Pattern recognition applied to surgery

Features in a feature vector are defined in the conventional pattern recognition manner, but classes are defined interactively by the user as regions in the feature vector space. By storing training samples, where a sample is a feature vector, the class conditional probability density is estimated.

The procedure is applied to surgical patient features, the features corresponding to the kind of operation, diagnosis, patient's age, patient's sex, etc. A class is then a patient in a specific age group, of a specific sex, and with a specific diagnosis. The procedure is useful for determining numbers of particular kinds of operations and diagnoses, numbers of particular kinds of operations performed by a certain physician, etc.     

Harmonic imaging improves sensitivity at the expense of specificity in the detection of patent foramen ovale

Contrast echocardiography using agitated saline is widely employed to detect right to left shunt in patients with suspected patent foramen ovale (PFO). The sensitivity of fundamental transthoracic echocardiography (FTTE) is often limited by poor far-field resolution. The purpose of this study was to evaluate the test characteristics of harmonic imaging during transthoracic echocardiography (HTTE) for the detection of PFO. METHODS: Sixty-four patients referred for transesophageal echo (TEE) for clinical indications underwent FTTE and HTTE during saline contrast injections. RESULTS: TEE identified nine PFOs. For FTTE, the sensitivity was 78% and the specificity was 100%. For HTTE, the sensitivity was 100% and the specificity was 82%. All ten false positives with HTTE occurred after five cardiac cycles, suggesting transpulmonary transit of the bubbles. CONCLUSION: In the detection of PFO, HTTE improves sensitivity at the expense of specificity, particularly if the timing of contrast appearance in the left heart is ignored.     

A comprehensive outcome comparison of surgical and Ponseti clubfoot treatments with reference to pediatric norms

Purpose

Isolated congenital clubfoot can be treated either operatively (posteromedial release) or conservatively (Ponseti method). This study retrospectively compared mid-term outcomes after surgical and Ponseti treatments to a normal sample and used multiple evaluation techniques, such as detailed gait analysis and foot kinematics.

Methods

Twenty-six children with clubfoot treated surgically and 22 children with clubfoot treated with the Ponseti technique were evaluated retrospectively and compared to 34 children with normal feet. Comprehensive evaluation included a full gait analysis with multi-segment and single-segment foot kinematics, pedobarograph, physical examination, validated outcome questionnaires, and radiographic measurements.

Results

The Ponseti group had significantly better plantarflexion and dorsiflexion range of motion during gait and had greater push-off power. Residual varus was present in both treatment groups, but more so in the operative group. Gait analysis also showed that the operative group had residual in-toeing, which appeared well corrected in the Ponseti group. Pedobarograph results showed that the operative group had significantly increased varus and significantly decreased medial foot pressure. The physical examination demonstrated significantly greater stiffness in the operative group in dorsiflexion, plantarflexion, ankle inversion, and midfoot abduction and adduction. Surveys showed that the Ponseti group had significantly more normal pediatric outcome data collection instrument results, disease-specific indices, and Dimeglio scores. The radiographic results suggested greater equinus and cavus and increased foot internal rotation profile in the operative group compared with the Ponseti group.

Conclusions

Ponseti treatment provides superior outcome to posteromedial release surgery, but residual deformity still persists.     

Simple bedside predictors of mechanical ventilation in patients with Guillain-Barre syndrome

Objective

The objective of the study is to develop and validate a predictor score for assessing the requirement of mechanical ventilation (MV) in patients with Guillain-Barre syndrome (GBS).

Study design

The study was conducted in patients admitted with GBS in neurointensive care unit in a tertiary care hospital. The demographic, clinical factors, electrophysiological, and spirometric data of all consecutive patients were prospectively collected. The study was undertaken in 2 stages. In the first stage, data were collected for development of a predictor score. In the second stage, the score developed was validated on a separate set of patient data.

Results

The data collected were compared between the 2 groups (ventilated vs nonventilated). On univariate analysis, time taken to reach maximum deficit, neck weakness, bulbar weakness, facial weakness, single breath count (SBC), forced vital capacity, and phrenic nerve latency predicted the need for MV. On multivariate analysis, only neck weakness, bulbar weakness, SBC, and forced vital capacity were independent predictors of MV. There was a good correlation between SBC and the spirometric tests and phrenic nerve distal motor latency, as reflected in receiver operating characteristics curve. The predictor score developed using the regression coefficient of independent predictors showed that the best cutoff score for prediction of ventilation was 60 (sensitivity, 0.95; 1 – specificity, 0.065). Internal cross validation of the neck weakness, SBC, and bulbar palsy (NSB) score showed good correlation (Pearson R = 0.76; P = .00). There was no statistically significant difference between predicted and observed outcomes (sensitivity, 95%; specificity, 93%).

Conclusion

Several independent risk factors were found to predict the requirement for MV in patients with GBS at admission. However, after scoring and analyzing them, it was found that combining a few of them was more useful to predict the need for MV. A model using NSB score, developed using clinical variables, accurately predicted the requirement of MV. In addition, among the NSB score parameters, simple bedside SBC could adequately assess the adequacy of vital capacity.     

Selective Adsorption of Potassium in Seawater by CoHCF Thin Film Electrode and Its Electrochemical Desorption/Regeneration

Cobalt Hexacyanoferrate (CoHCF) was tested for the selective uptake of K from seawater and the electrochemical method was adopted for the desorption and regeneration of the material. Powder form CoHCF could adsorb about 6.5 mmol/g of K from the seawater. For the ease of the electrochemical desorption and regeneration, CoHCF thin film was coated onto the Indium Tin Oxide (ITO) glass to obtain a CoHCF electrode. K adsorption kinetics on CoHCF thin film was found to be well fitted with the intraparticle diffusion model, which was a two-step process. Five consecutive adsorption-desorption-regeneration cycles were carried out to know the gradual decrease in the adsorption capacity owing to changes in the redox states of two metals, Co and Fe, in the material. Fourier Transform Infrared Spectroscopy (FT-IR) and Ultraviolet-Visible (UV-Vis) measurement results corresponded to the color change of CoHCF thin film, indicating the valence change of transition metals and the exchange of alkali metal cations happened on the CoHCF at different operation stages. In order to elucidate the reaction mechanism, composition of the material was analysis in the following steps: adsorption, desorption, and regeneration. It was proved that the system based on CoHCF thin film modified electrode had the potential of recovering potassium from seawater.     

R-VAPOL-phosphoric acid based 1H and 13C-NMR for sensing of chiral amines and acids

Enantiomers have significant importance in pharmaceuticals, biology and modern chemistry and therefore distinguishing and quantifying the enantiomeric forms is of utmost importance. Herein, we propose diphenyl-3,3′-biphenanthryl-4,4′-diyl phosphate (R-VAPOL-PA) as a promising chiral solvating agent to discriminate amines and acids of poly-functional groups such as chiral amines, amino alcohols and hydroxy acids. The methodological approach involves using the nature of hydrogen bonds and ion pairs as a mode of weak interactions to form diastereomers where the probe is associated with enantiomers. The resulting diastereomer difference in the NMR spectrum enables the chiral discrimination with a complete baseline peak separation and an accurate enantiomeric excess (ee) analysis. We also carried out density functional theory (DFT) calculations to understand the complex formation to explain enantiodiscrimination by analysing the formation and stability of different chiral complexes. The binding energy differences between enantiomeric forms revealed by DFT calculations are qualitatively in agreement with the diastereomer difference in the NMR spectrum and unequivocally establishes the suggested experimental protocol of R-VAPOL-PA-based enantiomeric discrimination.

R-VAPOL-chiral solvating agent for discrimination of chiral amines and acids using ¹H and ¹³C NMR.     

Identification of Duplicates in Ginger Germplasm Collection from Odisha Using Morphological and Molecular Characterization

Proceedings of the National Academy of Sciences, India Section B: Biological Sciences - In this investigation, sixty morphologically different ginger rhizomes, collected from an active germplasm...