Disodium Phosphate Solution Research Articles

Chemotropic vs Hydrotropic Stimuli for Root Growth Orientation in Microgravity.

Understanding how plants respond to spaceflight and extraterrestrial environments is crucial to develop life-support systems intended for long-term human explorations. Gravity is a main factor influencing root development and orientation, typically masking other tropisms. Considering that reduced levels of gravity affect many plant responses in space, the interaction of other tropic stimuli in microgravity represents the frontier to be investigated aiming at life-support systems optimization. In this paper we report on MULTITROP (Multiple-Tropism: interaction of gravity, nutrient and water stimuli for root orientation in microgravity), an experiment performed on the International Space Station during the Expedition 52/53. Scientific aim of the experiment was to disentangle hydrotropism from chemotropism for root orientation in absence of the gravity stimulus. Among several species relevant to space farming, Daucus carota was selected for the experiment because of its suitability with the experimental hardware and setup. At launch site, carrot seeds were placed between two disks of inert substrate (one imbibed with water and the other with a disodium phosphate solution) and integrated into a hardware developed, refurbished and flight-certificated by Kayser Italia. Post-flight, a Ground Reference Experiment was performed. Root development and orientation of seedlings grown in microgravity and at 1g condition were measured through 3D-image analysis procedures after imaging with X-ray microtomography. Radicle protruded preferentially from the ventral side of the seed due to the asymmetric position of the embryo. Such a phenomenon did not prevent the achievement of MULTITROP scientific goal but should be considered for further experiments on radicle growth orientation in microgravity. The experiment conducted in space verified that the primary root of carrot shows a positive chemotropism towards disodium phosphate solution in the absence of the gravity stimulus. On Earth, the positive chemotropism was masked by the dominant effect of gravity and roots developed downward regardless of the presence/absence of nutrients in the substrate. Taking advantage of altered gravity conditions and using other chemical compounds, further studies should be performed to deepen our understanding of root chemotropic response and its interaction with other tropisms.

Pulmonary clearance kinetics and extrapulmonary translocation of seven titanium dioxide nano- and submicron materials following intratracheal administration in rats

We evaluated and compared the pulmonary clearance kinetics and extrapulmonary translocations of seven titanium dioxide (TiO2) nano- and submicron particles with different characteristics, including size, shape and surface coating. Varying doses of TiO2 nano- and submicron particles dispersed in 0.2% disodium phosphate solution were intratracheally administered to male F344 rats. The rats were euthanized under anesthesia for 3, 28 and 91 days after administration. Ti levels in pulmonary and various extrapulmonary organs were determined using inductively coupled plasma-sector field mass spectrometry (ICP-SFMS). The lungs, including bronchoalveolar lavage fluid (BALF), contained 55–89% of the administered TiO2 dose at 3 days after administration. The pulmonary clearance rate constants, estimated using a one-compartment model, were higher after administration of 0.375–2.0 mg/kg body weight (bw) (0.016–0.020/day) than after administration of 3.0–6.0 mg/kg bw (0.0073–0.013/day) for six uncoated TiO2. In contrast, the clearance rate constant was 0.011, 0.0046 and 0.00018/day following administration of 0.67, 2.0 and 6.0 mg/kg bw TiO2 nanoparticle with Al(OH)3 coating, respectively. Translocation of TiO2 from the lungs to the thoracic lymph nodes increased in a time- and dose-dependent manner. Furthermore, the translocation of TiO2 from the lungs to the thoracic lymph nodes after 91 days was higher when Al(OH)3 coated TiO2 was administered (0.93–6.4%), as compared to uncoated TiO2 (0.016–1.8%). Slight liver translocation was observed (<0.11%), although there was no clear trend related to dose or elapsed time. No significant translocation was observed in other organs including the kidney, spleen and brain.

Dose-dependent clearance kinetics of intratracheally administered titanium dioxide nanoparticles in rat lung.

AEROSIL(®) P25 titanium dioxide (TiO2) nanoparticles dispersed in 0.2% disodium phosphate solution were intratracheally administered to male F344 rats at doses of 0 (control), 0.375, 0.75, 1.5, 3.0, and 6.0 mg/kg. The rats were sacrificed under anesthesia at 1 day, 3 days, 7 days, 4 weeks, 13 weeks, and 26 weeks after administration. Ti levels in various pulmonary and extrapulmonary organs were determined using sensitive inductively coupled plasma sector field mass spectrometry. One day after administration, the lungs contained 62-83% of TiO2 administered dose. Twenty-six weeks after administration, the lungs retained 6.6-8.9% of the TiO2 administered at the 0.375, 0.75, and 1.5 mg/kg doses, and 13% and 31% of the TiO2 administered at the 3.0 and 6.0 mg/kg doses, respectively. The pulmonary clearance rate constants from compartment 1, k1, were estimated using a 2-compartment model and were found to be higher for the 0.375 and 0.75 mg/kg doses of TiO2 (0.030/day for both) than for TiO2 doses of 1.5-6.0 mg/kg (0.014-0.022/day). The translocation rate constants from compartment 1 to 2, k12, were estimated to be 0.015 and 0.018/day for the 0.375 and 0.75 mg/kg doses, and 0.0025-0.0092/day for doses of 1.5-6.0mg/kg. The pulmonary clearance rate constants from compartment 2, k2, were estimated to be 0.0086 and 0.0093/day for doses of 0.375 and 0.75 mg/kg, and 0-0.00082/day for 1.5-6.0 mg/kg doses. Translocation of TiO2 from the lungs to the thoracic lymph nodes increased in a time- and dose-dependent manner, accounting for 0.10-3.4% of the administered dose at 26 weeks. The measured thoracic lymph node burdens were a much better fit to the thoracic lymph node burdens estimated assuming translocation from compartment 1 to the thoracic lymph nodes, rather than those estimated assuming translocation from compartment 2 to the thoracic lymph nodes. The translocation rate constants from the lungs to the thoracic lymph nodes, kLung→Lym, were 0.000037-0.00081/day, and these also increased with increasing doses of TiO2. Although a small amount of TiO2 had translocated to the liver by 3 days after the administration (0.0023-0.012% of the highest dose administered, 6.0 mg/kg), translocation to the other extrapulmonary organs was not detected.

Optimisation of pectin extraction from sweet potato (Ipomoea batatas, Convolvulaceae) residues with disodium phosphate solution by response surface method

Summary Disodium phosphate solution was used for extracting pectin from sweet potato residues, and response surface methodology was adopted to optimise the effects of extraction parameters on the pectin yield (%, w/w). The independent variables were liquid/solid ratio, extraction time (h), extraction temperature (°C) and solution pH. The optimal conditions were determined, and 3-D response surface plot was plotted from the mathematical models. The results indicated that all four factors significantly affected the pectin yield in the following order: solution pH > extraction time > extraction temperature > liquid/solid ratio. The selected optimal extraction conditions were liquid/solid ratio 20:1, extraction time 3.3 h, extraction temperature 66 °C and solution pH 7.9. These conditions yielded about 10.24% of pectin vs. 10.27% for the predicted value. The degree of esterification and gel strength of extracted pectin with disodium phosphate solution in the optimised condition were 11.2% and 115.6 g, respectively.

Tilletia indica

<i>Tilletia indica</i>

Measurement of K-27, an oxime-type cholinesterase reactivator by high-performance liquid chromatography with electrochemical detection from different biological samples

K-27 is a bisquaternary asymmetric pyridinium aldoxime-type cholinesterase reactivator of use in the treatment of poisoning with organophosphorous esterase inhibitors. A sensitive, simple and reliable reverse-phase high-performance liquid chromatographic method with electrochemical detection was developed for the measurement of K-27 concentrations in rat brain, cerebrospinal fluid, serum and urine samples. Male Wistar rats were treated intramuscularly with K-27 and the samples were collected 60 min later. Separation was carried out on an octadecyl silica stationary phase and a disodium phosphate solution (pH 3.7) containing citric acid, octane sulphonic acid and acetonitrile served as mobile phase. Measurements were carried out at 30 °C at E ox 0.65 V. The calibration curve was linear through the range of 10–250 ng/mL. Accuracy, precision and the limit of detection calculated were satisfactory according to internationally accepted criteria. Limit of quantitation was 10 ng/mL. The method developed is reliable and sensitive enough for monitoring K-27 levels from different biological samples including as little as 10 μL of cerebrospinal fluid. The method – with slight modification in the composition of the mobile phase – can be used to measure a wide range of other related pyridinium aldoxime-type cholinesterase reactivators.

Physicochemical and Gelling Characterizations of Pectin Extracted from Sweet Potato Pulp

A novel pectin was extracted from sweet potato (Ipomoea batatas) pulp (SPP) using 50 mM disodium phosphate solution. Uronic acids in the pectin extract were almost completely removed from the supernatant after the addition of 0.3 volumes 95% ethanol. The sweet potato pectin consisted of 64.8% galacturonic acid and small amounts of neutral sugars. The ash concentration was 21.6% and sodium comprised 6.1 g per 100 g of the pectin. The degree of esterification of the pectin was 1.4%. The infrared spectrum of the pectin was similar to that of sodium polypectate. These results indicate that most of the carboxyl groups of the pectin are replaced by sodium. The pectin had average molecular-weights of approximately 7.85×105 and 2.42×105 Da. The viscosity was of the pectin (2%) the 130 mm2/s at 5°C. The effect of extrinsic parameters, such as pH and concentrations of pectin, calcium and sucrose, on the breaking pressure of the pectin gel was evaluated. The results of the breaking pressure analysis of the pectin gel indicate that the pectin has properties typical of low methoxyl pectin.

Effects of additives on the rheological properties and injectability of a calcium phosphate bone substitute material

An injectable calcium phosphate bone substitute material has been prepared by mixing amorphous calcium phosphate (ACP) and dicalcium phosphate dihydrate (DCPD) for use in noninvasive surgery, and the influence of additives, such as disodium hydrogen phosphate, polyethylene glycol (PEG), glycerin, and citric acid, on the rheological properties and injectability of the ACP + DCPD cement system have been studied in this work. Novel approach of thixotropy measurement has been used to characterize the stability of the pastes. The results show that the injectability and the setting time can be augmented by the addition of disodium phosphate solution to the paste but reduced by the addition of PEG 200, glycerin, or citric acid to the paste. This study suggests that the injectability and the setting time of the ACP + DCPD bone substitute material can be balanced, and the injectable calcium phosphate bone substitute material with satisfied fluidity and injectability for clinical operation can be prepared by optimizing the additives and their concentrations, according to different clinical requirements.

A New Method of Treatment for Dentin Hypersensitivity by Precipitation of Calcium Phosphate in situ

The hydrodynamic theory is generally accepted as an explanation of hypersensitive dentin and suggests that occlusion of exposed dentinal tubules should result in a reduction of hypersensitivity. We tried to block tubules by in situ precipitation of insoluble calcium phosphate. Calcium phosphate crystals precipitated in situ on patent dentin surfaces and formed in the tubules immediately upon serial application of sodium phosphate and calcium chloride solutions, thus occluding the tubules. The size of crystals, their degree of coverage, and the thickness of the precipitate depended on the method of application and concentration of the solutions. The application of 5% disodium phosphate solution followed by rubbing with 10% calcium chloride solution resulted in immediate relief from dental hypersensitivity in 84% of patients treated.

Iron poisoning: Complications of hypertonic phosphatelavage therapy

IRON POISONING remains one o f the most serious o f accidental pediatric ingestions. Treatment following accidental iron ingestion includes the induction of emesis with syrup of ipecac or apomorphine, which is sometimes combined with a chelating agent, such as de f e roxamine . Exchange transfusion, peritoneal dialysis, or hemodialysis are occasionally utilized. Many commonly consulted references recommend routine gastric lavage with onequarter to one-half strength disodium phosphate solution (Fleet enemas)?-' until tablet fragments are no longer recovered. This solution combines with the ingested iron to form a poorly soluble complex of ferrous and ferric phosphate. An alternative lavage solution is a 5% solution of sodium bicarbonate, which forms ferrous and ferric bicarbonate, also relatively insoluble. This is a report of a case o f severe electrolyte imbalance following gastric lavage with sodium phosphate enema solution, and is presented to alert clinicians to a potentially severe complication of currently recommended therapy for iron poisoning.

The role of hydrogen sulphide in environmental transport of mercury

HYDROGEN SULPHIDE may be evolved in anoxic sulphur-containing river or lake sediments1. The effect of the presence of sulphide on the availability of inorganic mercury for biological methylation has been considered previously. Essentially mercury in the form of Hg(0) or Hg(II) may be converted into mercuric sulphide in anoxic sediments2. It might seem that this very insoluble material would not, in practice, be available for methylation and that sulphide formation would act as a method of removing mercury from availability to the general environment (that is, it would act as a mercury sink). However in a complex natural system (aquarium sediment) it has been shown that HgS may, in fact, be methylated in the sediments although to produce quantities of methyl mercury substantially less than those produced using a more soluble mercury substrate2. Therefore, although H2S in a sediment would be expected to reduce the rate of mercury methylation considerably by the formation of HgS, it would not be expected to prevent formation of methyl mercury entirely. The effect of H2S on methyl mercury itself has also been investigated using a purely inorganic model3. An aqueous solution of methyl mercuric chloride (1 mg dm−3) loses methyl mercury steadily over 3 days after initial exposure to H2S. A volatile product was evolved into the space above the solution. This product was trapped in a sodium carbonate–disodium phosphate solution, extracted with toluene and shown to co-migrate with methyl mercury on thin layer plates of silica gel. It was concluded that the evolved product of the reaction system was a volatile organo-sulphur derivative of mercury that reverted to methyl mercury on extraction. These observations suggest that reaction between methyl mercury and H2S generated in sediments reduces the amount of methyl mercury available for accumulation by fish and shellfish and represents a powerful mechanism adding to the general mobility of mercury compounds in the environment. It is therefore important to identify the unknown mercury compound evolved from the system described above. We have now investigated the interaction of H2S with River Mersey (England) inter-tidal estuary sediment samples in order to determine its effect on methyl mercury levels in real systems. We have also investigated similar reactions in a model system, leading to the identification of the previously unknown volatile mercury species responsible for the transport of mercury in the work of Rowland et al.3

レゾルシン誘導体のヨード化に関する研究 (第4報)

Following previously reported iodination of resorcinol and resorcylic acid derivatives, iodination of p-orsellinic acid, one of the carboxylic acids of orcinol, was carried out. For the iodination of p-orsellinic acid, iodine-potassium iodide solution was added at ordinary temperature to the phosphoric acid disodium phosphate solution (pH 2.50) of p-orsellinic acid and the mixture was allowed to stand for two hours. Diiodo-p-orsellinic acid was obtained in quantitative yield as slightly yellowish white crystals, m.p. 179-180° (decomp.). Its diacetate formed white needles, m.p. 157-160° (decomp.). Both these substances are new compounds.

Collagen fractions in lathyritic rats

The effect of β-aminopropionitrile (“Lathyrism”) on collagen was studied. Albino rats were fed with a diet containing 73 per cent sweet peas, and the bone changes resulting were ascertained by x-ray studies. The collagen fractions were prepared from skin and bone by extraction with disodium phosphate solution, acid citrate solution, and by gelatinization. The alkali-soluble collagen was 5 times greater in cases of lathyrism. The solubility of non-collagenous proteins was also increased. The total collagen content was not altered.