•The ECP, RTM, IM and PP methods were used to determine adsorption isotherms in SFC.•Most modern SFC-systems are advantageous for determination of adsorption isotherms.•Careful system verification ...with external sensors for mass flow etc. is necessary.•The ECP, IM and RTM methods accurately predicted overloaded elution profiles.•The more tedious PP method, could not accurately predict overloaded profiles.
In this study we will demonstrate the potential of modern integrated commercial analytical SFC-systems for rapid and reliable acquisition of thermodynamic data. This will be done by transferring the following adsorption isotherm determination methods from liquid chromatography (LC) to supercritical fluid chromatography (SFC): Elution by Characteristic Points (ECP), the Retention Time Method (RTM), the Inverse Method (IM) and the Perturbation Peak (PP) method. In order to transfer these methods to SFC in a reliable, reproducible way we will demonstrate that careful system verification using external sensors of mass flow, temperature and pressure are needed first. The adsorption isotherm data generated by the different methods were analyzed and compared and the adsorption isotherms ability to predict new experimental elution profiles was verified by comparing experiments with simulations. It was found that adsorption isotherm data determined based on elution profiles, i.e., ECP, IM and RTM, were able to accurately predict overloaded experimental elution profiles while the more tedious and time-consuming PP method, based on small injections on concentration plateaus, failed in doing so.
High-quality placebo-controlled evidence for food, nutrient or dietary advice interventions is vital for verifying the role of diet in optimising health or for the management of disease. This could ...be argued to be especially important where the benefits of dietary intervention are coupled with potential risks such as compromising nutrient intake, particularly in the case of exclusion diets. The objective of the present paper is to explore the challenges associated with clinical trials in dietary research, review the types of controls used and present the advantages and disadvantages of each, including issues regarding placebos and blinding. Placebo-controlled trials in nutrient interventions are relatively straightforward, as in general placebos can be easily produced. However, the challenges associated with conducting placebo-controlled food interventions and dietary advice interventions are protean, and this has led to a paucity of placebo-controlled food and dietary advice trials compared with drug trials. This review appraises the types of controls used in dietary intervention trials and provides recommendations and nine essential criteria for the design and development of sham diets for use in studies evaluating the effect of dietary advice, along with practical guidance regarding their evaluation. The rationale for these criteria predominantly relate to avoiding altering the outcome of interest in those delivered the sham intervention in these types of studies, while not compromising blinding.
The shifted fracture method (SFM) is an embedded method that enables sharp crack representations while using mesh‐fitted data structures. In the SFM, the true crack is embedded in the computational ...grid, but the crack interface conditions are approximated by, or shifted to, a surrogate crack composed of element boundaries (i.e., edges/faces in two/three dimensions). This avoids enriched degrees‐of‐freedom and cut elements, so that data structures and geometrical treatment are much simpler, while still maintaining mesh‐independent and accurate crack approximations. This article presents a continuous‐discontinuous model of fracture based on blending a phase‐field (PF) model with the SFM. The PF tracks the evolution of cracks inside a numerical fracture processing zone: diffuse cracks initiate, propagate, branch, and merge according to the field equations of energy minimization; no ad‐hoc criteria are needed. The PF damage variable is then used to define the geometry of the true crack. With computational efficiency in mind, the PF model is only solved in subdomains where additional crack growth is expected and the SFM representation is used elsewhere. The efficiency and accuracy of the proposed approach in capturing complex crack patterns are illustrated by a representative set of two‐dimensional numerical examples.
Targeted mass spectrometry (MS)-based absolute quantitative analysis has been increasingly used in biomarker discovery. The ability to accurately measure the masses by MS enabled the use of ...isotope-incorporated surrogates having virtually identical physiochemical properties with the target analytes as calibrators. Such a unique capacity allowed for accurate in-sample calibration. Current in-sample calibration uses multiple isotopologues or structural analogues for both the surrogate and the internal standard. Here, we simplified this common practice by using endogenous light peptides as the internal standards and used a mathematical deduction of “heavy matching light, HML” to directly quantify an endogenous analyte. This method provides all necessary assay performance parameters in the authentic matrix, including the lower limit of quantitation (LLOQ) and intercept of the calibration curve, by using only a single isotopologue of the analyte. This method can be applied to the quantitation of proteins, peptides, and small molecules. Using this method, we quantified the efficiency of heart tissue digestion and recovery using sodium deoxycholate as a detergent and two spiked exogenous proteins as mimics of heart proteins. The results demonstrated the robustness of the assay.
Skin‐to‐skin care for procedural pain in neonates Johnston, Celeste; Campbell‐Yeo, Marsha; Disher, Timothy ...
Cochrane database of systematic reviews,
02/2017, Letnik:
2017, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Background
Skin‐to‐skin care (SSC), often referred to as 'kangaroo care' (KC) due to its similarity with marsupial behaviour of ventral maternal‐infant contact, is one non‐pharmacological ...intervention for pain control in infants.
Objectives
The primary objectives were to determine the effect of SSC alone on pain from medical or nursing procedures in neonates compared to no intervention, sucrose or other analgesics, or additions to simple SSC such as rocking; and to determine the effects of the amount of SSC (duration in minutes), method of administration (e.g. who provided the SSC) of SSC in reducing pain from medical or nursing procedures in neonates
The secondary objectives were to determine the safety of SSC care for relieving procedural pain in infants; and to compare the SSC effect in different postmenstrual age subgroups of infants.
Search methods
For this update, we used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 1); MEDLINE via PubMed (1966 to 25 February 2016); Embase (1980 to 25 February 2016); and CINAHL (1982 to 25 February 2016). We also searched clinical trials' databases, conference proceedings, and the reference lists of retrieved articles for randomized controlled trials and quasi‐randomized trials.
Selection criteria
Studies with randomisation or quasi‐randomisation, double‐ or single‐blinded, involving term infants (≥ 37 completed weeks' postmenstrual age (PMA) to a maximum of 44 weeks' PMA and preterm infants (< 37 completed weeks PMA) receiving SSC for painful procedures conducted by healthcare professionals.
Data collection and analysis
The main outcome measures were physiological or behavioural pain indicators and composite pain scores. A mean difference (MD) with 95% confidence interval (CI) using a fixed‐effect model was reported for continuous outcome measures. We included variations on type of tissue‐damaging procedure, provider of care, and duration of SSC.
Main results
Twenty‐five studies (n = 2001 infants) were included. Nineteen studies (n = 1065) used heel lance as the painful procedure, one study combined venepuncture and heel stick (n = 50), three used intramuscular injection (n = 776), one used 'vaccination' (n = 60), and one used tape removal (n = 50). The studies were generally strong and had low or uncertain risk of bias. Blinding of the intervention was not possible, making them subject to high risk, depending on the method of scoring outcomes.
Seventeen studies (n = 810) compared SSC to a no‐treatment control. Although 15 studies measured heart rate during painful procedures, data from only five studies (n = 161) could be combined for a mean difference (MD) of −10.78 beats per minute (95% CI −13.63 to −7.93) favouring SSC. Meta‐analysis of four studies (n = 120) showed no difference in heart rate following the painful procedure (MD 0.08, 95% CI −4.39 to 4.55). Two studies (n = 38) reported heart rate variability with no significant differences. Two studies (n = 101) in a meta‐analysis on oxygen saturation at 30 and 60 seconds following the painful procedure did not show a difference. Duration of crying meta‐analysis was performed on four studies (n = 133): two (n = 33) investigated response to heel lance (MD = −34.16, 95% CI −42.86 to −25.45), and two (n = 100) following IM injection (MD = −8.83, 95% CI −14.63 to −3.02), favouring SSC. Five studies, one consisting of two substudies (n = 267), used the Premature Infant Pain Profile (PIPP) as a primary outcome, which favoured SCC at 30 seconds (MD −3.21, 95% CI −3.94 to −2.47), at 60 seconds (3 studies; n = 156) (MD −1.64, 95% CI −2.86 to −0.43), and at 90 seconds (n = 156) (MD −1.28, 95% CI −2.53 to −0.04); but at 120 seconds there was no difference (n = 156) (MD 0.07, 95% CI −1.11 to 1.25). No studies on return of heart rate to baseline level, cortisol levels, and facial actions could be combined for meta‐analysis findings.
Eight studies compared SSC to another intervention with or without a no‐treatment control. Two cross‐over studies (n = 80) compared mother versus other provider (father, another female) on PIPP scores at 30, 60, 90, and 120 seconds with no significant difference. When SSC was compared to other interventions, there were not enough similar studies to pool results in an analysis. One study compared SSC (n = 640) with and without dextrose and found that the combination was most effective and that SSC alone was more effective than dextrose alone. Similarly, in another study SSC was more effective than oral glucose for heart rate (n = 95). SSC either in combination with breastfeeding or alone was favoured over a no‐treatment control, but not different to breastfeeding. One study compared SSC alone and in combination with both sucrose and breastfeeding on heart rate (HR), NIPS scores, and crying time (n = 127). The combinations were more effective than SSC alone for NIPS and crying. Expressed breast milk was compared to SSC in one study (n = 50) and found both equally effective on PIPP scores. There were not enough participants with similar outcomes and painful procedures to compare age groups or duration of SSC. No adverse events were reported in any of the studies.
Authors' conclusions
SSC appears to be effective as measured by composite pain indicators with both physiological and behavioural indicators and, independently, using heart rate and crying time; and safe for a single painful procedure. Purely behavioural indicators tended to favour SSC but with facial actions there is greater possibility of observers not being blinded. Physiological indicators were mixed although the common measure of heart rate favoured SSC. Two studies compared mother‐providers to others, with non‐significant results. There was more heterogeneity in the studies with behavioural or composite outcomes. There is a need for replication studies that use similar, clearly defined outcomes. Studies examining optimal duration of SSC, gestational age groups, repeated use, and long‐term effects of SSC are needed. Of interest would be to study synergistic effects of SSC with other interventions.
Due to its ability to simulate complex microstructure evolution, the phase-field modeling has been extensively developed to investigate brittle fracture in recent years. However, low computational ...efficiency still imposes substantial difficulties in the development of phase-field models. In this work, we develop a novel adaptive phase-field approach based on the isogeometric meshfree collocation method (IMCM) to simulate the crack propagation in 2D and 3D polycrystalline materials. The concept of IMCM is based upon the correspondence between the isogeometric collocation and reproducing kernel meshfree method to facilitate a robust mesh adaptivity in isogeometric collocation. The strong form collocation formulation further enhances the computational efficiency of phase-field modeling by reducing the number of point evaluations. The present numerical framework is utilized for the adaptive phase-field modeling which introduces the anisotropy of fracture resistance for each grain in polycrystals. Furthermore, the discrete displacement and phase-field equations are generalized to enable the calculation of both second- and fourth-order gradients, which are required to solve the phase-field models using IMCM. The smoothness and higher-order continuity of IMCM enable the fourth-order phase-field equation to be solved directly without splitting it into two second-order differential equations. The fourth-order model can capture the crack surface accurately with fewer nodes than the second-order model. Several numerical examples of isotropic and anisotropic brittle fracture in polycrystalline materials are investigated to demonstrate the effectiveness and robustness of the proposed approach.
This study considers an implicit finite element formulation for an ideal fully-ionized multifluid electromagnetic plasma system. The formulation is based on fully-implicit Runge-Kutta time ...discretizations and a monolithic discrete algebraic flux corrected (AFC) continuous Galerkin (CG) spatial discretization of the coupled system. The AFC approach adds scalar artificial diffusion to the high-order, semi-discrete Galerkin method and uses mass lumping in the time derivative term. The result is a low-order method that attempts to enforce local-extremum-diminishing properties for the hyperbolic system. An element-based iterative limiter is applied to reduce the amount of artificial diffusion that is used in regions where the solution is smooth and the additional stabilization is not required. Two models are considered for the electromagnetics portion of the system: an electrostatic model, and a full Maxwell system with a parabolic divergence cleaning approach that enforces the required involutions on the electric and magnetic fields. Results are presented that demonstrate the accuracy and robustness of the formulation for smooth and discontinuous solutions to challenging plasma physics problems. This includes a demonstration that the solution of the full multifluid system yields the expected behavior in the ideal shock-MHD limit.
•A fully nodal continuous Galerkin discretization of the multifluid plasma system is presented.•The discretization is stabilized using an algebraic flux correction (AFC) method.•A parabolic divergence cleaning approach is used to enforce Gauss' laws.•The full multifluid system is shown to produce the expected behavior in the ideal shock-MHD limit.
Soil contamination by heavy metals is an increasingly important problem worldwide. Quick and reliable access to heavy metal concentration data is crucial for soil monitoring and remediation. Visible ...and near-infrared reflectance spectroscopy, which is known as a noninvasive, cost-effective, and environmentally friendly technique, has potential for the simultaneous estimation of the various heavy metal concentrations in soil. Moreover, it provides a valid alternative method for the estimation of heavy metal concentrations over large areas and long periods of time. This paper reviews the state of the art and presents the mechanisms, data, and methods for the estimation of heavy metal concentrations by the use of visible and near-infrared reflectance spectroscopy. The challenges facing the application of hyperspectral images in mapping soil contamination over large areas are also discussed.
This letter focuses on the power flow problem and shows the formal analogy between the Levenberg's method and a fictitious ODE built using Lyapunov's second stability criterion. The letter also ...illustrates theoretical caveats and numerical issues of both methods. In particular, the case study, based on a 2383-bus system, shows that the fixed points of these methods are not necessarily a solution of the power flow problem.
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