Helpers

Most reactions in cells are carried out by enzymes [1], In many instances the rates of enzyme-catalysed reactions are enhanced by a factor of a million. A significantly large fraction of all known enzymes are proteins which are made from twenty naturally occurring amino acids. The amino acids are linked by peptide bonds to fonn polypeptide chains. The primary sequence of a protein specifies the linear order in which the amino acids are linked. To carry out the catalytic activity the linear sequence has to fold to a well defined tliree-dimensional (3D) stmcture. In cells only a relatively small fraction of proteins require assistance from chaperones (helper proteins) [2]. Even in the complicated cellular environment most proteins fold spontaneously upon synthesis. The detennination of the 3D folded stmcture from the one-dimensional primary sequence is the most popular protein folding problem. 

How to design sequences tliat adopt a specified fold [9] This is tire inverse protein folding problem tliat is vital to the biotechnology industry. There are some proteins tliat do not spontaneously reach tire native confomiation. In tire cells tliese proteins fold witli tire assistance of helper molecules referred to as chaperonins. The chaperonin-mediated folding problem involves an understanding of tire interactions between proteins. 

Sofh are applications can mainly be divided into stand-alone programs that have to be installed on a local computer, and web-based appUcation.s. Furthermore, there arc two different tcchniquc.s u.scd in web-based applications for providing the programs applets and plug-ins. Whereas plug-ins (helper applications) have to be installed to be displayed correctly in a browser, java applets are loaded by the browser on demand. The basic requirement for executing java applets is that the java Virtual Machine (jVM) must be pre-installed on the local computer, which is oltcn the case. 

L. M. Gedansky and L. G. Helper, Thermochemisty of Gold and Its Compounds, Engelhard Industries Technical Bulletin X(1), Engelhard Minerals Chemicals Corp., Edison, N.J., 1969. 

Gradual diminution of 004 T-lymphocytes from the peripheral blood is the most consistent feature observed in HIV infection. Because the majority of 004 cells are T-helper lymphocytes, removal leads to deficiency of cellular immunity, which depends on T-helper cells to initiate cytotoxic T-ceU killing of vims-infected cells of cancer. The loss of immune surveillance leads to the appearance of viraHy induced tumors from unopposed clonal expansion of viraHy transformed cells. Furthermore, depletion of cellular immunity leads to exaggerated viral, fungal, and proto2oal infections. 

Adjuvants are substances which can modify the immune response of an antigen (139,140). With better understanding of the functions of different arms of the immune system, it is possible to explore the effects of an adjuvant, such that the protective efficacy of a vaccine can be improved. At present, aluminum salt is the only adjuvant approved for use in human vaccines. New adjuvants such as QS-21, 3D-MPL, MF-59, and other liposome preparations are being evaluated. Several of these adjuvants have been in clinical trial, but none have been approved for human use. IL-12 has been proposed as an adjuvant which can specifically promote T-helper 1 ceU response, and can be a very promising adjuvant for future vaccine development. 

In contrast to steam turbines, in which runaway overspeediug is always a problem, pump-turbines operating at design head go to zero torque at about 130 to 140 percent of design speed. Thus, overspeed protection may not be necessary if the pump-turbine can withstand 140 to 150 percent of design speed and it is the sole driver. When a steam-turbine helper is used, it should be provided with the usual overspeed trip-out mechanism. 

Very few self-sufficient viruses have only 60 protein chains in their shells. The satellite viruses do not themselves encode all of the functions required for their replication and are therefore not self-sufficient. The first satellite virus to be discovered, satellite tobacco necrosis virus, which is also one of the smallest known with a diameter of 180 A, has a protein shell of 60 subunits. This virus cannot replicate on its own inside a tobacco cell but needs a helper virus, tobacco necrosis virus, to supply the functions it does not encode. The RNA genome of the satellite virus has only 1120 nucleotides, which code for the viral coat protein of 195 amino acids but no other protein. With this minimal genome the satellite viruses are obligate parasites of the viruses that parasitize cells. 

Gas turbine frame sizes are limited, and custom sizing is not done as it is with steam turbines therefore, the increment matching can only be done with a helper turbine. There is some benefit besides the power matching when used with a single-shaft turbine. The steam turbine can be used as the starter. For two-shaft turbines, a dedicated starter is needed on the gasifier turbine compressor package. 

The expander is somewhat difficult to govern, and is someluiics used with a helper steam turbine for use in starting and speed control. 

The crucial experiments that determined the structures of a number of very simple crystals, beginning with sodium chloride, were done, not by von Laue and his helpers, but by the Braggs, William (1862-1942) and Lawrence (1890-1971), father... 

Operator utilization = Helper utilization = Machine utilization =... 

Hetfer, m. helper, assistant Helio-echtrot, n. (Dyes) helio fast red. -farb-stoff, m. helio dye. 

Laborant, m. (male) laboratory helper, technician. -in,/, (female) laboratory helper, technician. 

In addition to antibodies, the immune system also consists of bone-marrow derived lymphocytes, or B cells, and T cells that come from the thymus gland, both of which (indirectly) produce antibodies. These cells, in turn, may be helped by helper cells (= H) and suppressed by suppressor cells (= S). Helper cells may be alarmed as to the presence of antigens by macrophages (= M) that eat the antigens and leave parts of their meal on their cell surface. 

The normal immune response is modeled using antibodies A, B cells, helpers H, suppressors S and antigens, or viruses, V. Each of these concentrations can be either high (= 1) or low 0). The dynamics is defined as follows ... 

We can interpret these equations in the following way. The first line assures us that antibodies will be present only when B cells, helper cells and antigens are all present. The second line states that B cells will grow if antigens and/or B cells are present and if helped by helper cells. The third line indicates that helper cells arise either if other helper cells ai e present or, if no suppressor cells are present, if there are any antigens. The fourth line yields suppressor cells if suppressor cells are already present and/or there are any helper cells. The last line implies that the antigen remains if there are no antibodies or vani.shes if antibodies are present. Since concentrations cannot exceed 1, it is understood that, in the above equations, 1 + 1 = 1. 

Now suppose the body s immune system malfunctions and begins attacking the body itself. A typical scenario might involve killer cells K attacking helper and/or suppressor cells. Chowdbury and Stauffer [chowdQO] developed a simple five-cell model using two types of helper cells Hi and H2). two type of suppressors Si and S2) and one killer cell (K) ... 

In patients infected with HIV (human immunodeficiency virus), the helper cell population is weakened to the point where the immune system is no longer able to function properly. The body thus becomes susceptible to otherwise nonlethal diseases such as pneumonia. 

A recent example of a CA model of the immune response in AIDS is Pandley s four-cell model using interactions among macrophages (= M) containing parts of the virus on their surface, helper T cells (= H), cytotoxic T cells (= C) and the virus (= V) ([pand89], [pandQl]) ... 

The first equation states that cytotoxic cells grow only if helper cells, macrophages and the virus are all present. The second equation implies that, when the virus is not present, helper cells grow if macrophages and/or helper cells are present. The third equation implies that macrophages grow both when the virus is present and there is already a concentration of macrophages. The last equation describes the... 

Stauffer [stauff92] reports that the concentration of cells in this system quickly saturates. For low initial concentrations po, the viral population wins over the population of cells of the immune system and the system can be said to develop Aids. For larger po, the population of helper T cells becomes greater than that of the virus and the immune system wins. 

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