Continuous Pd Research Articles

Teacher Growth Through Professional Development Centered on the Teaching for Robust Understanding Framework

Research on teacher learning has continually defined tenants of effective professional development. However, sweeping overhauls and mandates have not yielded the intended results. Instead, transforming approaches to teaching can and should be achieved through innovative and incremental changes that build upon teachers’ existing expertise. Informed by Communities of Practice theory, we employed case study methodology to describe, explain, and assess the experiences of one middle school mathematics teacher’s longitudinal participation in an innovative and incremental continuous PD model focused on the Teaching for Robust Understanding (TRU) framework. Based on classroom observations and interview data, our findings show evidence of TRU-aligned changes in teaching practice as a result of years of participation in the PD model. These findings strengthen the call for innovative and incremental PD programs.

Acetylene Semihydrogenation over Pd-Bi Intermetallic Compounds: A DFT Combined with Microkinetic Modeling Study.

Acetylene semihydrogenation is an important process both theoretically and experimentally. Pure Pd catalysts usually suffer from limited selectivity for ethylene products and poor stability. Pd-Bi bimetallic compounds are synthesized and show not only excellent catalytic performance but also remarkable long-term stability. However, the detailed mechanism is still unclear. In this paper, the acetylene semihydrogenation mechanism on Pd(100), Pd3Bi1(100), and Pd1Bi1(100) is studied by density functional theory (DFT) calculation and microkinetic modeling. Adding Bi causes the surface d-band center (εd) to move to a lower energy, and the adsorption strength of the intermediate becomes weaker. Besides, ethylidyne (CCH3) formation becomes more difficult on the Pd-Bi alloy due to the lack of continuous surface Pd atoms. As a spectator, CCH3 deactivates the Pd and Pd-Bi alloys by a steric effect. However, the selectivity for ethylene on the Pd-Bi alloy is still high because of the weakly bonded ethylene. We found the relationship between εd and the catalysts' activity and selectivity. This study may supply some clues for the design of selective hydrogenation catalysts.

Ultrafiltration Patterns during Automated Peritoneal Dialysis: Findings and Insights to Peritoneal Physiology.

With the growing use of automated peritoneal dialysis (APD), it is important to improve our knowledge of the clinical patterns and physiology of APD treatment sessions. The ultrafiltration (UF) achieved during each cycle of an APD treatment is assumed to be relatively linear if the delivered prescription is the same. We set out to determine if that is indeed the case. Single-center, cross-sectional study of prevalent PD patients. All adult APD patients (> 18 years of age), who had been on PD for >3 months, and >3 months on APD were included. Continuous ambulatory PD patients or those with peritonitis within 3 months of the consent date were excluded. Individual treatment data from 7 consecutive APD treatment sessions with consistent dialysate composition for each cycler exchange were collected for each subject. Thirty-nine subjects met the inclusion criteria and were enrolled. The probability of yielding a positive UF was 48.9% for cycle 1, rising to 90.5% by cycle 6. Adjusting for average dextrose concentration, dwell time, fill volume, solute transfer rate, and number of cycles, we observed that cycles 2 through 6 achieved progressively higher UF volumes than cycle 1 (p < 0.001). The first and last cycles demonstrated significantly different cycle UF volumes compared to a middle cycle (-230 ml and 277 ml, respectively, p < 0.001). We observed a consistent increase in UF volumes achieved per cycle over the course of an APD treatment session with numerous clinical and physiologic implications. This provides the foundation for future studies investigating peritoneal inter-cycle variations and membrane physiology.

Digital-analog hybrid control of an inverted pendulum robot based on memristor

Abstract Single inertial measurement unit sensor signals are inaccurate, and traditional digital processing systems with separate storage and computation architectures cannot directly handle analog sensor signals, leading to significant delays and high power consumption. In that case, the control capability for self-balancing robots has been limited. In this work, a three-terminal MoS2-based memristor device was fabricated and successfully integrated into a memristor-based hybrid control inverted pendulum robot system. This system achieved continuous multi-sensor analog data fusion computations and analog PD control computations by combining the least squares method and a gradient descent algorithm based on a reward mechanism in digital circuits to control the memristors dynamically. Additionally, simulation testing and real, inverted pendulum robot control confirmed the efficacy of its data fusion and the accuracy of its PD control. The comparative experiments demonstrated that the hybrid control system based on memristors was approximately 86.41 mJ lower than the digital system. This system holds significant importance for the processing of large-scale sensor data and robot control.

#2292 Incremental peritoneal dialysis: an individualized therapy with better clinical outcomes and reduced environmental and economic impact

Abstract Background and Aims Incremental peritoneal dialysis (IPD) is based on the prescription of a dose lower than the standard “full dose” (SPD). The achievement of individualized clearance goals is based on the combination of peritoneal and renal clearance. IPD as the initial PD strategy seems to be a convenient and resource-sparing technique, but its impact in long term outcomes and in the environment lacks evidence. The aim of this study is to evaluate IPD outcomes and to analyze the potential impact of this initial approach on costs, total and plastic waste, and water consumption. Method Single-center observational retrospective study that included a cohort of 87 prevalent PD adults. Patients were assigned in two groups according to their initial PD prescription—IPD group [continuous ambulatory PD (CAPD): less than 4 dwells daily, less than 2L dwell volume, and/or PD less than 7 days/week; automated PD (APD): without a long dwell, less than 10 L delivered, and/or PD for less than 7 days/week] and SPD group. Primary outcomes were residual kidney function preservation, technique survival and mortality. Secondary outcomes were peritonitis rate and hospitalizations. The reductions related to costs, total and plastic waste, and water usage were also compared between groups. Results In 57 (65%) of the patients IPD was the initial therapy, while 30 (35%) patients were prescribed SPD. The median follow-up was 23 months and the median transition time from 2 to 3 and from 3 to 4 exchanges were 6 and 14 months in CAPD, respectively. APD patients transitioned to SPD after a median of 9 months. Patients in IPD group had a higher glomerular filtration rate (7 vs. 3.7, mL/min/1.73 m2, p &amp;lt; 0.001) in the first 6 months, and after 24 months (4.8 vs. 1.9, mL/min/1.73 m2, p = 0.002. IPD was also associated with a longer technique survival (p = 0.026), lower hospital admissions per year (0.23 vs. 0.5, p = 0.001), and lower mortality (1.8% vs. 13.3%, p = 0.027). Compared to SPD, 2 and 3 exchanges per day led to a reduction in costs of approximately 8500 or 4100 euros/patient-year, total waste of 266 or 143 kg/year/patient, in plastic waste of 159 or 69 kg/year/patient, and water savings of 28,620 or 12,420 L/year/patient, respectively. In APD, IPD led to a reduction of 4400 euros/ patient-year in cost, 211 kg/year/patient in total and of 139 kg/year/patient in plastic waste, and water savings of 25,020 L/year/patient. Conclusion Prescription of initial individualized IPD is associated with better clinical outcomes in patients with substantial RKF. This approach was a significant economic and environmental impact, with a reduction in total and plastic waste, and water consumption.

Mesoporous α-Al2O3-supported PdCu bimetallic nanoparticle catalyst for the selective semi-hydrogenation of alkynes

The selective hydrogenation of alkynes to alkenes is widely applied in the chemical industry; nevertheless, achieving highly selective hydrogenation with high catalytic activity is considerably challenging. Herein, ultrafine PdCu bimetallic nanoparticles encapsulated by high-surface-area mesoporous α-Al2O3 were prepared by high-temperature calcination-reduction using a porous organic framework (POF) as the template. As-obtained PdCu@α-Al2O3 exhibited a high selectivity of 95% for the semi-hydrogenation of phenylacetylene as a probe reaction under mild reaction conditions. The separation of continuous Pd atoms and modification of the Pd electronic state by Cu atoms suppressed β-hydride formation and alkene adsorption, contributing to high selectivity for the catalytic hydrogenation of alkynes. The catalytic activity was maintained after 7 cycles due to the strong interaction between the PdCu bimetallic nanoparticles and α-Al2O3 as well as the encapsulation effect of mesoporous α-Al2O3. Thus, the current work provides a facile strategy for fabricating high-surface-area mesoporous α-Al2O3-supported catalysts for industrial catalysis applications.

#3658 PERITONEAL INFLAMMATION INDUCES SYSTEMIC ERYPTOSIS IN PERITONEAL DIALYSIS-ASSOCIATED PERITONITIS

Abstract Background and Aims Eryptosis is stress-induced RBC (Red Blood Cell) death mechanism. Our preliminary data show that there is a significative increased of eryptosis during peritoneal dialysis-associated peritonitis. Furthremore, there is an elevation of local and systemic inflammatory mediators. The aim of this study was to evaluate the relationship between systemic eryptosis levels in peritonitis and specific peritonitis biomarkers in peritonitis effluent (PDE), such as Peritoneal White Blood cell count (pWBC), peritoneal NGAL (pNGAL) and peritoneal cytokines levels. Method We enrolled 22 PD patients with peritonitis and 17 healthy subjects. PD-related peritonitis was defined according to the Guidelines of the International Society of Peritoneal Dialysis. At the time of diagnosis, blood samples were collected for eryptosis and peritoneal effluent were taken to evaluate pWBC, pNGAL and cytokines. All eryptotic measurements were made in freshly isolated RBCs. PS avidly binds AnnexinV, which is thus employed to identify eryptotic cells. Thus, PS exposure at RBC surface was estimated from FITC-AnnexinV binding using flow cytometric analyses. Results 13/22 patients were treated with continuous ambulatory PD (CAPD) and 9 with automated PD (APD). The median length of PD treatment was 28.1 months and the range was: minimum: 3 – maximum: 124.9 months. The percentage of AnnexinV-binding RBCs was significantly higher in PD patients with peritonitis than in CTR (PD patients with peritonitis: 7.7; IQR 4.3-14.2, versus CTR: 0.8; IQR 0.7-1.3; p&amp;lt;0.001) (Figure 1). WBC, NGAL and cytokines levels in PDE are reported in Table 2. We observed important correlation between eriptosis levels and peritoneal biomarkers (Figure 2). Conclusion In conclusion, we investigated a potential connection between systemic eryptosis and peritoneal biomarkers involved in peritonitis. The presented results revealed that upregulated inflammatory markers could be the cause of high levels of systemic eryptosis during PD-related peritonitis.

Histone deacetylase 8 inhibition prevents the progression of peritoneal fibrosis by counteracting the epithelial-mesenchymal transition and blockade of M2 macrophage polarization.

Peritoneal dialysis (PD) is an effective replacement therapy for end-stage renal disease patients. However, long-term exposure to peritoneal dialysate will lead to the development of peritoneal fibrosis. Epigenetics has been shown to play an important role in peritoneal fibrosis, but the role of histone deacetylases 8 (HDAC8) in peritoneal fibrosis have not been elucidated. In this research, we focused on the role and mechanisms of HDAC8 in peritoneal fibrosis and discussed the mechanisms involved. We examined the expression of HDAC8 in the peritoneum and dialysis effluent of continuous PD patients. Then we assessed the role and mechanism of HDAC8 in peritoneal fibrosis progression in mouse model of peritoneal fibrosis induced by high glucose peritoneal dialysis fluid by using PCI-34051. In vitro, TGF-β1 or IL-4 were used to stimulate human peritoneal mesothelial cells (HPMCs) or RAW264.7 cells to establish two cell injury models to further explore the role and mechanism of HDAC8 in epithelial-mesenchymal transition (EMT) and macrophage polarization. We found that HDAC8 expressed highly in the peritoneum from patients with PD-related peritonitis. We further revealed that the level of HDAC8 in the dialysate increased over time, and HDAC8 was positively correlated with TGF-β1 and vascular endothelial growth factor (VEGF), and negatively correlated with cancer antigen 125. In mouse model of peritoneal fibrosis induced by high glucose dialysate, administration of PCI-34051 (a selective HDAC8 inhibitor) significantly prevented the progression of peritoneal fibrosis. Treatment with PCI-34051 blocked the phosphorylation of epidermal growth factor receptor (EGFR) and the activation of its downstream signaling pathways ERK1/2 and STAT3/HIF-1α. Inhibition of HDAC8 also reduced apoptosis. In vitro, HDAC8 silencing with PCI-34051 or siRNA inhibited TGF-β1-induced EMT and apoptosis in HPMCs. In addition, continuous high glucose dialysate or IL-4 stimulation induced M2 macrophage polarization. Blockade of HDAC8 reduced M2 macrophage polarization by inhibiting the activation of STAT6 and PI3K/Akt signaling pathways. We demonstrated that HDAC8 promoted the EMT of HPMCs via EGFR/ERK1/2/STAT3/HIF-1α, induced M2 macrophage polarization via STAT6 and PI3K/Akt signaling pathways, and ultimately accelerated the process of peritoneal fibrosis.

Optimal temperature range for the separation of a mixture of 96% protium and 4% deuterium with a palladium membrane

Hydrogen isotope separation can be achieved using a palladium (Pd) membrane because protium (H) and deuterium (D) exhibit different solubility, diffusivity and, hence, mixed-gas permeability in Pd. The permeability of H (k H2 ) and D (k D2 ) were evaluated using a 4 vol% D 2 – 96 vol% H 2 feed mixture at temperatures of 293 K–473 K and pressures of 239 kPa–446 kPa in a continuous Pd membrane separation unit. The Pd foil membrane (0.1 mm thick) is shown to be selective toward H 2 over the entire temperature range, with both k H2 and k D2 increasing with temperature. As temperature increases, the mixed-gas selectivity (k H2 /k D2 ) rises from 4.0 at 300 K to a maximum value of 9.6 in the 363 K–373 K temperature range (which represents the operating temperatures that would render the highest concentration of H 2 in the permeate and the greatest concentration of D 2 in the retentate), then decreases to 6.2 at 480 K. Competitive transport during co-permeation is a likely cause for the maximum separation factor k H2 /k D2 observed in this temperature range, being larger than the values predicted using pure gases ( 2 for diffusion dominant separation). The membrane selectivity presumably decreases from the observed maximum because the reverse solubility isotope effect decreases as the temperature increases. Additionally, isotope diffusion begins to increasingly affect the selectivity at higher temperatures. • Hydrogen isotope separation using a continuous palladium membrane separation unit. • Feed gas contained lower deuterium content than typically studies; 4% D 2 - 96% H 2 . • Optimal temperature range (363–373 K) determined for hydrogen isotope separation. • Co-permeation affected by competitive transport in palladium membrane.

High Purity Pd Nanofilm Deposition Via Cu Incorporation Control in Slrr Process

Department of Materials Science & Chemical Engineering, Hanyang University, Ansan 15588, Korea *byyoo@hanyang.ac.kr ABSTRACT The deposition of palladium has been considered in many industrial applications and in fundamental science because of the high catalytic activities. Careful control of smooth and continuous Pd film less than 1nm thickness is critical for achieving highly active catalysts. Furthermore, perspective of cost-effective view, minimum usage of Pd is essential for catalyst while showing maximum activity for catalyst due to its high cost.Electrochemical-atomic layer deposition (E-ALD), can achieve the growth of atomic level of metal film under room temperature and simple condition. E- ALD protocol proceeds using surface limited redox replacement (SLRR). SLRR involves 2 step. First, Au substrate is covered with Cu monolayer, the result of underpotential deposition of Cu (sacrificial element). Underpotential deposition (UPD) is the deposition occurs at more positive potential than equilibrium potential which the potential where deposition actually strats and UPD can limit Cu deposition by atomic layer. Second, Cu atomic layer is replaced by more noble metal (Pd) by galvanic displacement without applying potential. In one cell approach, the concentration ratio of sacrificial metal and noble metal and potential set is carefully set in order to deposit pure noble metal layer. Therefore, precise control of potential and metal concentration is important to execute successful SLRR which prevent Cu incorporation and Pd overpotential deposition upon Cu UPD formation.In this study, pure Pd nanofilm was formed on Au substrate using Cu sacrificial metal by SLRR protocol. Effort of minimizing Cu incorporation was conducted by controlling Pd ion concentration, potential , open circuit potential condition and adding additive. Pd film was characterized by XPS, AFM and open circuit potential was analyzed by potentiostat. By controlling Pd deposition condition, pure Pd film was successfully formed. KEYWORDS Palladium, one-cell, nanofilm, SLRR, Cu UPD

Surface roughness improvement of Hastelloy X tubular filters for H2 selective supported Pd–Ag alloy membranes preparation

Thin Pd–Ag layers have been successfully deposited on ceramic supports with controlled surface characteristics. The need for less fragile membranes and ease of sealing and connection leads to the study of metallic supports for thin Pd-based membrane development. Metallic supported membranes are prone to intermetallic diffusion issues so an interdiffusion barrier must be introduced. However, metallic supports with sufficient surface quality for direct membrane deposition are expensive and not readily available in the market. It is thus important to study how to improve surface roughness of commercially available rough metallic filters, in order to allow deposition of a smooth, delamination-free Pd–Ag layer. This work reports a first attempt towards a standardized preparation procedure for Pd-based membranes on cheap, rough, and unrefined Hastelloy X tubular filters. The focus is on surface roughness reduction, in order to allow the deposition of a smooth, uniform Pd–Ag selective layer. The surface roughness of the tubes is tuned via 1) polishing and 2) addition of a smoothening interdiffusion barrier layer based on a boehmite dip-coated dispersion. The polishing time was assessed by studying the average support's roughness variation, permeation behavior and ability to retain ceramic coating. It was found that the best trade-off between polishing extent and gas permeance of the support amounts to 6 h. Moreover, it was assessed that increasing the boehmite load in the interdiffusion barrier precursor solution leads to thicker layers and larger surface roughness reduction, but greater solution instability. 1,2%wt of boehmite load proved the best trade-off between layer reproducibility and support coverage. Different dipping-sintering routes were evaluated in order to improve surface's suitability for electroless plating: a single interdiffusion layer deposition route proved the most suitable for Pd–Ag deposition. The electroless plating performed onto the treated supports results in a continuous Pd–Ag layer, proving Pd–Ag deposition possible on the selected filters. • The surface characteristics of rough tubes have been tuned to a media grade that allows membrane deposition. • The polishing time was assessed by studying the average support's roughness. 6 h are enough to produce good supports. • Boehmite-based interdiffusion layers are used to change the surface quality and as interdiffusion barrier. • Thin Pd–Ag layers can be deposited on the modified supports.

Low-Dimensional Palladium on Graphite-on-Paper Substrate for Hydrogen Sensing

To stabilize the detection signal of palladium-based hydrogen sensors on paper substrates, a graphite intermediate layer was painted on the surface of paper. The graphite-on-paper (GOP) substrate offers advantages such as good thermo-electrical conductivity, low cost, and uncomplicated preparation technology. Quasi-1-dimensional palladium (Pd) thin films with 8 nm and 60 nm thicknesses were deposited on the GOP substrates using the vacuum evaporation technique. Thanks to the unique properties of the GOP substrate, a continuous Pd microfiber network structure appeared after deposition of the ultra-thin Pd film. Additionally, the sensing performance of the palladium-based hydrogen sensor was not affected, whether using GOP or paper substrate at 25 °C. Surprisingly, heating-induced loss of sensitivity was restrained due to the increased electrical conductivity of the GOP substrate at 50 °C.

Vacuum-assisted continuous flow electroless plating approach for high performance Pd membrane deposition on ceramic hollow fiber lumen

Pd-based membranes have wide applications in H2-related fields given their excellent selectivity in H2 separation. Despite their unique advantages, the fabrication of continuous and dense Pd membrane layer in the lumen side of the hollow fibers remains a great challenge. Herein, a vacuum-assisted continuous flow electroless plating (VCFELP) approach was developed to deposit a 4 μm-thick compact Pd membrane layer on the lumen (i.e., inner surface) of YSZ-Al2O3 composite hollow fiber with outer and inner diameter of 1.5 and 1.0 mm, respectively. The Pd membrane displayed hydrogen flux of ∼0.075 mol m−2 s−1 at 773 K and the nitrogen was undetectable through bubble flow meter and gas chromatograph. Furthermore, the stability and durability of the Pd membrane were significantly improved by the VCFELP approach with the aid of vacuum and continuous flow system. The outstanding membrane stability was verified by the 240-h long-term operation, with up to 24 cycles of H2–N2 gas exchange tests, 40 thermal cycle tests (from high to low temperature) and 20 pressure cycle tests. Furthermore, the Pd membrane showed sufficient stability and excellent reaction performance during the 120-h reaction run in the one-step oxidation of benzene to phenol using hydrogen and oxygen as co-reactants, achieving the benzene conversion and phenol selectivity of 23.5% and 91.6%, respectively.

MO719PERITONEAL DIALYSIS IN ELDERLY PATIENTS

Abstract Background and Aims Peritoneal Dialysis (PD) is now often being initiated in older patients. The benefits of this modality of dialysis have been well demonstrated in the literature. The aim of our study was to analyse the epidemiological and clinical profile of the elderly patients and to determine predictive factors of mortality Method It was a retrospective study including 51 case defined as patients ≥65-year-old, treated by PD in the Internal Medicine Department of the Charles Nicolle hospital during the period between 1986 and 2020. Results Fifty one patients were enrolled in the study. Their mean age was 71,6 ± 5,4 years [65 - 86]. There were 32 men (62, 7%) and 19 women (37,2%) . The method of initiation was the PD in 53, 84%. Diabetic and vascular nephropathy was the first cause of End-Stage Renal Disease in 56% and 19,6%. The mean Charlson score was 5,5 ± 1,4 [3-9]. The mean age when using PD was 70.8 ± 6 years [54-86]. Autonomous and active patients were detected in 29.4%. Diabetes mellitus, hypertension and coronary artery disease was observed in 58,8%, 29,4% and 15.7% of patients. In our study, 82.35% started on automated PD (APD) and 17,6% on continuous ambulatory PD (CAPD). The rate of mortality was 53%. Switching modality from PD to hemodialysis occurred in 29,4% of cases. A univariate logistic regression identified a coronary artery disease as significantly associated with increased mortality (HR=2,1 [1-2,1, IC 95%](p=0.035)). Conclusion Elderly patients on dialysis face many issues but can have continued success with PD when they have adequate care and support. The control of the morbidities such as coronary artery disease is important to decrease the rate of mortality in patients using this modality of dialysis.

Catalytic Reactions on Pd-Au Bimetallic Model Catalysts.

ConspectusThe enhanced catalytic activity of Pd-Au catalysts originates from ensemble effects related to the local composition of Pd and Au. The study of Pd-Au planar model catalysts in an ultrahigh vacuum (UHV) environment allows the observation of molecular level catalytic reactions between the Pd-Au surface and target molecules. Recently, there has been progress in understanding the behavior of simple molecules (H2, O2, CO, etc.) employing UHV surface science techniques, the results of which can be applied not only to heterogeneous catalysis but also to electro- and photochemical catalysis.Employing UHV methods in the investigation of Pd-Au model catalysts has shown that single Pd atoms can dissociatively adsorb H2 molecules. The recombinative desorption temperature of H2 varies with Pd ensemble size, which allows the use of H2 as a probe molecule for quantifying surface composition. In particular, H2 desorption from Pd-Au interface sites (or small Pd ensembles) is observed from 150-300 K, which is between the H2 desorption temperature from pure Au (∼110 K) and Pd (∼350 K) surfaces. When the Pd ensembles are large enough to form Pd(111)-like islands, H2 desorption occurs from 300-400 K, as with pure Pd surfaces. The different H2 desorption behavior, which depends on Pd ensemble size, has also been applied to the analysis of dehydrogenation mechanisms for potential liquid storage mediums for H2, namely formic acid and ethanol. In both cases, the Pd-Au interface is the main reaction site for generating H2 from formic acid and ethanol with less overall decomposition of the two molecules (compared to pure Pd).The chemistry behind O2 activation has also been informed through the control of Pd ensembles on a gold model catalyst for acetaldehyde and ethanol oxidation reactions under UHV conditions. O2 molecules molecularly adsorbed on continuous Pd clusters can be dissociated into O adatoms above 180 K. This O2 activation process is improved by coadsorbed H2O molecules. It is also possible to directly (through a precursor mechanism) introduce O adatoms on the Pd-Au surface by exposure to O2 at 300 K. The quantity of dissociatively adsorbed O adatoms is proportional to the Pd coverage. However, the O adatoms are more reactive on a less Pd covered surface, especially at the Pd-Au interface sites, which can initiate CO oxidation at temperatures as low as 140 K. Acetaldehyde molecules can be selectively oxidized to acetic acid on the Pd-Au surface with O adatoms, in which the selectivity toward acetic acid originates from preventing the decarboxylation of acetate species. Moreover, the O adatoms on the Pd-Au surface accelerate ethanol dehydrogenation, which causes the increase in acetaldehyde production. Hydrogen is continuously abstracted from the formed acetaldehyde and remaining ethanol molecules, and they ultimately combine as ethyl acetate on the Pd-Au surface.Using Pd-Au model catalysts under UHV conditions allows the discovery of molecular level mechanistic details regarding the catalytic behavior of H and O adatoms with other molecules. We also expect that these findings will be applicable regarding other chemistry on Pd-Au catalysts.

Optimizing Formic Acid Electro-oxidation Performance by Restricting the Continuous Pd Sites in Pd–Sn Nanocatalysts

Bimetallic Pd-based electrocatalysts usually show enhanced activity toward the formic acid oxidation reaction (FAOR), while the ensemble effects on FAOR are less investigated compared with the elec...

P1200PERITONEAL PROTEIN LOSSES: WHAT DO WE MEAN

Abstract Background and Aims The report of peritoneal protein loss should be related with a timely collection (24-hour measurement or 4-hour PET assessment) or concentration. Standardized and reproducible estimation of peritoneal protein transport is obtained during PET. The 24-hour measurements estimate the real amount of PPL, but may be affected by other factors unrelated to the prognosis of PD patients, as inconsistencies in collection and management of the samples. Overall, PET protein loss quantification may be a more specific marker of peritoneal large-pore dysfunction and is seemingly more convenient than 24-hour measurements. The aim of this study was to compare the results of both sampling methods. Method A total of 144 adult incident PD patients were included. A standard peritoneal equilibration test, 24-hour urine and dialysate collection, and multifrequency bioimpedance analysis were performed. Independent-samples t test and Pearson correlation coefficient were performed to evaluate relevant clinical associations. Results Statistically significant univariable relationships for 24h PPL were found for continuous ambulatory PD technique (CAPD) and, with a correlation coefficient &amp;gt;0.20, for pulse pressure, 4-hour dialysate/plasma creatinine and extracellular water/total body water. Studying 240 min PPL, only with 4-hour dialysate/plasma creatinine, creatinine clearance and bicarbonate levels were statistically significant. In both samples there was no significant association with age, gender, type of effluent (biocompatible solutions or lactate plus bicarbonate comparing with bicarbonate), comorbidity Charlson Index, or presence of diabetes. Correlation between 240 min PPL and 24h PPL ensues, but it is not strong (p&amp;lt;0.001; r=0.365). Conclusion The weak correlation between 24h and 240 minutes show that these two measurements should not be considered equivalent. Measurements of a 24h sample might be more close to patients’ clinical status and prognosis, despite more frequent sampling errors. PET protein loss quantification should be regarded as a marker of peritoneal large-pore dysfunction.

MO047COMPARISON BETWEEN DUAL-ENERGY X-RAY ABSORPTIOMETRY AND BIOELECTRICAL IMPEDANCE FOR BODY COMPOSITION MEASUREMENTS IN ADULTS WITH CHRONIC KIDNEY DISEASE

Abstract Background and Aims Chronic kidney disease (CKD) patients frequently have an altered body composition driven by metabolic disorders from the uremic syndrome that usually leads to increased protein catabolism, with obesity and muscle impairment being common conditions associated with worse clinical prognosis and high mortality rates. Therefore, with increased mortality and disability rates of CKD patients in the last quarter of a century and the association of a poor body composition with low survival, routine and longitudinal assessment of body composition could improve clinical outcomes. Due to limited availability of reference methods to assess nutritional status, alternative methods are used. In view of the above, our goal was to evaluate the agreement between multifrequency bioelectrical impedance spectroscopy (BIS) and Dual-energy X-ray Absorptiometry (DXA) for assessment of body composition in CKD. Method Cross-sectional and prospective analyses by DXA (Hologic, GE®) and BIS (BCM, Fresenius Medical Care®) in whole-body (BISWB) and segmental (BISSEG) protocols were performed in CKD non-dialysis-dependent, hemodialysis and peritoneal dialysis (for at least 3 months), and renal transplantation (for at least 6 months) adult (18 ≤ age ≤ 60 years old) patients. Measurements were performed consecutively by the same professional after an 8-hour fast, drainage of the peritoneal dialysate and just after the midweek hemodialysis session. Intraclass correlation coefficient (ICC) and Bland-Altman plots were evaluated for agreement analysis in group and individual levels, respectively; linear regression analysis was performed for bias assessment and development of new equations; ROC curve was constructed for diagnosis of inadequate error tolerance (DXA - BIS &amp;gt; ± 2kg). Results A total of 266 patients were included: 137 men (M) and 129 women (W); 81 were in non-dialysis-dependent treatment, 83 in hemodialysis, 24 in peritoneal dialysis, and 80 had renal transplantation. Total sample had a mean age of 47 ± 10 years old. CKD was secondary to systemic arterial hypertension in 29% of the total sample, to glomerulonephritis in 25%, to diabetes mellitus in 10%, to polycystic kidney in 7%, to glomerulosclerosis and systemic syndromes in 8%, and to other causes and unknown etiology in 20%. Fourteen patients (4 M and 10 W) were in automated and 9 (4 M and 5 W) in continuous ambulatory PD. KTx was by living donor in 18 (14 M and 4 W) and by deceased donor in 63 (34 M and 29 W) patients. The agreement with DXA was greater for BISWB than BISSEG; for fat mass (FM) (ICC in M = 0.89; ICC in W = 0.93) than for fat free mass (FFM) (ICC in M = 0.57; ICC in W = 0.52). Bland-Altman plots showed high limits of agreement (FFM: from -9.51 to 15.64kg; FM: from -7.71 to 7.32kg) with greater bias for FFM as muscular mass increases and for FM in extremes of body fat. The agreement was lower when using the prospective data (body change analysis) (ICC for FFM in M = 0.20; ICC for FFM in W = 0.49; ICC for FM in M = 0.46; ICC for FM in W = 0.58). The factors that interfered in bias between methods were extra to intracellular water ratio (ECW/ICW), body mass index, fat mass index, waist circumference, resistance and reactance (adjusted r2 for FFM = 0.90; r2 for FM = 0.87). FFM had poorer agreement in the last tertile of ECW/ICW sample (ICC in M = 0.69, 0.68 and 0.51; ICC in W = 0.71, 0.74 and 0.38 for first, second and third tertiles, respectively). An ECW/ICW cut-off point of &amp;gt; 0.725 for inadequate error tolerance was determined. New prediction equations for FFM (r2 = 0.91) and FM (r2 = 0.89) presented adequate error tolerance in 55% and 63% in the validation sample compared to 30% and 39% of the original equation, respectively. Conclusion For body composition evaluation in CKD, BIS applied using the whole-body protocol, in normal hydration CKD patients is as reliable as DXA; BIS must be used with caution among overhydrated patients with ECW/ICW &amp;gt; 0.725. The newly developed equations are indicated for greater precision.

P1172IS PERITONEAL PROTEIN LOSS A CONSEQUENCE OF OVERHIDRATATION?

Abstract Background and Aims Peritoneal protein loss (PPL) in peritoneal effluent is a well-recognised detrimental result of peritoneal dialysis treatment since its inception. Hydrostatic convection is a major drive for peritoneal protein transport; therefore venous congestion may have a role in peritoneal protein loss (Krediet RT et al Perit Dial Int. 2019 ). The aim of this study was to explore the importance of overhydration on the magnitude of peritoneal protein clearance in incident PD patients. Method A total of 97 adult incident PD patients were included. A standard peritoneal equilibration test, 24-hour urine and dialysate collection, and multifrequency bioimpedance analysis were performed. Independent-samples t test and Pearson correlation coefficient were performed to evaluate relevant clinical associations and linear multivariable regression was done. Results Statistically significant univariable relationships for 24h PPL were found for continuous ambulatory PD technique (CAPD) and, with a correlation coefficient &amp;gt;0.20, for age, pulse pressure, 4-hour dialysate/plasma creatinine and extracellular water/total body water. On multivariable analysis, type of PD technique (β=0.327, p=0.011), 4-hour dialysate/plasma creatinine (β=0.247, p=0.037), and extracellular water/total body water (β=0.304, p=0.016) were significant independent predictors of peritoneal protein loss. Conclusion Overhydration revealed the most important connection with peritoneal protein loss. Mortality has been associated with PPL in some studies, but not others. This could be a result of this relationship, as volume overload has been strongly related with lower survival.

A yearlong, professional development model on genre-based strategy instruction on writing

The purpose of the study was to (a) design and examine the effects of a yearlong professional development model on the writing quality of 3rd to 5th graders across genres and on their teachers’ confidence, and (b) to make revisions based on results and teacher’s feedback. Participants were 11 teachers, 273 students, and a principal. The study had a one-year duration, and instruction was based on genre-based strategy instruction for the genres of opinion, story, and compare-contrast. Data were collected across the academic year, and results showed that students’ writing quality improved across genres taught during the academic year while there were no gender differences on performance. Teachers expressed challenges regarding time to teach writing and meet with peer. Further they shared the need to be provided with quality resources and continuous PD. Revisions for Cycle 2 are included and implications for research and practice are further discussed.