STERILIZATION AND PRESERVATION OF FORMULAS FOR INFANTS

PEDIATRICS ◽  
1957 ◽  
Vol 20 (6) ◽  
pp. 993-999
Author(s):  
Henry K. Silver
Keyword(s):  
Practical Method ◽  
Milk Mixture ◽  
Spore Forming Bacteria ◽  
Pathogenic Contamination

The "terminal" method of heating is the safest means of preparing artificial milk feedings for infants. There is no practical method of processing formula so that sterility is assured in every bottle. Certain organisms (particularly spore-forming bacteria) may survive regardless of the method used. Any departure from the usually recommended procedure for formula prepartion may be attended by the risk that the formula will become grossly contaminated. The term "terminal sterilization" as applied to the usual home method of preparation is a misnomer, since formulas may or may not be sterile even after "terminal" heating. The "aseptic" method of preparing formula, although theoretically safe if performed correctly, has the hazard that breaks in technique may occur and pathogenic contamination may result. Keeping terminally-heated formula at room or incubator temperatures for more than 6 hours may result in gross contamination of the formula by bacteria which were dormant in the milk-mixture. Although it is common practice in the home to prepare the required formula every day, the present experiments indicate that terminally-heated formula which is prepared with clean equipment, and then cooled and refrigerated immediately thereafter is bacteriologically safe for at least 2 or 3 days. A new supply of formula need not be made daily.

REPORT OF COMMITTEE ON FETUS AND NEWBORN

PEDIATRICS ◽  
1961 ◽  
Vol 28 (4) ◽  
pp. 674-675
Author(s):  
Keyword(s):  
Pathogenic Bacteria ◽  
Bacterial Count ◽  
Practical Method ◽  
Gastrointestinal Disorders ◽  
Past Century ◽  
The Past ◽  
Spore Forming Bacteria ◽  
Formula Preparation ◽  
Increased Susceptibility ◽  
Significant Factors

ONE OF THE SIGNIFICANT FACTORS in decreasing mortality among children during the past century has been the recognition of the role that contaminated milk played in the production of various gastrointestinal disorders. For several decades it has been generally accepted that all milk-mixtures should be sterilized before being fed to infants. Recently, however, the question has been raised regarding the feasibility of preparing individual bottles of milk mixtures using clean but not sterilized ingredients and placing them in unsterilized equipment. Although there is no practical method of processing and preparing milk mixtures so that sterility is assured in every bottle, the increased susceptibility of infants to diarrheal diseases and the severity of diarrheas and dysenteries in early infancy make, it obligatory to take every effort to guarantee that all food fed to infants during the first months of life should be prepared by the safest possible method. It has been shown that the terminal method of heating will destroy most pathogenic bacteria and viruses and is probably the best means now available for preparing milk mixtures for infant feeding, but even this method permits certain organisms (particularly spore-forming bacteria and a few viruses) to survive, especially when unclean equipment containing milk scum is used to prepare and store the mixture. It has also been shown that most mothers can prepare milk mixtures satisfactorily at home by any of several different methods; the bacterial count in resultant mixtures varied inversely with the care and cleanliness exercised by mothers, so that the counts occasionally reached potentially unsafe levels. The use of a technique of formula preparation that does not necessitate sterilization of equipment or ingredients might be a great boon to busy mothers.

The role of differential phase contrast in electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 176-177
Author(s):  
E.M. Waddell ◽  
J.N. Chapman ◽  
R.P. Ferrier
Keyword(s):  
Phase Contrast ◽  
Practical Method ◽  
Position Vector ◽  
Differential Phase ◽  
Pure Phase ◽  
Differential Phase Contrast ◽  
The Difference ◽  
Image Position ◽  
First Moment

Dekkers and de Lang (1977) have discussed a practical method of realising differential phase contrast in a STEM. The method involves taking the difference signal from two semi-circular detectors placed symmetrically about the optic axis and subtending the same angle (2α) at the specimen as that of the cone of illumination. Such a system, or an obvious generalisation of it, namely a quadrant detector, has the characteristic of responding to the gradient of the phase of the specimen transmittance. In this paper we shall compare the performance of this type of system with that of a first moment detector (Waddell et al.1977).For a first moment detector the response function R(k) is of the form R(k) = ck where c is a constant, k is a position vector in the detector plane and the vector nature of R(k)indicates that two signals are produced. This type of system would produce an image signal given bywhere the specimen transmittance is given by a (r) exp (iϕ (r), r is a position vector in object space, ro the position of the probe, ⊛ represents a convolution integral and it has been assumed that we have a coherent probe, with a complex disturbance of the form b(r-ro) exp (iζ (r-ro)). Thus the image signal for a pure phase object imaged in a STEM using a first moment detector is b2 ⊛ ▽ø. Note that this puts no restrictions on the magnitude of the variation of the phase function, but does assume an infinite detector.

Practical Method for Transient Stability with Unbalanced Condition based on Symmetric Coordinates

2011 ◽  
Vol 131 (7) ◽  
pp. 550-556
Author(s):  
Shuhei Fujiwara ◽  
Yoshiyuki Kono ◽  
Masashi Kitayama ◽  
Tadahiro Goda
Keyword(s):  
Transient Stability ◽  
Practical Method

Total Synthesis of the Antitumor Depsipeptide FE399 and its S-Benzyl Derivative: A Macrolactamization Approach

2020 ◽  
Author(s):  
Takayuki Tonoi ◽  
Miyuki Ikeda ◽  
Teruyuki Sato ◽  
Ryo Kawahara ◽  
Takatsugu Murata ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Total Synthesis ◽  
Natural Product ◽  
Condensation Reaction ◽  
Practical Method ◽  
Equilibrium Mixture ◽  
Conformational Isomers ◽  
Single Isomer

<div>An efficient and practical method for the synthesis of (9R,14R,17R)-FE399, a novel antitumor bicyclic depsipeptide, was developed. A 2-methyl-6-nitrobenzoic anhydride (MNBA)-mediated dehydration condensation reaction was effectively employed for the formation of the 16-membered macrocyclic depsipeptide moiety of FE399. FE399 was found to exist as an inseparable equilibrium mixture of conformational isomers; the mixture was quantitatively transformed into the corresponding S-benzyl product and isolated as a single isomer. Thus, we could confirm that the molecular structure of FE399 obtained by this method is identical to that of the natural product.</div>

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