Surgery, Computer-Assisted: Surgical procedures conducted with the aid of computers. This is most frequently used in orthopedic and laparoscopic surgery for implant placement and instrument guidance. Image-guided surgery interactively combines prior CT scans or MRI images with real-time video.Image Processing, Computer-Assisted: A technique of inputting two-dimensional images into a computer and then enhancing or analyzing the imagery into a form that is more useful to the human observer.Computer-Assisted Instruction: A self-learning technique, usually online, involving interaction of the student with programmed instructional materials.Diagnosis, Computer-Assisted: Application of computer programs designed to assist the physician in solving a diagnostic problem.ComputersProtein Sorting Signals: Amino acid sequences found in transported proteins that selectively guide the distribution of the proteins to specific cellular compartments.Therapy, Computer-Assisted: Computer systems utilized as adjuncts in the treatment of disease.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Sperm Motility: Movement characteristics of SPERMATOZOA in a fresh specimen. It is measured as the percentage of sperms that are moving, and as the percentage of sperms with productive flagellar motion such as rapid, linear, and forward progression.Radiographic Image Interpretation, Computer-Assisted: Computer systems or networks designed to provide radiographic interpretive information.Decision Making, Computer-Assisted: Use of an interactive computer system designed to assist the physician or other health professional in choosing between certain relationships or variables for the purpose of making a diagnostic or therapeutic decision.Bone Malalignment: Displacement of bones out of line in relation to joints. It may be congenital or traumatic in origin.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Image Interpretation, Computer-Assisted: Methods developed to aid in the interpretation of ultrasound, radiographic images, etc., for diagnosis of disease.Numerical Analysis, Computer-Assisted: Computer-assisted study of methods for obtaining useful quantitative solutions to problems that have been expressed mathematically.Arthroplasty, Replacement, Knee: Replacement of the knee joint.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Reproducibility of Results: The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results.Software: Sequential operating programs and data which instruct the functioning of a digital computer.Anatomy: A branch of biology dealing with the structure of organisms.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Computer-Aided Design: The use of computers for designing and/or manufacturing of anything, including drugs, surgical procedures, orthotics, and prosthetics.Drug Therapy, Computer-Assisted: Adjunctive computer programs in providing drug treatment to patients.Microcomputers: Small computers using LSI (large-scale integration) microprocessor chips as the CPU (central processing unit) and semiconductor memories for compact, inexpensive storage of program instructions and data. They are smaller and less expensive than minicomputers and are usually built into a dedicated system where they are optimized for a particular application. "Microprocessor" may refer to just the CPU or the entire microcomputer.Imaging, Three-Dimensional: The process of generating three-dimensional images by electronic, photographic, or other methods. For example, three-dimensional images can be generated by assembling multiple tomographic images with the aid of a computer, while photographic 3-D images (HOLOGRAPHY) can be made by exposing film to the interference pattern created when two laser light sources shine on an object.User-Computer Interface: The portion of an interactive computer program that issues messages to and receives commands from a user.Automatic Data Processing: Data processing largely performed by automatic means.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Signal Processing, Computer-Assisted: Computer-assisted processing of electric, ultrasonic, or electronic signals to interpret function and activity.Neuroanatomy: Study of the anatomy of the nervous system as a specialty or discipline.Observer Variation: The failure by the observer to measure or identify a phenomenon accurately, which results in an error. Sources for this may be due to the observer's missing an abnormality, or to faulty technique resulting in incorrect test measurement, or to misinterpretation of the data. Two varieties are inter-observer variation (the amount observers vary from one another when reporting on the same material) and intra-observer variation (the amount one observer varies between observations when reporting more than once on the same material).Interviews as Topic: Conversations with an individual or individuals held in order to obtain information about their background and other personal biographical data, their attitudes and opinions, etc. It includes school admission or job interviews.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Mammography: Radiographic examination of the breast.Bone Screws: Specialized devices used in ORTHOPEDIC SURGERY to repair bone fractures.Neuronavigation: Intraoperative computer-assisted 3D navigation and guidance system generally used in neurosurgery for tracking surgical tools and localize them with respect to the patient's 3D anatomy. The pre-operative diagnostic scan is used as a reference and is transferred onto the operative field during surgery.Spermatozoa: Mature male germ cells derived from SPERMATIDS. As spermatids move toward the lumen of the SEMINIFEROUS TUBULES, they undergo extensive structural changes including the loss of cytoplasm, condensation of CHROMATIN into the SPERM HEAD, formation of the ACROSOME cap, the SPERM MIDPIECE and the SPERM TAIL that provides motility.Multimedia: Materials, frequently computer applications, that combine some or all of text, sound, graphics, animation, and video into integrated packages. (Thesaurus of ERIC Descriptors, 1994)MicrofilmingSoftware Validation: The act of testing the software for compliance with a standard.Fractures, Malunited: Union of the fragments of a fractured bone in a faulty or abnormal position. If two bones parallel to one another unite by osseous tissue, the result is a crossunion. (From Manual of Orthopaedic Terminology, 4th ed)Tomography, X-Ray Computed: Tomography using x-ray transmission and a computer algorithm to reconstruct the image.Audiovisual Aids: Auditory and visual instructional materials.Cadaver: A dead body, usually a human body.Cataloging: Activities performed in the preparation of bibliographic records for CATALOGS. It is carried out according to a set of rules and contains information enabling the user to know what is available and where items can be found.CD-ROM: An optical disk storage system for computers on which data can be read or from which data can be retrieved but not entered or modified. A CD-ROM unit is almost identical to the compact disk playback device for home use.Catalogs, LibraryKnee Prosthesis: Replacement for a knee joint.Knee Joint: A synovial hinge connection formed between the bones of the FEMUR; TIBIA; and PATELLA.Radiation: Emission or propagation of acoustic waves (SOUND), ELECTROMAGNETIC ENERGY waves (such as LIGHT; RADIO WAVES; GAMMA RAYS; or X-RAYS), or a stream of subatomic particles (such as ELECTRONS; NEUTRONS; PROTONS; or ALPHA PARTICLES).Nuclear Localization Signals: Short, predominantly basic amino acid sequences identified as nuclear import signals for some proteins. These sequences are believed to interact with specific receptors at the NUCLEAR PORE.Spermatocidal Agents: Chemical substances that are destructive to spermatozoa used as topically administered vaginal contraceptives.Videotape Recording: Recording of visual and sometimes sound signals on magnetic tape.Semen Analysis: The quality of SEMEN, an indicator of male fertility, can be determined by semen volume, pH, sperm concentration (SPERM COUNT), total sperm number, sperm viability, sperm vigor (SPERM MOTILITY), normal sperm morphology, ACROSOME integrity, and the concentration of WHITE BLOOD CELLS.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Histology: The study of the structure of various TISSUES of organisms on a microscopic level.Models, Anatomic: Three-dimensional representation to show anatomic structures. Models may be used in place of intact animals or organisms for teaching, practice, and study.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Joint Deformities, Acquired: Deformities acquired after birth as the result of injury or disease. The joint deformity is often associated with rheumatoid arthritis and leprosy.Biometric Identification: A method of differentiating individuals based on the analysis of qualitative or quantitative biological traits or patterns. This process which has applications in forensics and identity theft prevention includes DNA profiles or DNA fingerprints, hand fingerprints, automated facial recognition, iris scan, hand geometry, retinal scan, vascular patterns, automated voice pattern recognition, and ultrasound of fingers.Otologic Surgical Procedures: Surgery performed on the external, middle, or internal ear.Fluoroscopy: Production of an image when x-rays strike a fluorescent screen.Semen Preservation: The process by which semen is kept viable outside of the organism from which it was derived (i.e., kept from decay by means of a chemical agent, cooling, or a fluid substitute that mimics the natural state within the organism).Breast: In humans, one of the paired regions in the anterior portion of the THORAX. The breasts consist of the MAMMARY GLANDS, the SKIN, the MUSCLES, the ADIPOSE TISSUE, and the CONNECTIVE TISSUES.Sexual Behavior: Sexual activities of humans.Programmed Instruction as Topic: Instruction in which learners progress at their own rate using workbooks, textbooks, or electromechanical devices that provide information in discrete steps, test learning at each step, and provide immediate feedback about achievement. (ERIC, Thesaurus of ERIC Descriptors, 1996).Dental Implantation: The grafting or inserting of a prosthetic device of alloplastic material into the oral tissue beneath the mucosal or periosteal layer or within the bone. Its purpose is to provide support and retention to a partial or complete denture.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Questionnaires: Predetermined sets of questions used to collect data - clinical data, social status, occupational group, etc. The term is often applied to a self-completed survey instrument.Antelopes: Any of various ruminant mammals of the order Bovidae. They include numerous species in Africa and the American pronghorn.Image Cytometry: A technique encompassing morphometry, densitometry, neural networks, and expert systems that has numerous clinical and research applications and is particularly useful in anatomic pathology for the study of malignant lesions. The most common current application of image cytometry is for DNA analysis, followed by quantitation of immunohistochemical staining.Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, and practicability of these interventions in individual cases or series.Osteotomy: The surgical cutting of a bone. (Dorland, 28th ed)Anatomic Landmarks: Reference points located by visual inspection, palpation, or computer assistance, that are useful in localizing structures on or within the human body.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Chlormerodrin: A mercurial compound that has been used as a diuretic but is now superseded by more potent and less toxic drugs. The radiolabeled form has been used as a diagnostic and research tool.Sensitivity and Specificity: Binary classification measures to assess test results. Sensitivity or recall rate is the proportion of true positives. Specificity is the probability of correctly determining the absence of a condition. (From Last, Dictionary of Epidemiology, 2d ed)Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Photography: Method of making images on a sensitized surface by exposure to light or other radiant energy.Computer Simulation: Computer-based representation of physical systems and phenomena such as chemical processes.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Color: The visually perceived property of objects created by absorption or reflection of specific wavelengths of light.Immunohistochemistry: Histochemical localization of immunoreactive substances using labeled antibodies as reagents.Semen: The thick, yellowish-white, viscid fluid secretion of male reproductive organs discharged upon ejaculation. In addition to reproductive organ secretions, it contains SPERMATOZOA and their nutrient plasma.Remedial Teaching: Specialized instruction for students deviating from the expected norm.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.Education, Medical, Undergraduate: The period of medical education in a medical school. In the United States it follows the baccalaureate degree and precedes the granting of the M.D.Attitude to Computers: The attitude and behavior associated with an individual using the computer.DNA Fingerprinting: A technique for identifying individuals of a species that is based on the uniqueness of their DNA sequence. Uniqueness is determined by identifying which combination of allelic variations occur in the individual at a statistically relevant number of different loci. In forensic studies, RESTRICTION FRAGMENT LENGTH POLYMORPHISM of multiple, highly polymorphic VNTR LOCI or MICROSATELLITE REPEAT loci are analyzed. The number of loci used for the profile depends on the ALLELE FREQUENCY in the population.Sperm Count: A count of SPERM in the ejaculum, expressed as number per milliliter.Mercury Radioisotopes: Unstable isotopes of mercury that decay or disintegrate emitting radiation. Hg atoms with atomic weights 185-195, 197, 203, 205, and 206 are radioactive mercury isotopes.Femur: The longest and largest bone of the skeleton, it is situated between the hip and the knee.Evaluation Studies as Topic: Studies determining the effectiveness or value of processes, personnel, and equipment, or the material on conducting such studies. For drugs and devices, CLINICAL TRIALS AS TOPIC; DRUG EVALUATION; and DRUG EVALUATION, PRECLINICAL are available.Pathology: A specialty concerned with the nature and cause of disease as expressed by changes in cellular or tissue structure and function caused by the disease process.Pattern Recognition, Automated: In INFORMATION RETRIEVAL, machine-sensing or identification of visible patterns (shapes, forms, and configurations). (Harrod's Librarians' Glossary, 7th ed)Radiographic Image Enhancement: Improvement in the quality of an x-ray image by use of an intensifying screen, tube, or filter and by optimum exposure techniques. Digital processing methods are often employed.Pilot Projects: Small-scale tests of methods and procedures to be used on a larger scale if the pilot study demonstrates that these methods and procedures can work.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Osteoarthritis, Knee: Noninflammatory degenerative disease of the knee joint consisting of three large categories: conditions that block normal synchronous movement, conditions that produce abnormal pathways of motion, and conditions that cause stress concentration resulting in changes to articular cartilage. (Crenshaw, Campbell's Operative Orthopaedics, 8th ed, p2019)Cell Nucleus: Within a eukaryotic cell, a membrane-limited body which contains chromosomes and one or more nucleoli (CELL NUCLEOLUS). The nuclear membrane consists of a double unit-type membrane which is perforated by a number of pores; the outermost membrane is continuous with the ENDOPLASMIC RETICULUM. A cell may contain more than one nucleus. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)Sequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.Stereotaxic Techniques: Techniques used mostly during brain surgery which use a system of three-dimensional coordinates to locate the site to be operated on.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Retinal Vessels: The blood vessels which supply and drain the RETINA.Kinetics: The rate dynamics in chemical or physical systems.Video Recording: The storing or preserving of video signals for television to be played back later via a transmitter or receiver. Recordings may be made on magnetic tape or discs (VIDEODISC RECORDING).Data Collection: Systematic gathering of data for a particular purpose from various sources, including questionnaires, interviews, observation, existing records, and electronic devices. The process is usually preliminary to statistical analysis of the data.Bacterial Proteins: Proteins found in any species of bacterium.Prosthesis Fitting: The fitting and adjusting of artificial parts of the body. (From Stedman's, 26th ed)Computing Methodologies: Computer-assisted analysis and processing of problems in a particular area.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Range of Motion, Articular: The distance and direction to which a bone joint can be extended. Range of motion is a function of the condition of the joints, muscles, and connective tissues involved. Joint flexibility can be improved through appropriate MUSCLE STRETCHING EXERCISES.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Feasibility Studies: Studies to determine the advantages or disadvantages, practicability, or capability of accomplishing a projected plan, study, or project.Computer Systems: Systems composed of a computer or computers, peripheral equipment, such as disks, printers, and terminals, and telecommunications capabilities.Venules: The minute vessels that collect blood from the capillary plexuses and join together to form veins.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.Microscopy, Video: Microscopy in which television cameras are used to brighten magnified images that are otherwise too dark to be seen with the naked eye. It is used frequently in TELEPATHOLOGY.Acrosome Reaction: Changes that occur to liberate the enzymes of the ACROSOME of a sperm (SPERMATOZOA). Acrosome reaction allows the sperm to penetrate the ZONA PELLUCIDA and enter the OVUM during FERTILIZATION.Genu Varum: An outward slant of the thigh in which the knees are wide apart and the ankles close together. Genu varum can develop due to skeletal and joint dysplasia (e.g., OSTEOARTHRITIS; Blount's disease); and malnutrition (e.g., RICKETS; FLUORIDE POISONING).Robotics: The application of electronic, computerized control systems to mechanical devices designed to perform human functions. Formerly restricted to industry, but nowadays applied to artificial organs controlled by bionic (bioelectronic) devices, like automated insulin pumps and other prostheses.Surgical Procedures, Minimally Invasive: Procedures that avoid use of open, invasive surgery in favor of closed or local surgery. These generally involve use of laparoscopic devices and remote-control manipulation of instruments with indirect observation of the surgical field through an endoscope or similar device.Transfection: The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.Staining and Labeling: The marking of biological material with a dye or other reagent for the purpose of identifying and quantitating components of tissues, cells or their extracts.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Telephone: An instrument for reproducing sounds especially articulate speech at a distance. (Webster, 3rd ed)Computer User Training: Process of teaching a person to interact and communicate with a computer.Tibia: The second longest bone of the skeleton. It is located on the medial side of the lower leg, articulating with the FIBULA laterally, the TALUS distally, and the FEMUR proximally.Teaching: The educational process of instructing.Teaching Materials: Instructional materials used in teaching.Heart Auscultation: Act of listening for sounds within the heart.Breast Neoplasms: Tumors or cancer of the human BREAST.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Pelvis: The space or compartment surrounded by the pelvic girdle (bony pelvis). It is subdivided into the greater pelvis and LESSER PELVIS. The pelvic girdle is formed by the PELVIC BONES and SACRUM.Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.Arthroplasty, Replacement, Hip: Replacement of the hip joint.Sacrum: Five fused VERTEBRAE forming a triangle-shaped structure at the back of the PELVIS. It articulates superiorly with the LUMBAR VERTEBRAE, inferiorly with the COCCYX, and anteriorly with the ILIUM of the PELVIS. The sacrum strengthens and stabilizes the PELVIS.Risk-Taking: Undertaking a task involving a challenge for achievement or a desirable goal in which there is a lack of certainty or a fear of failure. It may also include the exhibiting of certain behaviors whose outcomes may present a risk to the individual or to those associated with him or her.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Palate, Soft: A movable fold suspended from the posterior border of the hard palate. The uvula hangs from the middle of the lower border.Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.Spine: The spinal or vertebral column.Analysis of Variance: A statistical technique that isolates and assesses the contributions of categorical independent variables to variation in the mean of a continuous dependent variable.Hip Joint: The joint that is formed by the articulation of the head of FEMUR and the ACETABULUM of the PELVIS.Internet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.Mice, Inbred C57BLImage Enhancement: Improvement of the quality of a picture by various techniques, including computer processing, digital filtering, echocardiographic techniques, light and ultrastructural MICROSCOPY, fluorescence spectrometry and microscopy, scintigraphy, and in vitro image processing at the molecular level.Prosthesis Implantation: Surgical insertion of a prosthesis.Social Desirability: A personality trait rendering the individual acceptable in social or interpersonal relations. It is related to social acceptance, social approval, popularity, social status, leadership qualities, or any quality making him a socially desirable companion.Orthopedic Procedures: Procedures used to treat and correct deformities, diseases, and injuries to the MUSCULOSKELETAL SYSTEM, its articulations, and associated structures.Membrane Proteins: Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).United StatesProteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.Neurons: The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.Educational Measurement: The assessing of academic or educational achievement. It includes all aspects of testing and test construction.Retinal Vein: Central retinal vein and its tributaries. It runs a short course within the optic nerve and then leaves and empties into the superior ophthalmic vein or cavernous sinus.Self Disclosure: A willingness to reveal information about oneself to others.Expert Systems: Computer programs based on knowledge developed from consultation with experts on a problem, and the processing and/or formalizing of this knowledge using these programs in such a manner that the problems may be solved.Data Display: The visual display of data in a man-machine system. An example is when data is called from the computer and transmitted to a CATHODE RAY TUBE DISPLAY or LIQUID CRYSTAL display.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.DNA, Complementary: Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.Adaptor Proteins, Signal Transducing: A broad category of carrier proteins that play a role in SIGNAL TRANSDUCTION. They generally contain several modular domains, each of which having its own binding activity, and act by forming complexes with other intracellular-signaling molecules. Signal-transducing adaptor proteins lack enzyme activity, however their activity can be modulated by other signal-transducing enzymesFeedback: A mechanism of communication within a system in that the input signal generates an output response which returns to influence the continued activity or productivity of that system.Unsafe Sex: Sexual behaviors which are high-risk for contracting SEXUALLY TRANSMITTED DISEASES or for producing PREGNANCY.HIV Infections: Includes the spectrum of human immunodeficiency virus infections that range from asymptomatic seropositivity, thru AIDS-related complex (ARC), to acquired immunodeficiency syndrome (AIDS).Automation: Controlled operation of an apparatus, process, or system by mechanical or electronic devices that take the place of human organs of observation, effort, and decision. (From Webster's Collegiate Dictionary, 1993)Plasmids: Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.Signal Detection, Psychological: Psychophysical technique that permits the estimation of the bias of the observer as well as detectability of the signal (i.e., stimulus) in any sensory modality. (From APA, Thesaurus of Psychological Index Terms, 8th ed.)Sequence Homology, Nucleic Acid: The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.Spinal Fusion: Operative immobilization or ankylosis of two or more vertebrae by fusion of the vertebral bodies with a short bone graft or often with diskectomy or laminectomy. (From Blauvelt & Nelson, A Manual of Orthopaedic Terminology, 5th ed, p236; Dorland, 28th ed)Chemotaxis: The movement of cells or organisms toward or away from a substance in response to its concentration gradient.Nuclear Export Signals: Specific amino acid sequences present in the primary amino acid sequence of proteins which mediate their export from the CELL NUCLEUS. They are rich in hydrophobic residues, such as LEUCINE and ISOLEUCINE.Cross-Sectional Studies: Studies in which the presence or absence of disease or other health-related variables are determined in each member of the study population or in a representative sample at one particular time. This contrasts with LONGITUDINAL STUDIES which are followed over a period of time.Microscopy, Fluorescence: Microscopy of specimens stained with fluorescent dye (usually fluorescein isothiocyanate) or of naturally fluorescent materials, which emit light when exposed to ultraviolet or blue light. Immunofluorescence microscopy utilizes antibodies that are labeled with fluorescent dye.DNA-Binding Proteins: Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Fertility: The capacity to conceive or to induce conception. It may refer to either the male or female.Biomechanical Phenomena: The properties, processes, and behavior of biological systems under the action of mechanical forces.Rats, Sprague-Dawley: A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.Rotation: Motion of an object in which either one or more points on a line are fixed. It is also the motion of a particle about a fixed point. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Arterioles: The smallest divisions of the arteries located between the muscular arteries and the capillaries.Artificial Intelligence: Theory and development of COMPUTER SYSTEMS which perform tasks that normally require human intelligence. Such tasks may include speech recognition, LEARNING; VISUAL PERCEPTION; MATHEMATICAL COMPUTING; reasoning, PROBLEM SOLVING, DECISION-MAKING, and translation of language.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Sperm Head: The anterior portion of the spermatozoon (SPERMATOZOA) that contains mainly the nucleus with highly compact CHROMATIN material.Cell Count: The number of CELLS of a specific kind, usually measured per unit volume or area of sample.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Hip Prosthesis: Replacement for a hip joint.Equipment Design: Methods of creating machines and devices.Prosthesis Design: The plan and delineation of prostheses in general or a specific prosthesis.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Computer Graphics: The process of pictorial communication, between human and computers, in which the computer input and output have the form of charts, drawings, or other appropriate pictorial representation.Single-Blind Method: A method in which either the observer(s) or the subject(s) is kept ignorant of the group to which the subjects are assigned.Cell Division: The fission of a CELL. It includes CYTOKINESIS, when the CYTOPLASM of a cell is divided, and CELL NUCLEUS DIVISION.Protein Transport: The process of moving proteins from one cellular compartment (including extracellular) to another by various sorting and transport mechanisms such as gated transport, protein translocation, and vesicular transport.Fluorescent Dyes: Agents that emit light after excitation by light. The wave length of the emitted light is usually longer than that of the incident light. Fluorochromes are substances that cause fluorescence in other substances, i.e., dyes used to mark or label other compounds with fluorescent tags.Femur Head: The hemispheric articular surface at the upper extremity of the thigh bone. (Stedman, 26th ed)Students, Medical: Individuals enrolled in a school of medicine or a formal educational program in medicine.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.