bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibitor of Apoptosis (
IAP
) and
BIR
‐containing Proteins
Authors: Vaux David L 
Published: September 2009

Abstract

The inhibitor of apoptosis (IAP) family of proteins are characterized by presence of one or more baculoviral IAP Repeat (BIR) domains, so they are also termed BIRCs, for ‘BIR‐containing’ proteins. The first IAPs were identified in insect‐attacking viruses, which use them to inhibit defensive apoptosis of the host cell. Subsequently, other BIR‐containing proteins have been found in organisms from yeasts to mammals. The human IAP XIAP can block apoptosis by directly inhibiting caspases, whereas cIAP1 and cIAP2 inhibit apoptosis by reducing caspase‐activating signals from tumour necrosis factor (TNF) receptor superfamily members. As the genes for some IAPs are amplified in cancers, they appear to be able to act as oncogenes. IAP‐antagonist compounds modelled on the IAP antagonist Smac/Diablo are being developed for the treatment of cancer, and are currently undergoing clinical trials.

Key concepts

All IAPs bear at least one BIR domain, but not all BIR‐containing proteins are inhibitors of apoptosis.

XIAP can block apoptosis by directly inhibiting caspases, but cIAP1 and cIAP2 inhibit apoptosis by reducing caspase‐activating signals from TNF receptor superfamily members, and by promoting activation of canonical NFκB pathways rather than noncanonical NFκB pathways.

Genes for some IAPs are amplified in cancers, and IAP‐antagonist compounds modelled on the IAP antagonist Smac/Diablo are being developed for the treatment of cancer.

Survivin and BRUCE are not apoptosis inhibitors, but are needed for cell division.
Autophagy in Nonmammalian Systems
Authors: Hill Jahda H , Baehrecke Eric H 
Published: September 2009

Abstract

Autophagy, or ‘self‐eating’, is a catabolic process that enables lysosome‐mediated degradation of cytoplasmic contents and recycling of macromolecules to be used in essential cellular processes. This process enables cells to survive during nutrient restriction, participates in cell death during development, and functions in clearance of protein aggregates and intracellular pathogens. Autophagy has been widely studied in yeast,

Drosophila

and

Caenorhabditis elegans

, and studies in these organisms have revealed regulation by multiple cellular pathways. These include cell growth regulators, such as the Class I
PI3 kinase
and target of rapamycin (TOR), as well as cell death regulators, including caspases. Defects in autophagy are associated with cancer, neurodegeneration and reduced lifespan. Genetic experiments in

Drosophila

and

C. elegans

have been critical in determining how impairment of autophagy functions in these diseases.

Key concepts

Several yeast screens in the 1990s revealed genes required for autophagy.

Over 30
atg
genes have been shown to regulate autophagy.

Autophagy is induced in response to starvation and oxidative stress, enabling cells to recycle macromolecules and degrade damaged organelles.

Autophagy is required for steroid‐triggered removal of larval tissues during

Drosophila melanogaster

development.

Autophagosomes can sequester intracellular pathogens, which evade the cell's phagocytic machinery, and traffic them to the lysosome for degradation.

Decreased autophagy leads to an inability to clear protein aggregates and mutant polyglutamine containing proteins from neurons in fly and worm neurodegeneration models.

Induction of autophagy in the adult fly brain by transgenic expression of ATG8 can extend lifespan, whereas knock down of

atg7

or

atg8

leads to increased neuronal cell death and reduced lifespan.
History of Cell Biology
Authors: Dröscher Ariane 
Published: September 2009

AbstractAlthough egg cells are visible to the naked eye, the history of cell biology is closely coupled to that of microscopy. In nearly 350 years, cell research has produced an extraordinary rich panorama of studies, concepts and representations. Robert Hooke's 1665 analogy to monk cells, the transition from ‘cellular tissue’ to single ‘cells’ around the year 1800, Schleiden and Schwann's identification of the cell as the elementary unit of life, the prominent status it gained during cytology's expansion to the other fields of biomedical inquiry, Schultze's definition as ‘a clump of protoplasm containing a nucleus’, the worlds of endocellular and ultrastructural organization, the ‘compartimentalization’ of the cell in the 1950s and 1960s, its role as map for biochemical and molecular research, all these are just few of the many historical answers to the question ‘what is a cell and what is it good for?’.Key concepts:For the beginning of cell biology as a new research field it was not sufficient to be merely able to see cells.The development of cell biology was coupled with the evolution of optical instruments and of anatomical theory.One indispensable prerequisite for the formulation of the first cell theory was the shift from the concept of cellular tissue to that of cells as single units.Cell research underwent ‘golden ages’ whenever cells were considered the basic units of life.Many outstanding life scientists did not attribute central importance to cells.The study of cells was (and still is) extraordinarily rich in different ways of seeing, describing, depicting and conceiving.Though it originated from a specific theory, the history of cell biology is characterized by its growing independence from general theory.Throughout its history cell biology was characterized by its ability to expand into neighbouring research fields and to integrate their concepts and methods.
Virus‐induced Tumourigenesis
Authors: Duensing Stefan 
Published: September 2009

Abstract

Some of the deadliest and most frequent malignant tumours worldwide are caused by microbes. It has been estimated that viruses contribute to approximately 15–20% of all malignancies in humans. Tumour viruses are not only a global health problem, they have also been instrumental for seminal discoveries in fundamental cancer research and helped to shape the current concepts of multistep tumourigenesis and malignant progression. This article will summarize the basic principles of viral oncogenesis followed by examples of known and emerging human tumour viruses.

Key concepts:

Oncogenic viruses are a major cause of cancer‐related death worldwide.

Oncogenic viruses have evolved to target key regulatory pathways of infected host cells through different mechanisms including insertional mutagenesis, gene piracy and specialized viral proteins, which target host cellular proteins (oncoproteins).

The most common host cell signalling pathways targeted by tumour viruses are the retinoblastoma (pRB) and p53 tumour suppressor pathways.

Tumour viruses frequently subvert host cell control of the cell division cycle, apoptosis, genome integrity and immune recognition.

Human tumour viruses include DNA viruses (HPV, EBV, KSHV and HBV) and RNA viruses (HTLV‐I and HCV).

The most recently discovered emerging human tumour virus is Merkel cell polyomavirus (MCPyV).
Caspases in Inflammation and Immunity
Authors: LeBlanc Philippe M , Saleh Maya 
Published: September 2009

Abstract

Two of the main challenges that eukaryotic multicellular organisms faced during evolution were to cope with invading microorganisms and to eliminate infected cells. The immune system evolved to handle both tasks. Intertwined with immunity is programmed cell death that tailors the immune response and provides an effective way to remove infected cells. Caspases, effectors of inflammation and programmed cell death cascades, are perfectly suited to regulate the host response to invaders and injury. Their activity as inflammatory and killer proteases is regulated by direct binding to sensors of pathogens or danger, they can be modified following activation of signalling cascades by feedback mechanisms to terminate the inflammatory response and control cell survival, and they associate with coactivators and corepressors whose expression is closely linked to the needs of the cell.

Key concepts

Cell death and innate immunity are ancient evolutionarily conserved processes that utilize a number of related effectors and parallel signal transduction mechanisms.

Innate immunity provides first line defences against pathogens and acts as a sentinel that primes adaptive immunity.

Innate immunity depends on evolutionarily conserved germline‐encoded pattern recognition receptors (PRRs) that ‘sense’ pathogen‐associated molecular patterns (PAMPs) and ‘danger’ signals.

The role of caspases in innate immunity is conserved through evolution.

Caspase‐1, the prototypical member of the inflammatory caspase subfamily, contributes to host defence through different interrelated mechanisms, notably cell repair, inflammation and cell death.

Caspase‐1 activity is necessary for host resistance to pathogens; however, when deregulated, it is at the basis of multiple inflammatory diseases.

Inflammatory caspases are activated in NLR‐scaffolded multiprotein complexes termed ‘inflammasomes’ that are reminiscent of the apoptosome. Caspase‐12, an inflammatory caspase related to caspase‐1, is an endogenous inhibitor of the inflammasome.

Apoptosis tailors adaptive immunity. Mutations in
Casp‐8
and
Casp‐10
cause autoimmune lymphoproliferative syndrome (ALPS).

Excessive apoptotic caspase activity contributes to the pathogenesis of inflammatory diseases such as severe sepsis.
Free and Forced Vibration Models
Authors: Haroon Muhammad 
Published: September 2009

AbstractThis article provides an overview of vibrations‐based structural health monitoring (SHM). The framework of vibrations‐based SHM is discussed by using Newton's Law to interpret the various aspects, including data types and classes of techniques available. The process of SHM is illustrated by discussing experimental and numerical examples of loads and damage identification drawn from the literature and the use of this SHM information in the development of empirical damage prognosis models.
Static Damage Phenomena and Models
Authors: Sundararaman Shankar 
Published: September 2009

AbstractThis article provides an overview of static damage phenomena and the physical models utilized to identify damage using measured data. Static damage models provide an understanding of the underlying physics associated with damage, which is usually described in terms of boundary conditions, loading conditions, and material, geometric, electromagnetic, and thermodynamic properties. Examples that apply static damage models to examine changes due to damage in elastic waves in structural materials are discussed. Additionally, as a sample sensitivity analysis study, damage in metallic, orthotropic, and composite plates is modeled as variations in local geometry, stiffness, damping, and mass density using two‐dimensional and three‐dimensional wave propagation models based on the local interaction simulation approach (LISA).
Damage Evolution Phenomena and Models
Authors: Grandt Alten F. 
Published: September 2009

AbstractThe goal of this article is to overview some of the structural health monitoring issues associated with the development and growth of structural damage. A brief summary of various structural failure modes is provided, with particular emphasis on cyclic fatigue. Although fatigue is one of the commonly recognized failure modes, it is problematic for structural health monitoring. The complexity of this mechanism leads to many subtle load history effects that must be recognized and captured to obtain an accurate prognosis of remaining fatigue life. The article concludes with a proposed “witness sample” method that could provide a cost‐effective approach for monitoring structures for evidence of potential fatigue damage.
Applications of Acoustic Emission forSHM: A Review
Authors: Wevers Martine , Lambrighs Kasper 
Published: September 2009

AbstractThis article reviews the application of acoustic emission (AE) for structural health monitoring. The basic principles of AE are explained and a historical background is given. The different types of AE, the wave propagation, the detection, the Kaiser effect and the Felicity ratio, the signal analysis, and the localization and discrimination methods are described in detail. This is followed by a literature review on the most common applications of AE for structural health monitoring. The article concludes with some future prospects of AE.
Ultrasonic Methods
Authors: Hillger Wolfgang 
Published: September 2009

AbstractUltrasonic testing (UT) is a well‐established nondestructive technique. It is based on ultrasonic waves in a frequency range usually from 0.5 to 20 MHz. UT provides a quality control, determination of material properties, and a flaw detection with location in all three dimensions. Using echo technique, only a one‐sided access of the test component is necessary. A flaw detector provides instantaneous results. Automated systems deliver images like C‐scans (top view) and B‐scans (view in cross‐section direction) of hidden defects. In this article, the physical principles of UT are explained and the parts of an imaging system are described.
Piezoelectric Impedance Methods for Damage Detection and Sensor Validation
Authors: Park Gyuhae , Farrar Charles R. 
Published: September 2009

Abstract
This article presents an overview and recent applications in impedance‐based structural health monitoring (SHM). The basic principle behind this technique is to apply high‐frequency structural excitations (typically greater than 30 kHz) through surface‐bonded piezoelectric transducers, and measure the local mechanical impedance by monitoring the current and voltage applied to the piezoelectric transducers. Changes in impedance indicate changes in the structure, which in turn can indicate that damage has occurred. Previous experimental studies are summarized to demonstrate how this technique can be efficiently used to detect structural damage in real time. The impedance method also has applications in the field of sensor self‐diagnostics and validation in determining the operational status of piezoelectric active sensors used in SHM. The feasibility of this sensor validation procedure is demonstrated by analytical studies and experimental examples, where the functionality of surface‐mounted piezoelectric sensors was continuously deteriorated.
Thermal Imaging Methods
Authors: Balageas Daniel L. 
Published: September 2009

AbstractThermal imaging methods, more particularly infrared (IR) thermography, are commonly used techniques in nondestructive evaluation. They are also beginning to be used in experimental mechanics. They could be very useful for structural health monitoring purposes, although they cannot be totally embedded in the structures. Two main approaches exist for using these techniques as structural health monitoring tools.The first approach is based on the fact that all mechanical phenomena are accompanied by correlated thermal effects (thermomechanical coupling). These effects can be reversible or irreversible. The reversible thermal phenomena are a link to the strain (and stress) state of structures. Generally, irreversible phenomena are the signature of the occurrence of damage. Mapping the thermal state of a structure is a means to detect abnormalities in the mechanical behavior of the structure.The second approach comes from classical nondestructive evaluation: damages are detected, localized, and characterized by the disturbances they introduce in the local thermal properties (heat conduction, heat diffusion, heat capacity, effusivity, interface thermal resistance) of the structure.The physical principles of IR radiometry and the state of the art IR thermography are recalled. The analysis of the thermographic process shows how to perform a quantitative measurement, a requisite for the identification of structural health and the characterization of damages. The different ways to perform structural health monitoring with IR thermography are finally detailed: diagnostic elaboration based on a thermomechanical analysis (strain mapping and fatigue detection), and damage detection and characterization by stimulated thermography.
Eddy‐Current Methods
Authors: Goldfine Neil , Washabaugh Andrew , Sheiretov Yanko , Windoloski Mark 
Published: September 2009

Abstract

In the context of structural health monitoring (SHM), eddy‐current testing (ET) is one of several techniques that the maintainers of high‐value assets can select as part of an asset life management program. In this article, conventional ET and advanced ET methods are described. The focus is on scanning and point‐by‐point ET using handheld or automated systems. This article also describes an advanced ET method called the
MWM‐Array
in detail and associated multivariate inverse methods called
grid methods
. In a companion article on eddy‐current
in situ
sensors, the focus is on surface‐mounted and embedded sensors for SHM, using onboard instrumentation or portable data‐acquisition units.
Full‐Field Sensing: Three‐Dimensional Computer Vision and Digital Image Correlation for Noncontacting Shape and Deformation Measurements
Authors: Sutton Michael A. 
Published: September 2009

AbstractComputer vision methods using digital image correlation for image matching, with emphasis on stereovision systems for three‐dimensional shape and displacement measurements, are described. Basic theoretical developments and details regarding a recent application of the methodology to quantify deformations in structural components are presented. Results indicate that vision‐based methods can be used successfully to quantify shape and deformation in a wide range of structural and component configurations.
Electric and Electromagnetic Properties Sensing
Authors: Lemistre Michel B. 
Published: September 2009

Abstract
A new family of electromagnetic techniques allowing to obtain information on the health of structures made of composite materials has been developed recently. These techniques, easily transposable in the domain of structural health monitoring (SHM), consist of determining the state of the health of a structure by measuring its two main electric parameters (i.e. the electric conductivity and/or the dielectric permittivity), the main damages inducing locally a significant variation of these two parameters. After a short recall of the elements of electromagnetic theory, necessary to fully understand these techniques, the various methods are explained and examples of application are provided.
Fiber Bragg Grating Sensors
Authors: Peters Kara 
Published: September 2009

Abstract
This article reviews the principles and application of optical fiber Bragg gratings (FBGs) as strain and temperature sensors for structural health monitoring applications. FBG sensors have many advantages for strain sensing in such applications including their small size, the potential to multiplex hundreds of sensors with a single ingress/egress fiber, their immunity to electromagnetic interference, and their corrosion resistance. The spectral properties of FBGs and their response to applied strain and temperature fields are derived. Multiplexing and interrogation strategies for large sensor networks are presented. Special focus is placed on the response of FBGs to multiaxis strain fields and rapidly varying strain fields such as near the location of structural damage. Common approaches to invert the spectral response of an FBG subjected to a complex strain field are also reviewed. Finally, this article reviews common fabrication techniques for FBGs and their relative impacts on the strength of these sensors.
Novel Fiber‐Optic Sensors
Authors: Peters Kara 
Published: September 2009

Abstract
This article reviews novel fiber‐optic sensors for the measurement of strain and temperature that are based on recently developed optical fiber technologies. Sensors based on surface relief gratings and sapphire optical fibers for high‐temperature environments are presented. Additionally, the response of fiber Bragg gratings in extremely low‐temperature environments is discussed. The optical and mechanical response of newly developed single‐mode polymer optical fibers over large‐strain ranges is explained, along with the fabrication of FBGs in such fibers. As compared to conventional silica fibers, single‐mode polymer optical fibers demonstrate increased phase sensitivity to strain and negative phase sensitivity to temperature. Recently fabricated microstructured optical fibers, which demonstrate little or no temperature sensitivity and can incorporate a variety of sensors with novel properties, are also reviewed. Multicore optical fibers, which have been applied for the measurement of local curvatures and networked for the measurement of the shape of flexible structures, are also discussed. Finally, recent examples of the application of microelectromechanical system (MEMS) technology to the fabrication of optical fiber sensors, including focused ion beam machining, are presented.
Intensity‐, Interferometric‐, and Scattering‐Based Optical‐Fiber Sensors
Authors: Peters Kara 
Published: September 2009

Abstract
This article presents the sensing mechanics, strain and temperature sensitivity, and data‐acquisition techniques for optical‐fiber sensors based on intensity, phase shifts, and intrinsic scattering. Such sensors are well suited for health‐monitoring applications. The utilization of standard optical fibers for the measurement of strain through fiber fractures or microbending is described. Afterward, the equation for the phase shift in a lightwave propagating through an optical fiber is derived. The sensitivity of this phase shift to external parameters such as strain and temperature is also derived and typical values for fused silica optical fibers cited. The measurement of this phase shift through Mach–Zehnder and Michelson in‐fiber interferometer configurations is presented. Active and passive homodyne techniques for the interrogation of these periodic phase shift signals to alleviate directional ambiguity and signal fading near quadrature points are described. The alternative interferometer configurations of low‐coherence and Fabry–Perot interferometers are described, which provide absolute measurements of strain and/or temperature for large structural applications. Finally, the measurement of distributed strain and temperatures through intrinsic scattering phenomena with the optical fiber and, in particular, stimulated Brillouin scattering is summarized.
Piezoelectric Wafer Active Sensors
Authors: Yu Lingyu , Giurgiutiu Victor 
Published: September 2009

AbstractEmbedded ultrasonic nondestructive evaluation (NDE) permits active structural health monitoring (SHM), i.e., the on‐demand interrogation of the structure to determine its current state of structural health. The enabling element of embedded ultrasonic NDE is the piezoelectric wafer active sensor (PWAS). We begin with reviewing the PWAS operational principles. Then the mechanism of using PWAS as guided‐wave transmitters and receivers is presented. PWAS interacts with the host structure through the shear‐lag model. Lamb wave mode tuning can be achieved by the judicious combination of PWAS dimensions, frequency value, and Lamb mode characteristics. The use of pitch‐catch, pulse‐echo, and phased‐array ultrasonic methods for Lamb wave SHM is addressed. Next, the use of electromechanical (E/M) impedance method with PWAS is described. The local dynamics of the structure can be identified directly through the E/M impedance spectrum of the PWAS permanently mounted to the structure. Simulation studies using analytical and finite element methods are run to predict the structural responses and verified with experimental results. Finally, novel PWAS developments are briefly addressed, including thein situfabricated PWAS and thin‐film PWAS. The article concludes with a discussion on the current status and the future directions for PWAS transducers.