Good Negative Correlation Research Articles

Quantitative evaluation of the characteristic of infrapatellar fat pad Fat Content and Unsaturation Index by using hydrogen proton MR spectroscopy

ObjectiveTo investigate the characteristics of fat content and component in IFP using hydrogen proton MR spectroscopy (1H-MRS), and to explore the correlation with the severity of OA, Hoffa-synovitis, and knee pain. Materials and methods80 volunteers were enrolled. Subjects were grouped based on Kellgren-Lawrence (K-L) grading. Fat fraction (FF) and unsaturation index (UI) of IFP were measured using 1H-MRS. Hoffa-synovitis was evaluated based on the MRI Osteoarthritis Knee Score system (MOAKS). Knee pain was assessed by a self-administered Western Ontario and McMaster Osteoarthritis Index (WOMAC) questionnaire. One-way ANOVA or Kruskal-Wallis test and Spearman's correlation tests were applied for statistical analysis. ResultsAfter matching BMI, waistline, and K-L grade, a total of 64 knees were included and divided into 23 normal, 25 mild OA, and 16 advanced OA. The mean values were 76.79% ± 7.24%, 70.35% ± 7.42%, and 58.29% ± 10.32% for FF in the healthy controls, mild OA, and advanced OA group, and 6.36 ± 1.19%, 6.08 ± 1.35%, and 5.69 ± 1.78% for UI, respectively, the statistical difference was found for FF (p < 0.01). A good negative correlation was observed between the FF and the severity of OA, Hoffa-synovitis (r = −0.625, −0.758, respectively, p < 0.0001), and a weak inverse correlation with knee pain. ConclusionFF alteration in IFP is associated with the severity of OA, Hoffa synovitis, and knee pain, and has the potential to be a new quantitative imaging biomarker in knee OA.

Description and Validation of the Anterior Glenoid Angle: A Novel MRI-Based Measure of Glenoid Morphologic Features and Version.

The goal of this study was to establish a normal value for, and evaluate the reliability of, a new measurement of glenoid morphologic features using magnetic resonance imaging: the anterior glenoid angle. A total of 90 magnetic resonance imaging scans of patients without shoulder arthritis were reviewed. The anterior glenoid angle of each glenoid was measured by 4 blinded physicians. The images were randomized and measured again. Finally, the Friedman angle was measured on the same images for reference. Descriptive statistics and inter- and intraclass correlation coefficients were calculated. The mean anterior glenoid angle was 60.4°±3.6°. Of the measured values, 77% were between 56° and 64°. Intraobserver reliability was very good to excellent in single measure (range, 0.763-0.901) and mean measure (range, 0.865-0.948) comparisons. Interobserver reliability was very good to excellent in both single measure (0.769) and mean measure (0.964) comparisons. The mean Friedman angle was 10.2°. Correlation between the anterior glenoid angle and Friedman angle ranged from a moderate negative (-0.496) to a strong negative correlation (-0.711) among the observers. The mean anterior glenoid angle measured via magnetic resonance imaging scan was 60.4° in normal shoulders, and more than 75% of the values were within 4° of the mean. The anterior glenoid angle has excellent inter- and intrarater reliability without using computed tomography scan or including the entire scapula in the field of view. The anterior glenoid angle has a good to very good negative correlation with the Friedman angle because decreasing anterior glenoid angles indicate increasing retroversion. [Orthopedics. 2022;45(6):361-366.].

Chlorophylls, lutein and β‐carotene play great but different roles in colour of rapeseed oil

AbstractNatural colourants have great effects on the colour of vegetable oil. A series of colourant–oil simulation systems were constructed to study the effects of chlorophyll, lutein and β‐carotene and their interactions on the colour of rapeseed oil. CIE L*a*b* and Lovibond RYBN colour codes were used to evaluate the colour of the simulation systems. There were good negative linear correlations between the concentrations of the three natural colourants and L* value in both single colourant–oil and two colourants–oil simulation systems. Chlorophyll had greater effect on lightness of rapeseed oil than lutein and β‐carotene. The contribution of the two carotenoids to the yellow colour was greater than that of chlorophyll. Lutein and β‐carotene contributed positively to the red colour of rapeseed oil. They had superposition effect on colour of rapeseed oil, and β‐carotene might contribute more to the colour than lutein. It provided a method to evaluate the contribution of colourant to the colour and a possibility to regulate oil colour in edible oil industry.

Relationship between forward head posture and headache related disability in migraine

Background. Migraine is the most common disorder that affects the population extensively and leads to significant disability in employment, domestic work, and social activities. Postural assessment is one of the important constituents of the clinical analysis of patients with musculoskeletal disorders. Incorrect posture can cause stress on the structures of neck and continuous stress that leads to FHP (forward head posture) and headache. The purpose of the study was to find out the relationship between forward head posture and headache related disability in migraine patients. Methods. The prospective correlational study was carried out to explore the relationship between forward head posture and headache related disability in migraine. 55 participants were recruited in this study examined by photographic method. The forward head posture was measured by craniovertebral angle. Various photographs were taken from the subjects and were uploaded on the Kinovea 08.15 software to measure the craniovertebral angle. Results. The results shows that negative correlation was found between forward head posture and headache related disability. Statistical analysis was done by using Pearson correlation test. Results also showed that lower the CVA (forward head posture), greater the headache related disability either sitting or standing position in migraine patient experienced more headache. Conclusion. FHP with headache related disability in migraine showed moderate to good negative correlation. This study concluded that subjects with migraine headache had more FHP. In migraine patients; CV angle was small as compared to normal subjects. So, CV angle showed negative correlation with migraine.

Aerosol Hygroscopicity and its Link to Chemical Composition in a Remote Marine Environment Based on Three Transatlantic Measurements.

The hygroscopicity of marine aerosols may largely impact particle optical properties, cloud activation ability, and consequently the global climate system. This study highlights findings from real-time hygroscopicity and chemical composition measurements in three open-ocean cruises over the Atlantic Ocean. Spatial variations in hygroscopicity (κ) for marine boundary layer particles (≤300 nm) were provided for the first time covering nearly 100° of the latitude over the Atlantic Ocean, ranging from 0.14 to 1.06. Externally mixed particles with remarkably low hygroscopicity (0.14-0.16) were observed near the equator influenced by biomass burning emissions transported from Africa. For marine aerosols, a positive linear correlation evidently existed between κ and wind speed within a range of 5-15 m/s even for nanometer particles. A closure study shows that the measured κ of 300 nm particles is well explained by the bulk chemical composition. A good negative correlation between measured κ and the organic mass fraction in PM1 for marine aerosols was found (slope = -2.26, R2 = 0.44), while a different linear relationship appeared for continental aerosols at several sites (slope = -0.47, R2 = 0.77). Accordingly, we provide a parameterization method to estimate bulk aerosol hygroscopicity both in continental and marine environments using particulate organic fractions.

Mitochondrial Sirt3 serves as a biomarker for sepsis diagnosis and mortality prediction

The purpose of this study is to determine whether the levels of serum Sirt3 correlate with disease severity and perfusion indicators in septic patients, as well as to assess the clinical value of Sirt3 as a potential novel marker for sepsis diagnosis and mortality prediction. A total of 79 patients in the ICU were included in the study, of which 28 were postoperatively noninfectious and the remaining 51 patients were all diagnosed with sepsis during the study period. The levels of Sirt3 were detected and dynamically monitored by enzyme-linked adsorption method, Pearson or Spearman coefficient for correlation analysis between Sirt3 and clinical indicators, ROC curve for evaluation of diagnosis and mortality prediction, Kaplan–Meier method for the significance of Sirt3 in 28-day survival. The serum levels of Sirt3 were lower in the sepsis patients on day 1 (P < 0.0001), and the septic shock group had lower Sirt3 levels than the sepsis group (P = 0.013). Sirt3 had good negative correlations with SOFA scores both in sepsis and septic shock groups (Pearson: r2 = − 0.424, − 0.518; P = 0.011, 0.040), and Sirt3 correlated strongly with ScvO2 in the septic shock group (Pearson: r2 = − 0.679, P = 0.004) and with PCT in the sepsis group (Pearson: r2 = − 0.409, P = 0.015). Sirt3 not only performed well in identifying sepsis (AUC = 0.995, 95% CI 0.987–1, P < 0.0001) but also greatly enhanced lactate's specificity in detecting septic shock (from 91.43 to 94.29%). Patients in the low Sirt3 group had higher ScvO2, lactate, APACHE II score, SOFA score, longer ICU stays, and worse indicators of inflammation (TNF-α, IL-6) and infection (PCT) than those in the high Sirt3 group (P < 0.05). Additionally, Sirt3 can predict mortality of sepsis (AUC = 0.746, 95% CI 0.571–0.921, P = 0.022), patients with serum Sirt3 < 10.07 pg/ml have a lower 28-day survival (log-rank P = 0.008). Low serum levels of Sirt3 are significantly correlated with the disease severity. At the same time, Sirt3 increases the sensitivity of lactate to detect “cellular hypoxia” in septic shock. Sirt3 is a promising biomarker for the diagnosis of sepsis and predicting mortality risk in septic patients.

Simplified Chinese version of the international prostate symptom score and the benign prostatic hyperplasia impact index: cross-cultural adaptation, reliability, and validity for patients with benign prostatic hyperplasia.

BackgroundThe aim of this study was to translate and cross-culturally adapt the international prostate symptom score (IPSS) and benign prostatic hyperplasia impact index (BII) into simplified Chinese for mainland Chinese patients with benign prostatic hyperplasia (BPH).MethodsThe original English IPSS and BII were translated into simplified Chinese versions based on cross-cultural adaptation guidelines. Internal consistency was evaluated with Cronbach’s α, then test-retest reliability with intraclass correlation coefficients (ICCs) in stable patients. The validity of these two adaptations was tested by the correlation between the IPSS and BII with visual prostate symptom score (VPSS) and 36 items Short Form Health Survey (SF-36). The floor and ceiling effects were calculated by the proportion of participants who obtained the highest and lowest possible score.ResultsA total of 105 native Chinese-speaking patients with BPH were enrolled. Cronbach’s α was over 0.75 for the simplified Chinese IPSS (IPSS 0.815; IPSS-symptom 0.782) and 0.709 for the simplified Chinese BII, indicating acceptable internal consistency. The ICCs for the test-retest reliability were over 0.75 (IPSS, r = 0.836; IPSS-symptom, r = 0.801; IPSS-quality of life, r = 0.794; BII, r = 0.758), indicating excellent test-retest reliability. There were very good positive correlations between IPSS and BII (r = 0.605), as well as VPSS (r = 0.634), and very good or good negative correlations between IPSS-Qol and SF-36 physical functioning (r = −0.621), and vitality (r = −0.659), and between BII and SF-36 physical functioning (r = −0.421). No floor or ceiling effect was detected in the simplified Chinese IPSS and BII.ConclusionsThis study indicates that the simplified Chinese IPSS and BII are reliable and valid measurements of the symptom and quality of life among Chinese patients with BPH, which is likely to be widely used in this population.

Diagnostic accuracy of global longitudinal strain in prediction of severity and extent of coronary artery stenosis in patients with acute coronary syndrome

Background 2 D Speckle tracking echocardiography (STE) is a non-invasive, angle-independent, semiautomatic and objective technique that quantitatively assesses global and regional longitudinal systolic strain and provides a single bull’s eye map for segmental wall strain of the left ventricle. Objectives assessment of the accuracy of global longitudinal strain (GLS) using STE in the detection of resting myocardial ischaemia and its severity compared with visual assessment of wall motion score index by conventional 2 D echo Patients and methods 100 patients who presented with ACS were included. Wall motion score index (WMSI) was calculated in a 16-segment model and compared with GLS assessed in left ventricle 17 segments and calculated automatically by summation of regional longitudinal peak systolic strain (RLS) using STE. Quantitative coronary angiography was performed on clinical indication and significant stenosis was defined as a 70% reduction of the arterial lumen. Results 56 patients (56%) of patients were males with a mean age of 58.3 years. GLS showed a significant positive correlation between ejection fraction (EF) and GLS (p < 0.05), (r value 0.514) and a good significant negative correlation between WMSI and GLS (p < 0.05), (r value 0.593). And a good significant correlation between GLS and both severity of the lesion and the number of affected vessels was found (p < 0.05). ROC curves showed the cut-off point of GLS was (−15.9) for predicting lesion ≥70% with 88.1% sensitivity, 90.2% specificity respectively, Conclusion GLS has higher specificity, sensitivity, and diagnostic accuracy for the detection of the severity of lesion and number of the vessel affected than WMSI.

The Relationship Between Measures of Postural Control in Concussion Assessment.

To determine the relationship between postural sway performance during commonly utilized postural control assessments following a concussion, including the modified Balance Error Scoring System (mBESS), concussion balance test (COBALT), and sensory organization test (SOT) in healthy young adults. Twenty participants completed all balance testing. The mBESS conditions included double limb stance, single limb stance, and tandem stance. The COBALT was comprised of yaw plane head shake (HS) and vestibular ocular reflex cancellation conditions performed on firm and foam surfaces. Subjects performed 6 conditions of the SOT (C1-C6), which systematically perturbed sensory inputs. Postural sway performance was measured using a single force plate and quantified as a sway score for the mBESS and COBALT, and an equilibrium score for the SOT. Spearman rank correlations were used to examine the relationship between postural sway performance for each test. There was a moderate positive correlation between mBESS-tandem stance and the HS on foam COBALT condition (r = .643, P = .002). There was a moderate negative correlation between mBESS-double limb stance and SOT-C6 (r = -.512, P = .021), and between mBESS-single limb stance and SOT-C6 (r = -.523, P = .018). The COBALT and SOT demonstrated numerous moderate to good negative correlations (r = -.448 to -.708, P ≤ .05), including a good negative correlation between HS on foam and SOT-C1 (r = -.725, P = .0003). Performance on the mBESS had minimal relationship to performance on the COBALT and SOT, suggesting that the clinical standard may not challenge sensory integration at the same capacity as other tests. All COBALT conditions had fair to good associations to at least 2 SOT conditions, suggesting both assessments are representative of sensory integration. Further investigation of the current clinical approach is warranted as the COBALT may be a clinically feasible test of sensory integration.

State-of-health estimation of retired lithium-ion battery module aged at 1C-rate

This research provides a novel estimation model for the state of health (SOH) of retired battery module at 1C-rate with the sampling frequency of 1/60 Hz. The retired 15P4S battery module from Chery S18B electric vehicle is aging at 1C-rate in the range of 0% - 100% SOC with the sampling frequency of 1/60 Hz until the SOH reduces to less than 60%. The regional capacity analysis (RCA) and differential voltage analysis (DVA) are employed for the modeling and validation of module SOH evaluation. The results show that the regional capacity from RCA is an effective SOH evaluation index for battery module. The terminal slope from DVA as a novel and effective indicator is linearly negatively correlated with module SOH. There are good linear negative correlations between ST and SOH. The R2 value of ST - SOH model during discharge is greater than that during charge. The maximum relative errors of evaluated SOH from the ST - SOH models are both smaller than those from the Cˆ - SOH models in the validation group whether charging or discharging. Among them, the ST during discharging is the most effective health factor for module SOH assessment.

A surface-enhanced Raman scattering aptasensor for ratiometric detection of aflatoxin B1 based on graphene oxide-Au@Ag core-shell nanoparticles complex

Aflatoxin B1 (AFB1) has the strongest carcinogenesis and mutagenesis effects. Herein, a novel ratiometric surface-enhanced Raman scattering (SERS) aptasensor based on graphene oxide (GO) as a corrective internal standard (IS) and signal amplifier was constructed for reliable detection of AFB1. 4-Mercaptobenzoic acid as Raman reporter embedded in [email protected] core-shell nanoparticles and AFB1aptamer conjugated to the Ag shell acted as the signal probes ([email protected] NPs-AFB1apt). AFB1apt was attached to the surface of GO with Raman signals modified Au NPs/Indium tin oxide glass (GO/Au NPs/ITO) via π–π stacking interaction, facilitating further amplification of the signal. With an increase of AFB1 concentration (0.0001 ng/mL–100 ng/mL), the probes were released owing to the affinity of aptamers, causing the decreased 4-MBA intensity (I4-MBA) and unchanged GO intensity (IGO). Therefore, the quantitative test was achieved based on the ratiometric value (I4-MBA/IGO). A good negative correlation (R2 = 0.992) was achieved and the limit of detection (LOD) was as low as 0.1 pg/mL, proving the proposed sensor can become an efficient analytical tool and shows a bright application prospect in the food detection field.

Effectiveness of laser fluorescence-based device in detecting the extent of re-mineralisation in primary teeth compared to the conventional method: An In vitro study.

Laser fluorescence (LF)-based clinical device DIAGNOdent™ is at present being used to detect caries. Can the same be used to detect therapeutic remineralisation of early white spot lesions? To explore the feasibility of using LF-based device in monitoring the changes following remineralisation of demineralised primary teeth. The sample number for the present experimental in vitro study was 10. The LF based device readings were correlated with surface microhardness (SMH) test values to evaluate its efficiency. SMH analysis was performed using a microhardness tester (Tescol-HT1000AD). All the samples were demineralised, followed by remineralisation using fluoride varnish and pH cycling. The data was analysed using the Statistical Package for the Social Sciences (SPSS) version 17.0 (IBM SPSS®) software. Paired t-test was performed to compare laser fluorescence readings and SMH test result values at baseline, after demineralisation, and after remineralisation. Pearson's correlation was used to compare the relation between the laser fluorescence and SMH test. A good negative correlation was seen between the two methods at the baseline readings even though it was not statistically significant (P = 0.069). A positive correlation between the methods existed following demineralisation which was not significant (P = 0.074). The correlation between the parameters following remineralisation showed a moderate negative correlation but was not significant (P = 0.55). DIAGNOdent™ values at baseline, after demineralisation, and after remineralisation was consistent with SMH values. Thus, DIAGNOdent™ can be explored to provide chairside assistance in identifying remineralisation of white spot lesions.

Estimation of the surface free energy and moisture susceptibility of asphalt mastic and aggregate system containing salt storage additive

The moisture susceptibility of asphalt mixtures containing salt storage additive is a focus. The objective of this study was to characterize adhesion characteristic of asphalt-aggregate system containing salt storage additive. The contact angle test and boiling water test were carried out to obtain the contact characteristics and stripping behaviour of them. The results indicate that the contact angle values of asphalt mastic increased with the increment of salt storage additive resulting in poor wettability. And the surface free energy values of asphalt mastic slightly reduced with increased salt storage additive, and were remarkably less than that of water leading to bad affinity with stone under moisture condition. The adhesion works under moisture condition mainly depended on stone lithology, and had good negative correlation with the stripping area ratio values from boiling water test.

Prediction of Droplet Sliding on the Continuity of the Three-Phase Contact Line.

Many animals and plants have evolved wonderful hydrophobic abilities to adapt to the complex climate environment. The microstructure design of a superhydrophobic surface focuses on bionics and will be restricted by processing technology. Although certain functions can be achieved, there is a lack of unified conclusion on the wetting mechanism and a few quantitative analyses of the continuity of the three-phase contact line. Therefore, the relationship between the surface microstructure of the lattice pattern and the critical sliding angle of the water droplet in the Cassie state was investigated in this paper, and we proposed a method to quantitatively analyze the continuity of the three-phase contact line by a dimensionless length f. The results showed that the three-phase contact line was an important factor to determine the sliding performance of the droplet. The upward traction force generated by the surface tension through the force analysis on the three-phase contact line can enhance the sliding ability of the droplet on the solid surface. There was a good negative linear correlation between the critical sliding angle and dimensionless length, which provided a guiding basis for the optimal design of superhydrophobic surfaces.

Relationship between Thermal Metamorphism of Coal and the Periodic Variation Law of Geochemical Behavior of Elements: A Study on the C2 Coal Seam in the Fengfeng Mining Area of the Handan Coalfield in Hebei, China

AbstractThis study highlights the response of the periodic variation of the geochemical behavior of elements to the thermal metamorphism of coal by considering the differentiation mode and differentiation degree of elements of the C2 coal seam in the Fengfeng mining area of the Handan Coalfield in Hebei, China. The periodic variation of the geochemical behavior of elements was observed to change towards a certain direction as the degree of metamorphism of a geological body increased. Based on the coincidence degree (or similarity degree) between the geochemical behavior of elements and periodic variation of elements, the 57 elements in this study were divided into two levels. The periodic variation of the geochemical behavior of first‐level elements was largely synchronous with that of their first ionization energy, suggesting that only one differentiation mode exists and the elements are mainly inorganically associated. The differentiation mode of the second‐level elements deviated to a certain extent from their first ionization energy; the larger the deviation, the more complicated and diverse was the differentiation mode. Among the second‐level elements, the grade of coal metamorphism has evident and intuitive effects on the proportion of elements with particular structural features, such as the 4q+3 type of elements and the odd‐odd elements. In addition, the distribution of elements in organic and inorganic matter within coal are subject to the structural features of the elements. The differentiation mode and differentiation intensity of elements could be characterized by the hierarchical parameter and differentiation intensity. The hierarchical parameter and differentiation intensity of certain elements showed a good positive or negative correlation with Rmax in coal. The 57 elements in this study were quantitatively ordered according to the degree of magmatic hydrothermal fluid influence and thermal metamorphism of coal through graphs depicting the goodness of fit, correlation coefficient with Rmax, and differentiation intensity. The results of this study are consistent with the results of previous field research, illustrating the scientific significance and application value of this study on the periodic variation of the geochemical behavior of elements.

Study of the Overflow Transport of the Nordic Sea

Changes in the climate system over recent decades have had profound impacts on the mean state and variability of ocean circulation, while the Nordic Sea overflow has remained stable in volume transport during the last two decades. The changes of the overflow flux depend on the pressure difference at the depth of the overflow outlet on both sides of the Greenland-Scotland Ridge (GSR). Combining satellite altimeter data and the reanalysis hydrological data, the analysis found that the barotropic pressure difference and baroclinic pressure difference on both sides of the GSR had a good negative correlation from 1993 to 2015. Both are caused by changes in the properties of the upper water, and the total pressure difference has no trend change. The weakening of deep convection can only change the temperature and salt structure of the Nordic Sea, but cannot reduce the mass of the water column. Therefore, the stable pressure difference drives a stable overflow. The overflow water storage in the Nordic Sea is decreasing, which may be caused by the reduction of local overflow water production and the constant overflow flux. When the upper interface of the overflow water body in the Nordic Sea is close to or below the outlet depth, the overflow is likely to greatly slow down or even experience a hiatus in the future, which deserves more attention.

The reliability and validity of the Turkish version of the Quality of Life Questionnaire of the European Foundation for Osteoporosis-31 (QUALEFFO-31).

SummaryThis study reveals the Turkish version of QUALEFFO-31 has a sufficient level of reliability, validity, and psychometric properties. The questionnaire, which is potentially capable of differentiating patients with fractures, does not appear to have the differential capacity in terms of osteoporosis.PurposeThis study aims to conduct the reliability and validity study of QUALEFFO-31 in Turkish and to evaluate the capacity of the questionnaire to distinguish patients in terms of osteoporosis.MethodsThe original English version was translated into Turkish by two translators whose native language was Turkish. Subsequently, this Turkish version was translated back into English by two different bilingual translators whose native language was English. After this preliminary questionnaire was tested in 30 patients, words, terminology, information errors, and parts difficult to understand were revised, and the questionnaire was finalized. Internal consistency and test–retest analyses were used for the reliability study. For the validity study, convergent-discriminant validity, concurrent validity, factor analysis, known-group validity, and receiver operating characteristic (ROC) analyses were performed.ResultsA total of 111 patients were evaluated. Internal consistency levels were optimal except for the mental function. ICC coefficients showed good retest reliability for all domains and total tests. The convergent and discriminant validity ratios for the mental function domain were 78% for both and 100% for the other domains. There was a moderate and good negative correlation between QUALEFFO-31 and SF-36 domains which had similar names. Exploratory factor analysis revealed 3 structures. However, there was a spread to the other factors in physical function domain items. Confirmatory factor analysis (CFA) markers were not at a very good fitting level except for the relative chi-square index. When CFA was performed according to the assumed model, the fitting level increased in all analyses. There was no significant differential capacity in terms of osteoporosis or fracture for either QUALEFFO-31 or SF-36.ConclusionThe Turkish version of QUALEFFO-31 has a sufficient level of reliability, validity, and psychometric properties. Nevertheless, improvements in pain and mental function domains and some changes applying to the model may increase the psychometric capacity of the questionnaire. The questionnaire, which is potentially capable of differentiating patients with fractures, does not appear to have the differential capacity in terms of osteoporosis.ClinicalTrials.gov identifierNCT04259099 (date of registration: February 6, 2020)Supplementary InformationThe online version contains supplementary material available at 10.1007/s11657-021-00997-4.

Linking fracturing and rock mechanic properties to the erosion of a beachrock shore platform

The intertidal zone and raised shore (supratidal) platform at Mission Rocks, northern KwaZulu-Natal coast, South Africa, consists of fracture-bounded Holocene beachrock units, and megagravel (boulder) deposits. This area is microtidal and wave-dominated, with swells approaching from the southeast. The area is also influenced by storm wave events. The seaward edge of the intertidal platform is undercut, leading to the formation of overhangs, which are modelled here as cantilevered beams. This analysis shows that beam volume/weight does not control failure because relatively short, thick beams (l:h < 2) are less susceptible to failure, and the beam length-to-thickness ratio is important. This accords with tensile strength testing which demonstrates that the bedding planes are weak and that saturated beachrock (i.e., at the platform edge) is ~25% weaker than unsaturated rock. Fracture, block and boulder analyses of seven coastal sections, and their geomorphological features (elevation, slope, terrain ruggedness), reveal three key relationships: (1) The number of fracture intersections and fracture density are higher in the raised shore platforms than in the intertidal, which is relatively unfractured, lower in elevation and less rugged than the raised shore platform. These parameters correlate positively with the number of fracture-bounded blocks. (2) Fracture-bounded blocks on the raised shore platform (n = 145) have a mean shape ratio of 2.25 and are 10–20 m2 in size, while the disarticulated boulders (n = 172) have a mean shape ratio of 1.3–1.5 and are 2–3 m2 in size. It is considered that the reduction in shape and size of the boulders is the result of fracture-bounded blocks being quarried and transported from the raised shore platform, and not from the intertidal platform, during high-energy storm events. (3) Coast-perpendicular fractures in the intertidal platform deepen and widen towards the sea, forming gullies in which wave run-up and retreat was observed. A relatively good negative correlation (r2 = 0.7) was found between the number of these gullies and values of maximum terrain ruggedness which suggests that platform lowering occurs when an appropriate fracture network (relatively dense and suitably orientated) receives unimpeded swells and waves. Overall, we find that the evolution of the beachrock platform in terms of ruggedness and downwearing is influenced, at least in part, by the fracture networks present, most notably in terms of their orientation, density, persistence and intersection geometry.

Biomechanical effect of intertrochanteric curved varus osteotomy on stress reduction in femoral head osteonecrosis: a finite element analysis.

BackgroundIntertrochanteric curved varus osteotomy (CVO) has been widely used to remove the necrotic bone away from the weight-bearing portion in the treatment of osteonecrosis of the femoral head (ONFH). However, whether all types of necrosis will benefit from CVO, in terms of the stress level, the effect of different center-edge (CE) angles of acetabulum on stress distribution of necrosis after CVO, and the relationship between the intact ratio and the stress of necrosis, has never been addressed. The purpose of the study was to evaluate the influence of CVO on the stress reduction in necrotic bone using a finite element analysis (FEA) with different CE angles.MethodsCVO finite element models of the hip joint were simulated with a lesion of 60°. The osteotomy angles were divided into four configurations (15°, 20°, 25°, and 30°), and three types (A, B, and C1) of lesions were established based on the Japanese Investigation Committee (JIC) classification. In addition, two CE angles (18° and 33°) of acetabulum were considered. The maximum and mean von Mises stress were analyzed in terms of the necrotic bone by a physiological loading condition. Moreover, the correlation of the intact ratio measured in 3D and the stress distribution after CVO was analyzed.ResultsStress reduction was obtained after CVO. For type B, the CVO angle was 20° (0.61 MPa), and for type C1, the CVO angle was 30° (0.77 MPa), if the mean stress level was close to type A (0.61 MPa), as a standard. The maximum and mean von Mises stress were higher in the CE angle of 18°models, respectively. The intact ratio measured in 3D had a good negative correlation with stress after CVO and had more influence on stress distribution in comparison to other geometric parameters.ConclusionsFor making decisions about the biomechanics of CVO, a CVO angle of > 20° was recommended for type B and > 30° was safe for type C1. The risk of progressive collapse was increased in the insufficient situation of the weight-bearing portion after CVO. The intact ratio could provide information about clinical outcomes and stress distribution after CVO.

Solvent Effects on the Phosphorescence of Gold(III) Complexes Chelated by β-Multisubstituted Corroles.

A set of gold corrole complexes containing four different β-substituent groups (Br/I/CF3), namely, 4Br-Au, 4I-Au, and 4CF3-Au, were investigated; all showed room temperature phosphorescence. The phosphorescence quantum yields of the corroles were determined using tetraphenylporphyrin as a reference: Φph (4I-Au, 0.75%) > Φph (4Br-Au, 0.64%) > Φph (4CF3-Au, 0.38%). 4CF3-Au exhibited near-IR emission (858 nm, aerobic); absorbance intensity for the Q-band was higher than that for the Soret band. Complex 4I-Au showed a longer phosphorescence lifetime (82 μs) compared to those of 4Br-Au (53 μs) and 4CF3-Au (28 μs; N2, tol). Thermally activated delayed fluorescence (TADF) emission of 4I/Br-Au complexes was observed: stronger emission intensity correlated with increasing temperature. Good negative correlations for 4I/Br-Au were observed between the Soret band absorption energy and the solvent polarizability: excited states of 4I/Br-Au are more polar than their ground states. TD-DFT calculations revealed very fast intersystem crossing (ISC) rate constants, 2.20 × 1012 s-1 (4CF3-Au) > 1.96 × 1011 s-1 (4Br-Au) > 1.15 × 1011 s-1 (4I-Au), and importantly, the reverse intersystem crossing (rISC) rate constants are determined as 1.68 × 107 s-1 (4I-Au) > 2.40 × 103 s-1 (4Br-Au) ≫ 8.09 × 10-8 s-1 (4CF3-Au). The exceptionally low rISC rate constant of 4CF3-Au is attributed to its more steric and deformed structure bearing a larger energy gap between the S1 and T1 states.