Massachusetts 02155, USA
M Ross-Lonergan Los Alamos National Laboratory (LANL), Los Alamos, New Mexico 87545, USA
C Rudolf von Rohr Universität Bern, Bern CH-3012, Switzerland
I Safa Columbia University, New York, New York 10027, USA
G Scanavini Wright Laboratory, Department of Physics, Yale University, New Haven, Connecticut 06520, USA
D W Schmitz University of Chicago, Chicago, Illinois 60637, USA
A Schukraft Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
W Seligman Columbia University, New York, New York 10027, USA
M H Shaevitz Columbia University, New York, New York 10027, USA
R Sharankova Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
J Shi University of Cambridge, Cambridge CB3 0HE, United Kingdom
E L Snider Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
M Soderberg Syracuse University, Syracuse, New York 13244, USA
S Söldner-Rembold The University of Manchester, Manchester M13 9PL, United Kingdom
J Spitz University of Michigan, Ann Arbor, Michigan 48109, USA
M Stancari Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
J St John Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
T Strauss Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
A M Szelc University of Edinburgh, Edinburgh EH9 3FD, United Kingdom
W Tang University of Tennessee, Knoxville, Tennessee 37996, USA
N Taniuchi University of Cambridge, Cambridge CB3 0HE, United Kingdom
K Terao SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
C Thorpe Lancaster University, Lancaster LA1 4YW, United Kingdom The University of Manchester, Manchester M13 9PL, United Kingdom
D Torbunov Brookhaven National Laboratory (BNL), Upton, New York 11973, USA
D Totani University of California, Santa Barbara, California 93106, USA
M Toups Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
Y-T Tsai SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
J Tyler Kansas State University (KSU), Manhattan, Kansas 66506, USA
M A Uchida University of Cambridge, Cambridge CB3 0HE, United Kingdom
T Usher SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
B Viren Brookhaven National Laboratory (BNL), Upton, New York 11973, USA
M Weber Universität Bern, Bern CH-3012, Switzerland
H Wei Louisiana State University, Baton Rouge, Louisiana 70803, USA
A J White University of Chicago, Chicago, Illinois 60637, USA
S Wolbers Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
T Wongjirad Tufts University, Medford, Massachusetts 02155, USA
M Wospakrik Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
K Wresilo University of Cambridge, Cambridge CB3 0HE, United Kingdom
W Wu University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
E Yandel University of California, Santa Barbara, California 93106, USA
T Yang Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
L E Yates Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
H W Yu Brookhaven National Laboratory (BNL), Upton, New York 11973, USA
G P Zeller Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
J Zennamo Fermi National Accelerator Laboratory (FNAL), Batavia, Illinois 60510, USA
C Zhang Brookhaven National Laboratory (BNL), Upton, New York 11973, USA

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First Double-Differential Measurement of Kinematic Imbalance in Neutrino Interactions with the MicroBooNE Detector

We report the first measurement of flux-integrated double-differential quasielasticlike neutrino-argon cross sections, which have been made using the Booster Neutrino Beam and the MicroBooNE detector at Fermi National Accelerator Laboratory. The data are presented as a function of kinematic imbalance variables which are sensitive to nuclear ground-state distributions and hadronic reinteraction processes. We find that the measured cross sections in different phase-space regions are sensitive to different nuclear effects. Therefore, they enable the impact of specific nuclear effects on the neutrino-nucleus interaction to be isolated more completely than was possible using previous single-differential cross section measurements. Our results provide precision data to help test and improve neutrino-nucleus interaction models. They further support ongoing neutrino-oscillation studies by establishing phase-space regions where precise reaction modeling has already been achieved.

First Measurement of Quasielastic Λ Baryon Production in Muon Antineutrino Interactions in the MicroBooNE Detector

We present the first measurement of the cross section of Cabibbo-suppressed Λ baryon production, using data collected with the MicroBooNE detector when exposed to the neutrinos from the main injector beam at the Fermi National Accelerator Laboratory. The data analyzed correspond to 2.2×10^{20} protons on target running in neutrino mode, and 4.9×10^{20} protons on target running in anti-neutrino mode. An automated selection is combined with hand scanning, with the former identifying five candidate Λ production events when the signal was unblinded, consistent with the GENIE prediction of 5.3±1.1 events. Several scanners were employed, selecting between three and five events, compared with a prediction from a blinded Monte Carlo simulation study of 3.7±1.0 events. Restricting the phase space to only include Λ baryons that decay above MicroBooNE's detection thresholds, we obtain a flux averaged cross section of 2.0_{-1.7}^{+2.2}×10^{-40}  cm^{2}/Ar, where statistical and systematic uncertainties are combined.

Measurement of the ν_{e}-Nucleus Charged-Current Double-Differential Cross Section at ⟨E_{ν}⟩=2.4 GeV Using NOvA

The inclusive electron neutrino charged-current cross section is measured in the NOvA near detector using 8.02×10^{20} protons-on-target in the NuMI beam. The sample of GeV electron neutrino interactions is the largest analyzed to date and is limited by ≃17% systematic rather than the ≃7.4% statistical uncertainties. The double-differential cross section in final-state electron energy and angle is presented for the first time, together with the single-differential dependence on Q^{2} (squared four-momentum transfer) and energy, in the range 1  GeV≤E_{ν}<6  GeV. Detailed comparisons are made to the predictions of the GENIE, GiBUU, NEUT, and NuWro neutrino event generators. The data do not strongly favor a model over the others consistently across all three cross sections measured, though some models have especially good or poor agreement in the single differential cross section vs Q^{2}.

Raman Snapshots of Side-Chain Dependent Polaron Dynamics in PolyThiophene Films

Photogenerated polarons in π-conjugated polymers are the precursors to free charges at donor-acceptor interfaces. Unraveling the relationship between film morphology and polaron formation is conjectured to enable efficient charge generation in organic photovoltaic devices. However, it has been challenging to track the ultrafast dynamics of polarons selectively and thus evaluate the molecular coordinates that drive charge generation in films. Using a combination of broadband femtosecond transient absorption and resonance-selective femtosecond stimulated Raman spectroscopy, here, we investigate the polaron generation dynamics exclusively in traditional crystalline poly(3-hexylthiophene) (P3HT) and its amorphous side-chain variant poly(3-(2-ethylhexyl)thiophene-2,5-diyl) (P3EHT) films. The transient Raman data unequivocally provides evidence for an initial delocalization of the polaronic states via thiophene backbone planarization in ∼100 fs while capturing the subsequent morphology-dependent cooling dynamics in a few picoseconds. Our work highlights the structural significance of crystalline morphology in generating hot-charges and thereby emphasizes the importance of side-chain engineering in designing highly efficient conjugated polymer films for hot-carrier photovoltaic devices.

First Constraints on Light Sterile Neutrino Oscillations from Combined Appearance and Disappearance Searches with the MicroBooNE Detector

We present a search for eV-scale sterile neutrino oscillations in the MicroBooNE liquid argon detector, simultaneously considering all possible appearance and disappearance effects within the 3+1 active-to-sterile neutrino oscillation framework. We analyze the neutrino candidate events for the recent measurements of charged-current ν_{e} and ν_{μ} interactions in the MicroBooNE detector, using data corresponding to an exposure of 6.37×10^{20} protons on target from the Fermilab booster neutrino beam. We observe no evidence of light sterile neutrino oscillations and derive exclusion contours at the 95% confidence level in the plane of the mass-squared splitting Δm_{41}^{2} and the sterile neutrino mixing angles θ_{μe} and θ_{ee}, excluding part of the parameter space allowed by experimental anomalies. Cancellation of ν_{e} appearance and ν_{e} disappearance effects due to the full 3+1 treatment of the analysis leads to a degeneracy when determining the oscillation parameters, which is discussed in this Letter and will be addressed by future analyses.

Process Intensification of Dendritic Fibrous Nanospheres of Silica (KCC-1) via continuous flow: A Scalable, and Sustainable Route to a Conventional Batch Synthesis

In this manuscript, we report the scalable continuous flow synthesis of dendritic fibrous nanospheres of silica (DFNS) which has been speedily making a significant mark in the world of heterogeneous...

Scintillation light detection in the 6-m drift-length ProtoDUNE Dual Phase liquid argon TPC

DUNE is a dual-site experiment for long-baseline neutrino oscillation studies, neutrino astrophysics and nucleon decay searches. ProtoDUNE Dual Phase (DP) is a 6  ×  6  ×  6 m 3 liquid argon time-projection-chamber (LArTPC) that recorded cosmic-muon data at the CERN Neutrino Platform in 2019-2020 as a prototype of the DUNE Far Detector. Charged particles propagating through the LArTPC produce ionization and scintillation light. The scintillation light signal in these detectors can provide the trigger for non-beam events. In addition, it adds precise timing capabilities and improves the calorimetry measurements. In ProtoDUNE-DP, scintillation and electroluminescence light produced by cosmic muons in the LArTPC is collected by photomultiplier tubes placed up to 7 m away from the ionizing track. In this paper, the ProtoDUNE-DP photon detection system performance is evaluated with a particular focus on the different wavelength shifters, such as PEN and TPB, and the use of Xe-doped LAr, considering its future use in giant LArTPCs. The scintillation light production and propagation processes are analyzed and a comparison of simulation to data is performed, improving understanding of the liquid argon properties.

Milk exosomes elicit a potent anti-viral activity against dengue virus

Background

Exosomes are nano-sized vesicles secreted by various cells into the intra and extracellular space and hence is an integral part of biological fluids including milk. In the last few decades, many research groups have proved the potential of milk exosomes as a sustainable, economical and non-immunogenic drug delivery and therapeutic agent against different pathological conditions. However, its anti-viral properties still remain to be unearthed.

Methods

Here, we have been able to isolate, purify and characterize the milk derived exosomes from Cow (CME) and Goat (GME) and further studied its antiviral properties against Dengue virus (DENV), Newcastle Disease Virus strain Komarov (NDV-K) and Human Immunodeficiency Virus (HIV-1) using an in-vitro infection system.

Results

TEM, NTA and DLS analysis validated the appropriate size of the isolated cow and goat milk exosomes (30–150 nm). Real-time PCR and immunoblotting results confirmed the presence of several milk exosomal miRNAs and protein markers. Our findings suggest that GME significantly decreased the infectivity of DENV. In addition, we confirmed that GME significantly reduces DENV replication and reduced the secretion of mature virions. Furthermore, heat inactivation of GME did not show any inhibition on DENV infection, replication, and secretion of mature virions. RNase treatment of GME abrogates the anti-viral properties indicating direct role of exosomes in DENV inhibition. In addition GME inhibited the infectivity of NDV-K, but not HIV-1, suggesting that the GME mediated antiviral activity might be virus specific.

Conclusion

This study demonstrates the anti-viral properties of milk exosomes and opens new avenues for the development of exosome-based therapies to treat viral diseases.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01496-5.

Resolving the backbone tilt of crystalline poly(3-hexylthiophene) with resonant tender X-ray diffraction

The way in which conjugated polymers pack in the solid state strongly affects the performance of polymer-based optoelectronic devices. However, even for the most crystalline conjugated polymers the precise packing of chains within the unit cell is not well established. Here we show that by performing resonant X-ray diffraction experiments at the sulfur K-edge we are able to resolve the tilting of the planar backbones of crystalline poly(3-hexylthiophene) (P3HT) within the unit cell. This approach exploits the anisotropic nature of the X-ray optical properties of conjugated polymers, enabling us to discern between different proposed crystal structures. By comparing our data with simulations based on different orientations, a tilting of the planar conjugated backbone with respect to the side chain stacking direction of 30 ± 5° is determined.

Environmental enrichment preserves hippocampal neurons in diabetes and stressed rats

This study evaluated the effect of Environmental Enrichment (EE) on neuron morphology in the CA1, CA3 and dentate hilus (DH) regions of the hippocampus by quantitating the total dendritic arborizations. EE is a potential intervention for stress and diabetes. It is capable of mitigating diabetes and stress-induced cognitive and memory deficit. Diabetes and stress were induced in male Wistar rats (4-5 weeks). Diabetic and stressed rats were exposed to EE on Day 2 post STZ injection and subsequently once daily for 30 days. All animals were sacrificed on Day 30. The hippocampus was dissected and processed for Golgi staining to quantitate dendritic arborizations at the CA1, CA2 and DH regions. Diabetes (D) and Diabetes+stress (D+S) groups had significantly fewer apical and basal dendritic branching points (ADBP, BDBP) at CA1 (p<0.01), CA3 (p<0.001) and DH (p<0.001) relative to control group (NC). Diabetes and stressed rats exposed to EE: [D+EE and D+S+EE groups] exhibited significantly denser ADBP and BDBP at all regions relative to D (p<0.001) and (D+S+EE) (p<0.001) groups respectively. EE significantly preserved neuronal arborizations in hippocampus of diabetic and stressed rats, suggesting a potential entity of diabetes and stress management.

Search for Active-Sterile Antineutrino Mixing Using Neutral-Current Interactions with the NOvA Experiment

This Letter reports results from the first long-baseline search for sterile antineutrinos mixing in an accelerator-based antineutrino-dominated beam. The rate of neutral-current interactions in the two NOvA detectors, at distances of 1 and 810 km from the beam source, is analyzed using an exposure of 12.51×10^{20} protons-on-target from the NuMI beam at Fermilab running in antineutrino mode. A total of 121 of neutral-current candidates are observed at the far detector, compared to a prediction of 122±11(stat.)±15(syst.) assuming mixing only between three active flavors. No evidence for ν[over ¯]_{μ}→ν[over ¯]_{s} oscillation is observed. Interpreting this result within a 3+1 model, constraints are placed on the mixing angles θ_{24}<25° and θ_{34}<32° at the 90% C.L. for 0.05  eV^{2}≤Δm_{41}^{2}≤0.5  eV^{2}, the range of mass splittings that produces no significant oscillations at the near detector. These are the first 3+1 confidence limits set using long-baseline accelerator antineutrinos.

Prospects for beyond the Standard Model physics searches at the Deep Underground Neutrino Experiment: DUNE Collaboration

The Deep Underground Neutrino Experiment (DUNE) will be a powerful tool for a variety of physics topics. The high-intensity proton beams provide a large neutrino flux, sampled by a near detector system consisting of a combination of capable precision detectors, and by the massive far detector system located deep underground. This configuration sets up DUNE as a machine for discovery, as it enables opportunities not only to perform precision neutrino measurements that may uncover deviations from the present three-flavor mixing paradigm, but also to discover new particles and unveil new interactions and symmetries beyond those predicted in the Standard Model (SM). Of the many potential beyond the Standard Model (BSM) topics DUNE will probe, this paper presents a selection of studies quantifying DUNE's sensitivities to sterile neutrino mixing, heavy neutral leptons, non-standard interactions, CPT symmetry violation, Lorentz invariance violation, neutrino trident production, dark matter from both beam induced and cosmogenic sources, baryon number violation, and other new physics topics that complement those at high-energy colliders and significantly extend the present reach.

In Vitro Evaluation of Substantivity, Staining Potential, and Biofilm Reduction of Guava Leaf Extract Mouth Rinse in Combination with its Anti-Inflammatory Effect on Human Gingival Epithelial Keratinocytes

This study aimed to assess the biofilm reduction, staining potential, and cytotoxicity of guava extract mouth rinse compared to chlorhexidine (CHX). Substantivity, staining, and antibiofilm potential were investigated by spectrophotometry, colony-forming units, and luminosity color meter, respectively. The cell viability assay was conducted using a colorimetric assay to determine nontoxic levels of guava (0.15%) and CHX in human gingival epithelial keratinocytes (HGEK-16). Cells were treated with lipopolysaccharides (LPS, 1μg/mL) and guava to assess inflammatory gene expression levels of interleukin-β1, tumor necrosis factor-α, and Prostaglandin E2. A scratch wound healing assay investigated the effects of guava on cell migration. The teeth coated in guava mouth rinse displayed 19.4% higher substantivity compared to CHX (0.2%), and the anti-biofilm reduction was observed with both guava and CHX mouth rinses (P < 0.05). The overall discoloration changes were higher with CHX and distilled water compared to guava. Also, guava significantly enhanced HGEK-16 cell viability (P < 0.05), and IL-β1, TNFα and PGE2 expression presented a 0.6-fold decrease when exposed to guava and LPS (P < 0.05). The present study showed that guava mouth rinse fulfilled the requirement for an effective and useful oral care product with desirable substantivity and anti-biofilm action. In addition, guava reduced the inflammation response in HGEK-16 and may be a potential oral rinse for oral anti-inflammatory therapies.

First measurement of neutrino oscillation parameters using neutrinos and antineutrinos by NOvA

The NOvA experiment has seen a 4.4σ signal of ν[over ¯]_{e} appearance in a 2 GeV ν[over ¯]_{μ} beam at a distance of 810 km. Using 12.33×10^{20} protons on target delivered to the Fermilab NuMI neutrino beamline, the experiment recorded 27 ν[over ¯]_{μ}→ν[over ¯]_{e} candidates with a background of 10.3 and 102 ν[over ¯]_{μ}→ν[over ¯]_{μ} candidates. This new antineutrino data are combined with neutrino data to measure the parameters |Δm_{32}^{2}|=2.48_{-0.06}^{+0.11}×10^{-3}  eV^{2}/c^{4} and sin^{2}θ_{23} in the ranges from (0.53-0.60) and (0.45-0.48) in the normal neutrino mass hierarchy. The data exclude most values near δ_{CP}=π/2 for the inverted mass hierarchy by more than 3σ and favor the normal neutrino mass hierarchy by 1.9σ and θ_{23} values in the upper octant by 1.6σ.

Remarkable colorimetric sensing behavior of pyrazole-based chemosensor towards Cu(ii) ion detection: synthesis, characterization and theoretical investigations

We report the synthesis of a new imine based ligand, 3-((3-methoxybenzylidene)amino)-1H-pyrazol-5-ol (HL) and its Cu(ii) complexes in 2 : 1 (HL : metal) and 1 : 1 : 1 (HL : metal : HQ) stoichiometric ratio using 8-hydroxyquinoline (HQ) as an additional bidentate ligand. The synthesized ligand (HL) and its Cu(ii) complexes (1 and 2) are structurally characterized using FT-IR, electronic absorption and emission, NMR and MS techniques. Furthermore, the complexation of Cu2+ with HL leads to the immediate formation of brown colour solution which indicates that HL can act as simple colorimetric sensor for Cu2+ ions. We further investigated that the sensor could selectively bind to the Cu2+ ions even in the presence of competitive ions such as Mn2+, Fe2+, Co2+, Ni2+, Zn2+, Ag+ and Na+ ions in aqueous solutions which was studied by electronic absorption spectroscopy. The HL ligand has been investigated for its reactive properties by density functional theory (DFT) calculations. Quantum molecular descriptors describing local reactive properties have been calculated in order to identify the most reactive molecule sites of title compounds. DFT calculations encompassed molecular electrostatic potential (MEP), local average ionization energies (ALIE), Fukui functions and bond dissociation energies for hydrogen abstraction (H-BDE).

Utility of fine needle aspiration cytology in evaluation of lymphadenopathy - An audit from a Cancer Centre in South India

BACKGROUND

Cytological evaluation and diagnosis of lymphadenopathy plays an important role in distinction between reactive hyperplasia and malignancy.Being a tertiary cancer care centre, lymph node enlargement clinically suspected to be due to malignancy constitute the commonest indication for fine needle aspiration cytology (FNAC) at our centre. The aim of this study was to determine the utility of FNAC in evaluating enlarged lymph nodes and to categorizethe causes of lymphadenopathy diagnosed byFNAC at our centre.

MATERIAL AND METHODS

Data was collected from the records of department of Pathology over a period of three months from January to March 2014. The data was analyzed and various parameters studied.

RESULTS

There were 2000 aspirates over a period of three months of which 270 (13.5%) were from lymph nodes. Of these, 130 cases (48.2%) have metastatic deposits.We also came across 16 cases (5.9%) of lymphoma, 5 cases (1.9%) of granulomatous lymphadenitis, 2 cases (0.7%) of suppurative lesion and 99 cases (36.7%) of reactive hyperplasia during this period. In 3 cases (1.1%), the lesion turned out to be of salivary gland origin. Aspirates were suboptimal for diagnosis in 15 cases (5.5%). Aspirates were more in males (181) as compared to females (89). The most common site of aspiration was the cervical lymph node(64.5%),followed by supraclavicular=81(30%), inguinal=33(12.22%), axillary=19(7.04%) sub mental=1(0.37%) and others=7(2.59%). Apart from metastatic carcinomas other metastatic malignancies we came across were malignant melanoma, neuroblastoma, germ cell tumor and synovial sarcoma.

CONCLUSION

FNAC of lymph nodes helps in rapid diagnosis of lymphadenopathy.Categorizingthe cause of lymph node enlargement as metastatic malignancy,lymphoma, reactive change, inflammatory cause,suppuration etc. can be done by FNAC.In patients with known histologically proven malignancy in whom a subsequent enlargement of lymph node occurs,a cytological diagnosis of metastasis helps in avoiding unwanted surgery for confirming metastasis.In patients without a previous diagnosis of malignancy, FNAC not only confirm metastatic deposit but in most conditions give a clue regarding site of primary. The use of immunocytochemistry and cell block preparations have increased the scope of FNAC.

The Revised Sonographic NASCET Index: A New Hemodynamic Parameter for the Assessment of Internal Carotid Artery Stenosis

PURPOSE

A previously described Doppler parameter, the sonographic NASCET index (SNI), was derived to be more directly analogous to the North American Symptomatic Carotid Endarterectomy Trial (NASCET) methodology for assessing carotid artery stenosis. However, this index does not account for complex changes affecting the Doppler waveform. We propose a revised SNI (rSNI) in an effort to improve predicting carotid stenosis.

MATERIALS AND METHODS

25 carotid bifurcations with stenoses ranging from 40 - 92 % were analyzed. For each vessel, the rSNI and original SNI were calculated. The peak systolic velocity (PSV), rSNI, and original SNI were correlated with angiography using linear regression analysis and relative accuracies were compared at two thresholds.

RESULTS

A correlation between rSNI and angiography was found to be significantly better than that between PSV or internal carotid artery-common carotid artery (ICA-CCA) peak velocity ratio and angiography (r² = 0.47 vs. 0.22; r² = 0.47 vs. 0.16). The accuracy of PSV in predicting high-grade stenosis was 68% and 72%, compared with 80% and 88% for rSNI, at each of two thresholds. The original SNI better correlated with angiography compared to the rSNI (r² = 0.55 vs. 0.47), but with slightly lower accuracy in predicting high-grade stenosis (76% vs. 80%).

CONCLUSION

The revised SNI correlates more closely with angiographic stenosis than either the PSV or the ICA-CCA ratio, and is more accurate in predicting high-grade stenosis. However, it is overall comparable to the original SNI, suggesting that the previously unaccounted for effects over the remainder of the cardiac cycle do not significantly improve the ability to sonographically predict significant stenosis.

Unusual self-assembly of a hydrophilic β-cyclodextrin inclusion complex into vesicles capable of drug encapsulation and release

A hydrophilic β-cyclodextrin bis-inclusion complex forms supramolecular vesicles which can be loaded with the anti-cancer drug doxorubicin. The loaded drug can be released upon addition of a competitive inclusion binder such as adamantane carboxylate.

Nonlinear control of voltage source converters in AC-DC power system

This paper presents the design of a robust nonlinear controller for a parallel AC-DC power system using a Lyapunov function-based sliding mode control (LYPSMC) strategy. The inputs for the proposed control scheme are the DC voltage and reactive power errors at the converter station and the active and reactive power errors at the inverter station of the voltage-source converter-based high voltage direct current transmission (VSC-HVDC) link. The stability and robust tracking of the system parameters are ensured by applying the Lyapunov direct method. Also the gains of the sliding mode control (SMC) are made adaptive using the stability conditions of the Lyapunov function. The proposed control strategy offers invariant stability to a class of systems having modeling uncertainties due to parameter changes and exogenous inputs. Comprehensive computer simulations are carried out to verify the proposed control scheme under several system disturbances like changes in short-circuit ratio, converter parametric changes, and faults on the converter and inverter buses for single generating system connected to the power grid in a single machine infinite-bus AC-DC network and also for a 3-machine two-area power system. Furthermore, a second order super twisting sliding mode control scheme has been presented in this paper that provides a higher degree of nonlinearity than the LYPSMC and damps faster the converter and inverter voltage and power oscillations.

Molecular & phenotypic characterization of Staphylococcus epidermidis in implant related infections

BACKGROUND & OBJECTIVES

The discrimination between the Staphylococcus epidermidis colonizing the deep seated indwelling devices and those which are mere commensals has always been a challenge for the clinical microbiologist. This study was aimed to characterize the S. epidermidis isolates obtained from device related infection for their phenotypic and molecular markers of virulence and to see whether these markers can be used to differentiate the pathogenic S. epidermidis from the commensals.

METHODS

Fifty five S. epidermidis isolates from various device related infections such as endophthalmitis following intra-ocular lens (IOL) implantation, intravascular (IV) catheter related sepsis and orthopaedic implant infections, were studied for slime production, biotyping, antibiotic sensitivity; and mec A and ica positivity by the recommended procedures.

RESULTS

Twenty three (41.8%) isolates were multi-drug resistant, 26 (65.2%) were slime producers, 30 (54.5%) were adherent, 23 (41.8%) possessed the intercellular adhesin (ica) gene, and 28 (50.9%) harboured the mec A gene. Biotypes I and III were the commonest, most members of which were multi- drug resistant. Twenty two (73.3%) of the 30 adherent bacteria were slime producers as opposed to only 4 (16%) of the 25 non-adherent bacteria (P<0.001). A vast majority i.e. 21 (91.3%) of the 23 ica positive organisms were adherent to artificial surfaces in contrast to only 9 (28.1%) of the 32 non-ica positive organisms (P<0.001). Twenty (86.9%) of the 23 ica positive bacteria were slime producers, as opposed to only 6 (18.7%) of the 32 ica negative bacteria (P<0.001). Of the 23 multi-drug resistant isolates, 19 (82.6%) carried the mec A gene.

INTERPRETATION & CONCLUSIONS

The present findings showed that ica AB and mec A were the two important virulence markers of S. epidermidis in implant infections and slime was responsible for the sessile mode of attachment on the devices.

Correlation of proteinase production with amphotericin B resistance in fungi from mycotic keratitis

Two hundred fungal isolates (Aspergillus and Fusarium species) from mycotic keratitis were tested for in vitro susceptibilities to amphotericin B and proteinase production. Geometric mean MICs for all fungal species increased fourfold with thousandfold increase in the inoculum. The MIC(50) and MIC(90) values ranged between 3.12-6.25 and 3.12-12.5 microg/ml, respectively. Proteinase production was noted in 113 (56.5%) isolates. Ninety-eight (49%) showed MICs of > or =1.56 microg/ml that was above the criteria of > or =1 microg/ml for amphotericin B resistance (CLSI). Seventy-three (74.5%) of these 98 isolates were proteinase producers, whereas only 40 (39.2%) of the remaining 102 with low MICs (<1.56 microg/ml) were proteinase producers (p < 0.001). Proteinase seems to be an important virulence marker of filamentous fungi in mycotic keratitis, correlating significantly with amphotericin B resistance.

Fungal infections of the eye--laboratory diagnosis and treatment

Infections of the eye give rise to severe ocular morbidity and blindness include keratitis, orbital cellulites, endophthalmitis and dacryocystitis. Corneal blindness, in developing countries is predominantly associated with infections. In India, nearly 30-35% of all culture positive infectious keratitis are caused fungi. Laboratory diagnosis mainly depends upon proper collection and transport of clinical specimens. In fungal keratitis, corneal scraping is the ideal sample, but occasionally corneal biopsy or anterior chamber aspirate may also be needed. Corneal scraping is usually by Kimura spatula, under a slit lamp examination, after anaesthetizing the cornea with topical anaesthetic like 0.4% proparcaine. Corneal biopsy is done by a minor trephining and AC aspirate using a sterile tuberculin syringe. In case of endophthalmitis, 150-200 ìl of aqueous humour is collected. Vitreous fluid (500-1000 ìl), however, is collected by pars plana vitrectomy onto sterile tuberculin syringe, the needle is then fixed to a sterile rubber bung after expelling air from the syringe. The collected sample is immediately transported to the laboratory. Swabs from the regurgitating lacrimnal sacs and wound aspirate/swabs are the ideal specimens for dacryocystitis and orbital cellulites, respectively. These samples are cultured onto SDA slants following standard procedures. The main draw back of culture is its long incubation time (5 to 14 days), though it is indispensable from the view point of the specificity. Direct examination (KOH wet mount, Gram's, Giemsa or calcofluor fluorescent staining methods) of the specimen, however, is quick and immensely helpful for ophthalmologist. The newer rapid methods, such as molecular techniques are also available and the management of patients can be according to the results obtained. With the advent of novel antifungal agents such as newer azoles and cell wall acting antifungals like echinocandins, the clinician has the wider option of selecting the therapeutic modality. In the event of the increasing reports of in vitro drug resistance to much frequently used azoles, polyenes and 5-fluorocytosines, clinical applicability of the newer antifungal agents seems to be quite promising.

Ultrastructural analysis of slime positive & slime negative Staphylococcus epidermidis isolates in infectious keratitis

BACKGROUND & OBJECTIVE

Slime is a major determinant of Staphylococcus epidermidis adherence. The established methods of laboratory detection of slime production by this organism i.e., Christensen's tube method and congo red agar plate method, can both yield inconclusive and/or intermediate results. We, therefore tried to find out electronmicroscopically the localization of slime in relation to the bacterial cell wall and look for the effect, if any of the slime location on the staphylococcal adherence as well as on the quantum of slime production.

METHODS

A total of 132 coagulase negative staphylococci from cases of infectious keratitis were identified as S. epidermidis following the recommended protocol. Slime was detected both by Christensen's tube method and congo red agar plate method. Antibiotic sensitivity testing was performed by standardized disc diffusion method. Adherence of the organisms to artificial surfaces was determined by a quantitative method and transmission electron microscopy was carried out by the conventional techniques.

RESULTS

Of the total 132 isolates, 57 (43.2%) were slime positive and 75 (56.8%) were slime negative. Twenty seven (47.4%) of the 57 slime producing organisms were multi drug resistant as compared to only 12 (16%) of 75 nonslime-producing organisms (P<0.001). A majority i.e., 45 (78.9%) of 57 adherent organisms were slime producers as against 12 (16%) of 75 nonadherent organisms. Electron microscopic study revealed a thick viscid layer of slime anchoring to the bacterial cell wall, especially in adherent organisms and those yielding positive slime test. Some of the organisms showed loose nonadherent slime and those were mostly nonadherent to artificial surfaces.

INTERPRETATION & CONCLUSION

Slime and multi drug resistance were the important virulence factors of S. epidermidis in bacterial keratitis. It was the adherent slime (i.e., slime in intimate association with the bacterial cell wall as shown by electron microscopy) only, which was responsible for resistance to multiple antibiotics and for the adhesion phenomenon observed in the quantitative slime test.

Decidual stromal cell response to paracrine signals from the trophoblast: amplification of immune and angiogenic modulators

During the invasive phase of implantation, trophoblasts and maternal decidual stromal cells secrete products that regulate trophoblast differentiation and migration into the maternal endometrium. Paracrine interactions between the extravillous trophoblast and the maternal decidua are important for successful embryonic implantation, including establishing the placental vasculature, anchoring the placenta to the uterine wall, and promoting the immunoacceptance of the fetal allograph. To our knowledge, global crosstalk between the trophoblast and the decidua has not been elucidated to date, and the present study used a functional genomics approach to investigate these paracrine interactions. Human endometrial stromal cells were decidualized with progesterone and further treated with conditioned media from human trophoblasts (TCM) or, as a control, with control conditioned media (CCM) from nondecidualized stromal cells for 0, 3, and 12 h. Total RNA was isolated and processed for analysis on whole-genome, high-density oligonucleotide arrays containing 54,600 genes. We found that 1374 genes were significantly upregulated and that 3443 genes were significantly downregulated after 12 h of coincubation of stromal cells with TCM, compared to CCM. Among the most upregulated genes were the chemokines CXCL1 (GRO1) and IL8,CXCR4, and other genes involved in the immune response (CCL8 [SCYA8], pentraxin 3 (PTX3), IL6, and interferon-regulated and -related genes) as well as TNFAIP6 (tumor necrosis factor alpha-induced protein 6) and metalloproteinases (MMP1, MMP10, and MMP14). Among the downregulated genes were growth factors, e.g., IGF1, FGF1, TGFB1, and angiopoietin-1, and genes involved in Wnt signaling (WNT4 and FZD). Real-time RT-PCR and ELISAs, as well as immunohistochemical analysis of human placental bed specimens, confirmed these data for representative genes of both up- and downregulated groups. The data demonstrate a significant induction of proinflammatory cytokines and chemokines, as well as angiogenic/static factors in decidualized endometrial stromal cells in response to trophoblast-secreted products. The data suggest that the trophoblast acts to alter the local immune environment of the decidua to facilitate the process of implantation and ensure an enriched cytokine/chemokine environment while limiting the mitotic activity of the stromal cells during the invasive phase of implantation.

Serotype distribution of Streptococcus pneumoniae isolates from ophthalmic and systemic infections and of commensal origin

BACKGROUND AND OBJECTIVES

Information regarding serotype distributions of Streptococcus pneumoniae causing ophthalmic infections is scanty. This study was therefore undertaken to determine the antimicrobial susceptibility status and serotypes of S. pneumoniae isolated from various ophthalmic infections and to compare with those isolated from systemic infections and commensal nasopharyngeal flora.

METHODS

Thirty eight of S. pneumoniae isolates from ophthalmic infections, 9 from systemic infections and 14 from the nasopharynx of apparently healthy school children were biochemically characterized and tested for in vitro antimicrobial susceptibility to various antibiotics. Serotyping of these 61 isolates was done by a rapid co-agglutination method.

RESULTS

All the 61 isolates were sensitive to oxacillin (penicillin) and susceptibility against other antimicrobials was variable. No multidrug resistance was observed. The 38 ophthalmic isolates were distributed in 15 different serotypes. Most prevalent serotypes were 14, followed by 8 and 19F. The 9 systemic and 14 commensal. isolates of S. pneumoniae were distributed in 7 and 11 serotypes respectively. Three of the systemic and six of the commensal serotypes were observed in ophthalmic infections whereas four of the commensal serotypes were observed in systemic infections.

INTERPRETATION AND CONCLUSION

Resistance to penicillin was not observed. In ophthalmic infections, a wide range of serotypes of S. pneumoniae were observed. More than half of the commensal serotypes obtained in the study as well as majority of the systemic serotypes were observed in ophthalmic infections.

Lead in paint and soil in Karnataka and Gujarat, India

Blood lead surveys in several areas of India have found very high percentages of children with elevated blood lead levels. Fifty-three percent of children under 12 years of age in a seven-city screening had blood lead levels equal to or greater than 10 microg/dL, the level currently considered elevated by the U.S. Centers for Disease Control and Prevention (CDC). A number of these surveys focused on populations near lead smelters or in areas with high lead levels from combustion of lead-containing gasoline. There is little information available, however, on the levels of lead in paint in India and in soil. Field portable X-ray fluorescence analyzers were used to determine environmental lead levels in paint, dust, air, soil, and other bulk samples near several lead-using industries and in the residential environments of children with very high blood lead levels, at least four times as high as the CDC limit. Soils near industrial operations, such as secondary lead smelters, and battery dismantling units contained levels up to 100,000 ppm of lead. Four of 29 currently available paints from five manufacturers measured 1.0 mg/cm2 or above--the current U.S. definition of lead-based paint in housing-after the application of a single coat; four others measured at least 1.0 after three coats, and three others likely reached this level after the application of an additional one or two coats. In 5 of 10 homes of the elevated blood lead children, three or more locations in or around the home were found to have lead paint levels of 1.0 mg/cm2 or higher. Soil exceeding the U.S. standard for residential areas (400 ppm) was found at only one of the houses. Other sources of lead exposure, including traditional ayurvedic medicine tablets, were also observed. Similar surveys would be useful elsewhere in India and in other developing countries.

Portable lead analyzer to locate source of lead

OBJECTIVE

To investigate the sources of lead in the environment in children with elevated blood, with the help of a Field Portable X-Ray Fluorescence Analyzer.

METHODS

One hundred and seven school children were chosen for this study on a random basis, from Mangalore and Karnataka. Their blood lead was analyzed. Of the cases analyzed, 10 students whose blood lead level was more than 40 microg/dl were investigated using a field portable X-Ray Fluorescence Analyzer. This is the first time such a device has been available for this purpose in India.

RESULTS

The 'likely' source of lead exposure could be determined in eight cases which was from the immediate environment of the children like 'lead-based' paint on surfaces in the house, on playground and other exterior equipment; lead storage batteries, contaminated dust and soil and other lead-containing substances.

CONCLUSION

The use of an X-Ray Fluorescence Analyser appeared to be useful in determining the source of lead.

Role of cell surface antigens of Vibrio cholerae 01 and non 01 serovars in intestinal adhesion

Decrease in adherence of Vibrio cholerae to rabbit small intestine was observed following treatment with antisera against outer membrane (OM), lipopolysaccharide (LPS) and flagella. Anti LPS antibodies were more efficient than the other two antibodies in inducing adherence inhibition and promoting in vivo protection.

A simple alternative method for rapid detection of slime produced by Staphylococcus epidermidis isolates in bacterial keratitis

BACKGROUND & OBJECTIVES

Slime is a known virulence factor of Staphylococcus epidermidis. The conventional Christensen's method for detection of slime in the laboratory takes at least 48 h. We, therefore, tried to evaluate the efficacy of the Congo red agar method as a routine procedure for detecting slime among isolates from corneal ulcers.

METHODS

A total of 244 isolates from corneal ulcers were identified as S. epidermidis by the standard procedures. Slime was detected both by the conventional Christensen's method as well as by the Congo red agar method.

RESULTS

Ninety two (37.7%) isolates were positive and 86 (35.2%) were negative for slime by both the techniques. Fifty four (22.1%) isolates were positive in Congo red agar, but negative by Christensen's method; whereas only 12 (4.9%) were negative by Congo red but positive by Christensen's method. Detection of slime by Congo red agar method was rapid i.e., all the 146 strains were positive within 24 h of incubation. On the other hand, Christensen's method had a delayed response; 42.3 per cent (44/104) strains being negative during the first 24 h of incubation.

INTERPRETATION & CONCLUSION

Our results suggested that culture on Congo red agar was a sensitive and rapid test for detecting slime. This might help in the quick identification in a routine laboratory of slime positive isolates in bacterial keratitis.

Development and validation of a novel technique for murine first-pass radionuclide angiography with a fast multiwire camera and tantalum 178

BACKGROUND

The use of genetically altered mice as a model system to study cardiovascular disease has created a need for accurate and quantitative assessment of murine ventricular function. To address this very challenging problem, we have developed a technique of murine first-pass radionuclide angiography using pinhole imaging and the short-lived isotope tantalum 178 (Ta-178) with a high-speed multiwire proportional camera (MPC). METHODS AND RESULTS. An MPC was fitted with a pinhole lens of 2-mm-diameter aperture positioned 15 cm from the camera face. The short-lived isotope Ta-178 (half-life 9.3 minutes) was generated from the tungsten 178 (W-178) (half-life 21.7 days)/Ta-178 generator and concentrated on site to an injection volume of 15 to 20 microL. Mice were imaged in the supine position with the chest wall 3 mm from the camera pinhole aperture, and images were acquired at 160 frames per second after a rapid bolus injection of Ta-178. In the absence of a true gold standard, the technology was validated with measurements in control mice and mice with surgically ligated left anterior descending arteries (LADs). In addition, the effects of pharmacologic intervention with verapamil and with dobutamine were observed. Finally, peak aortic velocity measurements obtained with this technology were compared with those obtained with echocardiographic Doppler ultrasonography, the only available quantitative comparator. There was a significant decrease in the mean left ventricular ejection fraction (LVEF) between normal mice (62% +/- 4.6% [mean +/- SEM], n = 12) and mice with experimentally induced myocardial infarction produced by surgical LAD ligation (22% +/- 2.0%, n = 41; P <.01). The LVEF decreased from 51% +/- 5.8% to 37% +/- 3.5% in a group of normal mice receiving verapamil (P <.05, n = 8) and increased from 34% +/- 2.2% to 43% +/- 2.3% in a group of LAD-ligated mice receiving dobutamine (P <.01, n = 48). Peak camera sensitivity during first pass was 25,000 cps/mCi injected. Intraobserver and interobserver variability of LVEF was studied, yielding r = 0.9639 and 0.9529 and SE of the estimate 2.6% and 3.1%, respectively. Reproducibility in serial studies was excellent (r = 0.92, SE of the estimate 5.18).

CONCLUSIONS

This study demonstrates the development and use of a promising new method that uses the short-lived radioisotope Ta-178 and MPC for noninvasive quantification of murine ventricular function, that produces accurate and highly reproducible results, and that can be applied in multiple serial studies.

Retinyl ester secretion by intestinal cells: a specific and regulated process dependent on assembly and secretion of chylomicrons

Retinyl esters (RE) have been used extensively as markers to study chylomicron (CM) catabolism because they are secreted in the postprandial state with CM and do not exchange with other lipoproteins in the plasma. To understand the mechanism of secretion of RE by the intestine under the fasting and postprandial states, differentiated Caco-2 cells were supplemented with radiolabeled retinol under conditions that support or do not support CM secretion. We observed that these cells assimilate vitamin A by a rapid uptake mechanism. After uptake, cells store retinol in both esterified and unesterified forms. Under fasting conditions, cells do not secrete RE but secrete free retinol unassociated with lipoproteins. Under postprandial conditions, cells secrete significant amounts of RE only with CM. The secretion of RE with CM was independent of the rate of uptake of retinol and intracellular free and esterified retinol levels, and was absolutely dependent on the assembly and secretion of CM. The secretion of RE was correlated with the secretion of CM and not with the secretion of total apolipoprotein B. Inhibition of CM secretion by Pluronic L81 decreased the secretion of RE and did not result in their increased secretion with smaller lipoproteins. These data strongly suggest that RE secretion by the intestinal cells is a specific and regulated process that occurs in the postprandial state and is dependent on the assembly and secretion of CM. We propose that RE are added to CM during final stages of lipoprotein assembly and may serve as signposts for these steps.