scholarly journals Evolution of ruminant headgear: a review

2011 ◽  
Vol 278 (1720) ◽  
pp. 2857-2865 ◽  
Author(s):  
Edward Byrd Davis ◽  
Katherine A. Brakora ◽  
Andrew H. Lee
Keyword(s):  
Regenerative Medicine ◽  
Early Development ◽  
Histological Study ◽  
Organismal Biology ◽  
Multiple Origins ◽  
Pronghorn Antelope ◽  
Integrative Study ◽  
Single Versus ◽  
Development And Evolution ◽  
Biomedical Fields

The horns, ossicones and antlers of ruminants are familiar and diverse examples of cranial appendages. We collectively term ruminant cranial appendages ‘headgear’; this includes four extant forms: antlers (in cervids), horns (in bovids), pronghorns (in pronghorn antelope) and ossicones (in giraffids). Headgear evolution remains an open and intriguing question because phylogenies (molecular and morphological), adult headgear structure and headgear development (where data are available) all suggest different pictures of ruminant evolution. We discuss what is known about the evolution of headgear, including the evidence motivating previous hypotheses of single versus multiple origins, and the implications of recent phylogenetic revisions for these hypotheses. Inclusion of developmental data is critical for progress on the question of headgear evolution, and we synthesize the scattered literature on this front. The areas most in need of attention are early development in general; pronghorn and ossicone development in particular; and histological study of fossil forms of headgear. An integrative study of headgear development and evolution may have ramifications beyond the fields of systematics and evolution. Researchers in organismal biology, as well as those in biomedical fields investigating skin, bone and regenerative medicine, may all benefit from insights produced by this line of research.

Graphene and Graphene-Based Materials in Biomedical Applications

2019 ◽  
Vol 26 (38) ◽  
pp. 6834-6850 ◽  
Author(s):  
Mohammad Omaish Ansari ◽  
Kalamegam Gauthaman ◽  
Abdurahman Essa ◽  
Sidi A. Bencherif ◽  
Adnan Memic
Keyword(s):  
Tissue Engineering ◽  
Thermal Properties ◽  
Gene Delivery ◽  
Regenerative Medicine ◽  
Biomedical Research ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Two Dimensional ◽  
Drug And Gene Delivery ◽  
Biomedical Fields

: Nanobiotechnology has huge potential in the field of regenerative medicine. One of the main drivers has been the development of novel nanomaterials. One developing class of materials is graphene and its derivatives recognized for their novel properties present on the nanoscale. In particular, graphene and graphene-based nanomaterials have been shown to have excellent electrical, mechanical, optical and thermal properties. Due to these unique properties coupled with the ability to tune their biocompatibility, these nanomaterials have been propelled for various applications. Most recently, these two-dimensional nanomaterials have been widely recognized for their utility in biomedical research. In this review, a brief overview of the strategies to synthesize graphene and its derivatives are discussed. Next, the biocompatibility profile of these nanomaterials as a precursor to their biomedical application is reviewed. Finally, recent applications of graphene-based nanomaterials in various biomedical fields including tissue engineering, drug and gene delivery, biosensing and bioimaging as well as other biorelated studies are highlighted.

Material for a Synthesis

2003 ◽  
Author(s):  
Mary Jane West-Eberhard
Keyword(s):  
Early Development ◽  
Evolutionary Theory ◽  
Environmental Influence ◽  
Phenotypic Flexibility ◽  
Immature Stages ◽  
Larval Stages ◽  
Key Concepts ◽  
Adaptive Radiations ◽  
Development And Evolution

The inconsistencies discussed in chapter 1 point toward two fundamental problems in need of solution: how to relate the environmental influence inherent in phenotype development to the genetic emphasis of evolutionary theory—Lewontin’s dilemma—and how to view the diverse phenomena of plasticity and development so as to illuminate evolutionary thinking in new ways—Wallace’s challenge. This chapter briefly describes some important, previously recognized connections among phenotypic flexibility, development, and evolution. It then defines key concepts for the chapters that follow. Important contributions toward a synthesis of development and evolution have accumulated over a period of many years. Some insights appear repeatedly in that cycle of inspiration and amnesia that characterizes important discoveries ahead of their times (for a concise review, see Hall, 1992, pp. 171-174). Some of these insights deal with the phenomenology of development and evolution—evidence that certain behavioral and developmental phenomena have influenced evolution in particular groups or in particular ways. These ideas, long familiar to evolutionary biologists, are the starting points for any attempt at a modern synthesis. Each of them will reappear again in later chapters. It does not require great sophistication in biology to realize that juveniles and adults have distinctive, divergent adaptations. Familiar extreme examples are the caterpillar and the butterfly, the tadpole and the frog. In such metamorphosing species, the juvenile has a dramatically different morphology, behavior, and ecology from that of the adult. Some hypermetamorphic insects show a striking series of differently specialized larval stages, and it is probably true of most organisms that juveniles and adults have different, evolved characteristics appropriate to their different niches, if for no other reason than the different requirements for dispersal, respiration, feeding, and defense that confront individuals of differing size (Schmidt-Nielsen, 1984; see also McKinney and McNamara, 1991). As a corrolary of this, different life stages evolve semi-independently. Thus, immature stages may evolve and diversify, undergoing their own adaptive radiations. Many authors have been impressed with the conservatism of certain aspects of early development.

scholarly journals The ectodermal placodes: a dysfunctional family

2001 ◽  
Vol 356 (1414) ◽  
pp. 1655-1660 ◽  
Author(s):  
Jo Begbie ◽  
Anthony Graham
Keyword(s):  
Early Development ◽  
Evolutionary History ◽  
Sensory Systems ◽  
Dysfunctional Family ◽  
Single Entity ◽  
Embryonic Ectoderm ◽  
Development And Evolution

The ectodermal placodes are focal thickenings of the cranial embryonic ectoderm that contribute extensively to the cranial sensory systems of the vertebrates. The ectodermal placodes have long been thought of as representing a coherent group, which share a developmental and evolutionary history. However, it is now becoming clear that there are substantial differences between the placodes with respect to their early development, their induction and their evolution. Indeed, it is now hard to consider the ectodermal placodes as a single entity. Rather, they fall into a number of distinct classes and it is within each of these that the members share a common development and evolution.

scholarly journals Biopolímeros: aplicações farmacêutica e biomédica

2017 ◽  
Vol 41 (1) ◽  
pp. 01
Author(s):  
Eliane Trovatti ◽  
Aline Martins Dos Santos ◽  
André Capaldo Amaral ◽  
Andréia Bagliotti Meneguin ◽  
Bruna Driussi Mistro Matos ◽  
...  
Keyword(s):  
Regenerative Medicine ◽  
Drug Release ◽  
Potential Application ◽  
Life Quality ◽  
Synthesis Approach ◽  
Biomedical Fields

The study and development of polymers for pharmaceutical and biomedical use has been increasing due to their peculiar properties that contribute for the improvement of the life quality, such as the polymers used in regenerative medicine and in drug release systems. The development of new polymer based materials and its composites depends on several steps, such as the synthesis approach, the extraction, the composition, the influence of their properties on the specific applications, and others. This review describes the use of conventional and new polymers with potential application in pharmaceutical and biomedical fields, highliting the properties that allow them to be useful for such pourposes.

Individual differences, social attention, and the history of the social motivation hypotheses of autism

2019 ◽  
Vol 42 ◽  
Author(s):  
Peter C. Mundy
Keyword(s):  
Individual Differences ◽  
Early Development ◽  
Emotional Development ◽  
Social Motivation ◽  
Social Attention ◽  
Social Emotional Development ◽  
Social Emotional ◽  
Precise Understanding ◽  
The Social ◽  
History Of

Abstract The stereotype of people with autism as unresponsive or uninterested in other people was prominent in the 1980s. However, this view of autism has steadily given way to recognition of important individual differences in the social-emotional development of affected people and a more precise understanding of the possible role social motivation has in their early development.

Classical social reward signatures in infants with later ASD

2019 ◽  
Vol 42 ◽  
Author(s):  
Teodora Gliga ◽  
Mayada Elsabbagh
Keyword(s):  
Early Development ◽  
Social Motivation ◽  
Self Report ◽  
Social Reward ◽  
Socially Motivated

Abstract Autistic individuals can be socially motivated. We disagree with the idea that self-report is sufficient to understand their social drive. Instead, we underscore evidence for typical non-verbal signatures of social reward during the early development of autistic individuals. Instead of focusing on whether or not social motivation is typical, research should investigate the factors that modulate social drives.

Early Development of Drug-Induced Hepatic Necrosis

1971 ◽  
Vol 29 ◽  
pp. 576-577
Author(s):  
F. G. Zaki ◽  
E. Detzi ◽  
C. H. Keysser
Keyword(s):  
Early Development ◽  
Hepatic Necrosis ◽  
Screening Tests ◽  
Dense Matrix ◽  
Sprague Dawley ◽  
Electron Microscopic ◽  
Drug Induced ◽  
Hepatocellular Damage ◽  
Sprague Dawley Rats ◽  
Microscopic Studies

This study represents the first in a series of investigations carried out to elucidate the mechanism(s) of early hepatocellular damage induced by drugs and other related compounds. During screening tests of CNS-active compounds in rats, it has been found that daily oral administration of one of these compounds at a dose level of 40 mg. per kg. of body weight induced diffuse massive hepatic necrosis within 7 weeks in Charles River Sprague Dawley rats of both sexes. Partial hepatectomy enhanced the development of this peculiar type of necrosis (3 weeks instead of 7) while treatment with phenobarbital prior to the administration of the drug delayed the appearance of necrosis but did not reduce its severity.Electron microscopic studies revealed that early development of this liver injury (2 days after the administration of the drug) appeared in the form of small dark osmiophilic vesicles located around the bile canaliculi of all hepatocytes (Fig. 1). These structures differed from the regular microbodies or the pericanalicular multivesicular bodies. They first appeared regularly rounded with electron dense matrix bound with a single membrane. After one week on the drug, these vesicles appeared vacuolated and resembled autophagosomes which soon developed whorls of concentric lamellae or cisterns characteristic of lysosomes (Fig. 2). These lysosomes were found, later on, scattered all over the hepatocytes.

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