Difference Plots Research Articles

Comparison of transferrin isoform analysis by capillary electrophoresis and HPLC for screening congenital disorders of glycosylation.

Transferrin, a major glycoprotein has different isoforms depending on the number of sialic acid residues present on its oligosaccharide chain. Genetic variants of transferrin as well as the primary (CDG) & secondary glycosylation defects lead to an altered transferrin pattern. Isoform analysis methods are based on charge/mass variations. We aimed to compare the performance of commercially available capillary electrophoresis CDT kit for diagnosing congenital disorders of glycosylation with our in-house optimized HPLC method for transferrin isoform analysis. The isoform pattern of 30 healthy controls & 50 CDG-suspected patients was determined by CE using a Carbohydrate-Deficient Transferrin kit. The results were compared with in-house HPLC-based assay for transferrin isoforms. Transferrin isoform pattern for healthy individuals showed a predominant tetrasialo transferrin fraction followed by pentasialo, trisialo, and disialotransferrin. Two of 50 CDG-suspected patients showed the presence of asialylated isoforms. The results were comparable with isoform pattern obtained by HPLC. The commercial controls showed a <20% CV for each isoform. Bland Altman plot showed the difference plot to be within +1.96 with no systemic bias in the test results by HPLC & CE. The CE method is rapid, reproducible and comparable with HPLC and can be used for screening Glycosylation defects.

Assay-dependent variability of serum insulin concentrations: a comparison of eight assays

Although insulin measurement is essential for both clinical and research purposes, there is currently no reference method for insulin assays. The aim of this study was to compare results of serum insulin determined by a number of commercially available assays. We compared eight insulin assays by analyzing 165 serum samples. Assays included two chemiluminescence (Roche and DiaSorin), four ELISA (Tosoh, Mercodia, Monobind, and Diametra), and two IRMA (Izotop and BioSource) methods. Each assay was compared with the mean of all assay methods and Bland-Altman difference plots were used to measure agreement between each assay and overall mean. Least squared perpendicular distance regression analysis (Deming’s method) was used to calculate slope and intercept for bias and also for each assay vs. mean of eight assays. Findings showed that the lowest and highest median insulin concentrations varied by a factor of 1.8. Maximum and minimum correlations with mean of assays were observed for Roche (0.992) and BioSource (0.844), respectively. Significant bias was observed in six assays. In pairwise comparisons of different assays, the highest and least mean differences were 7.78 μU/mL and −0.14 μU/mL, respectively. In conclusion, serum insulin measurement with different assays showed a maximum of 1.8-fold difference, a point that should be taken into consideration in the interpretation of circulating insulin levels in both clinical and research fields.

Expressing analytical performance from multi-sample evaluation in laboratory EQA.

To provide its participants with an external quality assessment system (EQAS) that can be used to check trueness, the Dutch EQAS organizer, Organization for Quality Assessment of Laboratory Diagnostics (SKML), has innovated its general chemistry scheme over the last decade by introducing fresh frozen commutable samples whose values were assigned by Joint Committee for Traceability in Laboratory Medicine (JCTLM)-listed reference laboratories using reference methods where possible. Here we present some important innovations in our feedback reports that allow participants to judge whether their trueness and imprecision meet predefined analytical performance specifications. Sigma metrics are used to calculate performance indicators named 'sigma values'. Tolerance intervals are based on both Total Error allowable (TEa) according to biological variation data and state of the art (SA) in line with the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Milan consensus. The existing SKML feedback reports that express trueness as the agreement between the regression line through the results of the last 12 months and the values obtained from reference laboratories and calculate imprecision from the residuals of the regression line are now enriched with sigma values calculated from the degree to which the combination of trueness and imprecision are within tolerance limits. The information and its conclusion to a simple two-point scoring system are also graphically represented in addition to the existing difference plot. By adding sigma metrics-based performance evaluation in relation to both TEa and SA tolerance intervals to its EQAS schemes, SKML provides its participants with a powerful and actionable check on accuracy.

Comparative study of structural, electronic and elastic behavior of OsAl and OsSi in B2 and B20 phases under pressure

The structural, electronic, bonding, elastic and mechanical properties of osmium intermetallic OsX (X = Al and Si) compounds in B2-phase as well as in B20-phase have been studied using full-potential linearized augmented plane wave method in the framework of density functional theory within generalized gradient approximation. The calculated lattice constants (a0) and bulk modulus (B) are in good agreement with experimental and available theoretical results. From the band structure calculations, it is shown that OsAl is metallic in both the phases while OsSi is found to be semiconductor in B20-phase with the indirect band gap of 0.33 eV but at high pressure the density of states at Fermi level N(EF) decreases and the bands spread over the entire reason in both the compounds. The elastic constants of these compounds obey the stability criteria for cubic system at 0 pressure as well as at high pressure. With increasing pressure, all the elastic constants for OsAl and OsSi increase almost linearly with pressure in both the phases except C44 for OsAl-B20 which shows its softening nature. Bonding nature is discussed in terms of charge density difference plots and Fermi surfaces.

Effect of phototherapy on the diagnostic accuracy of transcutaneous bilirubin in preterm infants

Objectives: The objective of this study was to evaluate the diagnostic accuracy of JM-103 transcutaneous bilirubinmeter (TcB) in preterm infants during phototherapy (PT) and in post-PT phase. Methods: This was a prospective cohort study. Infants born between 28 and 35 weeks of gestation and at <28 days of postnatal age were eligible if they required bilirubin estimation during the NICU stay. TcB was measured within 30 minutes of the blood sampling for serum bilirubin, at forehead and sternum. Mean difference (±standard deviation [SD]) and 95% limits of agreement between TcB and total serum bilirubin (TSB) were calculated by analyzing Bland–Altman difference plots. We also calculated correlation coefficients. Results: Ninety infants were enrolled. During PT, the difference plots revealed a wide TcB-TSB disagreement; 95% agreement limits of data indicated that TcB could underestimate bilirubin levels by up to 132 μmol/L at forehead and 157 μmol/L at sternum (Mean difference ± SD of −52.4 mmol/L ± 40.7 at forehead and −69.2 mmol/L ± 42.5 at sternum) and a poor TcB-TSB correlation (r = 0.72 at forehead and 0.51 at sternum). In post-PT phase, correlation coefficients improved significantly and were equivalent to the estimates before the onset of PT (r = 0.88 at forehead and 0.87 at sternum). The analyses of difference plots revealed that TcB could underestimate bilirubin levels up to 88 μmol/L in this phase (Mean difference ± SD of −28.8 mmol/L ± 30.5 at forehead and −19.6 mmol/L ± 34.7 at sternum). Conclusions: JM-103 device is unreliable for estimating bilirubin during PT. However, TcB-TSB agreement improved substantially in the post-PT phase such that use of the TcB device could lead to a reduction in blood sampling during this phase.

Stability of Biochemical Components in Blood Samples Transported by Tempus600/Sysmex GLP Robot Reception System.

The Department of Clinical Immunology and Biochemistry, Lillebaelt Hospital, Denmark, and TIMEDICO invented and developed the Tempus600®, a pneumatic tube system (PTS). This system is only 2.5 cm in diameter and sends blood tubes directly, without packing before transport. Request forms need not be enclosed, since samples are labeled with patient and barcode ID. At the end of the pipes, a robot receives and places the tubes onto a GLP transport system after the principle of "first in, first out" (FIFO), whereafter the tubes are delivered to centrifuges and analytical equipment. The whole system has decreased the total turnaround time (ToTAT) from 2 to 3 h to <60 min. The aim of the study was to validate the Tempus600/GLP robot system for the 89 most frequent or critical components. Two sets of blood samples were drawn from 100 patients. One set was sent by the Tempus600/GLP robot system, and the other was couriered directly to the laboratory for analysis. Results were compared using difference plots. The results for 85 of the components did not deviate from the optimized fast courier reference transport more than could be expected by the analytical variation. O2 saturation, oxyhemoglobin, and partial pressure of oxygen (Po2) deviated considerably from a clinical point of view. Partial pressure of carbon dioxide (Pco2) results were clinically acceptable for assessing patients with obstructive lung disease for hypercapnia. The Tempus600/GLP robot system can be used for transport of the majority of routinely used analytical tests.

Comparative Agreement Analysis of Differences in 1,5-Anhydroglucitol, Glycated Albumin, and Glycated Hemoglobin A1c Levels between Fasting and Postprandial States in Steamed Bread Meal Test.

Background Our previous study indicated that serum 1,5-anhydroglucitol (1,5-AG) levels slightly increased after a glucose load; therefore, this study was conducted to explore short-term changes in 1,5-AG levels after a steamed bread meal test (SBMT) and compare the agreement of 1,5-AG, glycated albumin (GA), and glycated hemoglobin A1c (HbA1c) levels between fasting and postprandial states after an SBMT. Methods 104 participants were recruited and underwent a 100 g SBMT. Fasting, 30 min, and 120 min of 1,5-AG, GA, and HbA1c were measured. Results Levels of 1,5-AG slightly increased from 30 to 120 min after an SBMT (P < 0.01), and HbA1c and GA levels showed stability at 30 and 120 min. The Passing-Bablok regression linear equation showed that postprandial 1,5-AG, GA, and HbA1c levels were well fitted (all P > 0.05), and Bland-Altman difference plot showed that 100% of data points for HbA1c30 and HbA1c120 fell within the limits of agreement; 94.2%, 96.2%, 95.2%, and 95.2% of data points for 1,5-AG30, 1,5-AG120, GA30, and GA120 fell within the limits of agreement, respectively. Conclusion Agreement analyses indicated good stability of 1,5-AG, GA, and HbA1c levels after the SBMT. HbA1c had an optimal stability, which was superior to that of GA or 1,5-AG.

A Multistage Deep Belief Networks Application on Arrhythmia Classification

An electrocardiogram (ECG) is a biomedical signal type that determines the normality and abnormality of heart beats using the electrical activity of the heart and has a great importance for cardiac disorders. The computer-aided analysis of biomedical signals has become a fabulous utilization method over the last years. This study introduces a multistage deep learning classification model for automatic arrhythmia classification. The proposed model includes a multi-stage classification system that uses ECG waveforms and the Second Order Difference Plot (SODP) features using a Deep Belief Network (DBN) classifier which has a greedy layer wise training with Restricted Boltzmann Machines algorithm. The multistage DBN model classified the MIT-BIH Arrhythmia Database heartbeats into 5 main groups defined by ANSI/AAMI standards. All ECG signals are filtered with median filters to remove the baseline wander. ECG waveforms were segmented from long-term ECG signals using a window with a length of 501 data points (R wave centered). The extracted waveforms and elliptical features from the SODP are utilized as the input of the model. The proposed DBN-based multistage arrhythmia classification model has discriminated five types of heartbeats with a high accuracy rate of 96.10%.

Granzyme B Expression in T-Regulatory Cells Is a Strong Predictor of Acute Graft-Versus-Host Disease after Day +30 in Patients with "Classic" Immunosuppression after Allo-HSCT

Introduction. Granzyme B is a serine protease commonly found in the granules of cytotoxic lymphocytes and natural killer cells. It is secreted with the pore forming protein perforin and mediates apoptosis in target cells. Granzyme B mediated cytolysis is one of the regulatory mechanisms (together with IL-2 receptors (CD25)) by which T-regulatory cells (T-regs) influence on T-effectors cells. Despite the well-known fact that T-regs participate in pathogenesis of aGVHD and their amount after allo-HSCT inversely correlates with the probability of aGVHD incidence, data about functional status of T-regs and aGVHD is still limited.Patients and methods. Peripheral blood samples were collected in EDTA-tubes at day +30 after allo-HSCT. We use PBMC from 29 patients with hematological malignancies obtained by density gradient media. This method was used due to lymphopenia in this group of patients. Group with no aGVHD consist of 22 patients (AML=12, ALL n=5, LPD=1, CML=2, AA=1, MDS=1) after allo-HSCT n=17 from MUD, n=5 from mismatch unrelated donor. MAC conditioning regimen was used in 17 cases, 5 patients receive RIC. The group of aGVHD after day +30 include 7 patients. (AML=4, ALL n=3) after allo-HSCT from MUD (n=5), mismatch unrelated donor (n=1) and n=1 from sibling HLA-identical donor. Two patients receive MAC and 5 patients receive RIC conditioning regimen. All patients in both groups receive standard immunosuppression (MMF+CSA+ATG). All patients developed II-IV grade aGVHD (II (n=1); III (n=4); IV (n=2)) with a median time onset on day +50 (34-150).The anti-CD4-APC-Cy7, anti-CD25-APC, anti-CD127-FITC and anti-Granzyme B-PE (Becton Dickinson, USA) antibodies were used to determine T-regulatory cells population. A Bland-Altman plot (difference plot) was used in analyzing the agreement between the two different methods of T-regs assay (CD4+CD25high and CD4+CD25highCD127low) - differences were not found (p=0,942). Due to this fact in our experiments CD4+CD25high cells were identified as T-reg cells (Gregg et al., 2005). 30000 of CD4+ cells were analyzed on a BD FACSCanto II to achieve sufficient statistical power (Becton Dickinson, USA).Results. As we can see on chart 1 level of Granzyme B was higher in patients who never developed aGVHD. In accordance with chart 2 percentage of Granzyme B positive T-regs in group of patients who never developed aGVHD was 7,26±1,89% in comparison with 2,04±0,93% in group who developed aGVHD after day +30 (p=0,02*). We should note that according to our previous experiments bacterial or viral infection (e.g CMV) and HLA-disparity does not affect the level of granzyme B expression in T-regs. Using ROC- curve analysis (see Chart 3) we obtained area under curve (AUC) 0,74.Conclusion. Our data shows that Granzyme B in T-reg cells after allo-HSCT in patients with standard IST may predict aGVHD onset after day +30 with satisfactory test results (AUC=0,74, «cut-off» - 4,15%; sensitivity - 85,71%; specificity - 45,45%).). According to data of our transplant center (for 2006-2016), "granzyme B-based strategy" can help us to predict up to 47,3% of all aGVHD.Disclosures: No relevant conflicts of interest to declare.Chart 1: Example of Granzyme B expression (right; shown on horizontal axis) in T-regs (left; upper right quadrant) on day +30 after allo-HSCT in group with standard immunosuppressionChart 2: Percentage of Granzyme B positive T-reg cells in patient without aGVHD and patients who develop aGVHD after day +30.Chart 3: ROC curve analysis of Granzyme B in T-regs as predictor of aGVHD. [Display omitted] [Display omitted] [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Robustness of the Reichert Unistat Bilirubinometer for analysis of hemolyzed samples from neonates

Background and objectives: Bilirubin is routinely measured in neonates to avoid the irreversible effects of kernicterus. Grossly hemolyzed samples are routinely rejected under the assumption that bilirubin cannot be accurately measured in hemolyzed samples. The objective of this study was to determine the effect of hemolysis on bilirubin measurement in neonates.Methods: Data included 2-years of paired bilirubin results (n=70) where hemolyzed and non-hemolyzed samples were collected and measured within 6h of each other. Bilirubin results were compared by Passing-Bablock linear regression and difference plots. Bilirubin results were also compared using the Bhutani nomogram to determine if hemolysis affected the hyperbilirubinemia risk-category.Results: Gross hemolysis resulted in a mean negative bias of −5.2μmol/L (95% CI: −30.7 to 20.3μmol/L). Based on the Bhutani nomogram, 1/70 samples would have been classified as Low-intermediate instead of High-intermediate risk and 3/70 would have been classified as Low instead of Low-intermediate risk; 5/70 samples would have been classified as Low-intermediate instead of Low risk.Conclusions: Collectively the data support that neonatal bilirubin may be reported from grossly hemolyzed samples measured using the Reichert Unistat Bilirubinometer. This practice has been adopted at our institution where results are reported with comments describing the effects of hemolysis. Implementation of this approach has decreased the number of blood re-collections in neonates.

Theoretical study of YD2-o-C8-based derivatives as promising sensitizers for dye-sensitized solar cells

To screen efficient sensitizers for dye-sensitized solar cells (DSSCs), two series of porphyrin sensitizers have been reengineered based on one of the best sensitizers YD2-o-C8 by introducing different heterocycles into acceptor part to form stronger acceptors. The electronic structures and optical properties of these sensitizers have been investigated using density functional theory and its time-dependent density functional theory version. The computational results suggest that the stronger acceptor can result in a narrower HOMO–LUMO energy gap, an obvious red-shift and stronger absorption in long-wavelength region compared with YD2-o-C8. Meanwhile, the analyses of electron density difference plots suggest that all designed sensitizers possess longer electron transfer distance, larger fraction of electron exchange, and smaller overlap between the zones of density depletion and increment than these of YD2-o-C8, indicating enhanced electron transfer ability from donor to acceptor groups. Moreover, the designed dyes exhibit good performance in terms of the electron injection ability, the excited state lifetime, and the strength of the interaction between dye and the TiO2 surface. As a whole, all the designed dyes, especially P4 and P6 may act as excellent sensitizers for high-efficiency DSSCs.

Evaluation of a reduced centrifugation time and higher centrifugal force on various general chemistry and immunochemistry analytes in plasma and serum

Background Centrifugation of blood samples is an essential preanalytical step in the clinical biochemistry laboratory. Centrifugation settings are often altered to optimize sample flow and turnaround time. Few studies have addressed the effect of altering centrifugation settings on analytical quality, and almost all studies have been done using collection tubes with gel separator. Methods In this study, we compared a centrifugation time of 5 min at 3000 × g to a standard protocol of 10 min at 2200 × g. Nine selected general chemistry and immunochemistry analytes and interference indices were studied in lithium heparin plasma tubes and serum tubes without gel separator. Results were evaluated using mean bias, difference plots and coefficient of variation, compared with maximum allowable bias and coefficient of variation used in laboratory routine quality control. Results For all analytes except lactate dehydrogenase, the results were within the predefined acceptance criteria, indicating that the analytical quality was not compromised. Lactate dehydrogenase showed higher values after centrifugation for 5 min at 3000 × g, mean bias was 6.3 ± 2.2% and the coefficient of variation was 5%. Conclusions We found that a centrifugation protocol of 5 min at 3000 × g can be used for the general chemistry and immunochemistry analytes studied, with the possible exception of lactate dehydrogenase, which requires further assessment.

Effects of solid inertial particles on the velocity and temperature statistics of wall bounded turbulent flow

The effect of solid inertial particles on the velocity and temperature statistics of a non-isothermal turbulent channel flow is studied using direct numerical simulation. The particles inertia is varied by changing the particles diameter. The density of particles is kept constant. A two-way coupled Eulerian–Lagrangian approach is adopted to solve the carrier flow field and the motion of dispersed particles. Three different particle Stokes numbers of St=24, 60, 192, at a constant particle mass loading of ϕm=0.54, are considered. The mean and rms profiles of velocity and temperature for fluid and particles, and the scatter plots of fluid-particle temperature differences are presented. In addition, the variations of different budget terms for the turbulent kinetic energy equation and fluctuating temperature variance equation in the presence of particles are reported. The fluid turbulent heat flux is reduced by the presence of particles, and in spite of the additional heat exchange between the carrier fluid and the particles, the total heat transfer rate stays always lower for particle-laden flows. To further clarify this issue, the total Nusselt number is split into a turbulence contribution and a particle contribution, and the effects of particles inertia on fluid turbulent heat flux and fluid-particle heat transfer are examined in detail.

Basic geometry and aberration characteristics of conicoidal conformal domes.

This paper investigated the geometry and aberration characteristics of conicoidal conformal domes. First, on the basis of previous research, we got the expression that was suitable for describing the external surface of the conicoidal conformal dome. Based on the theory of differential geometry, this paper first proved that the Dupin index line of a quadric surface was an ellipsoid and the radius of curvature had extreme values in the meridian plane and sagittal plane. Then the uniform formulas of curvature which were suitable for ellipsoid, paraboloid, and hyperboloid were deduced in the meridian plane and sagittal plane, respectively. Meanwhile, the angle between the axis of imaging systems and the surface normal was calculated. With the help of computers, the plots of curvature differences and the angle in the case of different edge slopes, fineness ratios, and the locations of the rotational center were obtained. Finally, we analyzed the Zernike polynomial coefficients of Z4, Z5, and Z8, which represent defocus, astigmatism and coma, respectively for the model established in CODE V. The research indicates that the dynamic ranges of defocus, astigmatism, and coma increase with the growing of edge slopes and fineness ratios, but have little change with the variation of the rotational center positions. Moreover, the curves of Z5 and Z8 have turning points, and the curves of curvature differences and angle difference are only similar to the curves of Z5 and Z8 when the look angle changes after the turning point. For the look angle changing from zero to the turning point, the curves of Z5 and Z8 change rapidly. This is mainly caused by the significant variations of the symmetry of the conformal dome participating in imaging. Therefore, the aberrations with small scanning angles should be given more attention when designing the conformal systems.

An ab initio study on properties of cationic chalcogen bonds in XF2Y+⋯NCZ (X═H, CN, F; Y═S, Se; Z═H, Cl, Br) complexes

ABSTRACTThe geometries, interaction energies, and bonding properties of cationic chalcogen bonds are studied in binary complexes XF2Y+⋯NCZ (X═H, CN, F; Y═S, Se; Z═H, Cl, Br). The nature of these interactions is studied by a vast number of methods, including molecular electrostatic potential (MEP), Noncovalent Interaction Index (NCI), quantum theory of atoms in molecules (QTAIM), and natural bond orbital (NBO) analyses. The interaction energies of these complexes vary between −20.94 kcal/mol in HF2S+⋯NCH and −33.72 kcal/mol in F3Se+⋯NCBr. According to the QTAIM analysis, all these cationic chalcogen bonds are classified as a closed-shell interaction with a partial covalent character. Moreover, cooperative effects between cationic chalcogen bond and hydrogen or halogen bond interactions are studied in ternary XF2Y+⋯NCZ⋯NH3 complexes. These cooperative effects are analyzed in terms of the parameters derived from the QTAIM and NBO analyses, and electron density difference plots.

Analysis of amino acids in human blood using UHPLC-MS/MS: Potential interferences of storage time and vacutainer tube in pre-analytical procedure

ObjectivesTo investigate potential interferences of two pre-analytical variables, the storage time and the vacutainer tube, on the quantification of 20 amino acids using a UHPLC-MS/MS method. Design and methodsBlood samples from 25 apparently healthy subjects were collected into duplicate sets of EDTA-2K, EDTA-3K, coagulation, heparin and citrate tubes, and stored in capped vacutainer tubes at 4°C for 6h, 12h and 24h before sample analysis. A UHPLC-MS/MS method was established for simultaneous quantification of 20 amino acids. ANOVA for repeated measurement was conducted based on the model of Mauchly's test of Sphericity. Student's t-test was applied for comparison between amino acid concentrations obtained from different vacutainer tubes, and consistency of the results was checked through Bland-Altman difference plots and Passing-Bablok regression analysis. ResultsMost of the 20 amino acids showed a least concentration fluctuation with storage time in heparin plasma, followed by EDTA-3K and citrate plasma. The amino acid concentrations were significantly lower in citrate plasma and slightly higher in serum, compared with those in heparin plasma. No fixed bias was observed for amino acid concentrations in EDTA and heparin plasma, but the differences were mostly of statistical significance. Amino acid concentrations in EDTA-3K plasma achieved a good consistency with those in heparin plasma by UHPLC-MS/MS analysis. ConclusionsStorage time and vacutainer tube were important variables for amino acid analysis. They should draw researchers' attention and then be controlled in good laboratory practice to reduce pre-analytical errors.

Verification of a formula developed to predict the postoperative intraocular pressure after cataract surgery in primary angle-closure glaucoma

BackgroundThe aim of this study was to verify the accuracy of a formula predicting postoperative intraocular pressure (IOP) after phacoemulsification and intraocular lens implantation (PHCE-IOL) in primary angle-closure glaucoma (PACG). In a retrospective chart review of patients with PACG who underwent PHCE-IOL between 2011 and 2014, we collected preoperative IOP, axial length, anterior chamber depth (ACD), number of pre-PHCE glaucoma medications, and IOP and glaucoma medications at 1 month and 3 months post-PHCE. MethodsPost-PHCE IOP values at 1 month and 3 months were compared with those predicted using the formula: postoperative IOP = 6.354 + 0.186 pre-PHCE IOP × pre-PHCE ACD. Agreements between measured and predicted IOP values were analyzed using correlation coefficients and Bland–Altman plots. ResultsOf the 62 eyes included, the average pre-PHCE IOP was 19.47 ± 5.84 mm Hg. Post-PHCE IOP values were 14.94 ± 4.03 mm Hg at 1 month and 14.21 ± 3.51 mm Hg at 3 months. Patients using more preoperative medications tended to show greater postoperative declines in medication usage. Predicted IOP significantly correlated with post-PHCE IOP measured at 1 month (R = 0.314, p = 0.013) and 3 months (R = 0.325, p = 0.01). Bland–Altman plots of difference against average of measured and estimated IOP revealed two cases falling outside±1.96 standard deviation at 1 month, and five cases at 3 months, indicating good consistency between measurement and prediction. ConclusionThis formula was useful for predicting IOP at 1 month and 3 months after PHCE-IOL in PACG. It aids clinicians in preoperative assessment of whether PHCE-IOL alone is likely to achieve acceptable postoperative IOP control.

Advanced vegetation indices for sensing paddy growth via hyperspectral measurements

In this study, field-based spectroradiometer measurements were carried out in 72 plots with eight rice varieties along with three nitrogen applications. The critical wavelengths for the studied rice varieties at which the effects of nitrogen applications on spectral reflectance response were found significant, are ρ550, ρ560, ρ655, ρ750, ρ755, ρ780, ρ810, ρ840, ρ900, ρ920, ρ1000, ρ1010, ρ1020. Using the critical wavelengths, three derived vegetation indices were compared with established indices (VI and GRI) sensitive to nitrogen. VI1 and VI2 were efficiently able to discriminate the level of nitrogen treatments for most of the rice genotypes whereas VI and GRI were unable to find significant difference in nitrogen treatments for rice genotypes except two. Furthermore, nitrogen difference plots exhibited that the paddy crop growth has started earlier with N3 (150 kg/ha) than N2 (100 kg/ha) application. Quantitative analysis of rice genotypes revealed that VI2 can be applied functionally for the assessment of nitrogen stress in rice agriculture system.

Assessing the GOANNA Visual Field Algorithm Using Artificial Scotoma Generation on Human Observers.

PurposeTo validate the performance of a new perimetric algorithm (Gradient-Oriented Automated Natural Neighbor Approach; GOANNA) in humans using a novel combination of computer simulation and human testing, which we call Artificial Scotoma Generation (ASG).MethodsFifteen healthy observers were recruited. Baseline conventional automated perimetry was performed on the Octopus 900. Visual field sensitivity was measured using two different procedures: GOANNA and Zippy Estimation by Sequential Testing (ZEST). Four different scotoma types were induced in each observer by implementing a novel technique that inserts a step between the algorithm and the perimeter, which in turn alters presentation levels to simulate scotomata in human observers. Accuracy, precision, and unique number of locations tested were measured, with the maximum difference between a location and its neighbors (Max_d) used to stratify results.ResultsGOANNA sampled significantly more locations than ZEST (paired t-test, P < 0.001), while maintaining comparable test times. Difference plots showed that GOANNA displayed greater accuracy than ZEST when Max_d was in the 10 to 30 dB range (with the exception of Max_d = 20 dB; Wilcoxon, P < 0.001). Similarly, GOANNA demonstrated greater precision than ZEST when Max_d was in the 20 to 30 dB range (Wilcoxon, P < 0.001).ConclusionsWe have introduced a novel method for assessing accuracy of perimetric algorithms in human observers. Results observed in the current study agreed with the results seen in earlier simulation studies, and thus provide support for performing larger scale clinical trials with GOANNA in the future.Translational RelevanceThe GOANNA perimetric testing algorithm offers a new paradigm for visual field testing where locations for testing are chosen that target scotoma borders. Further, the ASG methodology used in this paper to assess GOANNA shows promise as a hybrid between computer simulation and patient testing, which may allow more rapid development of new perimetric approaches.

Dissociation of N2O on anatase TiO2 (001) surface – The effect of oxygen vacancy and presence of Ag cluster

The increase in concentration of nitrous oxide (N2O) in the atmosphere is one of the major contributors to the greenhouse effect, ozone depletion and climate change. Therefore, it is important to decompose harmful N2O molecule into harmless N2. In the present work, we have studied the decomposition of N2O on anatase TiO2 (001) surface using first principle calculations. The results indicates that the N2O molecule is physisorbed on perfect TiO2 surface without any dissociation, and is dissociated into N2 and oxygen on the reduced TiO2 surface. In addition, it has been found that the interaction between N2O and TiO2 is augmented by the presence of Ag cluster on anatase (001) surface. On the basis of Bader charge analysis and electron density difference plot, it has been found that the excess charge in the reduced anatase TiO2 (001) surface is transferred to the adsorbed N2O molecule, which results the weakening of N–O bond of N2O followed by the decomposition of N2O into N2 and O. Vibrational frequency analysis also performed to confirm the decomposition of N2O molecule. From the pathway for N2O dissociation on reduced TiO2 and Ag/TiO2 surfaces, it has been observed that the dissociation reaction of N2O on TiO2 surface is highly exothermic with activation energy barrier of 0.25eV. The results presented in this work show that the reduced anatase TiO2 with (001) facet is a good catalyst for the decomposition of N2O molecule.