scholarly journals The Influence of Phosphate Buffer on the Formation of N-Nitrosodimethylamine from Dimethylamine Nitrosation

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Long Xu ◽  
Zhi Sun ◽  
Qing Ming Liu ◽  
Yong Dong Liu ◽  
Ru Gang Zhong ◽  
...  
Keyword(s):  
Significant Role ◽  
Phosphate Buffer ◽  
Inhibitory Effect ◽  
Buffer Solution ◽  
Citrate Buffer ◽  
Buffer Solutions ◽  
Water Plants ◽  
Almost All ◽  
Nitrosation Reaction

Buffer solutions were widely used for almost all the investigations concerning N-nitrosodimethylamine (NDMA), a member of powerful mutagenic and carcinogenic compounds which are ubiquitous in the environment. However, whether or how the buffer matrixes influence NDMA formation is still unknown. The effect of buffer solutions on NDMA formation from the nitrosation of dimethylamine (DMA) by nitrite (NaNO2) was investigated at pH 6.4 in four kinds of buffer solutions, that is, Na2HPO4/C6H8O7, Na3(C6H5O7)/C6H8O7, NaH2PO4/NaOH, and NaH2PO4/Na2HPO4. Our observations demonstrate an unexpected inhibitory effect of the buffer solutions on NDMA formation and the phosphate buffer plays a more significant role in inhibiting NDMA formation compared to the citrate buffer. Moreover, the amount of the phosphate in the buffer was also found to greatly impact the formation of NDMA. A further investigation indicates that it is the interaction between NaH2PO4and reactant NaNO2rather than DMA that leads to the inhibitory effect of phosphate buffer during the DMA nitrosation reaction. This study expands the understanding of the influence of buffer solution on nitrosamines formation through the nitrosation pathway and further gives a hint for water plants to reduce the formation of nitrosamines.

scholarly journals THE PROPERTIES OF MAMMALIAN STRIATED MYOFIBRILS ISOLATED BY AN ENZYMATIC METHOD

1950 ◽  
Vol 91 (6) ◽  
pp. 655-664 ◽  
Author(s):  
Armin F. Schick ◽  
George M. Hass
Keyword(s):  
Ionic Strength ◽  
Potassium Chloride ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Potassium Phosphate ◽  
Microscopic Structure ◽  
Buffer Solution ◽  
Buffer Solutions ◽  
Alkaline Side ◽  
Fresh Frozen

A new method for the isolation of large numbers of individual myofibrils from fresh mammalian skeletal and cardiac muscle has been described. Purification of isolated myofibrils was accomplished by differential centrifugation of fresh frozen sections of muscle which had been mechanically agitated after exposure for 30 to 45 minutes at 0°C. to the action of a dilute solution of trypsin in a phosphate buffer solution with a pH of 7.0 and an ionic strength of 0.25. Isolated skeletal myofibrils of the rabbit and man have similar constant solubility properties. They dissolve in an aqueous mixture of 0.5 N potassium chloride and 0.03 N sodium bicarbonate, giving viscous solutions which exhibit conspicuous birefringence of flow. They are soluble in buffer solutions (ionic strength 0.15) on the acid side of pH 4 and alkaline side of pH 10. If the ionic strength of potassium phosphate buffer solutions is increased to 0.5 or if the ionic strength of phosphate-borate buffer solutions is increased to a similar value by addition of potassium chloride, the isolated myofibrils become soluble at neutrality. Hence, it is possible, first to isolate the myofibrils and then dissolve them without deviating appreciably from physiologic ranges of pH. The extent to which myofibrils are modified by the conditions imposed by the method of isolation is unknown. There is no significant change in microscopic structure or optical birefringence. Furthermore, there is retention of a form of physiological reactivity, for when the isolated skeletal myofibrils are immersed in solutions of adenosinetriphosphate, they promptly and irreversibly change from elongated fibrils with distinct structural detail into dense spherical masses without recognizable microscopic structure.

scholarly journals Chemical detections of active compounds in Melilotus indica extracts

2009 ◽  
Vol 3 (1) ◽  
pp. 130-140
Author(s):  
Faisal K. Mutasher ◽  
Ghazi M. Aziz ◽  
Amani A.W . Abdul-Razzak
Keyword(s):  
Phosphate Buffer ◽  
Volatile Oils ◽  
Buffer Solution ◽  
Active Compounds ◽  
Buffer Solutions ◽  
Negative Results ◽  
Sodium Phosphate Buffer ◽  
Crude Extracts ◽  
Layer Chromatography ◽  
Positive Results

The crude extracts of the leaves of melilotus indica which collected in two dates (midFebruary, mid March) have been prepared by three solvents (Distilled water, ethanol 80% and chloroform) and three buffer solutions (Sodium acetate buffer, Sodium phosphate buffer and Tris-hydrochloric acid buffer), the greater percentage of crude extracts achieved by phosphate buffer which were 47.3% and 29.2% for second and first dates, respectively, while the lowest percentage of crude extracts achieved by chloroform extracts which were 13.2% and 10.0% for second and first dates, respectively. The qualitative chemical detections for active compounds in crude extracts revealed a positive results for the saponins, tannins, coumarins, flavones and glycosides, while the detections revealed a negative results for the alkaloids, resins and volatile oils. The active compounds in crude extracts prepared by solvents and buffer solutions were studied by thin layer chromatography (TLC), the solvent extracts were contains five compounds with relative flow (RF) 0.65, 0.4 for coumarin and umbelliferon, respectively, and 0.5, 0.27, 0.2 which belong to simple coumarins compounds in melilotus indica, while buffer solution extracts were contains two compounds with RF value 0.65 and 0.4 for coumarin and umbelliferon, respectively.

Haemolysis of various mammalian erythrocytes in sodium chloride, glucose and phosphate-buffer solutions

1979 ◽  
Vol 13 (4) ◽  
pp. 329-331 ◽  
Author(s):  
Toshiaki Matsuzawa ◽  
Yasushi Ikarashi
Keyword(s):  
Sodium Chloride ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Human Erythrocytes ◽  
Buffer Solution ◽  
Buffer Solutions

Mouse, rat, rabbit, hamster, cow, pig, sheep, guineapig, dog and human erythrocytes were studied. A 0·9% or stronger solution of sodium chloride completely prevented haemolysis; sheep and pig erythrocytes appeared the more fragile, while human and dog erythrocytes were not haemolized in concentrations of 0·4% or more. Haemolysis of human, rabbit, cow, hamster, guineapig, pig and sheep erythocytes was not observed in solutions of 0·4% or more of glucose. Except for sheep, human and dog erythrocytes, haemolysis was depressed in rate but not completely prevented by phosphate-buffer solution of pH 7·0.

PRINCIPLE OF AUTONOMY IN LETTER OF CREDIT: MALAYSIAN PRACTICE

2012 ◽  
Vol 19 (2) ◽  
Author(s):  
Rosmawani Che Hashim ◽  
Ahmad Azam Othman ◽  
Akhtarzaite Abdul Aziz
Keyword(s):  
International Trade ◽  
Significant Role ◽  
Case Law ◽  
Huge Amount ◽  
Letter Of Credit ◽  
Relevant Case ◽  
Method Of Payment ◽  
Almost All

The term letter of credit (LC) is not uncommon in international trade as it is the most frequently used method of payment by seller and buyer in their sales contract. LC serves its significant role by facilitating payment between buyer and seller from different countries, who are always prejudiced towards each other on the issue of payment, especially when the deal involves a huge amount of money. By using LC, the seller and buyer will be represented by their own bankers whose function, among others is to issue an LC for the buyer and pay on presentation of seller’s documents which strictly comply to LC requirements. It is well-known that LC is governed by the principle of autonomy or also referred to as the principle of independence1 which indicates LC, being a contract of payment is totally separate from the underlying sales contract. Banks are concerned with documents only and not with the goods. LC transaction can be governed by the Uniform Custom and Practice for Documentary Credit, known as the UCP through express incorporation which provides the rules relating to LC matters and is adopted in almost all LC transactions. This paper discusses the nature, background and significance of principle of autonomy in LC transaction. In elaborating the provisions on the principle of autonomy in the UCP 600, comparisons between relevant articles in the UCP 500 are highlighted. The discussion also focuses on relevant case law and on the application of the autonomy principle in conventional and Islamic LC. The paper concludes with the finding that Malaysian bankers fully subscribe to the principle of autonomy as outlined by the UCP 600.

scholarly journals OBSERVATIONS IMPLICATING AN EXTRACELLULAR ENZYMIC MECHANISM OF CONTROL OF BONE MORPHOGENESIS

1974 ◽  
Vol 22 (2) ◽  
pp. 88-103 ◽  
Author(s):  
MARSHALL R. URIST ◽  
HISASHI IWATA ◽  
STUART D. BOYD ◽  
PETER L. CECCOTTI ◽  
MARLYS OKADA ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Phosphate Buffer ◽  
Bone Matrix ◽  
Chemical Extraction ◽  
Ammonium Bromide ◽  
Property A ◽  
Noncollagenous Proteins ◽  
Buffer Solutions ◽  
Sequential Chemical Extraction ◽  
Chloroform Methanol

Data on physicochemical conditions leading to loss of the bone morphogenetic property of bone matrix in neutral buffer solutions support the concept of an enzymic control mechanism better than a chemical blocking reaction or denaturation. The loss is associated with release of 35S-labeled constituents and not prevented by ε-amino caproic acid, an inhibitor of cathepsins. The loss is also associated with release of 35S-cysteine-labeled protein; about 60% of the yield is sustained by the addition of only 3 mmoles/liter of iodoacetic acid. A latent period of about 12 hr, decreased by extraction of bone matrix with CaCl2, is characterized by release of protein polysaccharide and other noncollagenous proteins. Release of sialic acid from the bone matrix by neuraminidase at pH 7.4 has no effect upon bone yield. At 2°C, Tris-HCl buffer or ethylenediaminetetraacetic acid extracts noncollagenous proteins without loss of bone yield; at 37°C, pH 7.4, these solutions also activate endogenous enzymes and reduce bone yield. The component of bone matrix responsible for reduction in bone yield is separable from bone matrix by extraction with phosphate buffer, by catheptic digestion of bone matrix in acidic buffer solutions, by sequential chemical extraction of noncollagenous proteins with cold slightly acidic salt solutions or by extraction-denaturation with chloroform-methanol. Detergents neither extinguish nor denature the morphogenetic property but some solubilize or extract degradative enzymes; hexodecyl trimethyl ammonium bromide, at pH 5.0, is positively charged and extracts hydrophobic proteins, including part of the bone morphogenetic property. A special selection of sulfhydryl chemical inhibitors remarkably different from the selection inhibiting known enzymes preserves the bone morphogenetic property of bone matrix; p-chloromercuribenzoate preservation is reversible by chemical reactions with cysteine. Reduction in bone yield in phosphate buffer is not attributable to a chemical block because chloroform-methanol extraction of the agent does not restore bone yield and is not attributable to denaturation because bone yield sustained by p-chloromercuribenzoate is lost by chemical reactions with cysteine. An hypothetical insoluble bone morphogenetic protein (BMP) firmly bound to collagen is degraded by a soluble neutral proteinase (BMPase). Digestion of the hypothetical BMP occurs without loss of the 640-A electron micrographic image of bone collagen, resembles tryptic digestion and is more selective as well as physiologic in action.

Rumination in sheep. III. Experimentally induced variations on the circadian pattern of rumination

1965 ◽  
Vol 16 (4) ◽  
pp. 649 ◽  
Author(s):  
GR Pearce
Keyword(s):  
Extended Period ◽  
High Protein ◽  
Circadian Pattern ◽  
Buffer Solution ◽  
Buffer Solutions ◽  
Experimentally Induced

The circadian (24-hr) pattern of rumination of caged sheep was found to be affected: (a) by the administration of a roughage ration per fistulam; (b) by the emptying of the rumen and the subsequent return of the rumen contents; (c) by the emptying of the rumen and the replacement of the contents by a buffer solution plus roughage. The period during which no rumination occurred following feeding was progressively shortened when increasing proportions of a ration of oaten chaff and lucerne chaff were administered per fistulam. The effect was much reduced when high protein sheep cubes were added to the chaff ration. The removal of the rumen contents after voluntary feeding and then their immediate return to the rumen tended to cause an early commencement of rumination. When the rumen contents were "pasteurized" before return, however, rumination did not occur for an extended period afterwards. When the rumen contents were replaced with buffer solutions plus roughage, variable rumination responses occurred. In one instance apparently uninhibited rumination resulted.

scholarly journals Antigen retrieval technique utilizing citrate buffer or urea solution for immunohistochemical demonstration of androgen receptor in formalin-fixed paraffin sections.

1993 ◽  
Vol 41 (11) ◽  
pp. 1599-1604 ◽  
Author(s):  
S R Shi ◽  
B Chaiwun ◽  
L Young ◽  
R J Cote ◽  
C R Taylor
Keyword(s):  
Androgen Receptor ◽  
Enzymatic Digestion ◽  
Antigen Retrieval ◽  
Urea Solution ◽  
Paraffin Sections ◽  
Buffer Solution ◽  
Solution Ph ◽  
Citrate Buffer ◽  
Formalin Fixed Paraffin ◽  
Formalin Fixed

We developed a staining protocol for demonstration of androgen receptor (AR) in formalin-fixed, paraffin-embedded tissue sections. The method is based on the antigen retrieval microwave (MW) heating technique. Results are compared with different types of enzyme digestion pre-treatments. The strongest immunostaining signal and clearest background were obtained by MW heating of dewaxed paraffin sections in 5% urea or citrate buffer solution (pH 6); pure distilled water gave less consistent results. Enzymatic digestion with pepsin (0.05% in 2 N HCl) for 30 min at room temperature, or trypsin followed by pronase, or pronase digestion alone, also produced enhanced staining of AR in some cases, but there was more nonspecific background, and specific reactivity was less intense. The antigen retrieval MW method can be used to demonstrate AR epitope in prostate tissue after fixation in formalin for as long as 7 days. AR immunolocalization was also compared in frozen and paraffin sections processed from the same specimen of prostate carcinoma tissue and was found to be qualitatively and quantitatively similar. This study also provided new information concerning the basic principles of the antigen retrieval MW method that may be helpful in further development of this technique.

Bioceramic Hydroxyapatite Granules for Purification of Biotechnological Products

2011 ◽  
Vol 284-286 ◽  
pp. 1764-1769 ◽  
Author(s):  
Vitalijs Lakevics ◽  
Janis Locs ◽  
Dagnija Loca ◽  
Valentina Stepanova ◽  
Liga Berzina-Cimdina ◽  
...  
Keyword(s):  
Bovine Serum Albumin ◽  
Serum Albumin ◽  
Phosphate Buffer ◽  
Bovine Serum ◽  
Phosphate Buffer Solution ◽  
Sorption Process ◽  
Buffer Solution ◽  
Ph Values ◽  
Bovine Serum Albumin Adsorption ◽  
Albumin Adsorption

Sorption experiments of bovine serum albumin (BSA) on hydroxyapatite (HAp) ceramic granules, prepared at three temperatures 900°C, 1000°C and 1150°C were performed at room temperature 18,6 °C and phosphate buffer, pH 5,83; 6.38 and 7,39. Thermal treatment contributed to the decrease of bovine serum albumin immobilization indicating that sorption process depended on HAp ceramics specific surface area and pH values of phosphate buffer solution. However, it was confirmed that granule size was also an important parameter for bovine serum albumin adsorption. As a result of these experiments, the most appropriate adsorption conditions and phosphate buffer pH values influence on to BSA sorption were analyzed.

Reduction of Escherichia coli O157:H7 Counts on Whole Fresh Apples by Treatment with Sanitizers

2000 ◽  
Vol 63 (6) ◽  
pp. 703-708 ◽  
Author(s):  
MARCY A. WISNIEWSKY ◽  
BONITA A. GLATZ ◽  
MARK L. GLEASON ◽  
CHERYLL A. REITMEIER
Keyword(s):  
Escherichia Coli ◽  
Chlorine Dioxide ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Escherichia Coli O157 ◽  
Peroxyacetic Acid ◽  
Water Control ◽  
Buffer Solution ◽  
E Coli ◽  
Log Reduction

The objectives of this study were to determine if washing of whole apples with solutions of three different sanitizers (peroxyacetic acid, chlorine dioxide, or a chlorine-phosphate buffer solution) could reduce a contaminating nonpathogenic Escherichia coli O157:H7 population by 5 logs and at what sanitizer concentration and wash time such a reduction could be achieved. Sanitizers were tested at 1, 2, 4, 8, and 16 times the manufacturer's recommended concentration at wash times of 5, 10, and 15 min. Whole, sound Braeburn apples were inoculated with approximately 1 × 108 or 7 × 106 CFU per apple, stored for 24 h, then washed with sterile water (control) or with sanitizers for the prescribed time. Recovered bacteria were enumerated on trypticase soy agar. Washing with water alone reduced the recoverable population by almost 2 logs from the starting population; this can be attributed to physical removal of organisms from the apple surface. No sanitizer, when used at the recommended concentration, reduced the recovered E. coli population by 5 logs under the test conditions. The most effective sanitizer, peroxyacetic acid, achieved a 5-log reduction when used at 2.1 to 14 times its recommended concentration, depending on the length of the wash time. The chlorine-phosphate buffer solution reduced the population by 5 logs when used at 3 to 15 times its recommended concentration, depending on wash time. At no concentration or wash time tested did chlorine dioxide achieve the 5-log reduction.

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