Analysis of fine-mode aerosol retrieval capabilities by different passive remote sensing instrument designs

Remote sensing of aerosol optical properties is difficult, but multi-angle, multi-spectral, polarimetric instruments have the potential to retrieve sufficient information about aerosols that they can be used to improve global climate models. However, the complexity of these instruments means that it is difficult to intuitively understand the relationship between instrument design and retrieval success. We apply a Bayesian statistical technique that relates instrument characteristics to the information contained in an observation. Using realistic simulations of fine size mode dominated spherical aerosols, we investigate three instrument designs. Two of these represent instruments currently in orbit: the Multiangle Imaging SpectroRadiometer (MISR) and the POLarization and Directionality of the Earths Reflectances (POLDER). The third is the Aerosol Polarimetry Sensor (APS), which failed to reach orbit during recent launch, but represents a viable design for future instruments. The results show fundamental differences between the three, and offer suggestions for future instrument design and the optimal retrieval strategy for current instruments. Generally, our results agree with previous validation efforts of POLDER and airborne prototypes of APS, but show that the MISR aerosol optical thickness uncertainty characterization is possibly underestimated.

Non-invasive alternating current stimulation induces recovery from stroke

BACKGROUND

Recovery of post-stroke deficits can be achieved by modulating neuroplasticity with non-invasive brain stimulation. To evaluate potential effects of repetitive transorbital alternating current stimulation (rtACS) on stroke recovery we carried out a randomized, drug-controlled clinical trial.

METHODS

Ninety-eight patients that had suffered ischemic stroke 21.4 months earlier were randomly assigned to either group D (n=30) receiving conventional drug therapy, group ACS (n=32) treated for 12 days with rtACS, or group D/ACS (n=36) receiving combined drug therapy/rtACS. Stroke severity level (SSL) was assessed by the NIH-NINDS stroke scale before and after treatment and at a 1-month follow-up to evaluate motor impairments (weakness, ataxia), sensory loss, visual field defects, and cortical deficits (aphasia, neglect). At each time point standard EEG recordings (10-20 system) were conducted.

RESULTS

Before therapy SSL was moderate (9.18 ± 0.78) without significant group difference (F =0.86, p=0.43). After 12 days of treatment, SSLs of groups ACS and D/ACS significantly improved by 22.5% and 25.1% over baseline, respectively, with no such change in the control group D (+3%). SSL improvements were mainly due to recovery of motor, sensory, and speech functions. After 1-month follow-up, an additional improvement of 9.7% and 9.4% was seen for the group ACS and D/ACS which led to a total change of +32.3% and +34.7% over baseline. EEG recordings revealed greater interhemispheric synchrony between both temporal lobes which were positively correlated with clinical outcome.

CONCLUSIONS

Non-invasive rtACS applied to post-stroke patients can modulate brain plasticity and induce recovery from neurological deficits long after the early post lesion recovery is over.

Photon Undulatory Non-Linear Conversion Diagnostic Method for Caries Detection: A Pilot Study

OBJECTIVE

The objective of this study was to evaluate a new optical method - photon undulatory non-linear conversion (PNC)--for use in different stages of caries detection.

BACKGROUND DATA

Caries should be considered an infectious disease managed by risk assessment, early detection, and preventive therapies, rather than simply "drilling and filling."

MATERIAL AND METHODS

Fluorescence emission spectroscopy was performed in vitro on 90 extracted teeth, with intact occlusal surfaces. This system differs from the basic Diagnodent unit in its ability to distinguish between different tissue components with respect to their spectrums. Histological analysis served as the gold standard for verification. The teeth sections correspond to the specific point with the highest reading of the detector. The system was compared to visual inspection, probing, and x-ray methods. The system tested (helium-neon [He-Ne], lambda = 633 nm) has a fiber optic device that delivers radiation to the tooth and a spectrophotometer device that detects bacterial porphyrins fluorescence, allowing detection of caries, fillings, and calculus by simultaneous measurement of backscattering and fluorescence intensity.

RESULTS

The system tested provides quantitatively reproducible measurements and detection even through sound enamel of more than 1 mm in thickness.

CONCLUSION

The PNC method detects different stages of caries lesions in real time, and it exceeds x-rays in sensitivity, without any ionizing radiation. Preliminary results showed a high potential of using the PNC method in clinical practice (98% accuracy) in comparison to the other methods.

A threshold level of gag expression is required for particle formation in rat cells transformed by avian retroviruses

To test the hypothesis that the block of polyprotein precursor processing and particle formation in RSV-transformed mammalian cells is due to a low level of pr76gag expression, rat tumor cell lines with different amounts of precursor molecules were used. The wild-type forms of pr76gag have been expressed at a high level by use of SV40-based vector and thirty-two stable transfected cell clones were isolated. The gag protein expression was detected in the cell lysate by immunoblotting. Untransfected cells released no proteins that could be detected by immunoprecipitation with anti-RSV serum. Membrane-enclosed gag precursor-polyprotein molecules and infectious virus particles from different stably transfected clones have been found in the medium. Both immature and mature virions of type C morphology were directly detected by transmission electron microscopy. Surprisingly, virus-like particles of morphology similar to mature type C retroviruses were found enclosed within intracellular membranes in a stably transfected nonproducing clone.

Electron-microscopic immunocytochemical study of the intracellular transport of the viral glycoproteins in ts1, a mutant of Moloney murine leukemia virus

The transport and localization of env-proteins of ts1 virus (a paralytogenic temperature-sensitive mutant of Moloney murine leukemia virus) in infected cells of the TB cell line have been studied at the ultrastructural level. It was found that the envelope precursor polyprotein gPr80-env of ts1 was inefficiently transported out of the endoplasmic reticulum at the restrictive temperature. It was speculated that inefficient transport correlates with inefficient processing of gPr80env into gp70 and Prp15E and leads to paralytic disease.

Fluorescent and electron-microscopy immunoassays employing polyclonal and monoclonal antibodies for detection of goose parvovirus infection

Polyclonal antibodies (PAbs) raised in geese and eight mice hybridomas secreting monoclonal antibodies (MAbs) against the goose parvovirus (GPV) were prepared. They were used for development of immunofluorescence (IF) and immunoelectron-microscopic (IEM) techniques to demonstrate the GPV infection in infected organs and biological fluids. The GPV antigens were established by immunofluorescence within the nuclei and the cytoplasm of many infected cells of the chorioallantoic membrane of goose and Peckin duck embryos, liver and heart of mortally diseased goslings. By means of IEM it was possible to detect the GPV in native organ homogenate supernatants and allantoic fluids. All techniques used in the study could be successfully applied for rapid diagnosis of the GPV infection. The test systems on the basis of MAbs should, however, be preferred. By means of immunoblotting (IB) using PAbs and MAbs four viral proteins (VP) with MW 88, 77, 65 and 60 kDa were demonstrated. Contrary to the others the VP with MW 65 kDa was the most antigenically reactive though invisible in the SDS-PAGE and Coomassie-blue dye-stained preparations.

Detection and identification of the Newcastle disease virus infection by electron and immunoelectron microscopy

Various electron microscopic (EM) and immunoelectron microscopic (IEM) techniques were used to demonstrate and identify the Newcastle disease virus (NDV) infection. By IEM, the number of virions in native allantoic fluids was increased 50-100 times in comparison with direct EM. The immunogold staining showed that a number of immunogold particles were specifically bound to the antigen determinants located on the virion surface and these results were much easier to interpret. The obtained results showed that the EM and IEM can be successfully employed for a precise and rapid detection of NDV as well as for identification of this infection among other viral or bacterial infections.

Demonstration of rabbit haemorrhagic disease virus antigen by Staphylococcus protein A coagglutination test

The Staphylococcus protein A coagglutination test (Sp A COAT) was developed for the diagnosis of rabbit haemorrhagic disease (RHD). Liver, spleen, lungs and kidneys from 176 rabbits dead from viral haemorrhagic disease as well as the same organs from 64 healthy animals were examined by Sp A COAT and haemaglutination test (HAT). The Sp A COAT was specific and considerably more simple to carry out than the HAT, which made it very useful for rapid identification of RHD.

Characterization of the virions of mopyridone-sensitive wild strain and mopyridone-resistant mutant of influenza virus A(H3N2)

Some differences were established between mopyridone-sensitive (MCU-s) wild strain and mopyridone-resistant (MCU-r) mutant progenies of influenza virus A/Hong Kong/1/68 (H3N2). The virions of MCU-r mutant had a lower buoyant density in linear sucrose gradient as compared to those of MCU-s strain, and an increased ability of aggregation as well. HA content (HAU/micrograms protein) in the purified virions of MCU-r mutant was twice lower as compared to MCU-s strain. The surface glycoproteins of MCU-r mutant were solubilized by octylglucoside faster than those of MCU-s strain. No differences were found between MCU-r strain and MCU-s mutant-induced red blood cell lysis at acid pH, and mopyridone did not influence this phenomenon. MCU-r mutant showed a lower thermostability as compared with MCU-s strain, but similar UV-inactivation curves for both viruses were observed. The quantity of the purified HA-NA complex and M1 protein incorporated into multilamellar liposomes was greater in the case of MCU-s mutant. Electron microscopy examination of liposomes which contained M1 protein from MCU-r mutant manifested pleomorphism with unusual gigantic forms tending to aggregate, whereas MCU-s M1 protein-containing liposomes were uniform and did not form aggregates. No morphological differences were found between the two viruses in HA-NA complex containing liposomes. These data indicate changes in the protein-lipid interactions in MCU-r mutant virions. Amino acid analysis of M1 protein revealed significantly lower content of asparagine, glutamine and serine, and a higher one oof hisitidine in MCU-r mutant as compared to MCU-s wild strain.

Electron- and immunoelectron-microscopic investigation on the rabbit haemorrhagic disease virus

Electron- and immunoelectron-microscopic methods were used for detection and investigation of rabbit haemorrhagic disease virus (RHDV). The observed virus particles were uncoated, with an icosahedral symmetry, with a 35-40 nm dia and capsids built up by 32 capsomers with a central hollow part and a 3.5-5 nm dia. Particles with empty capsids could also be seen among them. Single virions visible in 5-fold symmetry, exhibited 10 projections on the surface. Virions with a 33-34 nm dia and cup-shaped surface depressions were a rare finding. Some of these particles were indistinguishable from the caliciviruses, but in most of them the cup-shaped depressions were single or no more then 2-3 in number, localized predominantly unilaterally or asymmetrically. Particles 25-29 nm large with full or empty capsids without capsomers could also be seen. Most probably they were some immature forms in the process of development of the RHDV.

Immunohistochemical localization of the rabbit haemorrhagic disease viral antigen

Immunohistochemical investigations were carried out to determine organ and cellular localization of the rabbit haemorrhagic disease viral antigen (RHDVA). It was found in certain parenchymal liver cells near the interlobular septs and in some macrophages and pseudoeosinophils of all studied organs and blood. Whereas in morphologically preserved hepatocytes and macrophages the RHDVA accumulated in the nuclei, in cells with disintegrated nuclei it was distributed throughout the cytoplasm.