Approximation of modal wavenumbers and group speeds in an oceanic waveguide using a neural network.

Underwater acoustic propagation is influenced not only by the property of the water column, but also by the seabed property. Modeling this propagation using normal mode simulation can be computationally intensive, especially for wideband signals. To address this challenge, a Deep Neural Network is used to predict modal horizontal wavenumbers and group velocities. Predicted wavenumbers are then used to compute modal depth functions and transmission losses, reducing computational cost without significant loss in accuracy. This is illustrated on a simulated Shallow Water 2006 inversion scenario.

Multivariate temporal dictionary learning for EEG.

This article addresses the issue of representing electroencephalographic (EEG) signals in an efficient way. While classical approaches use a fixed Gabor dictionary to analyze EEG signals, this article proposes a data-driven method to obtain an adapted dictionary. To reach an efficient dictionary learning, appropriate spatial and temporal modeling is required. Inter-channels links are taken into account in the spatial multivariate model, and shift-invariance is used for the temporal model. Multivariate learned kernels are informative (a few atoms code plentiful energy) and interpretable (the atoms can have a physiological meaning). Using real EEG data, the proposed method is shown to outperform the classical multichannel matching pursuit used with a Gabor dictionary, as measured by the representative power of the learned dictionary and its spatial flexibility. Moreover, dictionary learning can capture interpretable patterns: this ability is illustrated on real data, learning a P300 evoked potential.

Single-receiver geoacoustic inversion using modal reversal.

This paper introduces a single-receiver geoacoustic-inversion method based on dispersion analysis and adapted to low-frequency impulsive sources in shallow-water environments. In this context, most existing methods take advantage of the modal dispersion curves in the time-frequency domain. Inversion is usually performed by matching estimated dispersion curves with simulated replicas. The method proposed here is different. It considers the received modes in the frequency domain. The modes are transformed using an operator called modal reversal, which is parameterized using environmental parameters. When modal reversal is applied using parameters that match the real environment, dispersion is compensated for in all of the modes. In this case, the reversed modes are in phase and add up constructively, which is not the case when modal reversal is ill-parameterized. To use this phenomenon, a criterion that adds up the reversed modes has been defined. The geoacoustic inversion is finally performed by maximizing this criterion. The proposed method is benchmarked against simulated data, and it is applied to experimental data recorded during the Shallow Water 2006 experiment.

Evaluating antioxidative activities of amino acid substitutions on mastoparan-B.

Mastoparan-B is a peptide toxin isolated from the venom of Vespa basalis, the most dangerous hornet found in Taiwan. This study is aimed to evaluate the antioxidative activities of several amino acid substitutions on MP-B, and examined the influences of mast cell degranulation and hemolytic activities in parallel with antioxidative activities. The correlations between the biological function and amino acid sequence were assessed. Our study shows original MP-B is a valuable antioxidant at low concentration in competing with nitric-oxide for oxygen molecules and possesses good antioxidative enzyme activities resembled to superoxidase dismutase and glutathione peroxidase. And there are no predominant rates of mast cell degranulation and hemolytic effects in such condition. With proper substitutions, the reducing power, DPPH scavenging activity and glutathione reductase-like enzyme activity of MP-B can increase clearly. The results demonstrate that MP-B analogs are very potential to be applicable antioxidants for other antioxidative usages.

Structural and biological characterization of mastoparans in the venom of Vespa species in Taiwan.

Mastoparans, a family of small peptides, are isolated from the wasp venom. In this study, six mastoparans were identified in the venom of six Vespa species in Taiwan. The precursors of these mastoparans are composed of N-terminal signal sequence, prosequence, mature mastoparan, and appendix glycine at C-terminus. These mature mastoparans all have characteristic features of linear cationic peptides rich in hydrophobic and basic amino acids without disulfide bond. Therefore, these peptides could be predicted to adopt an amphipathic α-helical secondary structure. In fact, the CD (circular dichroism) spectra of these peptides show a high content α-helical conformation in the presence of 8 mM SDS or 40% 2,2,2-trifluoroethanol (TFE). All mastoparans exhibit mast cell degranulation activity, antimicrobial activity against both Gram-positive and -negative bacteria tested, various degree of hemolytic activity on chicken, human, and sheep erythrocytes as well as membrane permeabilization on Escherichia coli BL21. Our results also show that the hemolytic activity of mastoparans is correlated to mean hydrophobicity and mean hydrophobic moment.

Modal depth function estimation using time-frequency analysis.

Acoustic propagation in shallow water is characterized by a set of depth-dependent modes, the modal depth functions, which propagate in range according to their horizontal wavenumbers. For inversion purposes, modal depth function estimation in shallow water is an issue when the environment is not known. Classical methods that provide blind mode estimation rely on the singular value decomposition of the received field at different frequencies over a vertical array of transducers. These methods require that the vertical array spans the full water column. This is obviously a strong limitation for the application of such methods in an operational context. To overcome these shortcomings, this study proposes to replace the spatial diversity constraint by a frequency diversity condition, and thus considers the case of a field emanating from an impulsive source. Indeed, because of the discrete nature of the wavenumber spectrum and due to their dispersive behavior, the modes are separated in the time-frequency domain. This phenomenon enables the design of a modal filtering scheme for signals received on a single receiver. In the case of a vertical receiver array, the modal contributions can be isolated for each receiver even when using a partial water column spanning array. This method thus eliminates the receiving constraints of classical methods of modal depth function estimation, although it imposes the use of an impulsive source. The developed algorithm is benchmarked on numerical simulations and validated on laboratory experimental data recorded in an ultrasonic waveguide. Practical applications are also discussed.

Comparison of the Q-fever complement fixation test and two commercial enzyme-linked immunosorbent assays for the detection of serum antibodies against Coxiella burnetti (Q-fever) in ruminants : recommendations for use of serological tests on imported animals in New Zealand.

AIM: To make valid recommendations on the use of serological test methods for the detection of serum antibodies in ruminants against Coxiella burnetii (Q-fever), by comparing the performance of the complement fixation test (CFT) and two ELISA, and by identifying reasons for discrepancies between the test methods. METHODS: A total of 73 serum samples from infected cattle, 69 from infected goats, and 100 samples from non-infected cattle and 57 samples from non-infected sheep, as well as 95 samples from infected cattle herds (mix of seropositive and seronegative samples), were tested using the CFT, the IDEXX ELISA (I-ELISA) and the Pourquier ELISA (P-ELISA). A mixed panel of 12 serum samples from sheep from inter-laboratory proficiency testing (proficiency panel) was also tested using the CFT and both ELISA, and further investigated using IgG- and IgM-specific ELISA. RESULTS: Generally, the two commercial ELISA were more sensitive than the CFT for the detection of infected ruminants. Good agreement between ELISA for positive and negative results was found for samples from the infected herd, while results for the positive panels varied between the two ELISA. For the total of the positive serum panels, the I-ELISA detected 95% of samples as positive or suspicious, while the P-ELISA detected only 81%. In the P-ELISA, more samples were considered suspicious (18%) than in the I-ELISA (14%). All sera from non-infected sheep and cattle tested negative in the serological test methods employed, except for one positive sample from a sheep in the P-ELISA. Further investigation revealed that a CFT-positive but ELISA-negative result was due to high IgM and low IgG reactivity. CONCLUSIONS: The two commercial ELISA were more sensitive than the CFT in all panels from infected ruminants. However, they could only detect IgG. The I-ELISA should be the serological test method of choice for cattle, sheep and goats for import testing of animals into New Zealand because it was more sensitive than the P-ELISA and was equally specific to the PELISA and the CFT. For other animal species, such as deer and camelids, the CFT should still be used since none of the ELISA has been evaluated for these species. This study has shown that the two commercial ELISA will detect the majority of infected ruminants but may miss animals that have not developed an IgG response.

Prednisolone and flurbiprofen drops to maintain mydriasis during phacoemulsification cataract surgery.

PURPOSE: To compare the effects on the pupil of pretreatment with prednisolone 1% eyedrops, flurbiprofen 0.03% eyedrops, and sodium chloride 0.9% eyedrops in patients having phacoemulsification cataract surgery. SETTING: Christopher Home Eye Unit, Royal Albert Edward Infirmary, Wigan, United Kingdom. METHODS: One hundred thirty-six white patients having phacoemulsification with no history of eye disease, antiinflammatory medication, or diabetes were enrolled in this prospective randomized double-blind study. Patients were allocated to receive flurbiprofen 0.03%, prednisolone 1%, or sodium chloride 0.9% (placebo) eyedrops at 30-minute intervals beginning 2 hours before surgery. All patients received cyclopentolate 1% and phenylephrine 2.5% drops preoperatively and epinephrine 1:10(6) intraoperatively in the intraocular irrigating solution. The pupil diameter was measured from a television screen at the preset magnification of the operating microscope immediately before the incision, at the end of nucleus emulsification, at the end of irrigation/aspiration (I/A), and at the end of surgery. One hundred twelve patients with a baseline pupil diameter of at least 6.0 mm who had uneventful phacoemulsification were analyzed. RESULTS: The baseline pupil diameters were statistically similar. An analysis of variance did not reveal an overall significant mydriasis-maintaining effect of prednisolone or flurbiprofen compared to the placebo at any stage of surgery (P =.16 to.37). The 95% confidence interval showed flurbiprofen to be superior to prednisolone at the end of surgery. According to the paired t test, the reduction from the baseline at the end of I/A in the prednisolone group (P =.051) and at the end of surgery in the flurbiprofen group (P =.22) was not significant. CONCLUSION: In the presence of epinephrine in the intraocular irrigating solution, both prednisolone 1% and flurbiprofen 0.03% failed to maintain mydriasis at the crucial steps of nuclear emulsification and cortical I/A.

The acute effect of pilocarpine on pulsatile ocular blood flow in ocular hypertension.

PURPOSE: To determine the acute effects of application of 2% pilocarpine on pulsatile ocular blood flow. METHODS: In a randomised prospective controlled study of an exploratory nature, 18 subjects with ocular hypertension had pilocarpine 2% eye drops instilled into a randomly chosen eye three times at 10 min intervals. Physiological saline was instilled into the contralateral control eye. Intraocular pressure (IOP) and pulsatile ocular blood flow (POBF) measurements were taken before the first application and 90 min after the last application using the OBF tonometer (OBF Laboratory, Wilts, UK). Statistical analysis was performed using the Wilcoxon signed rank test. RESULTS: Of the 18 patients who entered the trial, 2 were suggested by the OBF system software as having 'poorly reliable' data. The analysis was made on the remaining 16. There was a significant reduction in IOP at 90 min for the treated eye in comparison with the contralateral control eye (p = 0.001; median difference -4.25 mmHg; 95% confidence interval, -5.85 to -2.40). There was a significant increase in POBF at 90 min in the treated eye in comparison with the contralateral control eye (p < 0.001; median difference 4.60 microl/s; 95% confidence interval, 2.35 to 6.75). CONCLUSION: Acute application of pilocarpine 2% drops increased POBF to a significant extent in untreated ocular hypertension.

Blinding choroidal rupture in a karateka.

A case of uniocular visual loss secondary to trauma sustained during a competitive karate bout is reported.

Epidemiological study of bovine respiratory syncytial virus infections in calves: influence of maternal antibodies on the outcome of disease.

A prospective epidemiological survey on bovine respiratory syncytial virus (BRSV) infections in calves was carried out on 21 dairy farms during one BRSV epidemic season. Special attention was paid to the role of maternal antibodies. On 15 farms the spread of the virus was demonstrated during the investigation period and on eight farms this was accompanied by an outbreak of acute respiratory disease. Disease seldom occurred in calves younger than two weeks old and the most severe disease was observed in calves from one to three months old. Although maternal antibodies did not effectively prevent the disease, both the incidence and severity of disease were inversely related to the level of specific maternal antibodies. Two serodiagnostic techniques were compared. In calves older than three months from herds with disease outbreaks associated with bovine respiratory syncytial virus the diagnosis was established in 80 per cent of the animals by an increase in IgG titre against BRSV and in 77 per cent by the detection of BRSV specific IgM. In comparison, only 10 per cent of the calves younger than three months were positive by IgG serodiagnosis, and 51 per cent by IgM serodiagnosis. On farms where the spread of the virus was accompanied by an outbreak of clinical disease more calves were present, a higher proportion of the calves was younger than three months, and calves of all ages were more often housed together.