Scan Interval Research Articles

Time dependency of superhydrophilic and superhydrophobic surfaces produced by nanosecond laser irradiation assisted by post-annealing and silanization

Modifying implant surfaces to be superhydrophilic or superhydrophobic is a promising approach to improve their biocompatibility. In this paper, nanosecond laser irradiation assisted by post-annealing and silanization was employed to control the wettability of Ti6Al4V surfaces. Through adjusting the scanning interval (h) and speed (v), smooth surfaces with gradient hydrophilicity were achieved by laser gentle ablation, and superhydrophilic surfaces with gradient roughness were achieved by laser strong ablation. Assisted by subsequent post-annealing treatment or silanization, various superhydrophobic surfaces were produced within only several hours. The wettability stability of these superhydrophilic and superhydrophobic surfaces in the atmosphere and different liquid solutions was evaluated, and the related mechanism was discussed in detail. Finally, long-term superhydrophilic surfaces in both atmosphere and normal saline were obtained by applying small v and h values. Meanwhile, various long-term (in the atmosphere) superhydrophobic surfaces in a metastable state (like a rose leaf) were obtained via post-annealing treatment, and those in a Cassie state (like a lotus leaf) were produced by silanization. The results in this paper could also be applied in several potential applications such as self-cleaning, micro-fluidic chips, and micro-operation of droplets.

A comprehensive geometric quality assessment approach for MSG SEVIRI imagery

Geometric Quality Assessment (GQA) of Earth Observation satellites is crucial for monitoring the system performance and anticipate the accuracy of their products. The Spinning Enhanced Visible and InfraRed Imager (SEVIRI) sensors aboard the geostationary Meteosat satellites of European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) acquire multispectral images at 5 min (rapid-scan) and 15 min (full-disk scan) intervals in whiskbroom fashion. The existing GQA method used for the SEVIRI images involves matching of landmark points located on the shorelines, which prevents from comprehensive analysis inland. Limitations on detecting further landmarks (keypoints) in the images arise from low spatial resolution (1 and 3 km), large radiometric differences between the spectral bands and low textural content, which is even poorer for night time thermal infrared images. Within the present study initiated by EUMETSAT, a new approach for SEVIRI Level 1.5 imagery was developed for the relative, absolute and interband GQA by using dense image matching with sub-pixel precision. In the study, various image filtering and texture extraction methods were evaluated to obtain dense and reliable keypoints over the full-disk image area. Global image mosaics with superior spatial resolution and accuracy were employed as external reference. 2D shifts between search and reference images were determined the using a sub-pixel image matching technique together with a robust outlier elimination strategy. The results show that the textural information in SEVIRI images can be enhanced greatly by using various filtering methods, such as Laplacian, Sobel, Wallis and Local Binary Patterns. The Laplacian filter was found more suitable for the absolute GQA of infrared band images, which was the most difficult to band to assess. Depending on the cloud cover, thousands of well-distributed keypoints can be detected and employed as independent check points in the absolute GQA process. With the developed GQA Tool, new acquisitions can be assessed rapidly and various accuracy measures on the image geometric quality can also be achieved.

The Effect Of Indium Addition on The Corrosion Kinetics of Sn–3Ag–0.5Cu Alloy In HCl Acid Solution

The aim of this study is to investigate the corrosion behavior of potentiodynamic polarization indium added Sn-3Ag-0.5Cu alloy in 1M HCl solution. SEM and EDX analyses were examined the properties of the alloy samples. Polarization analyses showed by the addition of 0.5, 1, and 2 wt.% indium to the SAC305 solder alloy does not lead to notably different corrosion potentials. The pseudo-passivation region is observed instead of a true passivation region that currents are nearly constant. By the scanning interval, this pseudo-passive region does not have a reactivation point. On the other hand, corrosion rates follow a pattern in which 0.5% wt of indium substitution of silver causes the corrosion rate to decrease. However, with further silver replacement by indium, the rate of corrosion increases. According to the results of microstructure analysis, the formation of corrosion products and the existence of voids and porous structures limit their stability.

A method for time-independent film dosimetry: Can we obtain accurate patient-specific QA results at any time postirradiation?

AimThe aim of this work was twofold. (1) To investigate and present a comparison between EBT3 and EBT‐XD in terms of postirradiation color changes. (2) Create an automated workflow to allow radiochromic film (EBT3/XD) to be scanned and converted to dose accurately at any postirradiation time.Materials and MethodsTen GafChromic EBT‐XD calibration films were exposed in 2 Gy increments up to 18 Gy. Calibrates were then scanned at 5‐min intervals postirradiation over 24 h using an AutoHotKey script, resulting in 288 TIFF images. Following the 24‐h scanning period, a MATLAB script was used to automatically read the tiff images and create a series of 288 calibration curves distinct in time which is termed as the “Temporal Calibration Model” (TCM). The model is saved as a series of polynomial fit coefficients to net optical density as a function of dose, timestamped in 5‐min increments. Ten patient‐specific film measurements (5 × EBT‐XD and 5 × EBT3) were then carried out and scanned using the same 5‐min scan intervals from 5 min postirradiation to 24 h postirradiation. The TCM was then automatically applied using eFilmQA software to convert the patient‐specific QA films to dose by applying the relevant calibration curve from the TCM, corresponding to the arbitrary postirradiation time that the film was scanned. Each dose plane at postirradiation scan intervals of 5 min up to 20 h was then compared to the ground‐truth dose plane using gamma analysis.ResultsGamma pass rates using the TCM at time t, normalized to the pass rate after 20 h postirradiation, were found to have a maximum coefficient of variation of 3% over any postirradiation time. Conversely, not using the TCM resulted in coefficients of variation of up to 39%. Clinical implementation of this method showed an average accuracy of 2.8% when comparing the clinical result to the TCM result.ConclusionsWe have developed a methodology that allows radiochromic film to be accurately used as a dosimeter at any arbitrary scan postirradiation time, whereas previously, waiting periods of 16–24 h before readout were needed to ensure the postirradiation changes had stabilized. The creation of a TCM can enable results from radiochromic film measurements to be obtained quickly postirradiation. Using a conventional single calibration curve generated at 20 h postirradiation can result in gamma pass‐rate difference of up to 75% for measurement films scanned at a much shorter postirradiation time.

Femtosecond laser nanostructuring on a 4H-SiC surface by tailoring the induced self-assembled nanogratings.

Ultrafast laser micromachining of crystalline silicon carbide (SiC) has great perspectives in aerospace industry and integrated circuit technique. In this report, we present a study of femtosecond laser nanostructuring on the surface of an n-type 4H-SiC single crystal. Except for uniform nanogratings, new types of large-area periodic structures including nanoparticle array and nanoparticle-nanograting hybrid structures were induced on the surface of 4H-SiC by scanning irradiation. The effects of pulse energy, scan speed, and the polarization direction on the morphology and periodicity of nanogratings were systematically explored. The proper parameter window for nanograting formation in pulse energy-scan speed landscape is depicted. Both the uniformity and the periodicity of the induced nanogratings are polarization dependent. A planar light attenuator for linear polarized light was demonstrated by aligning the nanogratings. The transition between different large-area periodic structures is achieved by simultaneous control of pulse energy and scan interval using a cross scan strategy. These results are expected to open up an avenue to create and manipulate periodic nanostructures on SiC crystals for photonic applications.

UV laser-ablated Cu superwetting surface with improved anti-icing and antibacterial properties

Ultraviolet laser-ablated technique was used to improve the anti-icing and antibacterial properties of copper (Cu) with the objective of achieving efficient heat exchange performance. The laser scanning space interval exhibited a critical influence on the surface topography. SEM observation showed that nano-villi-like products appeared on the surface, which resulted in the formation of a micro/nano-hierarchical structure when the scanning interval was below 40 µm. When the scanning space interval was above 40 µm, the surface presented only a micron-level papilla/groove pattern without any nano-villi-like product. Combined analysis of XRD, TEM, and XPS results indicated that the nano-villi products were partially crystallized copper oxide particles with 5–10 nm size. It was speculated that nano-oxide was obtained by vapor deposition of Cu caused by laser ablation. Furthermore, after modification with FAS-17, the hydrophobicity of the nano-villi-like surface became significantly higher than that of the papilla/groove surface. The highest water contact angle reached 156.30 ± 0.53° and the water sliding angle was as low as 1.57 ± 0.99°. In the anti-icing test at − 10 °C, the delayed freezing time of this superhydrophobic surface reached 9923 s. This excellent anti-icing property can be attributed to the improvement in critical activation energy for ice nucleation and reduction in interfacial thermal conductivity caused by superhydrophobic surface. Finally, the inhibition zone test proved that laser ablation could significantly improve the antibacterial activity of Cu against E. coli and S. aureus.

Test-Retest Reliability of Synchrony and Metastability in Resting State fMRI.

In recent years, interest has been growing in dynamic characteristic of brain signals from resting-state functional magnetic resonance imaging (rs-fMRI). Synchrony and metastability, as neurodynamic indexes, are considered as one of methods for analyzing dynamic characteristics. Although much research has studied the analysis of neurodynamic indices, few have investigated its reliability. In this paper, the datasets from the Human Connectome Project have been used to explore the test–retest reliabilities of synchrony and metastability from multiple angles through intra-class correlation (ICC). The results showed that both of these indexes had fair test–retest reliability, but they are strongly affected by the field strength, the spatial resolution, and scanning interval, less affected by the temporal resolution. Denoising processing can help improve their ICC values. In addition, the reliability of neurodynamic indexes was affected by the node definition strategy, but these effects were not apparent. In particular, by comparing the test–retest reliability of different resting-state networks, we found that synchrony of different networks was basically stable, but the metastability varied considerably. Among these, DMN and LIM had a relatively higher test–retest reliability of metastability than other networks. This paper provides a methodological reference for exploring the brain dynamic neural activity by using synchrony and metastability in fMRI signals.

Assessing the reproducibility of high temporal and spatial resolution dynamic contrast-enhanced magnetic resonance imaging in patients with gliomas

Temporal and spatial resolution of dynamic contrast-enhanced MR imaging (DCE-MRI) is critical to reproducibility, and the reproducibility of high-resolution (HR) DCE-MRI was evaluated. Thirty consecutive patients suspected to have brain tumors were prospectively enrolled with written informed consent. All patients underwent both HR-DCE (voxel size, 1.1 × 1.1 × 1.1 mm3; scan interval, 1.6 s) and conventional DCE (C-DCE; voxel size, 1.25 × 1.25 × 3.0 mm3; scan interval, 4.0 s) MRI. Regions of interests (ROIs) for enhancing lesions were segmented twice in each patient with glioblastoma (n = 7) to calculate DCE parameters (Ktrans, Vp, and Ve). Intraclass correlation coefficients (ICCs) of DCE parameters were obtained. In patients with gliomas (n = 25), arterial input functions (AIFs) and DCE parameters derived from T2 hyperintense lesions were obtained, and DCE parameters were compared according to WHO grades. ICCs of HR-DCE parameters were good to excellent (0.84–0.95), and ICCs of C-DCE parameters were moderate to excellent (0.66–0.96). Maximal signal intensity and wash-in slope of AIFs from HR-DCE MRI were significantly greater than those from C-DCE MRI (31.85 vs. 7.09 and 2.14 vs. 0.63; p < 0.001). Both 95th percentile Ktrans and Ve from HR-DCE and C-DCE MRI could differentiate grade 4 from grade 2 and 3 gliomas (p < 0.05). In conclusion, HR-DCE parameters generally showed better reproducibility than C-DCE parameters, and HR-DCE MRI provided better quality of AIFs.

Irregular LIPSS produced on metals by single linearly polarized femtosecond laser

Currently, supra-wavelength periodic surface structures (SWPSS) are only achievable on silica dielectrics and silicon by femtosecond (fs) laser ablation, while triangular and rhombic laser induced periodic surface structures (LIPSS) are achievable by circularly polarized or linear cross-polarized femtosecond laser. This is the first work to demonstrate the possibility of generating SWPSS on Sn and triangular and rhombic LIPSS on W, Mo, Ta, and Nb using a single linearly polarized femtosecond laser. We discovered, for the first time, SWPSS patches with each possessing its own orientation, which are completely independent of the light polarization direction, thus, breaking the traditional rules. Increasing the laser power enlarges SWPSS periods from 4–6 μm to 15–25 μm. We report a maximal period of 25 μm, which is the largest period ever reported for SWPSS, ∼10 and ∼4 times the maximal periods (2.4 μm/6.5 μm) of SWPSS ever achieved by fs and ns laser ablation, respectively. The formation of triangular and rhombic LIPSS does not depend on the laser (power) or processing (scan interval and scan methodology) parameters but strongly depends on the material composition and is unachievable on other metals, such as Sn, Al, Ti, Zn, and Zr. This paper proposes and discusses possible mechanisms for molten droplet generation/spread/solidification, Marangoni convection flow for SWPSS formation, and linear-to-circular polarization transition for triangular and rhombic LIPSS formation. Reflectance and iridescence of as-prepared SWPSS and LIPSS are characterized. It was found that besides insufficient ablation on W, the iridescence density of Ta-, Mo-, Nb-LIPSS follows the sequence of melting temperatures: Ta > Mo > Nb, which indicates that the melting temperature of metals may affect the regularity of LIPSS. This work may inspire significant interest in further enriching the diversity of LIPSS and SWPSS.

Multi-vendor and multisite evaluation of cerebrovascular reactivity mapping using hypercapnia challenge

Cerebrovascular reactivity (CVR), which measures the ability of cerebral blood vessels to dilate or constrict in response to vasoactive stimuli such as CO2 inhalation, is an important index of the brain's vascular health. Quantification of CVR using BOLD MRI with hypercapnia challenge has shown great promises in research and clinical studies. However, in order for it to be used as a potential imaging biomarker in large-scale and multi-site studies, the reliability of CO2-CVR quantification across different MRI acquisition platforms and researchers/raters must be examined. The goal of this report from the MarkVCID small vessel disease biomarkers consortium is to evaluate the reliability of CO2-CVR quantification in three studies. First, the inter-rater reliability of CO2-CVR data processing was evaluated by having raters from 5 MarkVCID sites process the same 30 CVR datasets using a cloud-based CVR data processing pipeline. Second, the inter-scanner reproducibility of CO2-CVR quantification was assessed in 10 young subjects across two scanners of different vendors. Third, test-retest repeatability was evaluated in 20 elderly subjects from 4 sites with a scan interval of less than 2 weeks. In all studies, the CO2 CVR measurements were performed using the fixed inspiration method, where the subjects wore a nose clip and a mouthpiece and breathed room air and 5% CO2 air contained in a Douglas bag alternatively through their mouth. The results showed that the inter-rater CoV of CVR processing was 0.08 ± 0.08% for whole-brain CVR values and ranged from 0.16% to 0.88% in major brain regions, with ICC of absolute agreement above 0.9959 for all brain regions. Inter-scanner CoV was found to be 6.90 ± 5.08% for whole-brain CVR values, and ranged from 4.69% to 12.71% in major brain regions, which are comparable to intra-session CoVs obtained from the same scanners on the same day. ICC of consistency between the two scanners was 0.8498 for whole-brain CVR and ranged from 0.8052 to 0.9185 across major brain regions. In the test-retest evaluation, test-retest CoV across different days was found to be 18.29 ± 17.12% for whole-brain CVR values, and ranged from 16.58% to 19.52% in major brain regions, with ICC of absolute agreement ranged from 0.6480 to 0.7785. These results demonstrated good inter-rater, inter-scanner, and test-retest reliability in healthy volunteers, and suggested that CO2-CVR has suitable instrumental properties for use as an imaging biomarker of cerebrovascular function in multi-site and longitudinal observational studies and clinical trials.

Horses' Use of Lying Halls and Time Budget in Relation to Available Lying Area.

Simple SummaryA safe and comfortable resting area to lie down and sleep in is an important factor in ensuring horse welfare. The lying times of stalled horses depend on factors such as bedding, housing, and lying area, while the sleeping behavior of group-housed horses may be influenced by such factors as social relations and competition for space. This study aimed to analyze time spent in, as well as activity taking place in, lying halls of various sizes. We compared single boxes and open barns with available lying areas of 8, 15, or 18 m2/horse, on the basis that a lying area of 8 m2 is the minimum requirement stipulated by Swedish legislation. We found that increasing lying area increased the horses’ use of the lying hall and their total lying time, and that the lying time of a horse housed in a single box was equivalent to the lying time of a horse in group housing with access to a lying area of 18 m2/horse. Hence, to ensure access to sufficient resting space for all horses in group housing, we recommend that the minimum requirement should be reassessed and increased.Sleep is crucial to horses’ wellbeing, and their lying time can vary according to such factors as climate, exercise, bedding, and housing. This study aimed to analyze behavior and time spent in lying halls of various sizes. We examined the influence of housing systems on total lying time and behavior, and how changes to available lying area can affect lying time. Two open barns were used in this study, with lying areas of 8, 15, and 18 m2/horse available in the lying halls. The horses’ behavior was video recorded and logged using scan sampling and interval observations. Individual boxes were used as a control. The horses were found to spend longer time in sternal and lateral recumbency in the hall with a lying area of 18 m2/horse than the hall with a lying area of 8 m2/horse. Increasing the area of the lying hall also increased overall time spent there. Consequently, the hypothesis that increasing lying area will increase the horses’ use of the lying hall, as well as their total lying time, was accepted.

Development of a Structured Query Language and Natural Language Processing Algorithm to Identify Lung Nodules in a Cancer Centre.

Importance: The stratification of indeterminate lung nodules is a growing problem, but the burden of lung nodules on healthcare services is not well-described. Manual service evaluation and research cohort curation can be time-consuming and potentially improved by automation.Objective: To automate lung nodule identification in a tertiary cancer centre.Methods: This retrospective cohort study used Electronic Healthcare Records to identify CT reports generated between 31st October 2011 and 24th July 2020. A structured query language/natural language processing tool was developed to classify reports according to lung nodule status. Performance was externally validated. Sentences were used to train machine-learning classifiers to predict concerning nodule features in 2,000 patients.Results: 14,586 patients with lung nodules were identified. The cancer types most commonly associated with lung nodules were lung (39%), neuro-endocrine (38%), skin (35%), colorectal (33%) and sarcoma (33%). Lung nodule patients had a greater proportion of metastatic diagnoses (45 vs. 23%, p < 0.001), a higher mean post-baseline scan number (6.56 vs. 1.93, p < 0.001), and a shorter mean scan interval (4.1 vs. 5.9 months, p < 0.001) than those without nodules. Inter-observer agreement for sentence classification was 0.94 internally and 0.98 externally. Sensitivity and specificity for nodule identification were 93 and 99% internally, and 100 and 100% at external validation, respectively. A linear-support vector machine model predicted concerning sentence features with 94% accuracy.Conclusion: We have developed and validated an accurate tool for automated lung nodule identification that is valuable for service evaluation and research data acquisition.

Effect of diabetes mellitus on coronary plaque characteristics and progression by serial Coronary Computed Tomography Angiography (CCTA)

Abstract Background Diabetes Mellitus (DM) is a major risk factor for coronary artery disease (CAD) and associated poor outcomes. There is a higher incidence of major adverse cardiac events in patients with DM than those without DM. Coronary plaque characteristics measured by CCTA are correlated with adverse cardiovascular (CV) outcomes. Purpose We sought to evaluate coronary plaque characteristics as well as rates of progression of coronary plaque burden as measured by serial CCTA in patients with DM and those without DM. Methods The study population included a total of 403 participants (mean age 61.4±11.4 years, 53% men; median scan interval 1.5 years) who were prospectively enrolled in serial CCTA trials. We identified 212 participants with DM and 191 participants without DM, who had undergone serial CCTA. Coronary Plaque volumes were measured and characterized as low attenuation plaque (LAP), total non-calcified plaque (TNCP) and total plaque (TP) using semi-automated plaque analysis software (Qangio medis). Multivariate linear regression was used to examine the effect of DM on coronary plaque progression. Results Patients with DM had greater rates of progression of normalized TP volume (median change in annualized plaque (IQR): 39.1 (9.9–114.4) in DM vs 23.5 (4.1–63.8) mm3 in non-DM, p=0.001), TNCP volume (21.6 (3.3–60.8) in DM vs 8.7 (0.1–35.6) mm3 in non-DM, p=0.003) and LAP volumes (0.7 (−0.6 to 7.8) in DM vs 0.1 (−0.4 to 1.9) mm3 in non-DM, p=0.04). After adjusting for relevant risk factors and baseline plaque, the annualized rates of progression were higher in patients with DM by 28% for TP (p=0.004), 27% for TNCP (p=0.011), 23% for fibrous plaque (p=0.026) and by 42% LAP (p=0.050), compared to those without DM. Conclusion Patients with DM have significantly higher rates of coronary plaque progression, including vulnerable LAP, than those without DM. Our findings reveal differences in rates, burden and characteristics of coronary plaque progression in patients with DM vs those without DM. These results provide mechanistic understanding of natural history of coronary atherosclerosis in this vulnerable population, that could explain the increased risk of CV events among patients with DM. Coronary atherosclerotic phenotyping by CCTA could serve as a potential surrogate measure for risk stratification and evaluation in clinical trials to examine therapeutic strategies in this vulnerable population. Funding Acknowledgement Type of funding sources: None.

Femtosecond laser surface modification of magnesium aluminate spinel and its effect on polishing

Magnesium aluminate spinel is a promising material for optical windows due to its outstanding comprehensive properties. However, the highly efficient polishing of spinel by traditional processing is difficult due to its high hardness, high strength and chemical inertness. In this study, a femtosecond laser was used to induce micro-nanostructures on the spinel surface to improve its machinability. The effects of laser power, scanning speed and scanning interval on the surface morphology of the spinel were studied. The experimental results indicate that the femtosecond laser modification reduced the surface hardness of the spinel, and the critical cutting depth was increased. Moreover, the micro-nanostructures resulting from the laser modification improved the contact area between the slurry and the substrate, which improved the polishing performance. Experiments were carried out to prove that the chemical mechanical polishing (CMP) process of spinel can be promoted by femtosecond laser surface modification. This method provides a new perspective for high-performance spinel ultra-precision manufacturing. • A highly efficient femtosecond laser surface modification assisted polishing for spinel is proposed, the improved mechanisms were analyzed. • The effect of laser modification parameters on the evolution of micro-nanostructures on the spinel was investigated. • This method has obvious advantages such as simplicity, flexibility, thus making it a very promising machining method.

Natural-Course Evaluation of Infants with Positional Severe Plagiocephaly Using a Three-Dimensional Scanner in Japan: Comparison with Those Who Received Cranial Helmet Therapy.

This study aimed to clarify the natural course of positional plagiocephaly using a three-dimensional (3D) scanner and investigate the effectiveness of cranial helmet therapy (CHT). One hundred infants with severe plagiocephaly who visited our institutions between April 2020 and March 2021 were included. Cranial shape was measured using an Artec Eva 3D scanner. A cranial asymmetry (CA) >12 mm was diagnosed as severe plagiocephaly. An infant whose CA subsided to <12 mm was considered to have improved naturally or by CHT. The difference in CA between the second and initial scans was defined as the improvement value (median scan interval was two months). In the natural-course group comprising 56 infants with severe plagiocephaly, 37 (66%) with a median CA of 15.6 mm exhibited no improvement after two months. In the scan age- and evaluation interval-matched case-control study, the CA value in the CHT group improved by three times that in the natural-course group (−4.6 mm [n = 33] vs. −1.55 mm [n = 24], p < 0.001). Severe plagiocephaly did not improve naturally in 66% of the cases. Therefore, CHT should be considered if the CA is >12 mm on the initial evaluation.

Microstructure and Mechanical Property of High Strength and High Toughness Titanium Alloy by Laser Deposition Manufacturing

In this study, the high strength and high toughness Ti-6Al-3Mo-2Sn-2Zr-2Cr alloy was fabricated by the laser deposition manufacturing (LDM) technology. The effect of process parameters on the forming quality of LDMed alloy was studied. The microstructure and mechanical properties of LDMed Ti-6Al-3Mo-2Sn-2Zr-2Cr alloy was deeply analysed by the optical microscope, scanning electron microscope, tensile tester and impact tester. The results show that the optimized process parameters are as follows: laser power is 2.4 kW, scanning speed is 10 mm/s and scanning interval is 2.4 mm. Due to the temperature gradient, the LDMed titanium alloy shows obvious microstructure anisotropy exhibiting fine β equiaxed grain in scanning direction (XY direction), but shows coarse β columnar grain in deposition direction (Z direction). The micro-morphology exhibits classic dual-phase microstructure with basket appearance composing of equally distributed α phase and metastable β-transformed phase. Due to the grain boundary strengthening effect, obvious mechanical anisotropy can also be observed in LDMed titanium alloy showing a higher tensile strength, lower plasticity and impact toughness in XY direction, but reverses in Z direction.

Hidroklorik Asit çözeltisinde bizmut ilavesinin Sn – 3Ag – 0.5Cu lehim alaşımının korozyon dinamiklerine etkisi

This paper aims to investigate the effect of bismuth addition on the corrosion behaviour of Sn–3.0Ag–0.5Cu (SAC 305) solder alloy in 1M HCl acid solution under potentiodynamic polarization. After electrochemical tests, scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) were used to examine the properties of the samples. Polarization studies indicated that an addition of 0.5, 1, and 2 wt.% Bi in the SAC305 solder alloy doesn't lead to significantly different corrosion potentials. Instead of a true passivation region, a pseudo-passivation region is observed in which currents are nearly constant (though high). This pseudo-passive region does not have a reactivation point within the scanning interval. Corrosion rates, on the other hand, follow a pattern in which 1 wt.% bismuth replacement of silver causes a drop-in corrosion rate. With the further replacement of silver with bismuth, however, the corrosion rate increases. Microstructure analysis reveals the existence of gaps and porosities which introduce limits on the formation and stability of protective passive corrosion products.

Accelerated aging in the brain, epigenetic aging in blood, and polygenic risk for schizophrenia

Schizophrenia patients show signs of accelerated aging in cognitive and physiological domains. Both schizophrenia and accelerated aging, as measured by MRI brain images and epigenetic clocks, are correlated with increased mortality. However, the association between these aging measures have not yet been studied in schizophrenia patients.In schizophrenia patients and healthy subjects, accelerated aging was assessed in brain tissue using a longitudinal MRI (N = 715 scans; mean scan interval 3.4 year) and in blood using two epigenetic age clocks (N = 172). Differences (‘gaps’) between estimated ages and chronological ages were calculated, as well as the acceleration rate of brain aging. The correlations between these aging measures as well as with polygenic risk scores for schizophrenia (PRS; N = 394) were investigated.Brain aging and epigenetic aging were not significantly correlated. Polygenic risk for schizophrenia was significantly correlated with brain age gap, brain age acceleration rate, and negatively correlated with DNAmAge gap, but not with PhenoAge gap. However, after controlling for disease status and multiple comparisons correction, these effects were no longer significant. Our results imply that the (accelerated) aging observed in the brain and blood reflect distinct biological processes. Our findings will require replication in a larger cohort.

Femtosecond laser induced simultaneous functional nanomaterial synthesis, in situ deposition and hierarchical LIPSS nanostructuring for tunable antireflectance and iridescence applications

Femtosecond laser induced periodic surface structures (LIPSSs) are excellent biomimetic iridescent antireflective interfaces. In this work, we demonstrate the feasibility to develop tunable iridescent antireflective surfaces via simultaneous synthesis of functional metal-oxide nanomaterials, in situ deposition and hierarchical LIPSSs nanostructuring by means of femtosecond laser ablation (fs-LA) of tungsten (W) and molybdenum (Mo) in air. Adjusting the scanning interval from 1 μm to 20 μm allows the modulation of particle deposition rates on LIPSSs. Diminishing the scan interval enables a higher particle deposition rate, which facilitates the development of better UV-to-MIR ultrabroadband antireflective surfaces with a less pronounced iridescence. Through comparing the reflectance of hierarchical LIPSSs with different densities of loosely/tightly deposited particles, it is found that the deposited WOx and MoOx particle aggregates have high UV-to-MIR ultrabroadband absorbance, especially extraordinary in the MIR range. Loosely deposited particles which self-assembly into macroporous structures outperform tightly deposited particles for ultrabroadband antireflective applications. The presence of loosely deposited MoOx and WOx particle absorbers can cause up to 80 % and 60 % enhancement of antireflectance performances as compared to the tightly particle deposited LIPSSs samples. One stone of “fs-LA technique” with three birds of (particle generation, in situ deposition and LIPSS hierarchical nanostructuring) presented in this work opens up new opportunities to tune the reflectance and iridescence of metallic surfaces.

Reduced Need for Urinary Bladder Catheterization in the Postanesthesia Care Unit After Implementation of an Evidence-based Protocol: A Prospective Cohort Comparison Study

BackgroundPostoperative urinary retention (POUR) is a known complication in the postanesthesia care unit (PACU). The variations in catheterization thresholds contribute to unnecessary invasive procedures. ObjectiveIn the current study, we implemented an algorithm for a sterile intermittent catheterization (SIC) threshold of 800 ml with volume-dependent bladder scan intervals and compared the incidence of SIC with that of a matched patient cohort threshold of 400 ml. Design, setting, and participantsThis comparative study of two prospective historical cohorts represented two thresholds for POUR, set at 400 ml without a standardized bladder scan protocol and 800 ml with a volume-dependent bladder scan protocol. Outcome measurements and statistical analysisThe primary outcome was the frequency of catheterization during the PACU stay. Secondary outcomes evaluated patient safety aspects in occurrence of thresholds above 400/800 ml. The study was set at the PACU under the Department of Anesthesia, Center for Cancer and Organ Diseases, Rigshospitalet, Denmark. Results and limitationsIn total, 741 patients were consecutively included, with 307 in the POUR-400 and 434 in the POUR-800 group, and with comparable group characteristics. Significantly fewer patients fulfilled the SIC/catheter a’ demeure (CAD) criteria in the POUR-800 (5.0%) versus POUR-400 (14.3%) group, equivalent to a 65.0% relative reduction in SIC. ConclusionsImplementation of a standardized ultrasound-guided protocol with volume-dependent scan intervals and an evidence-based catheterization threshold of 800 ml decreases the need for SIC by >65%, without increasing the need for urinary catheterization at the wards. Patient summaryIn this study, we implemented an algorithm for a sterile intermittent catheterization threshold of 800 ml with volume-dependent bladder scan intervals. A marked reduction was seen in catheterization in the postanesthesia care unit, without increasing catheterization rates at the ward.