Archives November 2013

Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines, trimethylamine, and aniline. Inorganic derivatives of ammonia are also called amines, such as chloramine (NClH2); Compounds with the nitrogen atom attached to a carbonyl of the structure R–CO–NR′R″ are called amides and have different chemical properties from amines. An aliphatic amine has no aromatic ring attached directly to the nitrogen atom. Aromatic amines have the nitrogen atom connected to an aromatic ring as in the various anilines. The aromatic ring decreases the alkalinity of the amine, depending on its substituents. The presence of an amine group strongly increases the reactivity of the aromatic ring, due to an electron-donating effect. Amines are organized more...

Carbon tetrachloride, also known by many other names (the most notable being carbon tet in the cleaning industry, and as Halon 104 or Freon 10 in HVAC), is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent. It is a colourless liquid with a "sweet" smell that can be detected at low levels. Both carbon tetrachloride and tetrachloromethane are acceptable names under IUPAC nomenclature. Carbon tetrachloride was originally synthesised by the French chemist Henri Victor Regnault in 1839 by the reaction of chloroform with chlorine, but now it is mainly produced from methane: CH4 + 4 Cl2 → CCl4 + 4 HCl The production often utilizes by-products of other chlorination reactions, such as from the syntheses of dichloromethane and chloroform. Higher chlorocarbons are also subjected to "chlorinolysis:" C2Cl6 + Cl2 → 2 CCl4 Prior more...

Chloroform reacts with oxygen in the air to form phosgene (COCl2), a poisonous gas, according to the equation: 2CHCl3 + O2 ---> 2COCl2 + 2HCl In order to prevent this oxidation, ethanol or methanol should be added if you were planning to store it for an extended period of time. You should ensure that the chloroform contains 1-2% ethanol. Ethyl carbonate is produced and is harmless. COCl2 + 2CH3CH2OH ---> (C2H5O)2CO + 2HCl Phosgene is the chemical compound with the formula COCl2. This colorless gas gained infamy as a chemical weapon during World War I.  It is also a valued industrial reagent and building block in synthesis of pharmaceuticals and other organic compounds. In low concentrations, its odor resembles freshly cut hay or grass. In addition to its industrial production, small amounts occur naturally from the breakdown and the combustion of organochlorine compounds, such as those used in refrigeration systems. more...

India is a democratic nation whose strength lies in the quality of its citizens. To make our democracy continue to grow and flourish in the right direction, its citizens must be vigilant towards their votes. This vote is extremely very important because it determines the kind of government that comes in power. The electorate must remember that it is his/her duty towards the nation to vote wisely. He or she must exercise his or her right to vote without fear or favour to have a real democracy. The vote rightly cast can help in rooting out corruption from public life. The candidates elected must have charismatic personality, character and merit. But unfortunately our country lacks these types of leaders or politicians. At present it is facing political corruption as well as crime at every level. The leaders have become self-seeking. They have no moral, they have no honesty, they have more...

The development of pastes designed to clean teeth and freshen the breath began in Egypt as early as 5000 B.C.E. Myrrh, volcanic pumice, and the burned ashes of ox hooves were mixed with crushed eggshells, oyster shells, and other fine abrasives, then applied with a finger to scour teeth and help remove food and bacterial deposits. In China around 300 B.C.E. a nobleman named Huang-Ti claimed that toothaches could be cured by inserting pins into certain areas of a patient's gums. Huang-Ti's theories grew to become the world's first recorded and systematic approach to oral hygiene. Generally, however, the composition of what people used as toothpaste remained an intriguing mix of practicality, myth, and superstition until well into the seventeenth century. In the first century C.E., for example, it was thought that toothaches could be avoided by removing animal bones from wolves' excrement and wearing them in a band around more...

7 Ways to Prevent the Spread of Infection  1. Wash Your Hands!                           2. Clean and Disinfect!            3. Handle Food Safely            4. Get Immunized!           5. Don’t over-use antibiotics!         6. Keep Pets Healthy         7. Stay Away From Wild Animals! more...

VACCINATION Vaccination is the administration of antigenic material (a vaccine) to stimulate an individual's immune system to develop adaptive immunity to a pathogen. Vaccines can prevent or ameliorate morbidity from infection. The effectiveness of vaccination has been widely studied and verified; for example, the influenza vaccine,the HPV vaccine,and the chicken pox vaccine.Vaccination is the most effective method of preventing infectious diseases;widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the restriction of diseases such as polio,measles, and tetanus from much of the world. The active agent of a vaccine may be intact but inactivated (non-infective) or attenuated (with reduced infectivity) forms of the causative pathogens, or purified components of the pathogen that have been found to be highly immunogenic (e.g., outer coat proteins of a virus). Toxoids are produced for immunization against toxin-based diseases, such as the modification of tetanospasmin toxin of tetanusto remove its toxic more...

Combinations of ResistorsResistors do not occur in isolation.  They are almost always part of a larger circuit, and frequently that larger circuit contains many resistors. It is often the case that resistors occur in combinations that repeat.Goals  Series Combinations of Resistors : Two elements are said to be in series whenever the same current physically flows through both of the elements. The critical point is that the same current flows through both resistors when two are in series.  The particular configuration does not matter.  The only thing that matters is that exactly the same current flows through both resistors.  Current flows into one element, through the element, out of the element into the other element, through the second element and out of the second element.  No part of the current that flows through one resistor "escapes" and none is added.  This figure shows several different ways that two resistors in more...

Odds are that if you check your purse or wallet right now, you'll find an invention that owes its existence as much to a desire for neatly pressed clothes as a need for portable data storage—the magnetic stripe card. Conceived by IBM engineer, Forrest Parry, as part of a government security system project, the technique of attaching a strip, or "stripe," of magnetic tape to a card facilitated a revolution in portable, personal data retrieval. Until the advent of the chip-based smart card during the 1980s, the magstripe ruled—from club membership cards, through to phone, credit, and debit bankcards. Parry had experienced several frustrating failures with trying to fix the magnetic material to the card with adhesive. When a forlorn-looking Parry returned home from the laboratory, his wife, who was ironing at the time, stepped in and suggested she try using the heat of the iron to bond the magstripe more...

Non Communicable Diseases  A non-communicable disease, or NCD, is a medical condition or disease, which by definition is non-infectious and non-transmissible among people. NCDs may be chronic diseases of long duration and slow progression, or they may result in more rapid death such as some types of sudden stroke. They include autoimmune diseases, heart disease, stroke, many  cancers, asthma,diabetes,  chronic  kidney disease, osteoporosis,Alzheimer's disease, cataracts, and more. While sometimes (incorrectly) referred to as synonymous with chronic diseases, NCDs are distinguished only by their non-infectious cause, not necessarily by their duration. Some chronic diseases of long duration, such as HIV/AIDS, are caused by transmittable infections. Chronic diseases require chronic care management as do all diseases that are slow to develop and of long duration. You will get friendly to this topic by clicking http://www.studyadda.com/videos/ix-class-biology-lectures/why-do-we-fall-ill/non-communicable-disease/1765Video Lecture Taught By-  Mrs. Shweta Sardana, Msc.,M.Phil Gold Medalist , AIPMT TrainerSardana Tutorials ï»¿ï»¿