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PubMed2006

Stabilization/solidification of hazardous and radioactive wastes with alkali-activated cements.

This paper reviews progresses on the use of alkali-activated cements for stabilization/solidification of hazardous and radioactive wastes. Alkali-activated cements consist of an alkaline activator and cementing components, such as blast furnace slag, coal fly ash, phosphorus slag, steel slag, metakaolin, etc., or a combination of two or more of them. Properly designed alkali-activated cements can exhibit both higher early and later strengths than conventional portland cement. The main hydration product of alkali-activated cements is calcium silicate hydrate (CSH) with low Ca/Si ratios or aluminosilicate gel at room temperature; CSH, tobmorite, xonotlite and/or zeolites under hydrothermal condition, no metastable crystalline compounds such as Ca(OH)(2) and calcium sulphoaluminates exist. Alkali-activated cements also exhibit excellent resistance to corrosive environments. The leachability of contaminants from alkali-activated cement stabilized hazardous and radioactive wastes is lower than that from hardened portland cement stabilized wastes. From all these aspects, it is concluded that alkali-activated cements are better matrix for solidification/stabilization of hazardous and radioactive wastes than Portland cement.

Alkalies↗
PubMed1996

Appearance of immune cells and expression of MHC II DQ molecule by fibroblasts in alkali-burned corneas.

Corneal alkali burns are characterized by persistent inflammatory response and recurrent epithelial erosions. We examine whether immune cell types, i.e., T-cells and B-cells, play a role in this devastating process. Rabbit alkali-burned corneas that healed for 1-49 days were subjected to immunostaining with monoclonal antibodies (mAb) L11/135 (anti-T-cells), and 2C4 (anti-MHC II DQ). Serum was collected weekly and subjected to Western blot immunostaining to detect antibodies against denatured corneal proteins. Our observations demonstrated that all injured corneas reepithelialized within 3 days but then developed recurrent erosions. Immunohistochemical studies revealed that PMN, monocytes, and B-cells labeled by 2C4 mAb and T-cells labeled by L11/135 mAb appeared in the periphery to the cornea at 1 day after alkali burn. Many of these myeloid and lymphoid cells invaded the central stroma after 2 weeks of injuries when the alkali-burned corneas were heavily vascularized. In addition, some fibroblastic cells also expressed the MHC II DQ molecules in the alkali-burned corneas that had healed for > 2 weeks. Plasma cells appeared in granulation tissue of injured corneas that had healed for > 3 weeks. Western blot analysis demonstrated a production of heterogeneous antibodies in a majority of the rabbits (11 of 14) to various denatured corneal proteins (between 80 kDa and 25 kDa) at 5 weeks of alkali burn. Inflammatory cell types, i.e., PMN, macrophages could be found underneath the detached epithelium. These observations are consistent with the notion that the myeloid and lymphoid cells may participate in and complicate the healing of corneal alkali burns.

Alkalies↗
PubMed1983

Effects of non-steroidal anti-inflammatory drugs and prostaglandins on alkali secretion by rabbit gastric fundus in vitro.

The effects of non-steroidal anti-inflammatory drugs and prostaglandins E(2) and F(2alpha) on the secretory and electrical activity of isolated rabbit fundic mucosa have been studied. Spontaneous acid secretion was inhibited by serosal side application of sodium thiocyanate (6x10(-2)M) and the resulting alkali secretion measured by pH stat tiration. Serosal side application of indomethacin (10(-5)M) or aspirin (3x10(-3)M) inhibited alkali secretion (0.55+/-0.06 to 0.12+/-0.06 mumol/cm(2)/h, n=6, p<0.01 and 0.28+/-0.06 to 0.11+/-0.03 mumol/cm(2)/h, n=7, p<0.02 respectively). Mucosal or serosal side prostaglandin E(2) (10(-5) to 10(-10)M) and F(2alpha) (10(-4) to 10(-10)M) failed to alter the rate of alkalinisation but secretion was significantly increased by serosal side 16,16-dimethyl-prostaglandin E(2) (10(-6)M) (0.90+/-0.20 to 1.50+/-0.30 mumol/cm(2)/h, n=6, p<0.01). Serosal side application of 10(-6)M prostaglandin E(2) to fundic mucosae pretreated with either aspirin (5x10(-3)M) or indomethacin (10(-5)M), to reduce endogenous E(2) formation, also failed to alter alkali secretion. Pretreatment of the mucosa with 16,16-dimethyl-E(2) (10(-6)M) abolished the inhibitory effect of indomethacin (10(-5)M) on alkali secretion (n=6) but did not modify the secretory response to aspirin (3x10(-3)M) (fall in alkali secretion with aspirin = 81+/-11% and with aspirin plus 16,16-dimethyl-E(2) = 72+/-10%, n=7). In the doses used, none of the prostaglandins or non-steroidal anti-inflammatory drugs altered transmucosal potential difference or electrical resistance. These results show that the damaging agents, aspirin and indomethacin, both inhibit gastric alkali secretion but that modes of action may differ. The observation that prostaglandins, E(2) and F(2alpha) failed to increase alkali production suggests that their protective activity against a variety of damaging agents as shown by others, may be mediated by another mechanism.

Alkalies↗
PubMed2004

Effect of alkali pretreatment of wheat straw on the efficacy of exogenous fibrolytic enzymes.

The effects of pretreating wheat straw with alkali on the efficacy of exogenous fibrolytic enzymes for improving straw digestibility were studied in vitro, in situ, and in vivo. In Exp. 1, untreated straw (US); alkali-treated (5% NaOH, wt/wt) straw (AS); and autoclaved, alkali-treated straw (AAS) were sprayed with 0 or 1.5 mg/g DM of enzyme mix (xylanase, beta-glucanase, carboxymethylcellulase, and amylase) and incubated for 30 h in buffered ruminal fluid (3 x 2 factorial arrangement). Enzymes increased (P < 0.001) gas production and the incorporation of 15N into microbial N at 4 h, more so with AS or AAS than with US (P < 0.001 for gas; P < 0.05 for 15N). In Exp. 2, US and AS were sprayed with enzymes at 0, 0.15, or 1.5 mg/g DM (2 x 3 factorial) and incubated ruminally in nylon bags for up to 80 h to determine the in situ DM disappearance (ISDMD). Interactive effects (P < 0.05) of pretreatment and enzymes were observed on all ruminal degradation parameters. Alkali increased the rate (P < 0.01) and extent (P < 0.001) of ISDMD irrespective of enzymes. Enzymes applied to US did not affect the extent of ISDMD, but they increased (P < 0.01) the extent of ISDMD when applied to AS. Substrates from Exp. 1 and 2 were incubated in acetate buffer for 24 h to measure the hydrolytic loss of DM and release of reducing sugars and phenolic compounds. Alkali pretreatment and enzymes each increased (P < 0.001) DM loss and the release of reducing sugars and, in combination, exerted synergistic effects (P < 0.001). Enzymes did not affect the release of phenolic compounds from the straw. In Exp. 3, total-tract digestibility of untreated and enzyme-treated (100 mL/kg DM) ammoniated straw was assessed using 32 beef cows in eight pens. Wrapped straw bales were injected with NH3 (3% [wt/wt], DM basis) 4 mo before the study; enzymes were applied immediately before feeding. Applying enzyme to ammoniated straw increased (P < 0.05) digestibilities of DM, OM, and total N but did not affect the intake of DM or digestibility of ADF. Pretreatment of straw with alkali enhanced the efficacy of exogenous enzymes, presumably by breaking esterified bonds and releasing phenolic compounds and/or by swelling the crystalline cellulose and enhancing enzyme penetration. Including enzymes that mimic alkali hydrolysis (e.g., esterases) in commercial feed additives could substantially improve the value of these products for ruminants.

Alkalies↗
PubMed2001

Anaylsis of birefringence during wound healing and remodeling following alkali burns in rabbit cornea.

The use of synthetic inhibitors of metalloproteinases (SIMP) or medroxyprogesterone (MP) can prevent or significantly delay the ulceration of alkali-injured corneas by influencing collagen degradation. We have examined the remodeling of rabbit corneal stroma following alkali injury and have assessed the effect of SIMP and MP treatment. Following a defined alkali injury to the rabbit cornea, animals were divided into three subgroups, one group treated with topical beta-mercaptomethyl tripeptide (SIMP), one treated by subconjunctival injection of MP and one treated with a control solution. The corneal tissue was taken at 3 days, 1, 2, 3, 4, 9 and 26 weeks after alkali injury and prepared for light microscopy and transmission electron microscopy (TEM). A quantitative measurement of birefringence, in terms of the optical path difference (OPD), was made using a modified polarized microscopy technique based on the analysis of interference colours. The results showed that SIMP effectively prevented deep corneal ulceration. MP could delay the ulceration and the corneas treated with MP appeared to have better transparency than the other groups. There was a significant difference of the OPD between the anterior (5.8 +/-0.3 nm) and posterior (7.8 +/-0.4 nm) stroma of the normal cornea (P<0.001). The OPD values from the central corneas from alkali-injured eyes were generally lower than normal during the first 4 weeks and then gradually recovered to the normal level or above, except for the posterior stroma of the MP-treated eyes. We found that the OPD changes were very dependent on the presence of corneal lesions. The stroma near corneal ulceration, scar tissue, calcified stroma and the retro-corneal collagen layer showed a significant reduction of birefringence (lower OPD values). These OPD values remained much lower than normal up to the end of the experiment. TEM showed disrupted corneal stroma in all three groups, with thinner scar tissue in the MP group. The fibril diameters did not change significantly 3 days and 1 week after the alkali burns (27.1+/-2.3 nm in the control group, 27.3+/-2.2 nm in the SIMP group and 27.7+/-2.1 nm in the MP group) and there were no differences compared with 29.7+/-1.7 nm of the normal cornea (P>0.05). After 2 weeks of tissue remodeling, the fibril diameters in alkali-injured corneas showed a large variation (the range was between 11.5 and 80 nm) with a bimodal distribution, especially in the control group. The technique presented here for birefringence evaluation can provide an alternative way to monitor wound healing and tissue remodeling, both visually and quantitatively.

Animals↗
PubMed1989

Sequence and expression of human myosin alkali light chain isoforms.

In order to initiate the study of the functional differences between myosin alkali light chain isoforms and to investigate the mechanisms of their differential expression, we have isolated cDNA clones for two human alkali light chain isoforms. Here we report DNA sequence and RNA blotting analyses that demonstrate that these cDNAs represent transcripts encoding human MLC3F and MLC1Sb. The sequence of the human MLC1Sb cDNA offers the first fully characterized example of a slow-fiber skeletal muscle alkali light chain isoform from any species. The sequence analysis of these two cDNAs allows an examination of evolutionarily conserved features of mammalian alkali light chain genes. Examination of the genomic organization of the human alkali light chain isoform genes revealed that, in contrast with some strains of mice, both are single copy genes. RNA blot analysis conclusively demonstrates that the human skeletal muscle MLC1Sb gene is also expressed in the heart ventricle but not the atria. In addition, we examined the expression of alkali light chain isoforms during the in vitro differentiation of a variety of human and rodent myogenic cells and found striking variation in the pattern of alkali light chain isoform gene expression in different myogenic cells.

Amino Acid Sequence↗
PubMed1994

Molecular dynamics, phase diagrams and electronic properties of fullerenes and alkali fullerides: insights from solid-state nuclear magnetic resonance spectroscopy.

Solid-state nuclear magnetic resonance (NMR) measurements have made important contributions to the current understanding of the structural, dynamical, and electronic properties of fullerenes (C60 and C70) and the alkali fullerides AxC60 (A = alkali metal). These measurements and their interpretation are reviewed. One- and two-dimensional 13C NMR lineshapes and spin-lattice relaxation rates provide evidence for rapid molecular rotations and orientational order-disorder transitions in the fullerenes and alkali fullerides. The kinetics of molecular reorientations are determined from the NMR data. 13C and alkali metal NMR spectra indicate that the alkali fullerides are stoichiometric compounds. Each stable, stoichiometric phase has distinctive NMR signatures. 13C and alkali metal NMR spectra and relaxation measurements provide valuable and unique information about the electronic properties of the metallic, superconducting, and non-metallic phases of the alkali fullerides.

Carbon↗
PubMed2005

In vivo evaluation of plasma-sprayed titanium coating after alkali modification.

In this paper, plasma-sprayed titanium coatings were modified by alkali treatment. The changes in chemical composition and structure of coatings were examined by SEM and AES. The results obtained indicated that a net-like microscopic texture feature, which was full of the interconnected fine porosity, appeared on the surface of alkali-modified titanium coatings. The surface chemical composition was also altered by alkali modification. A sodium titanate compound was formed on the surface of the titanium coating and replaced the native passivating oxide layer. Its thickness was measured as about 150 nm which was about 10 times of that of the as-sprayed coating. The bone bonding ability of titanium coatings were investigated using a canine model. The histological examination and SEM observation demonstrated that more new bone was formed on the surface of alkali-modified implants and grew more rapidly into the porosity. The alkali-modified implants were found to appose directly to the surrounding bone. In contrast, a gap was observed at the interface between the as-sprayed implants and bone. The push-out test showed that alkali-modified implants had a higher shear strength than as-sprayed implants after 1 month of implantation. An interfacial layer, containing Ti, Ca and P, was found to form at the interface between bone and the alkali-modified implant by EDS analysis.

Alloys↗
PubMed2004

Alkali extraction of beta-d-glucans from Saccharomyces cerevisiae cell wall and study of their adsorptive properties toward zearalenone.

The isolated cell wall of Saccharomyces cerevisiae has some capacity to adsorb zearalenone (affinity near 30%) and reduce the bioavailability of toxins in the digestive tract. The adsorption process was quantified in vitro, and the data obtained when plotted with Hill's equation indicated a cooperative process. The model showed that the adsorption capacity was related to the yeast cell wall composition. This work focused on the role of various beta-d-glucan types in the efficacy of zearalenone adsorption by yeast cell wall and sought to elucidate some of the adsorption mechanisms. Zearalenone was mixed at 37 degrees C with a constant quantity of alkali-soluble or alkali-insoluble beta-d-glucans isolated from yeast cell walls, and the amount of adsorbed zearalenone was measured. Given that the alkali solubility of beta-d-glucans is a determining factor for their three-dimensional conformation and that the alkali-insoluble fraction had a greater affinity (up to 50%) than the alkali-soluble fraction ( approximately 16%), it was concluded that the three-dimensional structure strongly influences the adsorption process. The alkali insolubility of beta-d-glucans led to the formation of single and/or triple helices, which have been identified as the most favorable structures for zearalenone adsorption efficacy. The beta(1,3)-d-glucan and beta(1,6)-d-glucan compositions of the two alkali-extracted fractions and their involvement in the adsorption process are discussed.

Adsorption↗
PubMed2006

Comparative first-principles study of structural and optical properties of alkali metal azides.

A comparative first-principles study of the structural and optical properties of the alkali metal azides has been performed with density functional theory within the generalized gradient approximation. The crystal structures of the alkali azides compare well with experimental data. Their ionic character is manifested by the closeness of their internitrogen distances to the calculated N-N bond length for the free azide ion. An analysis of electronic structure, charge transfer, and bond order shows that the alkali azides are all wide-gap insulators and ionic compounds. The energy band and density of states for lithium azide and alpha-sodium azide are very similar, while these for potassium azide, alpha-rubidium azide, and alpha-cesium azide are alike, but some modifications are observed with the increment of alkali metals' electropositivity. These changes are closely related to the differences of the crystal structures. The general shapes of the real and imaginary parts of the dielectric function, adsorption coefficient, and electron energy-loss spectra are quite similar. The peaks originate from the electron transitions from the alkali metal s and p states to the conduction band. Our calculated optical properties for the alkali azides are found to be in good agreement with available experimental data. The absorption spectra of the alkali azides show a number of absorption peaks, which are believed to be associated with different exciton states, in the fundamental absorption region. In general, the electron energy-loss spectra have two plasma frequencies.

Journal Article↗
PubMed2001

In vitro and in vivo evaluation of e-PTFE and alkali-cellulose membranes for guided bone regeneration.

Guided bone regeneration (GBR) is employed to encourage the formation of new bone in osseous defects by restricting the infiltration of soft tissues. While a variety of membranes have been evaluated for this surgical procedure, the non-resorbable material of choice is currently expanded polytetrafluoroethylene (e-PTFE). A new alkali-cellulose membrane produced by a biotechnological process has been developed as an alternative to e-PTFE for GBR. In this study, the biocompatibility of this novel alkali-cellulose membrane and e-PTFE was compared using tissue culture and an in vivo GBR model. In vitro both materials supported the attachment, migration and differentiation of osteoblast-like cells in culture for up to 3 weeks. The in vivo model was based upon full-thickness transcortical bone defects in the mandibular rami of Sprague-Dawley rats. The right rami were used as controls, contralateral defects being covered bucally and lingually with either e-PTFE or alkali-cellulose membranes. Pathological and histomorphometric analysis was undertaken at 4 and 10 weeks post-implantation. Bone regeneration associated with alkali-cellulose membranes was predominantly endochondral in type in contrast to e-PTFE which induced direct bone formation (intramembranous ossification). The amount of new bone formed in defects was similar for both types of membrane, but alkali-cellulose membranes induced significantly greater inflammatory response; characterized by lymphocytes, macrophages and multinucleated giant cells. Degradation and possible exposure of individual cellulose fibres may account for the poor performance of alkali-cellulose membranes in vivo. This animal and in vitro study indicates that when choosing a non-resorbable membrane for GBR, e-PTFE membranes are likely to perform better than those produced from alkali-cellulose.

Alveolar Bone Loss↗
PubMed2006

Why alkali metals preferably bind on structural defects of carbon nanotubes: a theoretical study by first principles.

By using ab initio calculations we investigated the interaction of alkali metal atoms and alkali metal cations with perfect and defective carbon nanotubes. Our results show that the alkali metals prefer to interact with the pentagons and heptagons that appear on the defective site of the carbon nanotube rather than with the hexagons. The alkali metals remain always positively charged not depending on their charge state (neutral, cation) or the different carbon ring that they interact with. The molecular orbital energy level splitting from a defect creation on the carbon nanotube along with the localization of charge-electron density on the defect, results in binding the alkali metals more efficient. More interestingly, metallic sodium appears to bind very weak on the nanotube compared to the rest of alkali metals. The Na anomaly is attributed to the fact that unlike the K case, sodium's inner p shell falls energetically lower than carbon nanotube's p molecular orbitals. As a result, the Na p shell is practically excluded from any binding energy contribution. In the alkali metal cation case the electronegativity trend is followed.

Journal Article↗
PubMed1993

Alkali-degraded cells generate a respiratory burst stimulant for neutrophils.

Alkali treatment of whole cornea produces a high molecular weight polypeptide causing a respiratory burst in neutrophils. The current study was conducted to determine if this stimulant could be elicited from cultured or scraped corneal cells (epithelium, keratocytes, or endothelium). Fresh or previously frozen epithelium, endothelium, and stroma were isolated from bovine eyes, alkali treated, and tested for the presence of the respiratory burst stimulant. The same procedure was performed on cultured bovine epithelium, keratocytes, and endothelium. To determine if the stimulant is specific to corneal cells, the component parts of human blood (cellular and extracellular) were separated, treated with alkali, and tested individually. Activation of the respiratory burst of polymorphonuclear leukocytes (PMNs) was used as a marker for the presence of the stimulant. All alkali-degraded cell samples, except red blood cells, produced a respiratory burst when added to viable PMNs. Alkali-treated plasma induced weak stimulation. Bovine corneal epithelium was alkali-treated and separated by high-performance liquid chromatography (HPLC) according to molecular size. The stimulant was shown to have a high molecular weight by its recovery in HPLC fraction number 7. These results demonstrate that the PMN stimulant originates from cells. This PMN stimulant is proposed as an inflammatory mediator in the alkali-injured cornea.

Animals↗
PubMed1976

Hyaline membrane disease, alkali, and intraventricular haemorrhage.

The relation between intraventricular haemorrhage (IVH) and hyaline membrane disease (HMD) was studied in singletons that came to necropsy at Hammersmith Hospital over the years 1966-73. The incidence of IVH in singleton live births was 3-22/1000 and of HMD 4-44/1000. Although the high figures were partily due to the large number of low birthweight infants born at this hospital, the incidence of IVH in babies weighing 1001-1500 g was three times as great as that reported in the 1658 British Perinatal Mortality Survey. Most IVH deaths were in babies with HMD, but the higher frequency of IVH was not associated with any prolongation of survival time of babies who died with HMD as compared with the 1958 survey. IVH was seen frequently at gestations of up to 36 weeks in babies with HMD but was rare above 30 weeks' gestation in babies without HMD. This indicated that factors associated with HMD must cause most cases of IVH seen at gestations above 30 weeks. Comparison of clinical details in infants with HMD who died with or without IVH (at gestations of 30-37 weeks) showed no significant differences between the groups other than a high incidence of fits and greater use of alkali therapy in the babies with IVH. During the 12 hours when most alkali therapy was given, babies dying with IVD received a mean total alkali dosage of 10-21 mmol/kg and those dying without IVH 6-34 mmol/kg (P less than 0-001). There was no difference in severity of hypoxia or of metabolic acidosis between the 2 groups. Babies who died with HMD and germinal layer haemorrhage (GLH) without IVH had received significantly more alkali than those who died with HMD alone, whereas survivors of severe respiratory distress syndrome had received lower alkali doses than other groups. It is suggested that the greatly increased death rate from IVH in babies with HMD indicates some alteration of management of HMD (since 1958) as a causative factor. Liberal use of hypertonic alkali solutions is the common factor which distinguishes babies dying with GLH and IVH from other groups of babies with HMD. Although the causal nature of this association remains unproved, it seems justifiable to lrge caution in alkali usage.

Acid-Base Equilibrium↗
PubMed1992

The effects of heat, water, acid, and alkali treatment of tomato cannery wastes on growth, metabolizable energy value, and nitrogen utilization of broiler chicks.

Two experiments were conducted to determine the effects of heat, water, acid, and alkali treatment of tomato pomace on gain, feed to gain ratio, nitrogen utilization, and ME of diets for broiler chicks. In Experiment 1, both treated and untreated tomato pomace was included in broiler diets at a 10 or 20% level. Results indicated that the level or antinutritional factors present in untreated tomato cannery waste did not appreciably depress any measured production parameter. Hence, it appeared that untreated tomato cannery wastes might be used as a feed ingredient in low-energy poultry diets (broiler breeder and laying hen recycling rations), ruminant diets, and as a protein source in regions of the world where such feed ingredients are scarce. The second experiment was designed to test the effect of alkali concentration and treatment time of tomato pomace on the performance of broiler chicks. Alkali treatment of tomato cannery wastes increased gain and decreased feed to gain ratios of broiler chicks over those of untreated tomato waste controls. Results indicated that the increased gain and decreased feed to gain ratios of the chicks were due in part to the acid neutralization phase of the alkali treatment. Alkali treatment apparently affects the tomato cannery wastes almost instantaneously, as differences among actual treatment times and concentrations were small. However, only the highest alkali treatment increased the pH of the tomato cannery waste above 7, suggesting that a true alkali treatment might cause additional improvements in gain and feed to gain ratio when fed to broiler chicks.

Animal Feed↗
PubMed1982

The milk-alkali syndrome: current concepts.

The milk-alkali syndrome was first identified in 1923, and continues to occur in patients ingesting large amounts of calcium and absorbable alkali, particularly as calcium carbonate. Hypercalcemia, alkalosis, and renal impairment remain hallmarks of the syndrome, which may occur in acute, subacute, and chronic forms. Although the pathophysiology of the milk-alkali syndrome has not been completely studied, it appears to involve complex interactions between ingested calcium and alkali resulting in an impairment in renal calcium and bicarbonate excretion. The diagnosis of the milk-alkali syndrome is based on a history of calcium and alkali ingestion, the presence of characteristic clinical and laboratory features, and the exclusion of other causes of hypercalcemia. Conservative treatment, including discontinuing calcium and alkali ingestion and supportive measures, is usually effective.

Alkalosis↗
PubMed2003

[Physiological response to salt-alkali stress in experimental populations in two ecotypes of Leymus chinensis in the Songnen Plains of China].

The comparative study of physiological reaction to salt, alkali and mixed salt stresses in two ecotypes of grey-green and yellow-green of Leymus chinensis were made. At the stage of seedling, the content of chlorophyll and the leakage rate of electrolyte of leaves, free proline, Na/K of tillers were determined in planting containers with sands in two ecotypes by stress of salt, alkali and mixed salt of different concentrations. The results of quantitative analysis showed that the relationships between the content of chlorophyll and the leakage rate of electrolyte of leaves, free proline, Na/K of tillers and concentration of salt, alkali and mixed salt could expressed as linear equation, which were significant or obviously significant. There were capabilities of salt-alkali resistance in the physiological characteristics of two populations, but the capabilities of salt-alkali resistance were stronger in grey-green ecotype than in yellow-green ecotype. The differentiation of the content of chlorophyll, the leakage rate of electrolyte of leaves, free proline and Na/K of tillers were significant or obviously significant in two ecotypes under three kinds of salt stress. Physiological characteristics of salt-alkali resistance were significantly different in two ecotypes. The study provided physiological evidence for making sure that the main ecological factor was salt-alkali. It resulted in adaptive differentiation in Leymus chinensis ecotypes.

Carbonates↗
PubMed2004

[Effect of lamellar keratoplasty time on the production of serum specific antibody in corneal alkali burns].

OBJECTIVE: To observe the production of serum specific anti-denatured corneal antibody and the effects of lamellar keratoplasty on changes of corneal histopathology in different stages after alkali burns. METHODS: 20 male New Zealand rabbits, with alkali burns in right eye were randomly divided into 5 groups including: burned group; 2 early lamellar keratoplasty group (operation at 3 or 7 days post alkali burns respectively); 2 middle and later lamellar keratoplasty groups (operation at 2 or 5 weeks after alkali burns respectively). The level of serum specific antibody in each group was detected by ELISA and the corneal structure was evaluated by light and electron microscopy in different stages after alkali burns. RESULTS: The anti-denatured corneal antibody was induced after corneal alkali burns. The level of antibody significantly increased at 2th week post, peaking burn at 5 or 6th week, then decreasing. More antibodies were detected when contralateral eye was burn at 8 week post first burn. However, only slight increasing antibody was detected in early lamellar keratoplasty group. Furthermore, no significant changes of antibody production were observed in middle and later lamellar keratoplasty group. The light and electron microscopic analysis showed that, the corneal epithelium recovered better, the fibre of corneal stroma arranged better, inflammatory cells infiltrated less and neovascularization formed less in lamellar keratoplasty groups comparing to the burned group. The early lamellar keratoplasty groups recovered better than in middle and later lamellar keratoplasty groups. CONCLUSION: Early lamellar keratoplasty after corneal alkali burns can significantly decrease the immune response. Histopathological data also indicate that early lamellar keratoplasty can improve the tissue regeneration and recovery, prevent topical inflammatory reaction, and abate corneal neovascularization. This study suggests that early lamellar keratoplasty is more effective than the conservative treatment.

Animals↗