bluuebunny/crossref_metadata_2025 huggingface dataset:
Passive array micro-magnetic stimulation device based on multi-carrier wireless flexible control for magnetic neuromodulation
Authors: Tian Lei , Zhao Tong , Dong Lei , Liu Qiwen , Zheng Yu
Published: September 2023

Objective. The passive micro-magnetic stimulation (µMS) devices typically consist of an external transmitting coil and a single internal micro-coil, which enables a point-to-point energy supply from the external coil to the internal coil and the realization of magnetic neuromodulation via wireless energy transmission. The internal array of micro coils can achieve multi-target stimulation without movement, which improves the focus and effectiveness of magnetic stimulations. However, achieving a free selection of an appropriate external coil to deliver energy to a particular internal array of micro-coils for multiple stimulation targets has been challenging. To address this challenge, this study uses a multi-carrier modulation technique to transmit the energy of the external coil. Approach. In this study, a theoretical model of a multi-carrier resonant compensation network for the array µMS is established based on the principle of magnetically coupled resonance. The resonant frequency coupling parameter corresponding to each micro-coil of the array µMS is determined, and the magnetic field interference between the external coil and its non-resonant micro-coils is eliminated. Therefore, an effective magnetic stimulation threshold for a micro-coil corresponding to the target is determined, and wireless free control of the internal micro-coil array is achieved by using an external transmitting coil. Main results. The passive µMS array model is designed using a multi-carrier wireless modulation method, and its synergistic modulation of the magnetic stimulation of synaptic plasticity long-term potentiation in multiple hippocampal regions is investigated using hippocampal isolated brain slices. Significance. The results presented in this study could provide theoretical and experimental bases for implantable micro-magnetic device-targeted therapy, introducing an efficient method for diagnosis and treatment of neurological diseases and providing innovative ideas for in-depth application of micro-magnetic stimulation in the neuroscience field.
Progress in the studies of electronic and magnetic properties of layered MPX3 materials (M: transition metal, X: chalcogen)
Authors: Dedkov Yuriy , Guo Yefei , Voloshina Elena
Published: September 2023

The recent progress in the studies of 2D materials placed in front many experimental and theoretical works on the interesting class of materials, the so-called transition metal phosphorus trichalcogenides with structural formula MPX3 (M: transition metal, X: chalcogen). Here, the diversity in the M/X combination opens the possibility to tune the electronic and magnetic properties of these materials in a very wide range, resulting in many interesting physical phenomena followed by the promoting their use in different application areas. This review gives a timely overview of the recent progress in the fundamental studies of electronic structure and magnetic properties of MPX3 materials (M: Mn, Fe, Co, Ni, X: S, Se) focusing on the results obtained by density functional theory, Raman spectroscopy and electron spectroscopy methods. We pay close attention to the large amount of theoretical and experimental data giving critical analysis of the previously obtained results. It is shown how the systematic fundamental studies of the electronic and magnetic properties of MPX3 can help to understand the functionality of these interesting 2D materials in different applications, ranging from optoelectronics to catalysis.
Was the extreme rainfall that caused the August 2022 flood in Pakistan predictable?
Authors: Malik Iqura , Chuphal Dipesh Singh , Vegad Urmin , Mishra Vimal
Published: September 2023

Pakistan suffered from severe floods in the past, but in August 2022, the country experienced exceptional extreme rainfall events that caused widespread and catastrophic flooding. The 2022 flood affected all aspects of socio-economic lives including agriculture, infrastructure, and mortality of humans and livestock. The two-day accumulated extreme rainfall on 17–18 August was anomalous and contributed the most to the flood in the southern provinces of Pakistan. The damage caused by extreme rainfall and the subsequent flooding has raised questions regarding the predictability of extreme rainfall by the existing weather forecasting models. Here, we use ensemble forecasts from four numerical weather prediction models under THORPEX Interactive Grand Global Ensemble datasets to examine the predictability of extreme rainfall at a six-day lead. The extreme precipitation during 17–18 August 2022 was predictable a week before the event that contributed the most to the flooding. All the forecast models provided an early warning at a six-day lead time. UK Meteorological Office and European Centre for Medium-Range Weather Forecasts models produced comparable results to observations at all the lead times. Our findings highlight that an integrated framework of extended quantitative precipitation forecasts and hydrological modeling can help reduce the country’s flood vulnerability and risk associated with it.
Involvement of cathepsin L in the degradation and degeneration of postovulatory follicle of the medaka ovary
Authors: Kondo Yoshiko , Rajapakse Sanath , Ogiwara Katsueki
Published: September 2023

Cathepsin L plays physiological and pathological roles in immune responses, cancer, metamorphosis, and oogenesis in several species. However, the function of Cathepsin L in medaka ovaries remains unclear. Therefore, here, we examined the physiological functions of Cathepsin L in the medaka ovaries. Cathepsin L mRNA transcripts and proteins were found to be constitutively expressed in the ovaries of Oryzias latipes over a 24-h spawning cycle. Expression was localized within the oocyte cytoplasm of growing follicles and the follicle layer of preovulatory and postovulatory follicles. Moreover, the active form of Cathepsin L was highly expressed in the follicle layer of periovulatory follicles and the ovaries 2–6 h after ovulation. Recombinant Cathepsin L was activated under acidic conditions and exhibited enzymatic activity in acidic and neutral pH conditions. However, extracellular matrix proteins were degraded by recombinant Cathepsin L under acidic, not neutral pH conditions. Cathepsin L was secreted from preovulatory follicles, while active recombinant Cathepsin L was detected in the conditioned medium of a medaka cell line, OLHNI-2. Mechanistically, recombinant Cathepsin L activates recombinant urokinase-type plasminogen activator-1, which is expressed within the follicle layers post-ovulation. Meanwhile, the treatment of medakas with an E-64 or anti-Cathepsin L antibody effectively blocked follicular layer degeneration and degradation after ovulation, whereas in vitro ovulation was not inhibited by either. Collectively, the findings of this study indicate that although Cathepsin L does not impact ovulation in medakas, it contributes to the degeneration and degradation of the follicle layers following ovulation via activation of urokinase-type plasminogen activator-1, and not via the degradation of extracellular matrix proteins.
HLA-C*15:02 and epidermal growth factor receptor inhibitor-induced erosive pustular dermatosis of the scalp
Authors: Zhang Yuan , Grice Sophie , Wang Na , Liu Yongxia , Zhao Qing , Liu Tingting , Sun Lele , Mi Zihao , Wang Jianwen , Yu Gongqi , Zhang Fan , Meng Xiaoli , Liu Hong , Naisbitt Dean J , Sun Yonghu , Zhang Furen
Published: September 2023

Epidermal growth factor receptor inhibitors (EGFRIs) are widely used to treat various types of malignancies. One of the common adverse reactions is cutaneous toxicity, mostly presenting as acneiform eruptions, paronychia and xerosis. Erosive pustular dermatosis of the scalp (EPDS) is a rare cutaneous adverse reaction that develops during treatment with EGFRIs. The pathogenesis of EGFRI-induced EPDS is poorly understood. Here we present three cases of EPDS induced by EGFRIs. The proteins LTA4H (leukotriene A-4 hydrolase), METAP1 (methionine aminopeptidase 1), BID (BH3-interacting domain death agonist), SMAD1 (mothers against decapentaplegic homologue), PRKRA (interferon-inducible double-stranded RNA-dependent protein kinase activator A), YES1 (tyrosine-protein kinase Yes) and EGFL7 (epidermal growth factor-like protein 7) were significantly upregulated in EGFRI-stimulated peripheral blood mononuclear cell cultures, and validated in the lesions. All of the proteins colocalized with CD4+ and CD8+ T-cell expression. Next-generation-based human leucocyte antigen (HLA) typing showed all patients carried HLA-C*15:02, and modelling studies showed that afatinib and erlotinib bound well within the E/F binding pockets of HLA-C*15:02. Moreover, T cells were preferentially activated by EGFRIs in individuals carrying HLA-C*15:02. The case series revealed that EGFRI-induced EPDS may be mediated by drug-specific T cells.
Urine MMP7 as a kidney injury biomarker
Authors: Avello Alejandro , Guerrero-Mauvecin Juan , Sanz Ana Belen
Published: September 2023

Matrix metalloproteinase 7 (MMP-7) is a secreted endopeptidase involved in the degradation of extracellular matrix components and the activation of cytokines and growth factors. The regulation of MMP-7 can be transcriptionally regulated by AP-1 or Wnt/β-catenin or post-translationally by proteolytic activation. MMP-7 expression is low or absent in the healthy kidney, but is significantly upregulated in kidney injury, including AKI and CKD. The function of MMP-7 in kidney disease may differ for CKD and AKI; it may have a profibrotic role in CKD and an anti-apoptotic and regenerative function in AKI. Additionally, the potential of MMP-7 as a biomarker has been studied in different kidney diseases, and the results are promising. Recently, combined unbiased kidney proteomics and transcriptomics approaches identified kidney MMP-7 as the protein having the strongest association with both fibrosis and eGFR and confirmed the predictive role of plasma MMP-7 levels for kidney function decline in over 11 000 individuals. Additionally, urinary MMP-7, combined with urinary cystatin C (CysC) and retinol binding protein (RBP) was reported to provide information on tubular injury in focal segmental glomerulosclerosis and minimal change disease. We now present an overview of research on MMP-7 expression and function in kidney diseases and discuss its potential as a biomarker of kidney diseases.
Information intervention on long-term earnings prospects and the gender gap in major choice
Authors: Peter Frauke , Schober Pia , Spiess C Katharina
Published: September 2023

This study investigates whether an intervention that provided high school seniors with information on costs and economic returns to tertiary education and on the long-term earnings prospects of college graduates from different study fields enhances the probability that male and female students opt for financially more rewarding study fields and for business-related or STEM fields with a lower share of women. It extends our understanding on the potentials of information interventions for reducing gender segregation in tertiary education. We draw on a field experiment in one German federal state, Berlin, which included a randomized information intervention, and analyse longitudinal data from 1,036 students in schools with a high share of less privileged students. Our results show that a short and low-cost information intervention on costs and returns to college education, including returns in different fields of study, can substantially reduce women’s enrolment in care/social subjects, increase their enrolment in other, non-technical fields while also increasing men’s enrolment in technical fields with above-average earnings. The overall effects appear limited in challenging the gender-typicality of enrolment choices, as students tend to choose more profitable majors while avoiding gender-atypical fields.
Suggesting disease associations for overlooked metabolites using literature from metabolic neighbors
Authors: Delmas Maxime , Filangi Olivier , Duperier Christophe , Paulhe Nils , Vinson Florence , Rodriguez-Mier Pablo , Giacomoni Franck , Jourdan Fabien , Frainay Clément
Published: September 2023

In human health research, metabolic signatures extracted from metabolomics data have a strong added value for stratifying patients and identifying biomarkers. Nevertheless, one of the main challenges is to interpret and relate these lists of discriminant metabolites to pathological mechanisms. This task requires experts to combine their knowledge with information extracted from databases and the scientific literature. However, we show that most compounds (>99%) in the PubChem database lack annotated literature. This dearth of available information can have a direct impact on the interpretation of metabolic signatures, which is often restricted to a subset of significant metabolites. To suggest potential pathological phenotypes related to overlooked metabolites that lack annotated literature, we extend the “guilt-by-association” principle to literature information by using a Bayesian framework. The underlying assumption is that the literature associated with the metabolic neighbors of a compound can provide valuable insights, or an a priori, into its biomedical context. The metabolic neighborhood of a compound can be defined from a metabolic network and correspond to metabolites to which it is connected through biochemical reactions. With the proposed approach, we suggest more than 35,000 associations between 1,047 overlooked metabolites and 3,288 diseases (or disease families). All these newly inferred associations are freely available on the FORUM ftp server (see information at https://github.com/eMetaboHUB/Forum-LiteraturePropagation).
Belief maintenance as a media effect: a conceptualization and empirical approach
Authors: Shehata Adam , Thomas Fabian , Glogger Isabella , Andersen Kim
Published: September 2023

While prominent theories of media effects suggest that the maintenance of societal perceptions (and misperceptions) is a critical and distinct outcome of exposure to mediated communication, the “maintenance effect” remains poorly understood. This article provides a theoretical conceptualization and operational approach to the maintenance effect. The first part addresses the distinct properties of the maintenance effect and proposes a conceptualization anchored in theories of cognitive media effects. The second part focuses on the psychological mechanisms behind the maintenance effect, outlining factors operating in the short and long run. Finally, building upon recent statistical developments for longitudinal data analysis, the third part suggests and illustrates a specific empirical approach for analyzing the maintenance effect.
Accounting for Business
Authors: Scott Peter
Published: September 2023

Accounting for Business contains two parts. Part One is about financial accounting. Chapters include examinations on the statement of financial position, the income statement, cash flows, and ratio analysis. Part Two looks at cost and management accounting. This part includes chapters on costing, relevant costs, marginal costing, decision-making, budgeting, and capital investment appraisal.
Transplantation and Immune Responses
Authors: Juris Stephen
Published: September 2023

This chapter highlights the connection between transplantation medicine and the workings of the immune system, focusing on how the immune system reacts to transplanted tissue and the interventions used to prevent transplant rejection. It mentions transplantation medicine, whose goal is maintaining the tissue or hematopoietic system in the recipient. It also covers the three main types of transplantation performed: blood transfusions, solid organ transplantations, and hematopoietic stem cell transplantations. The chapter discusses solid organ transplantation and hematopoietic stem cell transplantation. These can be used to treat a variety of disorders and diseases, including organ failure, developmental abnormalities, and cancer. It describes several reactions that can occur as a result of transplantation and put the recipient at risk.
Concepts in Bioinformatics and Genomics
Authors: Momand Jamil , McCurdy Alison , Heubach Silvia , Warter-Perez Nancy
Published: September 2023

Concepts in Bioinformatics and Genomics starts with a review of molecular biology and looks at its relevance to the topic. It then goes on to consider information organization and sequence databases, molecular evolution, substitution matrices, and pairwise sequence alignment. Other topics covered include the basic local alignment sequence tool and multiple sequence alignment, protein structure prediction, phylogenetics, genomics, transcript and protein expression analysis, and basic probability. There are also chapters on advanced probability for bioinformatics applications, programming basics and applications to bioinformatics, and how to develop a basic bioinformatics tool.
Mixed-effects models
Authors: Baker Daniel H.
Published: September 2023

This chapter describes mixed-effect models, which are a class of statistical tests that build on simpler tests, such as regression, t-tests, and ANOVA. It explains that mixed-effects models involve the inclusion of one or more random effects. The general idea of mixed effects models is to try to account for as much of the overall variance in the data set as possible while using various predictors. Moreover, the distinction must be clear between fixed and random effects since a fixed effect can be either a continuous or categorical independent variable. The chapter discusses how to handle missing data and unequal groups with mixed-effects models. It also explains how to run mixed-effects models in R with lmerTest.
Bayesian statistics
Authors: Baker Daniel H.
Published: September 2023

This chapter focuses on Bayesian statistics and frequentist statistics. It starts with the philosophy of frequentist statistics that highlighted the significance of using a p-value. Bayes' theorem is an equation that governs the combination of conditional probabilities, so the Bayesian methods involve different assumptions and different procedures in an effort to achieve a sensible choice in data analysis. Moreover, Bayesian techniques try to estimate the probabilities of both the experimental and the null hypotheses being true. The chapter then looks at Bayes' theorem and its approach to statistical inference. It explains how to calculate Bayes factors in R using the BayesFactor package.
Marine Biology
Authors: Levinton Jeffrey S.
Published: September 2023

Marine Biology looks at organismal and ecosystem ecology topics from an evolutionary perspective. The first few chapters focus on the principles of oceanography and marine ecology. Then the book looks at marine organisms, their function and environment. Chapters that follow this consider organisms in the open sea, such as plankton and marine vertebrates. Next, the text turns to the patterns and processes in the water column. Then it looks at the organisms of the seabed, including benthic microorganisms, seaweeds, and sea grasses. The next part looks at coastal benthic environments. There are also chapters on the area of the shelf to the deep sea. The latter part of the book concentrates on the human impact on the sea.
Productivity, Food Webs, and Global Climate Change
Authors: Levinton Jeffrey S.
Published: September 2023

This chapter correlates the notion of productivity with food webs and global climate change. It explains that water column primary production is the basis of the food web in most of our important fisheries. Productivity primarily expresses the rate of production of biological materials, and biomass refers to the amount of biological material present at any one time. The chapter looks into the impact of global climate change on current and future oceanic productivity and elemental cycling. It cites how global warming has a negative feedback effect on planetary temperature and caused greenhouse gases, increased water column stratification, and reduced nutrient supply and primary production.
Benthos from the Continental Shelf to the Deep Sea
Authors: Levinton Jeffrey S.
Published: September 2023

This chapter looks into the conditions in the deeper seabed. It explains that dredges of the deep sea by remote sampling cannot give a complete picture of seafloor biology. Despite the poor food conditions, the deep sea consiss of the vicinity of the continental slope, and continental rise has more soft-bottom species than corresponding environments on the inner continental shelf. Due to the pressure in the deep sea, enzymes of deep-sea fishes are structurally far more stable than those of shallow-water species. The chapter notes that cell membranes taken from deep-water fish species are designed to remain fluid at pressures much higher than membranes from shallow-water species.
Molecular Tools for Marine Biology
Authors: Levinton Jeffrey S.
Published: September 2023

Introduction and Definitions

Molecular techniques use DNA, RNA, and related molecules to understand a wide range of biological processes.

DNA is the fundamental molecule that determines the structure of life, and in recent years, DNA technology has become a necessity in understanding natural systems,...
Nervous System Organisation and Biological Clocks
Authors: Hill Richard W. , Cavanaugh Daniel J. , Anderson Margaret
Published: September 2023

This chapter examines the correlation between the organisation of the nervous system and biological clocks. It cites how the organisation of behavioural adaptation results from the function of the nervous system. The organisation of neurons into functional nervous systems allows for the complexity of neural control of animal physiology and behaviour. The chapter cites the central nervous system (CNS) and peripheral nervous system (PNS) as the major division in the nervous system in most animals. It explains how biological clocks endow animals with an intrinsic temporal organisation, which is a timed pattern of change in physiology or behaviour independent from a change in environment.
Diving by Marine Mammals
Authors: Hill Richard W. , Cavanaugh Daniel J. , Anderson Margaret
Published: September 2023

This chapter looks into the science of diving by marine mammals by considering the interplay between oxygen, carbon dioxide, and internal transport. Advances in technology have provided new options for getting time and depth information on the swimming of the Weddell seal. The size of a diving mammal's total O2 store is a key determinant of how long the animal can stay submerged. Moreover, circulation holds a special place in the chronicles of diving physiology because the very first physiological observations on diving were measures of heart rates. The chapter also looks into the notion of metabolism during dives and the aetiology of decompression sickness.
Platytrochozoa and Two Enigmatic Phyla
Authors: Brusca Richard C. , Giribet Gonzalo , Moore Wendy
Published: September 2023

This chapter tackles the protostome clade Platytrochozoa and its enigmatic phyla, Entoprocta and Cycliophora. Unlike the Gnathifera, the Platytrochozoa phyla are highly variable, and divergences such as blind versus through guts or the presence versus absence of primary and secondary body cavities seem to have evolved multiple times. Cycliophora and Entoprocta are fundamentally marine animals, and both groups are so rare that common names do not exist for them. Entoprocts are small, probably acoelomate, solitary or colonial, polyplike creatures that have been known since the nineteenth century. On the other hand, cycliophorans are microscopic, solitary, acoelomate symbionts on the mouthparts of lobsters, where they form large aggregations.
Phylum Chordata
Authors: Brusca Richard C. , Giribet Gonzalo , Moore Wendy
Published: September 2023

This chapter details the characteristics of the phylum Chordata. Unlike its subphylum Vertebrata, Chordata features the subphyla Cephalochordata and Urochordata as two subphylums whose members exist without backbones. Modern phylogenomic research shows that Urochordata is the sister group to Vertebrata, a clade known as Olfactores. Like all chordates, cephalochordates possess a notochord, dorsal hollow nerve cord, pharyngeal gill slits, postanal tail, and true coelom. The chapter also showcases some illustrations to feature the parts of Cephalochordata and Urochordata members. It mentions that future research should consider looking into the evolutionary-developmental pathways of urochordates or using tunicates to better understand the derivation of vertebrate neural development.
Vertebrate Life
Authors: Harvey Pough F. , Bemis William E. , Mcguire Betty , Janis Christine M.
Published: September 2023

Vertebrate Life explores how the anatomy, physiology, ecology, and behaviour of animals interact to produce organisms that function effectively in their environments, and how lineages of organisms change through evolutionary time. It looks at the evolution, diversity, and classification of vertebrates. It considers chondrichthyes, osteichthyes as well as teteapods. Ectothermy is examined as an example of a low-energy approach to life. Other vertebrates considered are turtles, lepidosaurs, crocodylians, and extant birds and mammals.
Diversity, Classification, and Evolution of Vertebrates
Authors: Harvey Pough F. , Bemis William E. , Mcguire Betty , Janis Christine M.
Published: September 2023

This chapter explores the diversity, classification, and evolution of vertebrates. It highlights how evolution is central to biology since its overarching principles allow further understanding of how living organisms operate and organize their diversity. Phylogenetic systematics produces branching evolutionary diagrams or phylogenetic trees which show changes in characteristics. The chapter then covers the genetic mechanisms and environmental events that have shaped the evolution and biology of vertebrates. It looks into Earth's history in relation to the evolution of vertebrates and Earth's pattern of fragmentation and coalescence which isolated and renewed contacts of major groups of vertebrates, and which then produced the biogeographic distributions of vertebrates.
Origins of Lissamphibia and Amniota
Authors: Harvey Pough F. , Bemis William E. , Mcguire Betty , Janis Christine M.
Published: September 2023

This chapter examines the origins of lissamphibia and amniota. It provides an overview of Paleozoic tetrapods, which includes the taxa on the divergence and diversification of lissamphibians and amniotes. Evolutionary changes in skulls, vertebrae, limb girdles, limbs, and ankles have enabled the tracking of the diversification of Paleozoic tetrapods and the interpretation of aspects of their biology. Meanwhile, the evolution of the amniotic egg in the Carboniferous has allowed amniotes to escape their dependence on water for reproduction. The chapter details the characteristics of amniotes that allowed for greater independence from moist habitats and the ability to grow very large. It explains how studying fossils can result in a greater understanding of the biology, ecology, and functional morphology of amniotes and their subsequent diversification.
Avemetatarsalia and the Origin of Dinosauria
Authors: Harvey Pough F. , Bemis William E. , Mcguire Betty , Janis Christine M.
Published: September 2023

This chapter looks into early avemetatarsalians and the origin of Dinosauria. From the period of late Triassic and Mesozoic, Avemetatarsalia is a large and diverse clade including many familiar extinct vertebrates, such as pterosaurs and non-avian dinosaurs like birds. Moreover, Avemetatarsalians decoupled the functions of the fore and hindlimbs, which then allowed the subsequent evolution of bipedalism and flight. The chapter also looks into the biology, characteristics, and evolution of pterosaurs, ornithischians, and sauropodomorphs. It mentions how the origin and diversification of birds coincided with an increase in the body size of pterosaurs, which suggested that birds may have outcompeted pterosaurs at small body sizes.
Synapsids and the Origin of Mammals
Authors: Harvey Pough F. , Bemis William E. , Mcguire Betty , Janis Christine M.
Published: September 2023

This chapter considers the sequential acquisition of the most important mammalian characters within the synapsid lineage. It explores the evolutionary history of synapsids in relation to their feeding, hearing, locomotion and breathing. The three clades of Mammalia range between Prototheria (monotremes and extinct relatives), Allotheria (multituberculates and related taxa), and Theria. Mammals have more complex social systems than most other vertebrates, and these complexities correlate with many features of their biology. The chapter cites that the classic features defining mammals are hair and mammary glands. It mentions how studying fossilized skeletons helps with the understanding of the origins of mammals.
An Introduction to Conservation Biology
Authors: Sher Anna A.
Published: September 2023

An Introduction to Conservation Biology provides up-to-date perspectives on high-profile issues such as sustainable development, global warming, and strategies to save species on the verge of extinction. The book focuses on biological diversity and its value; threats to biological diversity; conservation at the population and species levels; protecting, managing, and restoring ecosystems; and sustainable development. Each chapter is illustrated with diverse examples from the current literature. Throughout, the text maintains a focus on the active role that scientists, local people, conservation organizations, government, and the general public play in protecting biodiversity, even while providing for human needs. The last chapter, crucially, looks at presenting an agenda for the future.
The Endoderm
Authors: Barresi Michael J. F. , Gilbert Scott F.
Published: September 2023

This chapter discusses the Sox17 transcription factor, which is crucial for the specification of the endoderm that constructs the digestive (gut) tube and the respiratory tube. It analyzes the endoderm in the posterior which becomes a collection of midgut-hindgut precursor cells forming the intestines and the endoderm near the head that form the anterior foregut cells that generate the precursors of the lung and thyroid glands. It also mentions the pharyngeal pouches which become the endodermal lining of the eustachian tubes, the tonsils, the thymus, and the parathyroid glands. The chapter describes the muscular layers of the gut which are specified and placed in their particular locations by Shh signals from the intestinal endoderm. It reveals the three modes of branching morphogenesis in the developing lung: domain branching, planar bifurcation, and orthogonal bifurcation.
Photosynthesis: Physiological and Ecological Considerations
Authors: Taiz Lincoln , Møller Ian Max , Murphy Angus , Zeiger Eduardo
Published: September 2023

This chapter discusses photosynthesis and refers to the rate of net photosynthesis, the difference between photosynthetic carbon assimilation, and the loss of CO2 via photorespiration and mitochondrial respiration in the light. It focuses on how naturally occurring variation in light and temperature influences photosynthesis in leaves and how leaves in turn adjust or acclimate to such variation. It also explores how atmospheric CO2 and temperature influence photosynthesis, which is an important consideration in a world where CO2 concentrations and temperature are rapidly increasing as humans continue to burn fossil fuels for energy production. The chapter analyzes the leaf anatomy that is highly specialized for light absorption, noting how some plants maximize light absorption by solar tracking. It highlights the carbon isotope ratios of leaves that can be used to distinguish photosynthetic pathway differences among different plant species.
Translocation in the Phloem
Authors: Taiz Lincoln , Møller Ian Max , Murphy Angus , Zeiger Eduardo
Published: September 2023

This chapter examines the patterns and pathway of translocation and the loading of sugars in mature leaves. It describes the sugar movement in the phloem from source to sink and the mechanism of phloem transport, including the rate of movement, magnitude of pressure gradients between sources and sinks, materials translocated in the phloem, and its wound response. It also reviews the destination of the journey with sugar molecules through the plant, which is their unloading in sink organs and subsequent consumption and storage. The chapter explores the role of the phloem in coordinating plant growth by the allocation and partitioning of photosynthetic products and by offering a rapid pathway for signaling. It points out how the transport phloem forms a passive low-resistance pathway and is actively involved in unloading and reloading of sugars to axial sinks.
Calcium channel blockers in the treatment of angina and hypertension
Authors: Saunders John
Published: September 2023

This chapter discusses calcium channel blockers-agents which address myocardial oxygen deficiency by reducing the heart rate without affecting the force of contraction and by providing vasodilatory effects on coronary arteries. The chapter reviews drugs that act predominantly on the voltage-gated ion channels. It describes the synthesis of nifedipine which involves the classical Hantzsch condensation, isolation of the intermediate Knoevenagel product, and Hantzsch reaction with ethyl 3-aminocrotonate. The chapter also explains the synthesis of amlodipine, which gained success from its longer duration of action in man to the extent that once daily dosing can effectively manage hypertension in most patients. Furthermore, it tackles the preparation of diltiazem. Lastly, the chapter discusses the synthesis of verapamil-the first calcium blocker to be approved in the USA.
Alicyclic Chemistry
Authors: Grossel Martin
Published: September 2023

Alicyclic Chemistry provides an overview of the study of non-aromatic organic compounds made up of one or more carbocyclic rings. Such compounds, which range from simple ring systems to complex bridged and polycyclic structures, provide a framework for the understanding of many concepts which underlie organic chemistry. The topics covered include a discussion of the stability and conformational behaviour of carbocyclic ring systems, and the factors which control the choice of synthetic methods and reactivity of such compounds. Many aspects of alicyclic chemistry provide an important framework for a proper understanding of the behaviour of organic molecules.
Introduction
Authors: Grossel Martin
Published: September 2023

This chapter describes alicyclic chemistry as the chemistry of organic compounds which contain one or more non-benzenoid rings, focusing on saturated and unsaturated carbocyclic ring structures and heterocyclic systems. It highlights the major role alicyclic chemistry plays in organic chemistry as several natural products exploit saturated or partially unsaturated rings as a structural framework in terpenoid derivatives. It also mentions small cyclic terpene derivatives. These provide scents in the plant kingdom and large carbolic ring derivatives. These are found in pheromones and are important to the perfume industry. The chapter talks about large macrocyclic structures which contain several heteroatoms due to their selective abilities on complex metal and other ions.
The conformational analysis of alicyclic rings
Authors: Grossel Martin
Published: September 2023

This chapter reviews several aspects of molecular stereochemistry, which is important in the discussion about the behavior of alicyclic compounds. It analyses various types of isomerism in a given molecular formula, such as the assembly of atoms in a variety of different ways that lead to a number of alternative chemical structures and different atom-atom connectivity patterns. It also describes structural arrangements that form additional isomers and have the same connectivity but are different in the spatial arrangement of the atoms within the molecule. The chapter analyzes enantiomers and diastereoisomers as the two classes of stereoisomers. Enantiomers occur in pairs and are defined as structures that are non-superimposable mirror images of each other, while diastereoisomers are derived from a particular structural formula.
Conformation and reactivity in alicyclic compounds
Authors: Grossel Martin
Published: September 2023

This chapter discusses how the presence of other groups on a substituent on a cyclohexane ring can perturb the conformational equilibrium and lead to conformational locking of the ring geometry. It probes the effect of different conformations on the reactivity of substituted cyclohexanes and considers steric and stereo-electronic factors as the two main types of effect. It also explains that steric effects are derived from large and repulsive close contacts or small attractive interactions operating over greater distances. The chapter talks about the significance of steric interference in the transition that increases the activation energy for the process and cause the reaction rate to be retarded by steric hindrance. It considers the hydrolysis of ethyl cyclohexane carboxylates as an appropriate example of the consequences of steric hindrance.
Introduction
Authors: Robertson Jeremy
Published: September 2023

This introductory chapter provides an overview of the strategy of protecting group chemistry. In general, a protecting group is introduced onto a functional group to block its reactivity under the experimental conditions needed to make modifications elsewhere. The conditions under which a particular protecting group is either removed or left unaffected must be known; therefore, this book is organised around the mechanistic principles that influence protecting group reactivity. The choice of protecting group is heavily influenced by the type of reactivity that must be blocked, which requires a knowledge of the characteristic reactivity of each functional group. The chapter then looks at protecting group devices and temporary protecting group. Identification of a device within a given protecting group allows one to predict whether the protecting group will be labile (or stable) under specified reaction conditions.
The ultrasonic probe
Authors: Mason Timothy J.
Published: September 2023

This chapter examines the ultrasonic probe. Despite its convenience for use, the major disadvantages of the ultrasonic cleaning bath as a general source of ultrasound for sonochemistry are a low maximum power and the absence of energy control. One solution to both of these problems has been found in a piece of equipment originally developed for plastic welding and biological cell disruption: the ultrasonic probe. In the laboratory, it is possible to introduce ultrasonic energy into a reaction using a probe system up to some 100 times greater than can be achieved using a cleaning bath. On a larger scale, the energies can be much greater than this. Modern probe systems are generally based on piezoelectric transducers and are all of a similar construction. The chapter then looks at the construction of the ultrasonic probe and the process of choosing a probe system for sonochemistry.
The scope of process development
Authors: Atherton John H. , Carpenter Keith J.
Published: September 2023

This chapter discusses the scope of process development, which is an essential part of the chain of events preceding the introduction of a new chemical product to the market place. It is the link between the research department, which discovers the new compound, and the manufacturing departments, which make the product for sale. In the discovery of new products, the chemists involved will make their compounds by whichever synthetic route is most convenient on the laboratory scale. Thus, the scientists involved in process development must have an appreciation of the physicochemical principles underlying synthesis. Statistical techniques are widely used in process development. Ultimately, the output from the process development exercise is a total process. This book focuses on the chemical transformations and product isolations which are at the heart of the process performance and where solutions to many of the problems require constant interaction between engineers and chemists.
Equilibria in multiphase systems
Authors: Atherton John H. , Carpenter Keith J.
Published: September 2023

This chapter addresses equilibria in multiphase systems. Many processes are operated under conditions where more than one phase is present. This is often due to economic considerations: when it is necessary to contact large water-insoluble reactants with inorganic reagents, reactions are frequently run with either a separate solid phase or else a solution phase containing the inorganic reagent. Workup processes frequently involve the washing of a solution of a water-insoluble product which is dissolved in an organic solvent such as toluene with water in order to remove inorganic residues. The chapter then looks at simple distribution equilibria; solubilities of ionisable substrates; liquid–liquid partition of ionisable substrates; and ternary phase diagrams.
Chemical kinetics
Authors: Lawrence Nathan , Wadhawan Jay , Compton Richard
Published: September 2023

This chapter addresses basic topics that include the rates of reaction and their concentration dependence, order of a chemical reaction, and the relationship of reaction mechanisms to kinetic rate laws. It discusses the temperature dependence of chemical reaction rates and cites examples of the kinetics and mechanism of solution and gas phase reactions. It also covers integrated rate laws, the kinetics of gas phase reactions as revealed by pressure measurements, and steady state approximation. The chapter talks about reaction via tunneling, the use of the Arrhenius equation to predict the vapour pressures of gases, and the Clausius-Clapeyron equation. It explains kinetics that imply that the formation of the transition state for the reaction that involves the prior reaction of two molecules of NO and one of O2.
Probability and statistics
Authors: Bowley Roger , Sánchez Mariana
Published: September 2023

This chapter explores two notions of probability used in science: classical probability and statistical probability. It clarifies that the classical notion of probability assigns, a priori, equal probabilities to all possible outcomes of an event while statistical probability measures the relative frequency of an event. It also explains that simple events, which are events that cannot be broken up into simpler parts, can build up compound events, that is, aggregates of simple events. The chapter also introduces the acid test for determining whether two events are independent of each other. It reviews the use of classical probability and the importance of counting the number of ways in which various events can happen, leading to the concepts of arrangement, permutations, and combinations.
Phase transitions
Authors: Bowley Roger , Sánchez Mariana
Published: September 2023

This chapter talks about the cooling of a system that results in the appearance of new states of matter, such as gas that forms a liquid or a liquid that can form a solid when it is cooled enough. It describes the transitions between gas, liquid, solid, and superfluid in different phases of the ecosystem. These are called phase transitions. It also explains that the term 'phase' is a state of matter that is uniform throughout in both chemical composition and in physical state. The chapter highlights the importance of uniformity as physical properties, such as density or conductivity, and chemical composition must be the same throughout the system. It clarifies that the notion of uniformity means that any representative sample of the solid of macroscopic size appears to be the same as any other representative sample.
Ginzburg–Landau theory
Authors: Bowley Roger , Sánchez Mariana
Published: September 2023

This chapter discusses the extension of the theory to allow spatial variation in the order parameter and determining the shape of the interface and the surface contribution to the free energy. It describes the size of fluctuations of the order parameter, determining whether they are sufficiently small to be ignored or whether they dominate the properties of the system and require careful treatment. It discusses Vitaly Ginzburg and Lev Landau's sophisticated model which allows the order parameter to vary in space. The chapter outlines the benefits of Ginzburg and Landau's model, which includes the description of the interface between phases and estimation of the surface free energy. It elaborates how the model predicts the existence of topological singularities in the order parameter, such as quantified vortices in superfluid systems.
Foundations of Organic Chemistry: Worked Examples
Authors: Michael Hornby , Josephine Peach
Published: September 2023

Foundations of Organic Chemistry provides problems, with answers and tutorial guidance, on organic chemistry. The first three chapters cover basic physical organic chemistry, setting the scene for the mechanistic organic chemistry covered later. Chapters look at molecules, mechanisms, acids and bases, reactions with nucleophiles, reactions with electrophiles, and reactions with radical intermediates.
Molecules
Authors: Michael Hornby , Josephine Peach
Published: September 2023

This chapter talks about atoms, molecules, and bonding, particularly the electronic configurations of atoms and ions in the periods Li to Ne and Na to Ar. It illustrates dot diagrams of atoms, ions, and molecules, and reviews predictions of shapes using electron pair repulsion theory. It also discusses ion and covalent, such as dipoles, and examines hybridization, which includes single, double, and triple bonding by carbon and other elements. The chapter describes drawing and naming molecules, using skeletal diagrams, and highlights the interconversion of names and diagrams. It analyes isomerism and stereochemistry and deals with structural and stereoisomerism, noting geometrical and optical isomerism.
Acids and bases
Authors: Michael Hornby , Josephine Peach
Published: September 2023

This chapter discusses equilibria and factors effecting acidity and basicity of organic compounds and other areas of chemistry, such as electronegativity of the atom that bear the charge. It examines delocalization, resonance, inductive effects, indicators, and interactions between molecules and ions. It also deals with the protonation on the carbonyl oxygen atom that gives the more stable, delocalized protonated form of the COOH group. The chapter mentions the inductive electron-withdrawing effect of the C=O that helps to weaken the adjacent O-H bond and carboxylic acids that are more acidic than alcohols, whose anions are not stabilized by delocalisation. It refers to Tenormin, which is a drug used in the treatment of high blood pressure, angina, and abnormal heart rhythms.
Reactions with nucleophiles
Authors: Michael Hornby , Josephine Peach
Published: September 2023

This chapter explores the nature and distinction of bases and nucleophiles, including interconversions and synthesis. It discusses reactions of halogenoalkanes by bimolecular processes. Here it covers the mechanism, transitions state, energy profile, stereochemistry, and competition with elimination. It also talks about the mechanism of addition reactions of the carbonyl group and various reagents, such as H-and CN-addition. The chapter deals with the intermediates of the addition-elimination reactions of the carbonyl group, ester hydrolysis, and other addition-eliminations on carboxylic acids and their derivatives. It analyses the transition states, energy profile, stereochemistry, and competition with elimination of the reactions of halogenoalkanes by unimolecular processes.