Bacteriostatic and bactericidal actions of boric acid against bacteria and fungi commonly found in urine

Abstract
 Boric acid has been used for  over 20 years to preserve urine while in transit fer bacteriological examination.
It has been suggested that it may be toxic for some urinary pathogens. To investigate this several strains of
bacteria and fungi commonly found in urine were exposed to different concentrations. of boric acid in
nutritnt broth. Viable counts were made at the outest and nt intervals for up to 24 hours at room temperature todetect bacteriostatic and bactericidal effect at the concentration between 10 and 20 g/l boric acid was bacteriostatic or fungi static for very nearly all the common urinary pathogens. At 10 g/l boric acid acid was weakly bactericidal for Some strians  of Acinetobacter calcoaceticus and Pseudomonas aeruginosa though higher concentrations were bacteriostatic only Group B streptococel varied in their response to boric acid but for most of them 10 to 20 g/l was satisfactorily bacteriostatic. It is concluded that boric acid is rarly toxic and when it is the effect is usually sufficiently delayed to be of only theoretical importance In 1969 Porter and Brodie described the use of boric acid at a concentration of 18 g/l to preserve urine while in transit for bacteriological examination. Although urine is a culture medium, they showed that when boric acid was added the number of any bacteria presented did not chnge significantly for up to 48 hours at room temperature and other cellular elements remained substantially intact.
 They claimed this effective bacteriostasis allowed the numericla criteria for the labooatory diagnosis of urinary tract infection (UTI) to be applied despite delay in performing the examination. This cheap and simple way to increase accuracy in the diagnosis of bacteriauria and pyuria has not been widely adopted.

How to Alleviate an Orbital Traffic Jam

Spacemaker. Assisted by solar sails, spacecraft could park in uncrowded geostationary orbits.

Credit: ASCL/University of Strathclyde

There's gridlock in orbit. More than 400 telecommunications satellites, plus an indeterminate number of retired, failed, and secret spacecraft, occupy a narrow band of space some 35,000 kilometers above Earth's equator. Now, researchers have found a way to alleviate the congestion: attaching solar sails to satellites that would propel them 10 to 30 kilometers north or south of the standard orbit. Space experts say that such sails could also open up other orbital positions that were previously considered unattainable.
Telecommunications satellites must remain in the same position above Earth at all times—in a so-called geosynchronous orbit—so that satellite dishes don't have to constantly swivel to track them. Thanks to the laws of gravity and orbital mechanics, the only way for a satellite to maintain a geosynchronous position has been to orbit above the equator.
But this prime real estate is growing scarce. The satellites could move north or south, but the extra rocket fuel needed to maintain these less-stable orbital positions would be expensive and would limit the life of the craft.
That's where solar sails come in. A large square of reflectively coated Mylar—say, a hundred meters on a side—could catch enough sunlight to propel a satellite above or below the plane of the equator and maintain enough thrust to hold it in geostationary position.
To see if the idea would work, aerospace engineer Colin McInnes and one of his graduate students, Shahid Baig, at the University of Strathclyde in the United Kingdom started with calculations developed by Robert Forward, a physicist and NASA consultant. Forward, who died in 2002, posited that the photons of sunlight streaming across the solar system contained sufficient energy to push a solar-sail–arrayed satellite out of geostationary orbit and maintain its new position without the need for heavy, liquid-fueled thrusters. The Japanese IKAROS spacecraft, which was launched last month, is testing the basic solar-sail concept.
Other scientists questioned Forward's calculations, because, they argued, his figures weren't precise enough. But using superaccurate computer models, McInnes and Baig have determined that Forward was indeed correct. The new calculations, published in the May/June Journal of Guidance, Control, and Dynamics, showed that sunlight hitting a solar sail would be sufficient to push the satellite into a geostationary orbit. And due to its continuous pressure, the sunlight could also hold the spacecraft in that orbit indefinitely without the need for thrusters.
Although the research provides only a theoretical proof of concept, experts see a bright future for solar-sail satellites. For example, says aerospace engineer Ben Diedrich of the National Oceanic and Atmospheric Administration in Silver Spring, Maryland, researchers could park satellites over Earth's poles to provide continuous climate monitoring at these latitudes. Or the sails could push solar-research spacecraft into more advantageous orbits to study the sun. Solar-sail–assisted orbits, he says, are "one more viable option for future mission planners to consider."
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Different kind of steel

Steel, on the basis of its nature and components, can be classifi~d into five kinds as under:
1. CARBON STEEL:
Most of the kinds of steel ,in use are classified ,as 'carbon steel', The proportion of carbon in different kinds of carbon steel but Manganese proportion is not more than 1 .65 per cent nevertheless, the proportion of Silicon is 0.60 per cent and copper is also 0.60 per cent. In other words, Manganese, Silicon and Copper are mixed in Carbon Steel.Carbon steel is used .for making springs for bed mattresses, structure of the ships, buildings structure, motor cars body and machines.
2. ALLOY STEEL:
Different kinds of Alloy steel are being made in which different proportions of various metals are mixed to change their properties so that they could be used for desired purposes. 20 per cent in the world production of steel is constituted by Alloy Steel. If a certain proportion of Vanadium and Molybdenum is mixed, the steel becomes more hard and strong having the capability of bearing the shocks and vibrations. This is the reason that his kind of alloy steel is used for making the Excel and gear of motor vehicles.
If high proportion of manganese is mixed in steel, steel becomes more hard and is used for mining machines electric machines and heavy machinery. If Nickel is mixed,steel, it becomes very hard to be used for boll bearing armourd plates.By 'mixing chromium, steel is can into Stainless Steet
and used in man~fact!Jring such which can be rusted like milk bottles&nd,airplanes etc.
If Tungsten and Cobalt is mixed in steel, it can be used in making iron cutting blades like blades of lath machines. By mixing Silicon and Copper: common steel is made.
3. HIGH STRENGTH lOW-ALLOy STEEL:
 " This kind of steel is the most modern invention amongest all the kinds of steel in use'which is a1so termed as HSLA is called  'low alloy' because the cheap metals are mixed in this kind of steels.But this steel is more strong than t·carbon steel. For example, loading trucks and vehicle are made' of this steel because the walls of the vehicle arEin weight but stronger that the Carbon Steel.
4. STAINLESS STEEL:
Nickel, Chromium and other elements are mixed, Stainless Steel. Stainless·steel is not only strong but retain its glittering and is save from rusting and moisture Gases and acids do not a.ffect the stainless steel. Sta steel is used for making chemical plants and petre refininy pipes. Apart from it, it is also used for airplane:
space capsules. Surgical instrunents are also mE' stainless steel. In the home kitcher,s, food processing and for cutlery making, stainless steel is utilized because this metal is not only rust proof but it can also be cleaned easily.
5. TOLL STEEL:
Toll steel is fabricated in the bands of different tool and implements. It is also used in machines generated by energy. Molybdenum, Tungsten and such other metals mixed in Toll Steel which provide iron extra ord strength, hardness and power of resistance.
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Principal basic fatliquoring substances

The degree of purity of the oils should be observed. Filtered or refined products are suitable. Heavy impurities cause odour problems. Products of high iodine value (except for chamois tannage) have a tendency to effect intensive yellowing of the leather and quick oxidation.When using neatsfoot oil, cold-resistant products should be chosen. Lard oil should not have solid constituents either as otherwise
there is a risk of fatty spew. All products have an increased content of stearic fatty acid and thus a very strong tendency to form fatty spew. The use of raw materials which have been stored for some time should be avoided because of the rancid smell.Only refined products should be used as this category of products is prone to rancidity which may cause disagreeable smells. Only scmi-drying and non-drying oils are suitable for fat liquoring of leathers. Some products have a tendency to oxidation and thus to develop strong,
 disagreeable smells. Wool grease (lanolin) should be used in purified form because products of inferior quality have a disagreeable smell. Products based on wool grease reduce the wetting properties of the leather.
Paraffin oils only have an adequate fatliquoring effect from a medium chain length of C 20.
Mineral oils should be Iight-coloured, odourless, and the viscosity should not be too low. Furthermore they should have only a low content of aromatic hydrocarbons as othenvise increased yellowing may occur.

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