In latest generation of tiny biosensors, size isn’t everything

4 hours ago by Bill Kisliuk

(Phys.org) When it comes to nanomedicine, smaller issurprisinglynot always better.

UCLA Henry Samueli School of Engineering and Applied Science researchers have determined that the diminutive size of nanowire-based biosensorswhich healthcare workers use to detect proteins that mark the onset of heart failure, cancer and other health risksis not what makes them more sensitive than other diagnostic devices. Rather, what matters most is the interplay between the charged ions in the biological sample being tested and the charged proteins captured on the sensors' surface.

The finding counters years of conventional wisdom that a biosensor can be made more sensitive simply by reducing the diameter of the nanowires that make up the device. This assumption has driven hundreds of costly research-and-development efforts in the field of nanomedicinein which tiny materials and devices are used to detect, diagnose and treat disease.

The research suggests new directions for designing biosensors to improve their sensitivity and make them more practical for doctorsand, eventually, patients themselvesto use.

"This is the first time the understanding of why nanowire biosensing works has been challenged," said Chi On Chui, an associate professor of electrical engineering and bioengineering at UCLA whose lab performed the research. "The advantage is not from the fact that the wires are nanoscale, but rather how their geometry reduces the ability of the ions to inhibit protein detection. This research could be a step toward developing sophisticated, cost-efficient and portable devices to accurately detect a range of illnesses."

The research was published March 25 in the Proceedings of the National Academy of Sciences.

Nanowire biosensors are, in essence, electronic transistors with a diameter smaller than the width of a single red blood cell. When they are exposed to a sample of blood or another bodily fluid, the specific charged proteins being tested for are captured on the nanowires' surfaces. The charge of the captured proteins changes the rate of electric current flowing through the nanowire transistor. By monitoring the electrical current, researchers can quantify the concentration of proteins in the sample, which can give them an indication of heart health, diabetes and a number of other medical conditions.

A challenge to the practical use of the technology is that in addition to the charged proteins, many physiological fluids contain a large concentration of charged ions, such as sodium, potassium and chloride. These ions surround the proteins and mask the protein charge, which prevents the sensor from detecting the proteins.

Researchers in labs can circumvent this problem. But doctors performing tests on their patients or patients monitoring their own health at home cannot do so without the assistance of a technician. This has hampered the adoption of the technology.

Continue reading here:
In latest generation of tiny biosensors, size isn't everything

Agnosticism – Religion-wiki

Template:Certainty

Agnosticism is the view that the truth value of certain claimsespecially claims about the existence or non-existence of any deity, but also other religious and metaphysical claimsis unknown or unknowable.[1] Agnosticism can be defined in various ways, and is sometimes used to indicate doubt or a skeptical approach to questions. In some senses, agnosticism is a stance about the similarities or differences between belief and knowledge, rather than about any specific claim or belief.

Thomas Henry Huxley, an English biologist, coined the word agnostic in 1860. However, earlier thinkers and written works have promoted agnostic points of view. They include Protagoras, a 5th-century BCE Greek philosopher,[2] and the Nasadiya Sukta creation myth in the Rig Veda, an ancient Hindu religious text.[3] Since Huxley coined the term, many other thinkers have written extensively about agnosticism.

Demographic research services normally list agnostics in the same category as atheists and/or non-religious people.[4] Some sources use agnostic in the sense of noncommittal.[5] Agnosticism often overlaps with other belief systems. Agnostic theists identify themselves both as agnostics and as followers of particular religions, viewing agnosticism as a framework for thinking about the nature of belief and their relation to revealed truths. Some nonreligious people, such as author Philip Pullman, identify as both agnostic and atheist.[6]

Thomas Henry Huxley defined the term:

Agnostic (Greek: - a-, without + gnsis, knowledge) was used by Thomas Henry Huxley in a speech at a meeting of the Metaphysical Society in 1876[7] to describe his philosophy which rejects all claims of spiritual or mystical knowledge. Early Christian church leaders used the Greek word gnosis (knowledge) to describe "spiritual knowledge." Agnosticism is not to be confused with religious views opposing the ancient religious movement of Gnosticism in particular; Huxley used the term in a broader, more abstract sense.[8] Huxley identified agnosticism not as a creed but rather as a method of skeptical, evidence-based inquiry.[9][10]

In recent years, scientific literature dealing with neuroscience and psychology has used the word to mean "not knowable".[11] In technical and marketing literature, agnostic often has a meaning close to "independent"for example, "platform agnostic" or "hardware agnostic."

Scottish Enlightenment philosopher David Hume contended that meaningful statements about the universe are always qualified by some degree of doubt.[12] He asserted that the fallibility of human beings means that they cannot obtain absolute certainty except in trivial cases where a statement is true by definition (i.e. tautologies such as "all bachelors are unmarried" or "all triangles have three corners"). All rational statements that assert a factual claim about the universe that begin "I believe that ...." are simply shorthand for, "Based on my knowledge, understanding, and interpretation of the prevailing evidence, I tentatively believe that...." For instance, when one says, "I believe that Lee Harvey Oswald shot John F. Kennedy," one is not asserting an absolute truth but a tentative belief based on interpretation of the assembled evidence. Even though one may set an alarm clock prior to the following day, believing that waking up will be possible, that belief is tentative, tempered by a small but finite degree of doubt (the alarm might break, or one might die before the alarm goes off).

The Catholic Church sees merit in examining what it calls Partial Agnosticism, specifically those systems that "do not aim at constructing a complete philosophy of the Unknowable, but at excluding special kinds of truth, notably religious, from the domain of knowledge."[13] However, the Church is historically opposed to a full denial of the ability of human reason to know God. The Council of the Vatican, relying on biblical scripture, declares that "God, the beginning and end of all, can, by the natural light of human reason, be known with certainty from the works of creation" (Const. De Fide, II, De Rev.)[14]

Agnosticism can be subdivided into several categories. Recently suggested variations include:

See the original post:
Agnosticism - Religion-wiki

Behavioral Sciences FREE Behavioral Sciences …

BIBLIOGRAPHY

The behavioral sciences study human behavior by scientific means; as a preliminary approximation, they can be distinguished from the social sciences as designating a good deal less but, at the same time, somewhat more. The term social sciences typically includes the disciplines of anthropology, economics, political science, sociology, and most of psychology. As a case in point, the scholarly associations in these five disciplinesalong with history and statisticsprovide the core membership of the (American) Social Science Research Council. The behavioral sciences, as that term was originally intended and as it is usually understood, include sociology; anthropology (minus archeology, technical linguistics, and most of physical anthropology); psychology (minus physiological psychology); and the behavioral aspects of biology, economics geography, law, psychiatry, and political science. The edges of any such broad concept tend to be fuzzyas are the edges of the social sciences themselvesbut the center seems to be reasonably clear. Given time, the term will probably settle down to one or two generally accepted meanings, if it has not already done so.

The term behavioral sciences came into currency, one might even say into being, in the United States in the early 1950s. A decade and a half later, it appears to be well established in American universities and disciplines and is well on its way to acceptance abroad. Before 1950 the term was virtually nonexistent; since then it has come into such general use that it appears in the titles of books and journals, of conference sessions, programmatic reports, university departments, professorships, and courses, as well as in the names of a book club, a book prize, several publishers series, and in the mass media of communication.

The story begins with a committee that undertook a study for the Ford Foundation in the late 1940s, when the foundation was about to enter on the enlarged program that made it, overnight, the largest private foundation in the world. This study committee, given the task of suggesting how the Ford Foundation can most effectively and intelligently put its resources to work for human welfare, concluded that the most important problems of human welfare now lie in the realm of democratic society, in mans relation to man, in human relations and social organizations and it recommended that the over-all objective be pursued in five program areasthe establishment of peace, the strengthening of democracy, the strengthening of the economy, education in a democratic society, and individual behavior and human relations. Among the social science disciplines, political science became involved in the first and second programs, economics in the third, and, in a more or less residual way, anthropology, psychology, and sociology in the fifth. In the study committees report appeared the term that soon became current, the behavioral sciences, and the beginnings of a definition to distinguish them from the social sciences: We have in the social sciences scientifically-minded research workers who are both interested in, and equipped for, the use of such techniques. Among these are the psychologists, sociologists, and anthropologists. In addition, there are psychiatrists and psychoanalysts, as well as natural scientists, including geneticists and other biologists (Ford Foundation 1949, p. 92).

What happened to give rise to the term? The key event was the development of a Ford Foundation program in this field. The program was initially designated individual behavior and human relations but it soon became known as the behavioral sciences program and, indeed, was officially called that within the foundation. It was the foundations administrative action, then, that led directly to the term and to the concept of this particular field of study.

The conception was developed further in a staff paper, approved by the foundations trustees in early 1952, that put forward the first plan for the foundations program in this field. In that paper, hitherto unpublished, the notion of the behavioral sciences was characterized as follows:

In short, then, Program Five is conceived as an effort to increase knowledge of human behavior through basic scientific research oriented to major problem areas covering a wide range of subjects, and to make such knowledge available for utilization in the conduct of human affairs. (Ford Foundation 1953, pp. 35)

The report went on to identify the topics that constituted the subject matter of the behavioral sciences, at least insofar as the foundations interests were then concerned: political behavior, domestic and international; communication; values and beliefs; individual growth, development, and adjustment; behavior in primary groups and formal organizations; behavioral aspects of the economic system; social classes and minority groups; social restraints on behavior; and social and cultural change.

It was in this way that an administrative decision having to do with the programming and organization of a large foundation influenced at least the nomenclature, and probably even the conception, of an intellectual field of inquiry. The history of science contains several instances of intellectual concepts becoming administratively institutionalized, for example, psychoanalysis and gross national product (GNP). The concept behavioral sciences represents the reverse: an administrative arrangement that became intellectually institutionalized.

In the 1940s there were some similar stirrings within the universities themselves. In 1946 Harvard University organized a department of social relations, which was in fact, though not in name, a behavioral sciences department, even to the exclusion of economics, political science, parts of anthropology and psychology, and, after a brief experimental period, history. And about 1950 a group of social and biological scientists at the University of Chicago began to seek a general theory of behavior under the term behavioral sciences first, because its neutral character made it acceptable to both social and biological scientists and, second, because we foresaw a possibility of someday seeking to obtain financial support from persons who might confound social science with socialism (Miller 1955, p. 513). Earlier still, a somewhat similar effort was launched at the Institute of Human Relations at Yale University, although the line-up of specialties was different from what is now known as the behavioral sciences.

Here is the original post:
Behavioral Sciences FREE Behavioral Sciences ...

Food Science Experiments: Biochemistry of Milk – Mozzarella Cheese (Accessible Preview) – Video


Food Science Experiments: Biochemistry of Milk - Mozzarella Cheese (Accessible Preview)
Students demonstrate the process for making cheese and how the composition of milk aids the cheese making process. Producer/Distributor: LEARNING ZONE EXPRES...

By: dcmpnad

More:
Food Science Experiments: Biochemistry of Milk - Mozzarella Cheese (Accessible Preview) - Video