These allow the user to stop and restart the simulation at any time, insert simulator breakpoints ( independent of the HDL code ), and monitor or modify any element in the HDL model hierarchy.

Linking is system-dependent ( Win32 / Linux / SPARC ), as the HDL simulator and user libraries are compiled and linked outside the HDL environment.

The majority of the initial test / debug cycle is conducted in the HDL simulator environment, as the early stage of the design is subject to frequent and major circuit changes.

* MyHDL Python based HDL — generates Verilog or VHDL

An HDL description can also be prototyped and tested in hardware — programmable logic devices are often used for this purpose.

The PALASM ( from " PAL assembler ") language was used to express boolean equations for the output pins in a text file which was then converted to the ' fuse map ' file for the programming system using a vendor-supplied program ; later the option of translation from schematics became common, and later still, ' fuse maps ' could be ' synthesized ' from an HDL ( hardware description language ,) such as Verilog.

To simulate an HDL model, an engineer writes a top-level simulation environment ( called a testbench ).

The testbench code is event driven: the engineer writes HDL statements to implement the ( testbench-generated ) reset-signal, to model interface transactions ( such as a host – bus read / write ), and to monitor the DUT's output.

Events occur only at the instants dictated by the testbench HDL ( such as a reset-toggle coded into the testbench ), or in reaction ( by the model ) to stimulus and triggering events.

Replacing animal fats with partially hydrogenated oil reduces cholesterol but adds trans fat, which has been shown to both raise LDL cholesterol and lower HDL cholesterol.

High-density lipoprotein ( HDL ) is one of the five major groups of lipoproteins, which, in order of sizes, largest to smallest, are chylomicrons, VLDL, IDL, LDL, and HDL, which enable lipids like cholesterol and triglycerides to be transported within the water-based bloodstream.

It is often contrasted with low-density or LDL cholesterol or LDL-C. HDL particles are able to remove cholesterol from within artery atheroma and transport it back to the liver for excretion or re-utilization, which is the main reason why the cholesterol carried within HDL particles ( HDL-C ) is sometimes called " good cholesterol " ( despite the fact that it is exactly the same as the cholesterol in LDL particles ).

A plasma enzyme called lecithin-cholesterol acyltransferase ( LCAT ) converts the free cholesterol into cholesteryl ester ( a more hydrophobic form of cholesterol ), which is then sequestered into the core of the lipoprotein particle, eventually making the newly synthesized HDL spherical.

HDL is removed by HDL receptors such as scavenger receptor BI ( SR-BI ), which mediate the selective uptake of cholesterol from HDL.

The triglycerides are not stable in HDL, but degraded by hepatic lipase so that finally small HDL particles are left, which restart the uptake of cholesterol from cells.

However, HDL carries many lipid and protein species, several of which have very low concentrations but are biologically very active.

In the stress response, serum amyloid A, which is one of the acute-phase proteins and an apolipoprotein, is under the stimulation of cytokines ( IL-1, IL-6 ), and cortisol produced in the adrenal cortex and carried to the damaged tissue incorporated into HDL particles.

However, using this 9-valued logic (< tt > U </ tt >,< tt > X </ tt >,< tt > 0 </ tt >,< tt > 1 </ tt >,< tt > Z </ tt >,< tt > W </ tt >,< tt > H </ tt >,< tt > L </ tt >,< tt >-</ tt >) instead of simple bits ( 0, 1 ) offers a very powerful simulation and debugging tool to the designer which currently does not exist in any other HDL.

Low-density lipoprotein ( LDL ) is one of the five major groups of lipoproteins, which in order of size, largest to smallest, are chylomicrons, VLDL, IDL, LDL, and HDL, that enable transport of multiple different fat molecules, including cholesterol, within the water around cells and within the water-based bloodstream.

Studies have shown that higher levels of type-B LDL particles ( as opposed to type-A LDL particles ) promote health problems and cardiovascular disease, they are often informally called the bad cholesterol particles, ( as opposed to HDL particles, which are frequently referred to as good cholesterol or healthy cholesterol particles ).

Development of torcetrapib, a drug that increases production of HDL, or " good cholesterol ", which reduces LDL thought to be correlated to heart disease, was cancelled in December 2006.

In general, as the design flow progresses toward a physically realizable form, the design database becomes progressively more laden with technology-specific information, which cannot be stored in a generic HDL description.

Examples include the high-density ( HDL ) and low-density ( LDL ) lipoproteins, which enable fats to be carried in the blood stream, the transmembrane proteins of the mitochondrion and the chloroplast, and bacterial lipoproteins.

This beneficial effect was attributed to bilirubin IXα which is recognised as a potent antioxidant, rather than confounding factors such as high-density lipoprotein ( HDL ) levels.

The flagship implementation, the OR1200, is an RTL model in Verilog HDL, from which a SystemC-based cycle-accurate model can be built in ORPSoC.

# Induction of lipoprotein lipolysis: Increased triglyceride-rich lipoproteins ( TRL ) lipolysis could be a reflection of changes in intrinsic lipoprotein lipase ( LPL ) activity which may contribute to the increase of plasma HDL concentrations and a more efficient reverse cholesterol transport.

The FPGA configuration is generally specified using a hardware description language ( HDL ), similar to that used for an application-specific integrated circuit ( ASIC ) ( circuit diagrams were previously used to specify the configuration, as they were for ASICs, but this is increasingly rare ) in one package, employing technology developed for 3D construction and stacked-die assemblies.

The HDL form is more suited to work with large structures because it's possible to just specify them numerically rather than having to draw every piece by hand.

In healthy individuals, about thirty percent of blood cholesterol is carried by HDL.

HDL is the smallest of the lipoprotein particles.

Delivery of HDL cholesterol to adrenals, ovaries, and testes is important for the synthesis of steroid hormones.

This pathway has been termed reverse cholesterol transport and is considered as the classical protective function of HDL toward atherosclerosis.

All these properties may contribute to the ability of HDL to protect from atherosclerosis, and it is not yet known what are the most important.

This ratio of large HDL to total HDL particles varies widely and is measured only by more sophisticated lipoprotein assays using either electrophoresis ( the original method developed in the 1970s ) or newer NMR spectroscopy methods ( See also: NMR and spectroscopy ), developed in the 1990s.

Both methods have long been promoted on the basis of lowest cost, though neither of these measurements directly, or reliably, reflects HDL particle functionality to remove cholesterol from atherosclerotic plaque and can therefore be misleading, especially on an individual patient-by-patient basis Labs use the routine dextran sulfate-Mg < sup > 2 +</ sup > precipitation method with ultracentrifugation / dextran sulfate-Mg < sup > 2 +</ sup > precipitation as reference method.

A variety of blood tests are available for analyzing cholesterol transport behavior, HDL, LDL, triglycerides, lipoprotein little a, homocysteine, C-reactive protein, blood sugar control: fasting, after eating or averages using glycosylated albumen or hemoglobin, myoglobin, creatine kinase, troponin, brain-type natriuretic peptide, etc.

Several steps in the metabolism of HDL can contribute to the transport of cholesterol from lipid-laden macrophages of atherosclerotic arteries, termed foam cells, to the liver for secretion into the bile.

Low concentrations of HDL ( below 40 mg / dL for men, below 50 mg / dL for women ) increase the risk for atherosclerotic diseases.

Data from the landmark Framingham Heart Study showed that, for a given level of LDL, the risk of heart disease increases 10-fold as the HDL varies from high to low.

On the converse, however, for a fixed level of HDL, the risk increases 3-fold as LDL varies from low to high.

< div class =" noprint "> Reference ranges for blood tests, comparing HDL cholesterol ( in orange at right ) to other blood constituents .</ div >

The American Heart Association, NIH and NCEP provides a set of guidelines for fasting HDL levels and risk for heart disease.

Niacin has been used for over 50 years to increase levels of HDL in the blood and has been found to modestly decrease the risk of cardiovascular events in a number of controlled human trials.

By lowering VLDL levels, niacin also increases the level of high-density lipoprotein ( HDL ) or " good " cholesterol in blood, and therefore it is sometimes prescribed for people with low HDL, who are also at high risk of a heart attack.

One can design hardware in a VHDL IDE ( for FPGA implementation such as Xilinx ISE, Altera Quartus, Synopsys Synplify or Mentor Graphics HDL Designer ) to produce the RTL schematic of the desired circuit.

In electronics, a hardware description language or HDL is any language from a class of computer languages, specification languages, or modeling languages for formal description and design of electronic circuits, and most commonly, digital logic.

Like concurrent programming languages, HDL syntax and semantics include explicit notations for expressing concurrency.

HDL can be used to express designs in structural, behavioral or register-transfer-level architectures for the same circuit functionality ; in the latter two cases the synthesizer decides the architecture and logic gate layout.

In short, logic synthesis propelled HDL technology into a central role for digital design.

However, VHDL and Verilog share many of the same limitations: neither HDL is suitable for analog / mixed-signal circuit simulation.