Strong Retention Research Articles

Molecular Engineering of Ultrabright Biomimetic NanoGhost for Site-Selective Tumor Imaging and Biodistribution.

Optically active ultrabright imaging agents are shown to delineate tumor location with deep tissue visualization in pre noclinical tumor models. NanoGhosts (NGs) particles are reconstructed from the cell membrane and integrated with organic fluorophores to attain ultra-brightness for solid tumor imaging. Moreover, the integration of amphiphilic and lipophilic molecules reveals structural characteristics of NGs (≈70nm), which also alter their brightness. Upon intravenous administration (10 mgkg-1 single dose), these ultrabright NGs (778 MESF) enable the high-resolution of tumor site and real-time tracking of vital organs with high-contrast fluorescence signals. Engineered biomimetic NGs demonstrates better resolution and tissue penetration as compared to the clinically approved indocyanine green (ICG). High precision in tumor detection (0.5h) and strong tumor retention (24h which is further up to 30th day) without affecting healthy tissues ensure the future scope of NGs in early-stage cancer imaging. These findings suggest that these NGs mimic the biological characteristics of native cells, enabling them to evade immune clearance and target the solid tumor naturally.

Creating Connection: Building a Culture of Belonging in the Workplace

This article explores how organizational leaders can cultivate a culture of connection where employees feel a strong sense of belonging by discussing the importance of social bonds for both individual well-being and organizational success based on research evidence showing that loneliness and lack of social connection are linked to poorer physical and mental health as well as lower performance, productivity and creativity at work, while socially-connected workplaces outperform those characterized by disconnect. The article provides strategies for leaders to promote meaningful social bonds by emphasizing the need to intentionally create an inclusive culture through implementing diversity, equity and inclusion initiatives to foster a sense of belonging for all employees, cultivating compassion by establishing formal and informal support systems that demonstrate care for employees' wellness, and facilitating shared experiences through community-building activities and social events that help employees connect on a personal level beyond just work tasks. Exemplar companies that comprehensively implement these types of initiatives through programs promoting unusually strong employee collaboration, retention, morale and organizational success are shown to benefit from nurturing social bonds so that when these bonds are cultivated, both individuals and their workplaces can thrive.

Effects of tillage practices on water storage and soil conservation in red soil slope farmland in Southern China

Under the current conditions of global climate change, many unreasonable tillage practices exacerbate soil erosion and seasonal drought in agriculture. The red soil slope farmland makes up a significant portion of agricultural land in southern China. It is crucial to enhance the water storage and soil conservation effects (WSE) by adopting appropriate agronomic practices on the red soil slope farmland, which ensures regional agriculture’s sustainable development. Therefore, this study employed a combination of experimental plot positioning observations and artificially simulated rainfall experiments to analyze the WSE of four tillage practices: Conventional tillage (CT), Downslope ridge tillage (DT), Cross-slope ridge tillage (RT), and Plastic Mulching (PM). This study proposed the optimal tillage practices based on a comprehensive evaluation of their effects. The results indicate that there is a significant interaction (p < 0.05) between tillage practices and growth stages on soil water retention and infiltration characteristics. Under the same growth stage conditions, PM can reduce soil bulk density by 0.03–14.29% (p < 0.05) and increase temperature, soil moisture content, and total porosity by 4.00–6.67%, 0.68–18.23%, and 1.30–13.47% (p < 0.05), respectively, demonstrating the best water retention capabilities among the four tillage practices. However, during the rainfall-runoff process, the surface runoff amount (SRA) generated by PM and DT accounts for 68.15% and 90.83% of the total runoff, respectively, which is detrimental to soil water infiltration during rainfall. Both practices exhibit poor resistance to soil erosion and demonstrate low water storage and soil conservation effect index (WSEI) values of 0.38 and 0.33, respectively. Secondly, RT’s SRA constitutes only 9.42% of the total runoff, which is beneficial for increasing the cumulative soil water infiltration amount (CIA) during rainfall. Among the three tillage practices, namely RT, DT, and CT, RT demonstrates strong soil water retention capabilities. It can significantly reduce the kinetic energy of soil erosion, enhance soil erosion resistance, and exhibit the highest WSEI of 0.84. Furthermore, CT exhibits a moderate WSEI of 0.75. In summary, from the perspective of WSEI, RT is the tillage practice that should be prioritized for promotion in the cultivation process of red soil slope farmland. Our research results can provide a scientific basis for constructing optimal tillage mode and improving the WSE of southern China’s red soil slope farmland.

Annealing textures of low stacking fault energy (SFE) FCC materials: Traversing binary to high entropy alloys (HEAs)

Although the origin of brass-type deformation texture in low SFE alloys has been extensively investigated, the annealing textures of such materials have received less attention, mostly limited to brass and different austenitic steels. On the other hand, the annealing textures of low SFE HEAs have been investigated more intensively recently; however, a comprehensive insight into annealing texture formation from HEAs down to binary systems is missing. To bridge the gap, the annealing texture of FCC single-phase Cu-11.6 at%Al alloy with SFE ∼10 mJm−2 comparable to HEAs was first investigated as a model binary system and compared with selected low SFE binary, medium entropy (MEAs), and HEAs to understand the similarities and characteristic differences. The cold-rolled alloy showed massive nanostructure and a typical brass-type texture featured by a strong B ({110}<112>) component expected for a low SFE alloy. Annealing resulted in ultrafine recrystallized microstructure but extensive grain growth at higher temperatures, like other binary alloys but unlike HEAs. The annealing texture showed the retention of deformation components, weak α-fiber (ND//<110>) components and a high random fraction. These features were very similar to HEAs/MEAs and attributed to the absence of oriented nucleation (ON) or oriented growth (OG) mechanisms. However, striking differences such as strong BR ({236}<385>) and D ({113}<332>) components in the brass alloy, selective growth of the G ({110}<001>) and G/B ({110}<115>) in binary Ni-60wt%Co alloy, and strong retention of the {110}<112> component in the annealing texture of (FCC+B2) dual-phase AlCrFe2Ni2 HEA were remarkable. These outcomes indicated underlying microstructural effects on annealing texture formation in low SFE binary to HEAs/MEAs and should motivate further research.

Coating development on mine waste rocks as a protective sink to attenuate the off-site migration of antimony in the environment

This study explored the feasibility of depositing protective coatings with an Sb scavenger function on mine waste rocks derived from the exploitation of stibnite deposits. Encapsulation treatments were performed using ferrous sulfate as the coating precursor. Different Fe/Sbleachable molar ratios (0.1, 1, and 10) were evaluated using hydrothermal and thermal processes at various temperatures (30, 50, 100, and 150 °C). The environmental characterization of the coated mine waste was established using standard leaching tests. The most effective coatings were analyzed for their mineralogy, chemical composition, and Sb attenuation using X-ray powder diffraction, scanning electron microscopy, and digestion/extraction processes. Additionally, stability tests were conducted to assess the effectiveness of encapsulation under changing environmental conditions. The Fe/Sbleachable molar ratio was found to be a critical factor in reverting the toxic and hazardous characteristics of mine wastes, with an optimal value of 10. The coatings were primarily composed of Fe oxyhydroxy sulfates/Fe oxyhydroxides and calcium sulfate minerals with a bulk Sb content of approximately 1 %. The adsorbed Sb content in the coatings was a small fraction of the total Sb content (< 0.5 %), indicating a strong retention. Moreover, such coatings were stable under different pH (3−8) and redox (100 to −100 mV) conditions.

Mapping the Trade Direction of Indian Rice with Markov Chain Analysis

Agriculture is a cornerstone of India’s economy, with rice being a critical crop that ranks second globally, feeding over half of the world’s population and serving as a staple in Southeast Asia. This study explores the direction of India’s rice trade using Markov Chain Analysis, following an examination of the compound annual growth rate (CAGR) in rice exports to various global regions. Results reveal a 2.26 per cent CAGR in rice production, while export values surged by 16.8 per cent annually. Specifically, the CAGR for rice exports to Iraq and Iran reached 58.6 per cent and 46.47 per cent, respectively. In quantity, India’s rice exports grew by 10.82 per cent, with Iraq and Iran at 44 per cent and 34 per cent. The Transitional Probability Matrix for 2001-2022 indicates strong regional retention, with Africa maintaining 78 per cent of trade value and Asia 93.7 per cent, and similar trends in quantity, where Asia retained 92.6 per cent and Africa 89.1 per cent. These findings highlight India’s potential to diversify rice exports and strengthen its global competitive edge, urging a focus on enhancing processing, transportation, and quality standards for wider market appeal.

Preparation and characterization of aptamer-based sorbent for the selective extraction of zearalenone and its derivatives from human urine.

The aim of this work is the development of a biomimetic strategy involving a molecular recognition mechanism using aptamers immobilized on a solid support for the analysis of the mycotoxin zearalenone (ZEA) and two of its derivatives in human urine: alpha-zearelenol (α-ZEL) and beta-zearelenol (β-ZEL). Three oligonucleotide sequences reported in theliterature as beingspecific to ZEA were thus covalently grafted onto activated sepharose, and a thorough study of the percolation and washing conditions was performed to promote the selective retention of the three targeted compounds. With the optimized extraction procedure, a strong and selective retention was obtained for ZEA and to a lesser extent α-ZEL and β-ZEL, with extraction recoveries of 88±9%, 77±15%, and 45±12% respectively, in standard solutions. Application of this procedure to spiked human urine strongly highlighted the efficiency of the clean-up effect resulting from the use of this selective sorbent. Limits of quantification of the whole analytical procedure including extraction on oligosorbent andLC-MS analysis were 0.18 and 0.24ngmL-1, for ZEA and α-ZEL, respectively, thus demonstrating clearly the potential of the developed method for monitoring human dietary exposure to these compounds.

Amelioration of extremely acidic environment of soy protein amyloid fibrils to enhance gelation performance by dialysis strategy: Effects of pH and ions

The application of soy protein amyloid fibrils (SAFs) to food industrialization field has received focused attention because of their advantages such as ordered supramolecular structure and anti-proteolytic properties. However, the comparatively weak gelation properties of SAFs make it difficult to form self-supporting hydrogels, limiting its potential for future applications. Additionally, the extremely acidic environment (pH 2) of SAFs hinders their practical application in the food pH range (4–7). To address this issue, a dialysis strategy was utilized to enhance the gel structure of SAFs in this paper. The SAFs were dialyzed by deionized water and zinc ions solutions with four different pHs (2, 4, 7, and 9), and the impact of various dialysates on rheological properties, water distribution, and microstructure was investigated. The results demonstrated the method significantly improved gelation properties and modified the extremely acidic environment of SAFs. Various samples were continuously deacidified during dialysis in solutions of different pHs (4, 7, and 9), transforming from pH 2 to a higher pH value. Visual images exhibited that self-supporting hydrogels can be formed by SAFs just at a low concentration of 3% (wt). SAFs-Zn2+-9 hydrogel exhibited the highest storage modulus with a 500-fold compared to SAFs-2. Notably, the SAFs-H2O hydrogels were fabricated without any exogenous substances, in which the storage modulus of SAFs-H2O-9 increased by over 300 times. AFM images demonstrated that the shift from long rigid fibrils to short flexible fibrils induced tightly entanglement among fibrils, which improved gelation performance. Moreover, the transform in pH and the incorporation of ions caused the hydrogels to show dense network structure and strong water retention capacity. The ingenious insights were provided for improving the gelation performance of SAFs and modifying the polar acidic environment in the study, fully exploiting the potential of SAFs as edible ingredients for food applications.

A fluorine-free bioinspired multifunctional slippery coating for ultra-long-term anticorrosion of Mg alloy, static/dynamic anti-icing, antibacterial and antifouling

Poor corrosion resistance limits the application of Mg alloy and it is meaningful to explore a surface coating technology for ultra-long-term corrosion protection of Mg alloy. Superhydrophobic surface (SHS) and smooth liquid-injected porous surface (SLIPS) have shown important application value in the field of Mg alloy corrosion protection. However, the unstable special interface of air layer or lubricant cannot act as stable corrosion barrier for the long term. Inspired by frog skin, a bionic fluorine-free multifunctional slippery coating (MSC) is prepared by one-step spraying a mixture of epoxy resin, silicone oil, modified nano TiO2 and modified micron mica powder. MSC exhibits a microstructure similar to frog skin, excellent slippery (sliding angle ∼ 3°) and strong lubricant retention. Different from anticorrosion mechanism of SHS and SLIPS by their special interface, MSC, storing silicone oil on the surface and inside the coating, demonstrates ultra-long-term anticorrosion to Mg alloy (both neutral salt spray and 3.5 wt% NaCl solution immersion for 60 days) due to excellent barrier effect throughout coating, and the scratch defect area of MSC is not significantly eroded after 14 days of salt spray. Moreover, MSC exhibits excellent static/dynamic anti-icing ability and low ice adhesion in a −20℃ environment, outstanding adhesion (level 4B), high hardness (3H), antibacterial (>94 %), antifouling, chemical stability and resistance to boiling water, ice water and UV radiation. All these excellent properties can promote the application of Mg alloy in a wider range of fields.

Extraction technology determines the properties of bamboo shoots dietary fiber concentrate and its application in chicken mince gels: Systematic analysis

This study investigated how physical, chemical, and enzymatic extraction technologies affected the physicochemical properties of bamboo shoot insoluble dietary fiber (IDF). Additionally, the effects of IDF extracted by these techniques on the gel properties, water retention, microstructure, and digestibility of chicken mince gels were evaluated. Results showed that IDFs extracted by physical (P-IDF), chemical (C-IDF), and enzymatic (E-IDF) exhibited a typical cellulose polysaccharide structure and strong water and oil retention capabilities, with the highest values reaching 14.18 g/g and 6.74 g/g, respectively. Compared to P-IDF, C-IDF and E-IDF displayed a rougher porous structure and stronger adsorption capacities for glucose (409.91 mg/g and 604.95 mg/g), cholesterol (54.46 mg/g and 64.06 mg/g), sodium cholate, and nitrite. The addition of IDF improved the water retention, water stability, texture, and rheological properties of chicken mince gels, and had no negative effect on the digestion of chicken mince proteins. On the one hand, the hydrophilic groups exposed in IDF absorb water and fill the gel networks, reducing the formation of water channels in the gel and improving water stability. Furthermore, the hydrophilic groups on the glucose unit that makes up the IDF interacts with the proteins through the hydrogen bond and the transformation of protein β-structure to α-structure, promoting the formation of gel network structure and improving gel texture and rheological properties. E-IDF and C-IDF showed better overall gel performances, but E-IDF had better dry matter digestibility, protein digestibility, and gastrointestinal digestive effects. Therefore, IDF prepared by enzymatic hydrolysis is more suitable for chicken mince processing.

Acid-treated waste sisal fiber derived activated carbon as efficient electrode material for solid-state supercapacitor

Activated Carbon (AC), obtained from biomass is highly adaptable and valued for its versatile benefits including high surface area, conductivity, chemical inertness, etc. in various applications. It is also used as an electrode in supercapacitors for applications requiring a high-power supply. Sisal fiber, derived from the Agave sisalana plant, has several advantages, including its fibrous and porous framework, that make it suitable for conversion into activated carbon for energy storage applications in the context of sustainability and reduced environmental impact. In this study, we have prepared H2SO4 treated KOH activated carbon from residual Sisal fiber (SFH2AC) which is then utilized as an electrode material for supercapacitors. SFH2AC exhibits hierarchical and structure-based porosity with a large specific surface area (SA) of 1185 m2/g and shows the maximum specific capacitance (Cs) of 340 F/g @ 0.5 A/g in 6 M KOH electrolyte. In KOH electrolyte, strong cycling retention (during the length of 9000 GCD cycles) is attained as; 98 % up to the first 3000 cycles at 10 A/g, 93 % up to next 3000 cycles at 20 A/g, and 90 % up to the last 3000 cycles at 30 A/g. Furthermore, the SFH2AC//SFH2AC(Gel) device was built by using SFH2AC as electrodes with PVA/KOH gel as an electrolyte in order to assess the supercapacitor performance in real time. The device has a specific power density of 7500 W/kg and a maximum energy density of 12 W h/kg. The device reveals an exceptional 97 % cycling stability, maintaining up to 9000 repeated GCD cycles at an increased current density (CD) of 30 A/g.

Selection of Wheat Miller's Bran Based on the Sub-aleurone Protein Content Allows Increase of the Quality of Bran-Enriched Bread.

Wheat miller's bran negatively affects the gluten network but contains the grain tissue with the highest gluten content, the sub-aleurone. Here, the aim was to investigate how sub-aleurone gluten proteins in miller's bran affect bran-enriched bread quality. A bread-making experiment was performed with six lab-scale-produced bran samples. These strongly differed in protein content (10.8-18.6%) but had a similar particle size (d50: 1266-1330 μm) and strong water retention capacity (0.71-0.80 mL of H2O/g). Bran protein content variation mainly originated from sub-aleurone protein content variation (10.7-26.2%). Incorporating the bran with the highest versus lowest sub-aleurone protein content increased the loaf volume by 22.4%. 99% of loaf volume variation could be explained by sub-aleurone protein content variation. Conclusively, sub-aleurone protein content is the most important factor regarding bran functionality in bread-making. This was strengthened using commercial bran. Therefore, bran selection based on (sub-aleurone) protein content could be a low-cost, low-effort opportunity for bran-enriched bread-making.

RGP: Neural Network Pruning Through Regular Graph With Edges Swapping.

Deep learning technology has found a promising application in lightweight model design, for which pruning is an effective means of achieving a large reduction in both model parameters and float points operations (FLOPs). The existing neural network pruning methods mostly start from the consideration of the importance of model parameters and design parameter evaluation metrics to perform parameter pruning iteratively. These methods were not studied from the perspective of network model topology, so they might be effective but not efficient, and they require completely different pruning for different datasets. In this article, we study the graph structure of the neural network and propose a regular graph pruning (RGP) method to perform a one-shot neural network pruning. Specifically, we first generate a regular graph and set its node-degree values to meet the preset pruning ratio. Then, we reduce the average shortest path-length (ASPL) of the graph by swapping edges to obtain the optimal edge distribution. Finally, we map the obtained graph to a neural network structure to realize pruning. Our experiments demonstrate that the ASPL of the graph is negatively correlated with the classification accuracy of the neural network and that RGP has a strong precision retention capability with high parameter reduction (more than 90%) and FLOPs reduction (more than 90%) (the code for quick use and reproduction is available at https://github.com/Holidays1999/Neural-Network-Pruning-through-its-RegularGraph-Structure).

Evaluation of inorganic and organic composite plugging materials with high performance and adaptive fracture scale

In order to address the problem that carbonate fracture-vuggy reservoirs are prone to severe lost circulation during drilling and the difficulty of existing plugging agents to improve the first-time plugging success rate, a composite plugging agent composed of organic and inorganic materials has been developed. The study demonstrates that the plugging agent exhibits high temperature-pressure resistance (exceeding 130 °C and 7 MPa), controllable solidification time and excellent fluidity. Additionally, the plugging agent has strong retention properties within the fractures, exhibiting the capacity to adapt to varying fracture dimensions and effectively form plugging structures due to its viscoelastic properties. The microstructure analysis reveals that the organic and inorganic components of the plugging agent are intertwined and filled with each other, forming a three-dimensional force network, which improves both the toughness and compressive strength of the plugging material, making it highly applicable for addressing severe lost circulation in carbonate fracture-vuggy reservoirs.

Overcoming strong retention barriers of A- and V-series nerve agents on silica sorbents

The present study explores the potential of silica solid phase extraction for gas chromatography mass spectrometric analyses of A- and V-series nerve agents. Owing to the presence of basic amidine and amine moieties, these analyte undergo strong ionic interactions with inherently acidic silica surfaces, producing poor recoveries. Subtle optimizations in the elution composition empowered the analytes to overcome the retention barriers from sorbent surfaces. Acetone containing 10 % (v/v) NH4OH effectively minimized strong analyte-sorbent interactions allowing good to excellent recoveries. Recoveries for A-series agents ranged from 88 to 96 %. VX, which is reported to be poorly recoverable from such sorbent matrices offered best data so far, reaching up to 74 % under optimized conditions. The method detection limits for the selected analytes in mass spectrometric analysis ranged from 47 to 171 ng/ml. Strong affinities of analytes towards silica sorbent were further exploited to expand the scope of analysis and establish the method's efficacy for a wide range of organic matrices. The applicability of the method to the real world applications was also validated in blind spiking exercises in diverse organic liquid samples received in 48th, 50th and 52nd proficiency tests conducted by the Organization for the Prohibition of Chemical Weapons (OPCW).

Visualization Experimental Investigation on Flow Regulation and Oil Displacement Characteristics of Gel Foam in Fractured-Vuggy Carbonate Reservoirs.

Fractured-vuggy reservoirs experience severe channeling during water and gas injection operations, and conventional foam shows weak regeneration capabilities in large-scale fracture spaces, thus failing to effectively seal them. Gel foam combines the advantages of both foam and gel, significantly enhancing the foam's stability and showing good suitability in fractured-vuggy reservoirs. In this article, the plugging and flow regulation properties of gel foam in fractures were studied through fracture displacement experiments. The dynamic plugging capability of gel foam was superior to that of ordinary foam, and its plugging effect was significantly influenced by the fracture opening. Gel foam had strong retention capacity in fractures, and after plugging large-opening fractures, the diversion rate of small-opening fractures was increased by at least 83.3 times during subsequent parallel water flooding, making the flow regulation effect remarkable. Through the oil displacement experiments in typical fractured-vuggy models, the profile control law and enhanced oil recovery performance of gel foam under different fractured-vuggy structures were studied. In the regular fractured-vuggy network, gel foam adhered to occupy the fractured-vuggy space for plugging and controlled the top gas migration direction to synergistically drive the recovery of remaining oil, ultimately achieving a recovery of 95%. In the combination of fractures and irregular vugs, due to the density, gel foam continuously pushed down and right along the fractures to the vugs, pushing the crude oil and formation water in the vugs to migrate to the production well. The recovery of the gel foam flooding stage was as high as 48%, and the final recovery reached 93.5; only a small amount of shielded remaining oil was difficult to drive. The research results are of great significance to the application of gel foam in enhancing oil recovery in fractured-vuggy reservoirs.

Capillary container array structures for efficient, energy-saving, and sustainable evaporative cooling and humidification

Evaporative cooling is a widely employed method for air conditioning and heat dissipation, utilizing the phase transition of water to achieve simultaneous cooling and humidification. It relies on high-surface-area solid materials to enhance air-liquid contact upon wetting. However, these water-absorbing materials have drawbacks such as increased air resistance, degradation of water quality, and limited water retention capabilities. This study introduces a novel structure called the capillary container array (CCA) for effective humidification and cooling. The CCA structure overcomes the limitations of traditional methods by incorporating interconnected capillary containers with adjustable spacing and utilizing capillary forces to capture liquid droplets while minimizing the solid component. Compared to commercial paper-based wet curtains, the CCA structure offers significant advantages including strong water retention capabilities, high humidification performance, low air resistance and high pollution resistance. It increases water capacity by 6 times, humidification capacity by 8 %, and temperature drop by 2.2 °C. Moreover, it exhibits a 5-fold longer in water retention duration, a 30 % reduction in air pressure drop and a 3-fold increase in the performance coefficient, and maintains excellent water quality (<1 NTU) over prolonged operation. These advancements make the CCA structure highly promising for various applications in agriculture, industry and environmental conservation.

Epoxy resin gel particles with adjustable stickiness and deformability for pesticide delivery

It is essential to develop a pesticide delivery system with a simple preparation process and strong leaf retention capability. In this study, epoxy resin (ER) was modified with alcohols with different carbon chain lengths through a one-step reaction to synthesize modified prepolymers (ModER). Among these, the ER modified by dodecanol (ER/Dodecanol) exhibited high flexibility, exceptional stickiness and the highest surface free energy. Subsequently, the organic phase containing emamectin benzoate (EB) and ModER was directly mixed with the aqueous phase containing sodium lignosulfonate (SL) to instantaneously obtain pesticide-loaded epoxy resin gel particles (ModERMP) through self-emulsification and electrostatic interaction. ER/Dodecanol loaded with EB (EB@ER/Dodecanol) had excellent flexibility. The particles underwent significant flattening, transitioning from micron-sized spherical particles to “biscuit-type” particles with nanoscale thickness. EB@ER/Dodecanol exhibited outstanding stickiness, enabling it to adhere to the mouthparts and legs of insects, thereby impacting their feeding behavior. Compared with that of the control, the leaf feeding rate for the experimental group was decreased by 9.36%. EB@ER/Dodecanol also had affinity for foliar micro/nanostructures while displaying excellent washout resistance. Following washing, the residue rate increased by 33.7% compared to that of the emulsifiable concentrate (EC). Furthermore, EB@ER/Dodecanol had excellent insecticidal activity both before and after washout. ModERMP represents a simple preparation process with robust washout resistance, thereby enhancing pesticide utilization rates.

Fluid distribution during surgery in the flat recumbent, Trendelenburg, and the reverse Trendelenburg body positions.

The distribution and elimination of infused crystalloid fluid is known to be affected by general anesthesia, but it is unclear whether changes differ depending on whether the patient is operated in the flat recumbent position, the Trendelenburg ("legs up") position, or the reverse Trendelenburg ("head up") position. Retrospective data on hemodilution and urine output obtained during and after infusion of 1-2 L of Ringer's solution over 30-60 min were collected from 61 patients undergoing surgery under general anesthesia and 106 volunteers matched with respect to the infusion volume and infusion time. Parameters describing fluid distribution in the anesthetized and awake subjects were compared by population volume kinetic analysis. General anesthesia decreased the rate constant for urine output by 79% (flat recumbent), 91% (legs up) and 91% (head up), suggesting that laparoscopic surgery per se intensified the already strong anesthesia-induced fluid retention. General anesthesia also decreased the rate constant governing the return of the distributed fluid to the plasma by 32%, 15%, and 70%, respectively. These results agree with laboratory data showing a depressive effect of anesthetic drugs on lymphatic pumping, and further suggest that the "legs up" position facilitates lymphatic flow, whereas the "head up" position slows this flow. Both Trendelenburg positions increased swelling of the "third fluid space". General anesthesia caused retention of infused fluid with preferential distribution to the extravascular space. Both Trendelenburg positions had a modifying influence on the kinetic adaptations that agreed with the gravitational forces inflicted by tilting to body.

Polymeric ionic liquids containing copper(I) and copper(II) ions as gas chromatographic stationary phases for olefin separations

Copper(I) ions (Cu+) are used in olefin separations due to their olefin complexing ability and low cost, but their instability in the presence of water and gases limits their widespread use. Ionic liquids (ILs) have emerged as stabilizers of Cu+ ions and prevent their degradation, providing high olefin separation efficiency. There is limited understanding into the role that polymeric ionic liquids (PILs), which possess similar structural characteristics to ILs, have on Cu+ ion-olefin interactions. Moreover, copper ions with diverse oxidation states, including Cu+ and Cu2+ ions, have been rarely employed for olefin separations. In this study, gas chromatography (GC) is used to investigate the interaction strength of olefins to stationary phases composed of the 1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([C6MIM+][NTf2−]) IL and the poly(1-hexyl-3-vinylimidazolium [NTf2−]) (poly([C6VIM+][NTf2−])) PIL containing monovalent and divalent copper salts (i.e., [Cu+][NTf2−] and [Cu2+]2[NTf2−]). The chromatographic retention of alkenes, alkynes, dienes, and aromatic compounds was examined. Incorporation of the [Cu2+]2[NTf2−] salt into a stationary phase comprised of poly(dimethylsiloxane) resulted in strong retention of olefins, while its addition to the [C6MIM+][NTf2−] IL and poly([C6VIM+][NTf2−]) PIL allowed for the interaction strength to be modulated. Olefins exhibited greater affinities toward IL and PIL stationary phases containing the [Cu2+]2[NTf2−] salt compared to those with the [Cu+][NTf2−] salt. Elimination of water from both copper salts was observed to be an important factor in promoting olefin interactions, as evidenced by increased olefin retention upon exposure of the stationary phases to high temperatures. To evaluate the long-term thermal stability of the stationary phase, chromatographic retention of probes was measured on the [Cu2+]2[NTf2−]/[C6MIM+][NTf2−] IL stationary phase after its exposure to helium at a temperature of 110 °C.