bluuebunny/crossref_metadata_2025 huggingface dataset:
Demosaicing and Aliasing Correction
Authors: Guarnera M. , Messina G. , Tomaselli V.
Published: November 2012

Acquisition of color images requires the presence of different sensors for different color
channels. Manufacturers reduce the cost and complexity by placing a color filter array (CFA)
on top of a single image sensor, which is basically a monochromatic device, to acquire color information
of the true visual scene. Since each image sensing element can detect only one color
of illumination, the missing information must be filled in. The color interpolation process (also
called demosaicing) aims to reconstruct the full resolution image acquired by the sensor, by calculating
the missing components. Picture quality is strictly related to the peculiarity of demosaicing
process. Due to the aliasing phenomenon, such as false colors and zipper effects, the color interpolation
has to guarantee the rendering of high quality pictures avoiding artifacts. In this chapter we
review some solutions devoted to demosaicing and antialiasing. Demosaicing algorithms can be
basically divided into two main categories: spatial-domain and frequency-domain. Demosaicing
solutions are not always able to completely eliminate false colors and zipper effects, thus imaging
pipelines often include a post-processing module, with the aim of removing residual artifacts.
Some of these techniques are also described.
Red Eyes Removal
Authors: Messina G. , Meccio T.
Published: November 2012

Since the large diffusion of mobile devices with embedded camera and flashgun, the
red eye artifacts have de-facto become a critical problem. Red eyes are caused by the flash light
reflected off the blood vessels of the human retina. This effect is more pronounced when the flash
light is closer to the camera lens, which often occurs in compact imaging devices. To reduce these
artifacts, most cameras have a red-eye flash mode which fires a series of pre-flashes prior picture
acquisition. The biggest disadvantage of the pre-flash approach is power consumption (flash is the
most power-consuming part of imaging devices), and thus it is not suitable for power-constrained
systems (e.g., mobile devices). Moreover, this approach does not guarantee total prevention of red
eye artifacts. Red eye removal must then be performed in post-processing, through the use of automatic
correction algorithms. The aim of this Chapter is to depict the state of the art of automatic
detection and correction of red eyes, taking into account strong points and drawbacks of the most
well-known techniques, with particular emphasis on the image degradation risk associated to false
positives in red eye detection and to wrong correction of red eyes. Furthermore the problem of
estimating the quality of the final result, without reference image, is examined.
Video Stabilization
Authors: Meccio T. , Puglisi G. , Spampinato G.
Published: November 2012

To make a high quality video with a hand-held camera is a very difficult task. The
unwanted movements of our hands typically blur and introduce disturbing jerkiness in the recorded
video. Moreover this problem is amplified when a zoom lens or a digital zoom is used. To solve
this problem many video stabilization techniques have been developed. Optical based approaches
measure camera shake and control the jitter acting on lens or on the CCD/CMOS sensor. On the
other hand digital video stabilization techniques make use only of information drawn from images
and do not need any additional hardware tools. This Chapter describes the algorithms typically
involved in the video stabilization pipeline (motion estimation, unwanted movement detection,
frame warping) highlighting their issues and weak points.
Image and Video Coding and Formatting
Authors: Bruna A. , Buemi A. , Spampinato G.
Published: November 2012

The data acquired by the sensor have to be processed by the coprocessor or the host
microprocessor, so both the systems have to share the same communication protocol and data
format. Moreover, at the end of the image generation pipeline the image must be coded in a
standard format in order to be read by every external device. Usually the sensor provides the image
in the Bayer format. In the past the Bayer data were stored and transmitted using proprietary
format and protocol; such solution has the drawback that every designer had to use the same
proprietary interface to manage the sensor data. In the latest years the majority of companies
making, buying or specifying imagine devices proposed a new standard called Standard Mobile
Imaging Architecture (SMIA). It allows interconnecting sensors and hosts of different vendors.
Concerning the output of the coprocessor, several standard formats are available. For still images
the most frequently used are the Joint Picture Expert Group (JPEG) with a lossy compression, the
Targa Interchange Format (TIF) with a lossless compression. In the top level imaging devices the
output of the sensors can also be stored directly by making use of a proprietary file format, such as
the Nikon Electronic Image Format (NEF), the Canon RAW File Format (CRW), etc. For videos
the most used are MJPEG, MPEG-4, H.263 and H264 standards. This chapter besides presenting
the main data formats gives also a short description to the next JPEG XR Image Coding Standard.
Moreover some techniques concerning the compression factor control and the error detection and
concealment are introduced.
Beyond Embedded Device
Authors: Battiato S. , Castorina A. , Messina G.
Published: November 2012

In the recent years, technology advances in sensors and image processing have allowed
significant improvements that encompass not only quality, but also image content analysis and
understanding. Consumer devices are now being equipped with sophisticated algorithms allowing
complex tasks such as face recognition, smile detection, automatic red eye removal, etc. In addition,
topics related to image forensics oriented to verify the authenticity of digital images, such as
camera identification and image manipulation detection are now available. This Chapter provides
an overview of the main topics representing a challenge to innovation both from hardware and
software point of view: Super Resolution, Temporal Demosaicing, Bracketing or High Dynamic
Range Reconstruction. Also some aspects of Computational Photography and Forensics Camera
Identification are briefly described. These topics represent the current trends and novel solutions
for the next generation of imaging devices.
Gamete Binding and Fusion
Authors: Yi Young-Joo , Sutovsky Peter
Published: November 2012

Fertilization is a stepwise process that starts before the actual gamete binding and fusion. Spermatozoa
travel through the female reproductive system and respond to chemotaxis and thermotaxis to reach the oocyte. In
most mammals, zona pellucida (ZP) glycoprotein ZPC is the primary sperm receptor that mediates sperm-ZP
binding and acrosomal exocytosis (AE). During AE, the outer acrosomal membrane, already primed for AE
during capacitation, fuses with the plasma membrane and undergoes vesiculation. The acrosomal matrix (AM) is
exposed and dispersed in a step-wise manner. Sperm-ZP penetration is supported by sperm motility and by
enzymatic activity of the hypothetical egg coat “lysin”, an acrosomal protease that digests the fertilization slit.
Acrosin has been considered as a zona lysin candidate. However, male mice lacking the Acr gene are fertile.
Recently, researchers have been focusing on the 26S proteasome as a mammalian and non-mammalian egg coat
lysin. Following zona penetration, spermatozoa reach the perivitelline space and adhere to and fuse with the
oolemma. Tetraspanin superfamily members CD9 and CD81 appear to act as sperm receptors on the oolemma,
possibly supported by integrins and other elements within the cortical tetraspanin web. IZUMO, a member of
immunoglobulin superfamily is a sperm ligand candidate for oolemma tetraspanins. Both CD9 and IZUMO are
essential for gamete adhesion and fertility in the mouse. However, there is no evidence yet supporting the
involvement of IZUMO and CD9 in sperm-egg plasma membrane fusion. After sperm-oolemma fusion, the
fertilizing spermatozoon is incorporated into the ooplasm, a process aided by oocyte cortex microfilaments.
Ionic Events at Fertilization
Authors: Dale Brian , Wilding Martin
Published: November 2012

The difference in ionic balance between the cytoplasm and the extracellular environment in all cells is
maintained by ion channels and transporters located in the plasma membrane. In this chapter we review the
voltage-gated channels and transporters common to both gametes and somatic cells and describe gamete specific
ligand-gated channels in spermatozoa and oocytes. In lower deuterostome oocytes the fertilization potential is
biphasic. The first event may be the result of gamete fusion, while the second larger depolarization is the result of
the activation of several hundred non-specific channels in the oocyte plasma membrane. The fertilization channel
is one of the largest channels known in biological membranes with a single channel conductance of upto 400pS
and a reversal potential of +20mV. A soluble sperm factor appears to gate this channel via the ADPr/NO
pathway. In higher deuterostomes the fertilization channel is a calcium-gated potassium channel. The type,
number and topographical distribution of channels and transporters change continually during gameteogenesis,
through fertilization to early embryonic cleavage stages indicating both the importance of ionic homeostasis and
the role of second messengers in early development.
Stem Cells from Oocytes and Oocytes from Stem Cells
Authors: Gandolfi Fulvio , Pennarossa Georgia , Vanelli Arianna , M. Rahman Mahbubur , A.L. Brevini Tiziana
Published: November 2012

Full oocyte competence is the indispensable requisite for embryonic development and, at present, no
ways are known to restore competence if, for any reason, it has been even slightly compromised. The same is not
true for sperm cells that can initiate and sustain development even if severely abnormal or damaged as long as the
DNA is intact. This points clearly to the uneven burden carried by the two gametes and indicates clearly the
essential role of the oocyte. Parthenogenesis is the obvious consequence of such disparity with a number of lower
species capable of giving birth to new individuals without any paternal contribution. Mammals are an exception
to the rule due to epigenetic mechanisms limiting the parthenotes developmental potential. However, the
blastocyst stage is easily reached and parthenogenetic stem cells can be generated whose differentiation potential
seems to be much wider than that of whole parthenotes. Switching perspective, we move from stem cells
originated from oocytes to oocytes originated from stem cells. Since embryonic stem cells can colonize the germ
cell lines when chimeras are generated, it was not so surprising that oocytes can be obtained from stem cells.
Although there is still a long way to go before full competence is reached it clearly opens the way to the
hypothesis of having an unlimited source of oocytes. Finally, a recent and highly controversial set of results
suggests that oocytes are not in such a limited supply as it is generally believed but post-natal oogenesis takes
place at a surprisingly high rate.
MicroRNAs and Cardiovascular Disease
Authors: Wang Zhiguo
Published: November 2012

Micro RNAs (miRNAs) are known to play an important role in gene expression regulation. Owing to their ever-increasing implications in the control of various biological and pathological processes, miRNAs have now been considered novel biomarkers of various human diseases including, cancer, viral disease, cardiovascular disorders, metabolic disturbances, etc. Unique expression profiles have been associated with specific pathological states.

Cardiovascular disease is among the main causes of mortality in developed countries. The pathological process of the heart is associated with altered expression profile of genes that are important for cardiac function. The implications of miRNAs in the pathological process of the cardiovascular system have recently been recognized, and the research on miRNAs in relation to cardiovascular disease is now in rapid progress. The aim of this ebook is to present updated research on the subject with analyses from published reports. Micro RNAs and Cardiovascular Disease caters to the growing interest and information needs of cardiac clinicians and gene expression researchers.
miRNAs in Myocardial Infarction
Authors: Wang Zhiguo
Published: November 2012

The aim of this chapter is to provide an overview on the role of miRNAs in myocardial ischemia,
ischemia/reperfusion injury and ischemic preconditioning. Myocardial ischemia due to occlusion of coronary
arteries constitutes the major cause of mortality and morbidity of humans worldwide by causing an array of
injuries. Timely myocardial reperfusion remains the most effective treatment strategy for reducing myocardial
infarct size, preventing left ventricular remodelling, preserving left ventricular systolic function and improving
clinical outcomes. However, the full benefits of myocardial reperfusion are not realized, given that the actual
process of reperfusing ischemic myocardium can independently induce myocardial injury. On the other hand,
heart has endogenous cardioprotective capability against myocardial/reperfusion injury, called ischemic
preconditioning. Recent studies indicate that miRNAs are implicated in all these different aspects of myocardial
ischemia. This chapter describes the role of miR-1 and mR-133 in myocardial ischemia, miR-21, miR-29 and
miR-320 in ischemia/reperfusion injury, and miR-21 and miR-199a in preconditioning.
miRNAs in Neointimal Lesion Formation
Authors: Wang Zhiguo
Published: November 2012

Several processes including endothelial angiogenesis, vascular neointimal lesion formation, vascular
inflammation process, lipoprotein metabolism, and hypertension are critically involved in atherosclerosis. This
chapter aims to introduce the role of miRNAs in neointimal formation. Neointimal formation is a common
pathological lesion in diverse cardiovascular diseases occurring at sites of subclinical atherosclerosis but are also
classical hallmarks of restenosis after stenting, angioplasty, endarterectomy, and arterial transplantation.
Neointimal growth is the balance between proliferation and apoptosis of vascular smooth muscle cells. A number
of miRNAs, miR-21, miR-143, miR-145, miR-221, and miR-222, have been demonstrated to play important role
in neointimal formation. Their corresponding target genes have also been established.
miRNAs in Inflammatory Macrophages
Authors: Wang Zhiguo
Published: November 2012

Several processes including endothelial angiogenesis, vascular neointimal lesion formation, vascular
inflammation process, lipoprotein metabolism, and hypertension are critically involved in atherosclerosis. This
chapter aims to introduce the role of miRNAs in vascular inflammation process. Atherosclerosis is now widely
accepted to be an inflammatory disease, characterized by degenerative as well as proliferative changes and
extracellular accumulation of lipid and cholesterol, in which an ongoing inflammatory reaction plays an important
role in both initiation and progression/destabilization, converting a chronic process into an acute disorder. In early
atheromotous plaques, inflammatory macrophages strive to alleviate the subendothelial accumulation of modified
lipoproteins carrying cholesterol esters. Consequently, the further recruitment and migration of cells induce
chronic inflammation. To date, only a few miRNAs have been shown to be involved in the vascular inflammation
process. These include miR-126 in regulating adhesion molecules, and miR-155 and miR-125a in regulating
inflammatory cytokine.
miRNAs in Cardiac Fibrosis
Authors: Wang Zhiguo
Published: November 2012

The goal of this chapter is to discuss the regulation of cardiac fibrosis by miRNAs. Cardiac myocytes
are normally surrounded by a fine network of collagen fibers. In the normal heart, two thirds of the cell
population is composed of nonmuscle cells, the majority of which are fibroblasts. Cardiac fibrosis is the result of
both an increase in fibroblast proliferation and extracellular matrix (ECM) deposition. A growing body of
evidence indicates that, along with cardiomyocytes hypertrophy, diffusion of interstitial fibrosis is a key
pathologic feature of myocardial remodelling in a number of cardiac diseases of different (e.g. ischemic,
hypertensive, valvular, genetic, and metabolic) origin. The extracellular matrix (ECM) is a dynamic
microenvironment; changes within ECM constitute the second important myocardial adaptation that occurs
during cardiac remodelling. A subset of miRNAs is enriched in cardiac fibroblasts compared to cardiomyocytes.
A number of studies have demonstrated the involvement of miRNAs in regulating myocardial fibrosis in the
settings of myocardial ischemia or mechanical overload. Some miRNAs (miR-208 and miR-21) have been shown
to favor fibrogenesis, being profibrotic miRNAs. Others including miR-29, miR-133, miR-30c, and miR-590
have been demonstrated to produce inhibitory effects on fibrogenesis, being anti-fibrotic miRNAs.
miRNAs in Cardiac Contraction
Authors: Wang Zhiguo
Published: November 2012

This chapter aims to introduce the role of miRNAs in regulating cardiac contraction. Cardiac
contraction is triggered by excitation–contraction coupling: the cascade of biological events that begins with
cardiac action potential and ends with myocyte contraction and relaxation. Cardiac muscle contraction is
determined by the intrinsic contractile proteins: α- and β-myosin heavy chain (αMHC and βMHC). αMHC and
βMHC are encoded by MYH6 and MYH7 genes, respectively, and their expression is species specific and varies
in response to developmental and pathophysiological signaling alterations. Remarkably, studies revealed that
myosin genes not only encode the major contractile proteins of muscle, but also act more broadly to control
muscle gene expression and performance through a network of intronic miRNAs: the transcripts from these genes
all contain pre-miRNAs. On the other hand, the cytoskeleton of cardiac myocytes consists of actin, the
intermediate filament desmin, the sarcomeric protein titin, and α- and β-tubulin, which form the microtubules by
polymerization. The loss of integrity of the cytoskeleton, with a resultant loss of linkage of the sarcomere to the
sarcolemma and extracellular matrix, would be expected to lead to contractile dysfunction. miRNAs have been
found to regulate both the contractile proteins (miR-208 and miR-21) and cytoskeleton proteins (miR-1 and miR-
133) to regulate cardiac contraction.
miRNAs in Neurohormonal Activation
Authors: Wang Zhiguo
Published: November 2012

This chapter aims to introduce the role of miRNAs in regulating neurohormonal activation. The natural
progression of heart failure is accompanied by the compensatory activation of cardiac and extracardiac
neurohormonal systems and changes in the anatomy and function of the left ventricle. An array of biologically
active molecules belong to the sympathetic adrenergic nervous system (norepinephrine) and renin–angiotensin–
aldosterone system (RAS) (Ang II and aldosterone), which are responsible for maintaining cardiac output through
increased retention of salt and water, peripheral arterial vasoconstriction, and contractility, as well as
inflammatory mediators that are responsible for cardiac repair and remodeling. Although, the role of miRNAs in
regulating the components of RAS and the adrenergic system is still poorly not well understood, several recent
observations are worth noting. In particular, miR-155 is implicated in suppressing the levels of the Ang II type 1
receptor, and miR-21 can increase aldosterone secretion in human adrenal cells. This chapter describes very
limited information in this regard.
Pulsating stars in the hot upper main sequence
Authors: Luis A. Balona
Published: November 2012

Although periodic light variability is rare among O-type stars, periodic line pro le variations are more common. The modes in these stars are probably all of high degree and the visibility may be a ected by obscuration. The observed frequencies in β Cep stars cover a wider range than predicted. This is a major unsolved problem which may point to problems in the current opacities. Observations of these stars in low-metallicity environments also present a challenge. Asteroseismology of these stars not been very successful due to the e ect of rotation and the fact that some observed modes are stable in the models. For the SPB stars, the decrease in amplitude with rotation is unexplained. The Be stars are clearly multiperiodic variables, but most of the periods are unresolved. Recent space observations suggest that some of the variability is probably due to rotational modulation. An alternative view is that the light and line pro le variations are due to obscuring clouds locked into co-rotation by a magnetic eld. The fact that the rotational velocities of early type Be stars are in general well below the critical velocity suggest that pulsation is not the trigger for mass loss. Recent space observations suggest that there may exist pulsating stars in the region between the SPB and δ Scuti instability strips. Models of pulsating supergiants are located in a high-luminosity extension of the β Cep and SPB instability strips, but observations do not support these calculations. Models of Wolf-Rayet stars invariably predict instability due to the strange mode mechanism, but like the O-type stars, observations of periodic variations are almost entirely absent.
roAp stars
Authors: Luis A. Balona
Published: November 2012

Rapidly pulsating Ap stars present the widest range of physical phenomena in any pulsating star. It seems probable that most of the driving is due to the κ mechanism in the H ionization zone in which convection is suppressed by the magnetic eld. Recent attempts to model some stars show that driving by this mechanism is sometimes insu cient and that another unknown mechanism is also at work. This is also indicated by the fact that the predicted instability strip for the κ mechanism is much hotter than observed. Much progress has occurred in the last decade and we now have a good understanding of the cyclic frequency jumps that occur in models as the magnetic eld is changed. Coupling of the pulsation with the magnetic eld induces a slow wave which is thought to damp δ Scuti pulsations in these stars. However, recent space observations have shown that in at least one roAp star a low frequency mode is also present, presenting a challenge to this idea. The eigenfunctions are far from simple spherical harmonics, considerably complicating mode identi cation. Observations indicate the presence of pulsational nodes in the atmosphere and variations in amplitude and phase shifts between di erent atomic species. This appears to be the result of chemical strati cation and running waves. The line pro le variations are axisymmetric except in the uppermost atmospheric layers. The non-axisymmetric variations are not understood, but may be a result of turbulence in the atmosphere or shock waves.
Pulsation in cool long-period variables
Authors: Luis A. Balona
Published: November 2012

In the period - luminosity (PL) diagram of pulsating red giants in the
LMC, five sequences can be identified. Recent observations have refined this initial
finding and many more sequences have been discovered. The two main sequences
comprise Miras and semiregulars which are stars in the fundamental and
first-overtone radial pulsation modes. Carbon-rich and oxygen-rich Miras form distinct
sub-sequences as do C-rich and O-rich semiregulars. At least four further sequences
roughly parallel to the Mira and semiregular sequences have been identified
which may correspond to higher overtone radial modes. The stars which populate
these sequences are the OGLE Small Amplitude Red Giants (OSARGs). The
OSARG sequences themselves are resolved into further subsequences of asymptotic
giant branch stars and stars below the tip of the red giant branch. It is likely that
nonradial modes are present in OSARGs as the Petersen diagram for these stars
show some period ratios close to unity. In addition to these complex sequences of
pulsating stars, there are two more sequences in the PL diagram. One sequence can
be shown to consist of contact binaries. The nature of stars in the other sequence is
a mystery. These stars have long secondary periods which do not seem to be due
to pulsation. Although it is certain that convection is responsible for driving pulsation
in these stars, the precise driving mechanism is not understood. It is possible
that in the low-amplitude stars pulsation may be driven stochastically.
Pulsations in white dwarfs and hot sub-dwarfs
Authors: Luis A. Balona
Published: November 2012

ZZ Ceti, V777 Her and DQV stars are white dwarfs with pulsations excited by convective driving. The highly distorted light curves in some of these stars provide information about the convective zone. In V777 Her itself, rotationally-split multiplets allow mode identi cation and a successful asteroseismological solution. The frequency spacings of the multiplets vary in a way which is not understood. A remarkable event occurred some years ago when V777 Her suddenly changed its pulsation characteristics in a very short time. Pulsations in DQ stars are probably caused by convective driving in the ionization zones of HeII or C (or both). Two recent suggestions for the so-called DB gap are discussed. Models indicate that the nuclear ε mechanism may be e ective in certain regions of the HR diagram, but so far no variables have been found in the predicted regions. The rates of period change in the pre-white dwarf GW Vir stars are puzzling. GW Vir itself has a very large number of frequencies and rotationally split multiplets which has led to a successful asteroseismological study. Di usion increases the abundance of Fe-group elements in the driving region of subdwarf B stars, leading to pulsations driven by the κ mechanism. While models can successfully reproduce the pulsation periods in the short-period V361 Hya group of sdB stars, this is not the case for the long-period V1093 Her group. The location of the instability strip and periods in these stars present a challenge. A number of asteroseismological solutions exist for V361 Hya stars by direct matching of observed and calculated periods. Recently a sdO star was found to be pulsating. Pulsations in He-rich subdwarfs and in extreme helium B stars are also discussed.
Space-Time-Frequency Pilot-Symbol Assisted Channel Estimation for MIMO-OFDM
Authors: (Clarence) Wong Kar Lun , Leib Harry
Published: November 2012

This chapter considers pilot symbol assisted linear mean square error channel estimation in the joint space-time-frequency (STF) domains, for multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) systems. Through the use of properly designed and placed pilot sequences, and three dimensional processing, the proposed STF channel estimator exploits the correlation that may exist in the three domains, yielding performance gains. Computer simulation results for a coded MIMO-OFDM system illustrate the performance advantages of our approach. As a specific example we show that in a MIMO-OFDM system employing a space-frequency orthogonal block code, such an STF channel estimation technique limits the bit error probability (BEP) degradation with respect to perfect channel knowledge to 2 dB at a BEP of 10-5 over the 3GPP fast-fading suburban macro environment with high transmit space correlation. Furthermore, we show that STF channel estimation reduces variability in BEP performance when the mobile speed varies.
Fast ML Decoding for OSTBC and QOSTBC Coded MIMO-OFDM Systems with Clipping
Authors: Xia Xiang-Gen , Li Zhefeng
Published: November 2012

An efficient way to reduce the peak-to-average power ratio (PAPR) in OFDM systems is clipping. After the clipping in an MIMO-OFDM system, the additive noise may not be white. In this chapter, we develop fast (single-symbol) maximum likelihood (ML) decoding algorithms for orthogonal space-time block codes (OSTBC) and (linearly transformed) quasi orthogonal space-time block codes (QOSTBC) in clipped MIMO-OFDM systems by using a clipping noise model with Gaussian approximation. By using the statistics of the clipping distortions, our newly developed fast ML decoding algorithms improve the performance for clipped MIMO-OFDM systems with OSTBC and QOSTBC while the decoding complexities are not increased. Simulation results are presented to illustrate the improvement.
Multiuser and Spatial Diversity in OFDM Systems with Co-channel Interference
Authors: Choi Wan
Published: November 2012

Orthogonal frequency division multiple access (OFDMA) becomes a popular framework of future cellular systems such as 3GPP LTE and IEEE 802.16e WiMAX. Spatial diversity and multiuser diversity are expected to play a key role in future OFDMA based cellular systems. Considering that cellular systems will operate in an interferencelimited environment, it is required to understand the effect of co-channel interference on spatial and multiuser diversity. This chapter highlights the effects of co-channel interference on spatial and multiuser diversity and provides insights into the interactions between multiuser diversity and spatial diversity in the presence of co-channel interference.
Multi-channel Communications with Adaptive Modulation, Power Loading, and Diversity Combining
Authors: Sang-Do Lee, Young-Chai Ko
Published: November 2012

To achieve higher spectral efficiency and more efficient usage of channel resources, adaptive modulation can be used jointly with diversity combining, or with power-loading, or with both selection diversity and power loading. We derive closed-form expressions of the performance of multi-channel systems with the conventional adaptive modulation and hybrid schemes, in terms of the spectral efficiency, the average bit error rate and the outage probability. Numerical results show that average modulation with selection-combining and power-loading (AMSP) offers higher spectral efficiency and lower outage probability than other schemes, and is more reliable in low signal to noise ratio (SNR) regions.
Mobile WiMAX MIMO Beamforming Algorithms and Simulations
Authors: Mao ian , Lin Zihuai , Xiao Pei
Published: November 2012

This chapter investigates performance of OFDMA based mobile WiMAX downlink Multiple Input Multiple Output (MIMO) beamforming algorithms and analyzes Signal to Interference plus Noise Ratio (SINR) distribution for the OFDMA based WiMAX uplink multi-user MIMO systems. MIMO techniques are supported in IEEE 802.16 standard to achieve array gain, diversity gain and multiplexing gain. Beamforming and beamforming plus MIMO increase transmission ranges and improve SINR for MIMO systems by reducing co-channel interferences. The beamforming-only scheme aims at interference cancelation to improve link SINR. The beamforming Plus MIMO scheme can not only exploit the array gain by using beamforming but can also achieve transmit or receive diversity gain and spatial multiplexing gain. Our simulation results show that beamforming plus MIMO significantly improves the performance by combining diversity gain and beamforming gain and alleviating the effect of antenna correlation. Therefore, the beamforming plus MIMO is a promising technique for the mobile WiMAX applications. For WiMAX uplink MIMO systems, a mathematical expression of the received SINR is derived, which provides an analysis tool for the studied WiMAX systems.
Overview of Escherichia coli
Authors: G Torres Alfredo , MP Arenas-Hernandez Margarita , Martinez-Laguna Ygnacio
Published: November 2012

Escherichia coli are Gram-negative bacteria found as normal commensal flora in the gastrointestinal
tract. As a pathogen, E. coli are the most frequent causes of bacterial infections, including urinary tract infections,
diarrheal disease, and other clinical infections such as neonatal meningitis, pneumonia and bacteremia. At least
six different categories of pathogenic E. coli causing enteric infections have been identified and further
characterized. In Latin America, as well as many other developing countries, diarrheal infections caused by E.
coli remain an important cause de infant morbidity - mortality. Due to the appearance of the highly virulent strain
of E. coli of serotype O157:H7 in the US and Canada in the 1980’s, and subsequently in other Latin American
countries, there is an increase need for accurate testing for this and other pathogenic E. coli strains, substantially
enhancing detection of virulent strains and, therefore, facilitating identification of sporadic E. coli infections and
outbreaks.
Enteroaggregative Escherichia coli
Authors: Navarro-Garcia Fernando , P Elias Waldir , Flores Jose , C Okhuysen Pablo
Published: November 2012

Enteroaggregative Escherichia coli (EAEC) have been identified in children and adults living in
developed and developing countries as well as in travelers returning from developing countries and in patients
infected with HIV. In addition to the acute complications of diarrhea, such as dehydration and death, EAEC can
also cause persisting diarrhea that can lead in turn to malnutrition and impaired growth and development in
children. EAEC strains are defined by the ability to produce a “stacked brick” appearance when placed on HEp-2
epithelial cells in culture, and contaminated food appears to be the main source of EAEC infection. EAEC are
genetically heterogeneous. EAEC strain 042 is the prototypical strain for the study of virulence factors and
pathogenicity; however, emergence of atypical EAEC has been described. Three major features of EAEC
pathogenesis have been defined; abundant adherence to the intestinal mucosa, elaboration of enterotoxins and
cytotoxins, and induction of mucosal inflammation. Infection with strains that possess specific virulence factors
correlate with elevated levels of fecal cytokines and inflammatory markers. Unfortunately, the diagnosis of EAEC
infection remains limited to research laboratories and therefore, are of little use in guiding antibiotic therapy.
EAEC induce short-term immunity in healthy individuals which suggests that immunoprophylaxis is a potential
option for control of EAEC.
Detection and Subtyping Methods of Diarrheagenic Escherichia coli Strains
Authors: Flores Jose , C. Okhuysen Pablo , Miliwebsky Elizabeth , Chinen Isabel , MI Vaz Tania , Irino Kinue
Published: November 2012

At least 6 categories of pathogenic E. coli are undoubtedly recognized as being associated with enteric
diseases. The importance of diarrheagenic E. coli is probably underestimated due to limited applications of
available diagnostic methods in routine laboratories, especially in developing countries. Several strategies have
been described for detection and characterization of diarrheagenic E. coli strains, mainly after the development of
more advanced techniques. Thus, this chapter presents culture- and DNA-based methods, as well as
immunological and biological assays to detect and characterize different diarrheagenic E. coli categories.
Additional methods for confirmation and subtyping are also presented. The method of choice will depend very
much on the facility of each laboratory, taking into account the sensitivity, specificity, reproducibility, reliability,
cost, infrastructural resources and technical skills required by each method. Apart from diagnostic methods we
also included some methods, which are more directed to research and epidemiological purposes, but may
eventually be useful for a more specific characterization of the E. coli strains.
Diarrheagenic Escherichia coli in Argentina
Authors: Rivas Marta , Lia Padola Nora , MA Lucchesi Paula , Masana Marcelo
Published: November 2012

In Argentina, a total of 1,117,718 diarrheal diseases cases were notified in 2008 with an incidence rate
of 28.12/100,000 inhabitants, being Diarrheagenic Escherichia coli (DEC) strains the most important etiological
agents associated to them. Several community-based studies have assessed the relative frequency of DEC
pathotypes, accounting for 6 to 28.8% (EPEC), 9.7 to 24.4% (ETEC), 0.3 to 17.1% (EIEC), 1.2 to 17.1% (STEC),
20 to 31.4% (EAEC), and 27.1 to 29% (DAEC). In the last 10 years, approximately 500 HUS cases were reported
annually, with an incidence that ranged between 7.8 and 17/100,000 children less than 5 years of age. STEC
O157:H7 was the major serotype isolated (60%), with prevalent genotype stx2/stx2c(vh-a)/eae/ehxA (81.4%), mainly
of the phage type 4 (40%). Two XbaI-PFGE patterns are prevalent, AREXHX01.0011 and AREXHX01.0022,
representing respectively 9.9% and 5.6% of the E. coli O157 Argentinean isolates in the database. Among the
non-O157 STEC strains, genetic profiles were more diverse, but stx2/eae/ehxA (66.2%) was prevalent. STEC
strains, mainly Stx2-producers, have been recovered from animals and food, being cattle an important reservoir,
with increased risk of illness linked to beef-related dietary habits, and animal exposure. The implementation of
integral preventive measures is necessary to decrease the incidence of diarrheal disease in Argentina and the
associated human and economic costs.
Epidemiology of Diarrheagenic Escherichia coli Pathotypes in Mexico, Past and Present
Authors: Navarro Armando , Estrada-Garcia Teresa
Published: November 2012

In Mexico, diarrhea diseases are the second leading cause of death in children ≤ 5 years old. Studies
regarding enteropathogens associated with severe acute diarrhea, requiring hospitalization, have revealed
diarrheagenic Escherichia coli pathotypes (DEC) as the second most prevalent group, only after rotavirus, in
children of this age. DEC epidemiology has changed throughout the years, until the mid ‘90s enterotoxigenic E.
coli and typical enteropathogenic E. coli (tEPEC) strains were more often isolated from children aged ≤ 5 years,
nowadays is enteroaggregative E. coli (EAEC) followed by atypical EPEC. Other DEC identified these days
include, ETEC, non-O157:H7 Shiga-toxin producing E. coli (STEC), tEPEC and enteroinvasive E. coli (EIEC).
DEC strains have been isolated from local food samples in enough quantities to cause disease. Non-O157:H7
STEC strains have been identified from stool samples from asymptomatic subjects, diarrhea cases and a variety of
food items, but O157:H7 serotype prevalence is extremely low. Mexican children and adult serum have shown,
cross reactivity against O157:H7, other E. coli serogroups (O7, O116), enteric bacteria and O157:H7 bactericidal
activity. Most DECs strains isolated from diarrhea patients and food samples were resistant to TMP-SMX and
ampicillin; almost all strains were ciprofloxacin and cefotaxime sensitive. A new E. coli serogroup (64474)
sharing only a common O antigen with S. boydii 16, has been identified. Further, substantial reductions in
diarrhea related deaths, complications and morbidity due to acute diarrhea episodes, will require sanitation
improvement, identification of enteropathogens and development of both new drugs to treat pediatric diarrhea and
vaccines against DEC.
Diarrheagenic Escherichia coli in Children from Uruguay, Colombia and Peru
Authors: Varela Gustavo , G Gomez-Duarte Oscar , Ochoa Theresa
Published: November 2012

The diarrheagenic E. coli (DEC) are important agents of acute and persistent diarrhea in children from
Uruguay, Colombia and Peru. The relative importance of each pathotype (and its variants) is variable, and may be
attributed to different factors, such as age of children and socioeconomic level, type of study, and laboratory
methodology used in each country. However, within the DEC group the most common agents are enterotoxigenic
E. coli, enteropathogenic E. coli and enteroaggregative E. coli. Further studies are needed, mainly in food and
animal reservoirs, in order to better define the transmission and the local and regional epidemiology of these
important diarrheal agents.
Future of Escherichia coli Research in Latin America
Authors: AT Gomes Tania , Ibarra Cristina , Navarro-Garcia Fernando , Palermo Marina , Prado Valeria , Rivas Marta , G Torres Alfredo
Published: November 2012

In the 21st century, diarrhea is still a leading cause of illness and death especially in children in Latin
American countries. ETEC, EHEC, EPEC, and EAEC remain as the major categories of pathogenic E. coli
associated with diarrheal disease; however, it is evident that a shift in the serotypes responsible for human disease
is occurring in this region. Recent reports implicated atypical EPEC as an important emerging category of E. coli
and the association of EHEC O157:H7 as a cause of hemolytic uremic syndrome in Latin America is becoming
evident. Significant improvements are required in the area of early diagnosis to increase the likelihood of an
effective treatment. In this region, very few studies have addressed the emergence of antimicrobial resistance and
high asymptomatic carriage rates for diarrheagenic E. coli (DEC), as well as non-human reservoirs and vehicles
of transmission, are largely unknown. It is evident that broadening the epidemiological surveys to include
emerging and re-emerging categories of DECs while increasing the capabilities of detection and novel treatment
is a priority for the future of the E. coli research in Latin America.
Biological Activity and Production of Monascus Metabolites
Authors: Lin Yii-Lih , Wang Teng-Hsu , Lee Min-Hsiung , Su Nan-Wei
Published: November 2012

Monascus fermented products are conventional food colorant and seasoning in many Asian countries.
In recent years, they were found to ameliorate several civilization diseases including hyperlipidemia,
hypercholesterolemia, and hypertension. Therefore, Monascus related products are popular on the market and are
vastly consumed as a dietary supplement. Monacolin K is one of its bioactive metabolites and has been approved
as a clinical prescription named Lovastatin. Monascus can be a potential source of various bioactive compounds.
In this chapter, we summarize these bio-functional metabolites and also review the process and factors controlling
the production of Monascus related products.
Fungal Biofiltration for the Elimination of Gaseous Pollutants from Air
Authors: Revah Sergio , Vergara-Fernández Alberto , Hernández Sergi
Published: November 2012

Biological technologies for air pollution control are environmentally sound and economic alternatives
and are being increasingly used in industry. Biofiltration involves passing waste air through a packed reactor
containing active microorganisms capable of degrading pollutants. In general, biofilters achieve the highest rates
of removal for compounds that are water soluble and biodegradable.

The low solubility of hydrophobic molecules in the aqueous biofilm is one of the major problems for their
treatment in biofilters. However, this obstacle may be reduced using fungi as the biological agent. Fungi have
several advantages for the abatement of hydrophobic volatile organic compounds (VOCs) in gas-phase biofilters,
including their ability to degrade a large number different molecules, their resistance to low humidity and pH,
their capacity to colonize unoccupied space with the aerial hyphae and to penetrate the solid support increasing
the availability of nutrients. On the other hand, fungi grow slower than bacteria, their filamentous growth
promotes increased pressure drop and under some conditions may produce spores that could represent some
health hazard if not contained. This review will present the state of the art on the research being done with fungal
biofiltration, covering the diversity of molecules and fungal species studied, the characteristics of fungal growth
in biofilters, the type of reactors and supports used, the operational problems and mathematical modeling of these
processes.
Index
Authors: Lúcia Leitão Ana
Published: November 2012

Full text available.
List of Contributors
Authors: Lúcia Leitão Ana
Published: November 2012

Full text available.
Cardiovascular Risk Factors - An Aetiologically Oriented Epidemiologist’s Perspective
Authors: S. Thelle Dag
Published: November 2012

Coronary heart disease (CHD) reached epidemic proportions during three to four
decades, and returned to lower levels after about two decades during the 20th century. The
factors which were associated with its increase and decline were blood lipids, blood pressure,
smoking, body weight and diabetes. These factors are not exclusive entities. They are both
overlapping and interrelated. Thus any analysis of their impact on disease frequency and
effects of intervention may be difficult when it comes to making a distinction of each factor’s
contribution. All these factors are associated with oxidation and inflammation; essential
mechanisms behind atherosclerosis and thrombosis. Two of the factors stand out as the most
important explanatory factors as to why the CHD epidemic reached such dramatic levels; the
adverse dietary pattern affecting blood lipids, and cigarette smoking. Other factors
contributed also but their contribution to changes in disease frequency was more modest. The
declining CHD incidence and mortality was subsequent both to declining cholesterol levels
and cigarette smoking. These changes coincided with declining intake of saturated fat, but
recent meta-analyses do not support a causal role of saturated fat. Industrially produced trans
fatty acids often consumed together with saturated fat are likely to have played a more
important role as they are directly affecting both oxidation and inflammation. Some of the
alleged risk factors are “innocent” bystanders, others have a direct detrimental effect, but they
may come in the same package, served at the same meal, or be results of the same lifestyle
habit. This will affect the results of the analyses and only underlines the need to assess
epidemiological data in a biological context, before one draws firm conclusions on risk
factors as direct and causal factors.
Laboratory Methods for Analyzing Correlation between Periodontitis and Cardiovascular Disease
Authors: Kristoffersen Anne  K.
Published: November 2012

Association between periodontitis and cardiovascular disease can be explored by a
various set of methods. Correlation between microflora in periodontitis and atherosclerosis
has to be solved at the strain level. The choice of methods depends on lab facilities, and
skilled hands. Combining different methods avoid false positive observations and verify
accurate identifications. Serology reveals the host response as systemic versus local by
analyzing body fluids for inflammation biomarkers and antibodies against invading
pathogens at species level. Scanning electron microscopy (SEM) is useful to explore the
localization and visualize the morphology of the microorganisms in the tissue. With the
fluorescence in situ hybridization (FISH) technique, specific gene sequences can be explored
in intact cells of the tissue sample and microorganisms can be differentiated at strain level.
Proteomic analysis of the tissue sample reveals the active part of the infection, and detection
of peptides that can be linked to specific microorganisms at strain level and host factors such
as immune related factors. High through-put sequencing of total DNA from tissue samples
reveals sequences from the tissue as well of microorganisms (metagenomics) but can be
difficult to solve 100% because of lack of reference genomes of yet unidentified
microorganisms when blasting those small sequence fragments. A sequence profile can be
performed by cloning the 16S/18S PCR product or a genus-specific hybridization profiles by
microarray hybridization. Whereas fingerprinting techniques based on pure bacteria or
Candida make a specific fingerprinting pattern that can indicate strong correlation or not
between samples from the same patient.