Large Pore Area Research Articles

Mesoporous manganese oxide/multiwalled carbon nanotubes as a base material for the 99mTc/99Mo generator: Development, characterization, and implementation study

The uptake capacity of Mo on the active MnO2 nanoparticles was determined in a previous study, and it was found to be 7 mg/g. This value is appropriate for 99Mo, which is more complex to separate due to its production using the 235U fission reaction with a high specific activity. Currently, multiwall carbon nanotubes (MWCNTs) linked to mesoporous MnO2 are being prepared and studied as a novel sorbent for the 99Mo produced with a low specific activity by thermal neutron activation of natural molybdenum consisting of 92M0, 94Mo, 95Mo, 96Mo, 97Mo, 98Mo, and 100Mo, based on the 98Mo(n,γ) reaction to prepare the 99Mo/99mTc generator with a high uptake capacity for Mo. FTIR spectroscopy, EDX-mapping, XRD, particle size analysis, FESEM, and TEM analysis were used to characterize the novel mesoporous MnO2/MWCNT sorbent with a large total pore area 193.3 m2/g and porosity about 52%. Several factors influencing the sorption of 99Mo and 99mTc onto the mesoporous MnO2/MWCNTs were studied, including the distribution coefficient (Kd), contact time, temperature, and sorbent/solute ratio, etc. The Mo uptake capacities on the novel sorbent were 133 and 115 mg Mo/g, respectively. A preliminary study on the prepared new sorbent for the 99Mo/99mTc generator was performed, and the elution yield of 99mTc was found to be 82.55% with low 99Mo breakthrough. The radiochemical, radionuclide, and chemical purity of the eluted 99mTc were checked to ensure that it was free of impurities.

Evaluation and comparison of the efficacy and safety of the combination of topical phenytoin and microneedling with microneedling alone in the treatment of atrophic acne scars: A controlled blinded randomized clinical trial.

Severe acne breakouts often lead to atrophic acne scars, which affect millions of people worldwide and can significantly affect a person's self-confidence and self-image. Given the difficulty in treating atrophic acne scars, this study aims to investigate the efficacy of topical phenytoin in the treatment of atrophic acne scars. This split face clinical trial on 25 patients between the ages of 18 and 40 involved the application of microneedling on one side of the face, with three sessions taking place over the course of a month. On the other side, a 1% phenytoin cream was administered three times daily for 1 week following the microneedling procedure. Baseline information was collected for all patients, and follow-up assessments were conducted during the treatment sessions and 2 months after the last session. The assessments included evaluating the number and area of pores and spots, determining scar severity, assessing patient satisfaction, and recording any potential complications. Among patients, 20 individuals (80%) were females, and the average age of the participants was 35.96±9.23. In terms of the fine pore area, despite the fine pore count, both groups showed improvement over time (p: 0.03vs. 0.06). Also, regarding large pore count and area, and the count and area of spots, both groups showed improvement over time (p: 0.001). However, there were no significant differences between the two groups (p>0.05). On the other hand, when it comes to acne scar grade and patients' satisfaction, the phenytoin group outperformed the control group in all follow-up sessions and this difference was found to be significant (p: 0.001). It is worth noting that no complications were observed among any of the patients. It appears that combining phenytoin cream with microneedling has a more effective therapeutic outcome in enhancing atrophic acne scars, when compared to microneedling alone, and this method can be regarded as a viable alternative in treating these types of scars.

Natural Wood-Derived Macroporous Cellulose for Highly Efficient and Ultrafast Elimination of Double-Stranded RNA from In Vitro-Transcribed mRNA.

Double-stranded RNA (dsRNA) is a major impurity that can induce innate immune responses and cause adverse drug reactions. Removing dsRNA is an essential and non-trivial process in manufacturing mRNA. Current methods for dsRNA elimination use either high-performance liquid chromatography or microcrystalline cellulose, rendering the process complex, expensive, toxic, and/or time-consuming. This study introduces a highly efficient and ultrafast method for dsRNA elimination using natural wood-derived macroporous cellulose (WMC). With a naturally formed large total pore area and low tortuosity, WMC removes up to 98% dsRNA within 5min. This significantly shortens the time for mRNA purification and improves purification efficiency. WMC can also be filled into chromatographic columns of different sizes and integrates with fast-protein liquid chromatography for large-scale mRNA purification to meet the requirements of mRNA manufacture. This study further shows that WMC purification improves the enhanced green fluorescent protein mRNA expression efficiency by over 28% and significantly reduces cytokine secretion and innate immune responses in the cells. Successfully applying WMC provides an ultrafast and efficient platform for mRNA purification, enabling large-scale production with significant cost reduction.

Simple emulsion template method towards self-anticoagulant and high-efficiency carboxymethyl chitosan-based adsorbent for low-density lipoprotein from whole blood

In this study, carboxymethyl chitosan (CMCS)-based double cross-linked network spheres, are constructed by an emulsion template method. The first crosslinking network comes from the chelation between the CMCS and zinc ions, while the second one is based on the covalent crosslinking of 2-acrylamido-2-methyl-1-propanesulfonicacid (AMPS); and the as-prepared spheres are termed as ECMCS@AMPSs. The emulsion template method endows the ECMCS@AMPSs with large pore area (58.3 m2/g) and ultra-high porosity (92.3 %). Thanks to the heparin-mimicking functional groups of –OH, –COO- and -SO3-, the ECMCS@AMPSs show excellent anticoagulant properties without the activation of the complement system, contact system and platelets. Compared with the spheres without emulsification, the porous structure of the ECMCS@AMPSs results in a 5.3-fold increase in low-density lipoprotein (LDL) adsorption capacity in hypercholesterolemia plasma. Most importantly, in vitro simulated hemoperfusion experiment shows that the cumulative adsorption capacity of LDL by the ECMCS@AMPSs is as high as 41.66 mg/g in 1 h, which is approximately 4.2 times that of high-density lipoprotein (HDL). In conclusion, the ECMCS@AMPSs with self-anticoagulant and high-efficiency adsorption of LDL fabricated via simple emulsion template method have great clinical application prospects in the field of lipoprotein apheresis.

Sb2X3 (X = S, Se) nanowires/graphene aerogel monoliths for effective photodegradation of dye/drug under visible light irradiation

The visible-light-responsive photocatalysts with high efficiency have been attracting tremendous focus in environmental remediation. Herein, three-dimensional (3D) Sb2X3 (X = S, Se) nanowires/graphene aerogel (Sb2X3/GA) monoliths were prepared by a facile hydrothermal route. The as-prepared Sb2X3/GA monoliths show the shape of a cylinder with a hierarchical porous structure. FESEM and porosimetry analyses revealed that the monoliths have high porosity, large total pore area as well as large pore volume. Sb2X3/GA demonstrated excellent photodegradation performance for the representative anionic/cationic dyes (methyl orange, rhodamine B, and crystal violet) and antibiotic drug (tetracycline hydrochloride) under 120 min of visible light irradiation. The degradation efficiencies of Sb2X3/GA were found to be 92.6–99.8% for the above-mentioned dye/drug, which were much larger than that of the pristine Sb2X3 nanowires. The enhanced photodegradation activity could be ascribed to the synergistic effect between the Sb2X3 nanowires and graphene aerogel, which was confirmed by the results of the photoluminescence and electrochemical impedance spectra. These findings provide an innovative strategy for designing 3D visible-light-responsive photocatalysts for water purification.

Pores Evolution of Soft Clay under Loading/Unloading Process

Loading/unloading tests and field emission scanning electron microscope (FESEM) tests were performed on undisturbed soft clay specimens to study the pore evolution under the loading/unloading process. The results showed that small pores (<0.2 μm) had intrinsic characteristics, and the distribution and the fragmentation fractal dimension of small pores were basically unchanged with pressure, while large pores (>0.6 μm) changed greatly under loading/unloading. The pore-size distribution was mainly influenced by large pores. The microstructure of soft clay before unloading has an influence on the change of the swelling index (Cs) and the pores evolution under unloading. Cs increased as the surface fractal dimension of the pores and the area of large pores decreased, and the fragmentation fractal dimension of the pores increased under the loading process. The variations in fractal dimensions and large pore area increased under unloading. Moreover, the compression index (Cc) changed nonlinearly with the pore evolution under loading. Below 100 kPa, Cc increased slightly with a small increase of the fractal dimensions and large pores area under loading. From 100 kPa to 400 kPa, Cc increased to a peak value of 0.484, and the fractal dimensions and large pore area were the greatest under loading. Above 400 kPa, all of them changed slowly. Based on the evolution of pore fractal characteristics, the loading/unloading process could be divided into three stages: the natural structural stage, the structural adjustment stage, and the new equilibrium stage, which was important to study the loading/unloading properties of soft clay.

Characterization and Proteomic Analysis of Decellularized Adipose Tissue Hydrogels Derived from Lean and Overweight/Obese Human Donors

While decellularized adipose tissue (DAT) has potential as an "off-the-shelf" biomaterial product for regenerative medicine, it remains to be determined if donor-source body mass index (BMI) impacts the functionality of DAT. This study set out to comparatively characterize lean versus overweight/obese-donor derived DAT hydrogel based on proteome and to analyze their respective effects on adipose stromal/stem cell (ASC) viability, and differentiation in vitro. Decellularized adipose tissue from lean (lDAT) and overweight/obese (oDAT) donors is produced and characterized. Variability in the fibril microstructures is found, with dense fibrotic fiber clusters and large pore area uniquely present in the oDAT samples. Proteomic analysis reveals that lDAT contains a greater proportion of enriched extracellular proteins and a smaller proportion of enriched intracellular proteins relative to oDAT. Biocompatibility studies show that ASCs cultured in lDAT and oDAT hydrogels remain viable. The adipogenic and osteogenic differentiation capability of ASCs seeded in lDAT and oDAT hydrogels is confirmed by an upregulation in marker gene expression and phenotypic analysis. In conclusion, this study establishes that DAT hydrogels derived from lean and overweight/obese adipose donors present similar physicochemical profiles with some distinctive features while comparably supporting the viability and adipogenic differentiation of ASCs in vitro.

Effect of low temperature on the aging characteristics of a potato starch gel

In this work, the freezing curve of a potato starch gel with different concentrations was determined. The water migration, texture, microstructure and gelatinization of a potato starch gel with 8% starch concentration were studied during aging. The results showed that the freezing characteristics of the potato starch gel with different starch concentrations were quite different. NMR results showed that the relaxation time and proportion of water with different existing states (T21, T22 and T23) in the potato starch gel varied significantly under different aging temperatures. Under different aging temperatures, the texture characteristics and the gel strength of the starch gel were significantly different. The water retention of the gel was better under aging temperatures of 3 °C and −3 °C than for other gel samples. SEM and C-cell results showed that under aging temperatures of 3 °C and 0 °C, the formation of a gel network structure was accelerated, and the gel was relatively firm, with small and uniform pores and a larger pore area and number. The rapid viscosity analysis results showed that the peak viscosity, breakdown and setback of the vacuum freeze-dried gel powder changed differently under the aging temperatures.

Fabrication of silica-based chitosan biocomposite material from volcanic ash and shrimp husk by sol gel method for adsorbent of cadmium (II) Ions

The utilization of volcanic ash and shrimp shell waste into composite material is very interesting to discuss as a strategy to make naturally available materials into valuable, stable and low cost adsorbent. The study is aimed to fabricate the silica-based chitosan biocomposite material from volcanic ash of Sinabung mountain and shrimp husk by sol gel method to be used as an adsorbent. The procedure is performed by converting volcanic ash into silica salt, extracting the chitosan from shrimp skeleton, and the synthesis of the silica-chitosan biocomposite by mixing the silica with chitosan in the aid of bifunctional glutaraldehyde cross-linking agent. The silica-based chitosan composite is successfully prepared from the mixture of 20 mL 58% (v/v) Na2SiO3 with 2% (w/v) chitosan to obtain biocomposite material (SChC1). A rapid and simple method to bind the silica with chitosan is achieved. The resulting biocomposite is amorphous, in the form of small crystals, a rough surface with a large pore area between 2θ = 20-24°. Adsorption capacity of the biocomposite material has been evaluated, where it has the capability to bind cadmium ion due to the presence of amine group in the material surface. The prepared material of silica-chitosan biocomposite has the potential to be used as an adsorbent.

Purification of Biodiesel from Waste Cooking Oil Using Bentonite as Dry Washing Agent

The process of biodiesel purification is an important step in getting biodiesel products that meet specifications as a substitute for fossil-based fuels. Dry washing method has been developed to achieve an effective purification strategy in order to produce high-quality biodiesel. Bentonite can be used as dry washing agent because it has a good adsorbing properties as well as a large pore and surface area therefore can attract polar substances such as glycerol and methanol. The purpose of this research is to know the capability of activated bentonite as dry washing agent for purification of biodiesel produced from waste cooking oil. The activation process of bentonite was carried out using sulfuric acid with concentration 1.5 M. Characterization of the bentonite was conducted using X-Ray Diffraction (XRD) for minerals content and Brunauer–Emmett–Teller (BET) method for surface area. Bentonite was used as dry washing agent for biodiesel purification by varying washing time (10, 20, 30, 40 and 50 minutes) and adsorbent amount (1, 2, 3, 4 and 5%). The experimental results showed that purification of biodiesel by dry washing using activated bentonite resulted in a better yield and quality than wet washing and dry washing using non-activated bentonite, except the acid number. The best operation condition resulted from this research is at 10 minutes washing time and 1% adsorbent with yield of 94.1%; acid number of 0.4208 mg KOH/gram; density of 0.8838 gram/cm3, viscosity of 3.0617 mm2/s and water content of 1.17%.

Impact of the fermentation broth of Ganoderma lucidum on the quality of Chinese steamed bread

The potential of fermentation broth of Ganoderma lucidum (FBG) in improving the quality of Chinese steamed bread (CSB) was firstly evaluated. The sensory quality scores of CSB treated by FBG are significantly higher than that of CSB in the control, and texture profile analysis also indicates the increase of CSB hardness and chewiness caused by FBG. Observation on micro-structure of CSB shows that formation of larger pores and expansion of starch granules are the important reasons for the improvement of CSB specific volume (volS), and granule expansion is due to that gluten network distributed in CSB is destroyed as a result of cross-linkage of flour proteins catalyzed by laccase, which makes starch granules releasing from the network easily contact with steam or other enzymes during the proofing and steaming of dough. Moreover, FBG contains amylases which not only convert amylopectin to amylose, but also degrade starch to glucose, maltose and polysaccharides, correspondingly resulting in changes of amylose/amylopectin (Ae/An) ratio of flour and CSB volS, and the latter is because more CO2 produced by the yeast during CSB making leads to the larger pore area in crumb. Both hardness and chewiness are determined by the comprehensive effect of protein cross-linkage, Ae/An ratio and volS change, and this viewpoint gives a logical explanation for the effects of 0.025–0.10 ml/g of FBG on hardness and chewiness of CSB.

Electrospun poly(styrene-co-maleic anhydride) nanofibrous membrane: A versatile platform for mixed mode membrane adsorbers

The traditional methods to introduce multi-functional groups onto the surface of membrane require unpleasant reaction conditions and complex procedures. Motivated by the need of an economical purification method in the downstream processing of therapic proteins, we develop a simple approach to fabricate mixed mode membrane adsorbers. Nanofibrous membrane support was fabricated by electrospinning a blend of poly(styrene-co-maleic anhydride) (SMA) with polyvinylidene fluoride (PVDF). Mixed mode ligands were then immobilized on the membrane through the conversion of anhydride moieties by aminolysis with functional amines, n-butylamine (BAE), n-octylamine(OAE), N-methyl-d-glumine(NMG). The obtained mixed-mode membrane adsorbers, PVDFS-g-BAE, PVDFS-g-OAE, and PVDFS-g-NMG, which contain hydrophobic interaction/ion exchange, reverse phase interaction/ion exchange, and hydrophilic interaction/ion exchange interactions respectively, were used for protein separation. The success of modification was supported by FTIR and XPS, indirectly confirmed by WCA measurements. Static protein binding property was measured with several model proteins. The PVDFS-g-BAE membrane showed a capacity of 120 mg/mL for IgG and fair selectivity over BSA or Lym; The PVDFS-g-OAE membrane showed a capacity of 140 mg/mL for ɑ-CTP and high selectivity over CYT-C. In addition, the nanofibrous membrane has large total pore area, high porosity, and good mechanical property, which is sufficient for the demands of practical use.

Self-Assembly of Free-Standing LiMn2O4-Graphene Flexible Film for High-Performance Rechargeable Hybrid Aqueous Battery

A novel LiMn2O4-graphene flexible film is successfully prepared by facile vacuum filtration technique. LiMn2O4 nanowires with diameters of 50–100 nm are distributed homogeneously on graphene sheet matrix. Used as cathode in rechargeable hybrid aqueous batteries, the LiMn2O4-graphene film exhibits enhanced electrochemical performance in comparison to LiMn2O4-graphene powder. The LiMn2O4-graphene film shows stable 13.0 mAh g−1 discharge capacity after 200 cycles at 1.0 C, benefitting from the presence of graphene with strong conductivity and large pore area in this free-standing film. This synthetic strategy for a free-standing film can provide a new avenue for other flexible materials and binder-free electrodes.

Investigation of physiological components involved in low water conservation capacity of in vitro walnut plants

To obtain benefits of in vitro plant micropropagation, successful acclimatization to ex vitro atmosphere is always required. However, a huge number of in vitro-produced plants cannot survive during ex vitro acclimatization. This study aims to analyze the components that contribute to poor water conservation capacity of in vitro plants after exposure to ambient environment during ex vitro acclimation. Micropropagated shoots grown in vitro (in vitro plants) or after acclimation to greenhouse conditions (greenhouse plants) were microscopically and biochemically analyzed for differences in morphological and biochemical components. Furthermore, dynamic responses of leaves to ex vitro condition were gravimetrically analyzed during 1.5h desiccation. Compared with greenhouse plants, thinner leaves together with bigger stomata with larger pore area, higher stomatal and epidermal densities were observed in in vitro plants. Plants cultured in vitro kept very high transpiration rate despite of dramatic decrease in leaf RWC during desiccation. Contribution of stomata was more pronounced than the role of cuticule in leaf water loss. Higher concentrations of proline and glycine betaine were observed in the leaves of in vitro plants. Higher (less negative) osmotic potential (ψs) in the leaves of in vitro plants was concurrent with lower levels of potassium and calcium in their leaves. In conclusion, higher compatible solute level in the leaf of in vitro plant does not contribute to water conservation during ex vitro acclimation and low foliar ion levels in in vitro plants can be due to low transpiration rate in plants as a result of in vitro production.

Molecular simulation of methane adsorption in shale based on grand canonical Monte Carlo method and pore size distribution

To explore the influence of the pore size distribution on the methane adsorption capacity of shale, methane adsorption amount for different pore sizes has been calculated by using the simulation results and pore size distribution data. In the study, excess adsorption per unit area of different pore sizes has been simulated by the grand canonical Monte Carlo (GCMC) method. And the pore size distribution of Longmaxi Formation shale samples was characterized by high pressure mercury injection (HPMI) experiment, low pressure nitrogen adsorption (LP-N2-GA) experiment, and low pressure CO2 adsorption (LP-CO2-GA) experiment. The results indicate that in the range of 0.5–1.5 nm, the excess adsorption per unit area shows a stepped increase with the pore size increasing. When the pore size is larger than 1.5 nm, the excess adsorption per unit area keep unchanged with the increase in pore size. According to the methane adsorption capacity and pore surface area, pores in the shale samples can be divided to three parts: <1 nm, 1–4 nm, >4 nm. Pores in the first part (width <1 nm) have a large specific surface area, but the excess adsorption per unit area is much smaller than other pores. They account for about 65% of the total specific surface area, while accounting for only 48% of the total adsorption amount. Pores in the second part (1–4 nm) have a large specific pore area and large methane adsorption capacity. They provide 30% of the total specific surface area, while providing 44% of the total adsorption amount. Pores in the third part (width >4 nm) contribute only 8% of total adsorption amount as the specific surface area of these pores is notably small.

Stomatal malfunctioning under low VPD conditions: induced by alterations in stomatal morphology and leaf anatomy or in the ABA signaling?

Exposing plants to low VPD reduces leaf capacity to maintain adequate water status thereafter. To find the impact of VPD on functioning of stomata, stomatal morphology and leaf anatomy, fava bean plants were grown at low (L, 0.23 kPa) or moderate (M, 1.17 kPa) VPDs and some plants that developed their leaves at moderate VPD were then transferred for 4 days to low VPD (M→L). Part of the M→L-plants were sprayed with ABA (abscisic acid) during exposure to L. L-plants showed bigger stomata, larger pore area, thinner leaves and less spongy cells compared with M-plants. Stomatal morphology (except aperture) and leaf anatomy of the M→L-plants were almost similar to the M-plants, while their transpiration rate and stomatal conductance were identical to that of L-plants. The stomatal response to ABA was lost in L-plants, but also after 1-day exposure of M-plants to low VPD. The level of foliar ABA sharply decreased within 1-day exposure to L, while the level of ABA-GE (ABA-glucose ester) was not affected. Spraying ABA during the exposure to L prevented loss of stomatal closing response thereafter. The effect of low VPD was largely depending on exposure time: the stomatal responsiveness to ABA was lost after 1-day exposure to low VPD, while the responsiveness to desiccation was gradually lost during 4-day exposure to low VPD. Leaf anatomical and stomatal morphological alterations due to low VPD were not the main cause of loss of stomatal closure response to closing stimuli.

The ethylbenzene hydrogenation over Ni–H3PW12O40/SiO2 in the presence of thiophene

Ni–HPW/SiO2 catalysts with H3PW12O40 (HPW) loading in the range of 0.1–8% were prepared by a modified sol–gel method. The as-prepared catalysts with bimodal pore distribution not only possess relatively large pore and surface area, but exhibit high activity for ethylbenzene hydrogenation even in the presence of thiophene up to 640ppm. It is evident that nickel oxide particles are small and well-dispersed on the surface of these catalysts from X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) characterization. The results of temperature-programmed reduction of hydrogen (H2-TPR), temperature-programmed desorption of hydrogen and ammonia (H2 and NH3-TPD) also strongly suggest the interaction between Ni component and HPW takes place, and consequently results in remarkable H2 spillover and considerable increase of acidic site concentration of Ni–HPW/SiO2 catalysts. Further, the results of Fourier transform infrared spectroscopy (FT-IR) with pyridine adsorption also show that most of the acid sites are related to Lewis acid and the metal Ni species on the surface of catalysts are therefore prone to be electron-deficient. It is confirmed that HPW plays a critical role in the improvement of sulfur resistance for Ni-based catalysts.

Bioprocess intensification in flow‐through monolithic microbioreactors with immobilized bacteria

Microporous polymers (with porosity up to 90%) with a well-prescribed internal microstructure were prepared in monolithic form to construct a flow-through microbioreactor in which phenol-degrading bacteria, Pseudomonas syringae, was immobilized. Initially, bacteria was forced seeded within the pores and subsequently allowed to proliferate followed by acclimatization and phenol degradation at various initial substrate concentrations and flow rates. Two types of microporous polymer were used as the monolithic support. These polymers differ with respect to their pore and interconnect sizes, macroscopic surface area for bacterial support, and phase volume. Polymer with a nominal pore size of 100 microm with phase volume of 90% (with highly open pore structure) yielded reduced bacterial proliferation, while the polymer with nominal pore size of 25 microm with phase volume of 85% (with small interconnect size and large pore area for bacterial adhesion) yielded monolayer bacterial proliferation. Bacteria within the 25 microm polymer support remained monolayered, without any apparent production of extracellular matrix during the 30-day continuous experimental period. The microbioreactor performance was characterized in terms of volumetric utilization rate and compared with the published data, including the case where the same bacteria was immobilized on the surface of microporous polymer beads and used in a packed bed during continuous degradation of phenol. It is shown that at similar initial substrate concentration, the volumetric utilization in the microreactor is at least 20-fold more efficient than the packed bed, depending on the flow rate of the substrate solution. The concentration of the bacteria within the pores of the microreactor decreases from 2.25 cells per microm2 on the top surface to about 0.4 cells per microm2 within 3 mm reactor depth. If the bacteria-depleted part of the microreactor is disregarded, the volumetric utilization increases by a factor of 30-fold compared with the packed bed. This efficiency increase is attributed to the reduction of diffusion path for the substrate and nutrients and enhanced availability of the bacteria for bioconversion in the absence of biofilm formation as well as the presence of flow over the surface of the monolayer bacteria.

Copper/MCM-41 as catalyst for the wet oxidation of phenol

A heterogeneous copper catalyst supported on mesoporous MCM-41 was developed. The parent MCM-41 has a large pore area of over 1400m2/g. Copper was chosen as the active element of catalyst and loaded into MCM-41 by adsorption at ambient temperature. The prepared catalysts were evaluated in the catalytic wet oxidation of phenol solution with an initial concentration of 1,300ppm at 150 and 200°C. The catalyst was found to be of high catalytic activity. It is also shown that the catalyst with a higher copper loading exhibits higher ability of accelerating the catalytic reaction to certain extent but reaches its constant level afterwards.

Glomerular size and charge selectivity in insulin-dependent diabetes mellitus

The pathogenesis of clinical nephropathy in Type 1 (insulin-dependent) diabetes was investigated by measuring renal fractional clearances of albumin, total IgG, IgG4 and beta 2-microglobulin, four plasma proteins which differ in size and charge. Seventy patients and eleven control subjects were studied. In diabetic patients with normal urinary albumin excretion (less than 30 mg/24 hr), fractional IgG clearance was two to three times higher than in control subjects, whereas fractional clearance of the anionic plasma proteins IgG4 and albumin was similar to that of control subjects. These alterations indicate an increase in anionic pore charge within the glomerular basement membrane concomitant with an increase in either pore size or impairment of tubular reabsorption. Diabetic patients, whose urinary albumin excretion has started to rise (30 to 100 mg/24 hr), had unchanged fractional IgG compared to patients with normal albumin excretion, while fractional IgG4 and albumin clearances were increased three- to fourfold; indicating unchanged glomerular pore size, but a decrease in anionic pore charge. In patients demonstrating urinary albumin excretion of greater than 100 mg/24 hr fractional IgG clearance increased to the same extent as fractional albumin clearance, indicating an increase in large pore area. Fractional beta 2-microglobulin clearances were similar to that of control subjects in the different patient groups indicating unchanged tubular reabsorption of proteins. Thus, the increase in large pore area seen in patients with clinical nephropathy is preceded by loss of anionic charge in the glomerular basement membrane. It is likely that this loss of anionic charge is due to loss of heparan sulphate-proteoglycan.