bluuebunny/crossref_metadata_2025_split huggingface dataset:
Molecular motion in crystals
Authors: Bürgi H B 
Published: November 2023

Abstract
The notion that molecules in crystals are static and undeformable objects, has been abandoned by crystallographers for some time now. Molecular flexibility in the solid state can be probed in several ways. One of them is to analyse in detail the structure of a molecule or molecular fragment in a variety of environment. This approach makes use of static structural data – distances, bond angles and conformational descriptors in particular; the structural parameters which are most susceptible to deformation, and also the type and extent of deformation, may be identified with the help of statistical methods. This way of drawing a parallel between the static and dynamic aspects of structure has become known under the heading of “Structure Correlation”. Many applications of the structure correlation method are reviewed in Bürgi and Dunitz (1993); others are described by Kaftory and by Klebe and Mietzner in this volume.
Utilization of crystallographic results for selecting and designing pharmacologically active compounds
Authors: Karolak-Wojciechowska Janina 
Published: November 2023

Abstract
In the model presented for the utilization of crystallographic results, the atomic coordinates in the crystal structure are used as a starting point for searching for the conformation of a molecule that would correspond to the energy minimum (or several minima). It is assumed that this would be a conformation close to that existing in solution. To attain this aim it is necessary to carry out. Crystallographic analysis of the chosen compounds. Conformational analysis of the molecules by means of the molecular mechanics method. Molecular-orbital optimization of the geometry of all molecules, starting with the conformation obtained in 2.
Isomorphism, solid state transformations, and disorder in the crystal structures of cytidinium and 2’-deoxycytidinium salts
Authors: Jaskólski M , Wiewiórowski M 
Published: November 2023

Abstract
The organic building blocks of nucleic acids -nucleosides -have been, and still are, rewarding objects of studies in the domain of organic crystal chemistry. Those studies have been the source of geometrical data which, in the past, were essential for compiling standard-group dictionaries used in structural studies of oligomers and polymers (Sussman, 1985; Westhof, Dumas & Moras, 1985) and, more recently, entered (in the form of parameters) the molecular dynamics protocols of refinement of macromolecular structures (Briinger, Kuriyan & Karplus, 1987). The past success of crystallography of low-molecular-weight components of nucleic acids does not mean that its role has been fulfilled. Accumulation of experimental data is still important for conformational studies of the flexibility (or rigidity?) of the nucleotide and nucleoside.
Total Synthesis of Neodolabellenol
Authors: Williams D R , Coleman, P J 
Published: November 2023

Abstract
Discussion Points Propose a synthesis of 1 starting from 2-methyl-2-cyclopentenone. The direct use of the vinyl lithium species generated from 2 preferentially afforded the Z-allylic alcohol in the coupling process c. Explain the change in stereoselectivity. Give an explanation for the preferential formation of the β-epimer in the Julia coupling j. A small amount of compound 7 was isolated from the Julia coupling. Give an explanation for its formation. Further Reading For another application of the Julia coupling to the synthesis of macrocycles, see: K. Takeda, A. Nakajima and E. Yoshii, Synlett, 1995, 3, 249. For various aspects of organocuprate-mediated epoxide opening, see: H. Bruce, R. S. Wilhelm, J. A. Kozlowski and D. Parker, J. Org. Chem., 1984, 49, 3928.
Total Synthesis of Octalactins A and B
Authors: McWilliams J C , Clardy J 
Published: November 2023

Abstract
Discussion Points Propose a mechanism for the cyclisation step f. Why is the seven­ membered cyclisation product 5 favoured over a six-membered ring system? What is the purpose of the tin tetrachloride in step i? Explain the regioselectivity obtained in steps j and s. Rationalise the stereoselectivity of these oxidative ring expansion steps. Give a motive for the acidic conditions adopted in step t. Further Reading For an extensive review on the Baeyer-Villiger reaction see: G. R. Krow, Org. React.,1993, 43,251.
Total Synthesis of (—)-Solavetivone
Authors: Hwu J R , Wetzel, J M 
Published: November 2023

Abstract
Discussion Points Suggest a mechanism for step d. The conversion of compound 6 into the tri none 7 was carried out in a single oxidative step. Propose alternative methods for the introduction of α, β unsaturation in a ketone. What factors govern the regioselectivity and stereoselectivity of the conjugate additon of the trimethylsilyl nucleophile in step g? A homonuclear NMR decoupling experiment was carried out on compound 11, simultaneously irradiating the two proton signals at δ 4.69 and 4.70 ppm. This resulted in the simplification of the single proton multiplet between δ 2.35–2.87 ppm. In a subsequent nOe experiment an 18% enhancement of the aforementioned multiplet was observed on irradiation of a methyl group doublet at 6 1.26 ppm. Rationalise the above observations in terms of the structure and stereochemistry given for 11. Suggest a mechanism for the Lewis acid catalysed rearrangement in step I.
Synthesis of a Key Intermediate of 1β-Methylcarbapenem Antibiotics
Authors: Kang S -H , Lee, H -S 
Published: November 2023

Abstract
Discussion Points When epi-3was submitted to the sequence outlined in steps d and e, a mixture of diastereoisomers was formed. Propose their structure and explain the reduced stereoselectivity observed. How could epi-3be converted into compound 3? What is the purpose of hydroquinone in step e? Give the structure of the reactive intermediate of step k. Further Reading For a review of the use of protected cyanohydrins as acyl anion equivalents, see: J. D. Albright, Tetrahedron,1983, 39,3207. For reviews on nitrone cycloadditions to olefins, see: P. N. Confalone and E. M. Huie, Org. React.,1988, 36,1; R. Annunziata, M. Cinquini, F.Cozzi and L. Raimondi, Gazz. Chim. Ital.,1989, 119,253. For reviews of the Mitsunobu reaction, see: D. L. Hughes, Org. React.,1992, 42,335;D. L. Hughes, Organic Preparations and Procedures Int.,1996, 28,127.
Synthesis of Isochromanquinones
Authors: Winters M P , Stranberg M , Moore, H W 
Published: November 2023

Abstract
Discussion Points What is the the mechanism of the bromination steps involved in the synthesis of compound 2? Suggest a structure for the unstable intermediate 6. Suggest a reaction mechanism for the thermal rearrangement of cyclobutenone 8 into the isochromanhydroquinone 9. Further Reading For a recent study of squarate ester reactivity see: L.A. Paquette and T. Morwick, J. Am. Chem. Soc., 1995, 117, 1451. For a review, in German, of the reactions of squaric acid and its derivatives see: A. H. Schmidt, Synthesis,1980, 961. For a recent application of this rearrangement to 4-allenylcyclobutanones see: M. Taing and H. W. Moore, J. Org. Chem.,1996, 61,329.
Total Synthesis of (+)-Longifolene
Authors: Lei B , Fallis, A G 
Published: November 2023

Abstract
Discussion Points Explain the selectivity obtained in step f and give reasons for the use of cadmium chloride in the condensation reaction. Which one of the cyclopentadienyl regioisomers 6 a-c leads to compound 7? Propose structures for the other possible Diels-Alder adducts. Further Reading For a review on the use of microwave heating, see: G. Bond, R. B. Moyes and D. A. Whan, Cat. Today,1993, 17,427. For a study of the influence of tether length on intramolecular Diels-Alder reactions, see: J. R. Stille and R. H. Grubbs, J. Org. Chem.,1989, 54,434.
Synthesis of the AB Ring Moiety of Ciguatoxin
Authors: Oguri H , Hishiyama S , Oishi T , Hirama, M 
Published: November 2023

Abstract
Discussion Points During the sequence d-e a new chiral centre is introduced. Which one of the steps is responsible for the stereoselectivity observed? In step j the selective protection of one hydroxyl group is accomplished. Suggest a reason for this selectivity. Give reasons for the stereoselectivity observed in the Yamamoto cyclisation of step q. Explain the regioselectivity of the DBU mediated elimination of step u. The compound obtained from Dess-Martin oxidation w proved to be unstable and had to be used without purification. Suggest a structure for the more stable compound formed on storage of 9. Which analytical technique could be used to determine the absolute configuration of 11 a, b?
Approach Towards the Asteriscanolide Skeleton
Authors: Booker-Milburn K I , Cowell, J K 
Published: November 2023

Abstract
Discussion Points What is the mechanism of the photolysis step c? What dictates the relative stereochemistry of the product 4? Propose a mechanism for the rearrangement sequence leading to the epimeric cyclooctanones 8 and 9. An attempt at oxidising the carboxylic acid 4 under the conditions reported in step e resulted in the formation of lactone 10. Rationalise the formation of this product bearing in mind the mechanism of this kind of oxidation.
Total Synthesis of (-)-Suaveoline
Authors: Fu X , Cook J M J 
Published: November 2023

Abstract
Discussion Points What is the mechanism of step d? Which of the products 6,7 and 8 is formally derived from a magnesium-ene reaction? Suggest a reason why it was necessary to protect the aldehydes 7 and 8 before the oxidative demolition steps m and n. When methanol was used as the solvent for debenzylation step p, compound 11 was isolated. Give an explanation for its formation.
Synthesis of (20S)-Camptothecin
Authors: Curran D P , Ko S -B , Josien, H 
Published: November 2023

Abstract
Discussion Points Explain the regioselectivity observed in the reaction sequence a to d and give reasons for the fact that it is possible to use a nucleophilic base such as n-BuLi in step c. What is the mechanism of the reductive etherification step e? Suggest structures for the intermediates formed in the radical cascade reaction of 8 with phenyl isonitrile.
Enantioselective Total Synthesis of (–)-Strychnine
Authors: Knight S D , Overman L E , Pairaudeau, G 
Published: November 2023

Abstract
Discussion Points Suggest a structure for compound 7. Give a method for the preparation of starting material 1 or its enantiomer. Explain the diastereoselectivity in the reduction of 2 to 3. What is the mechanism for the elimination step d? What is the mechanism for step q? What is the purpose of sodium methoxide in step u?
Properties of odorous molecules
Authors: Gardner Julian W , Bartlett Philip N 
Published: November 2023

Abstract
The odours that we perceive in the world around us arise through the interaction of molecules, given off by the odorous material, with sensory cells located in our nose. When we sniff a rose, for example, we are drawing up into our nose volatile molecules given off by the rose. The smell of the rose is the result of the interaction of these molecules with our sensory cells and our interpretation of the nerve impulses generated by this interaction. Typically, the odour of a flower or of a foodstuff or some other natural material will comprise a large and complex mixture of molecules of different types present in the mixture at different concentrations. On the other hand, in some cases a single, pure compound comprising molecules of just one type can be the dominant odour.
Energy and biomass consumption patterns in India
Authors: Ravindranath N H , Hall D O 
Published: November 2023

Abstract
The main focus of this book is to explore the potential and feasibility of bioenergy options in meeting the energy needs of a developing country such as India and to draw some lessons from this for other such countries. The first step in such an exercise is to understand the current energy scene, particularly that of biomass energy. Detailed information is required on the sources and end uses of biomass fuel, sustainability of its supply, features of use such as efficiency and socio-economic aspects, and production and conservation potential. Unfortunately, the data available on biomass energy are very poor compared to commercial energy data in most countries. Among developing countries, India was a pioneer in rural energy studies in the aftermath of the first oil crisis, with detailed micro-level (Ravindranath et al. 1981; Reddy 1982) and macro-level (NCAER 1981,1985) studies. The Indian energy research scene has been active and several studies are available on rural energy use (ABE 1985; Leach 1987; Veena 1988; Bose et al. 1991; Bhide 1992; Joshi et al. 19926). This does provide an opportunity to analyse the bioenergy situation in India. But as seen later in this chapter, the database is rather weak on certain aspects of biomass energy, for example, on the sources of the fuel wood used in rural India. In this chapter, an attempt is made to consolidate the existing information on various aspects of energy use in India with particular reference to biomass energy.
Bioenergy—a modernized fuel option for India
Authors: Ravindranath N H , Hall D O 
Published: November 2023

Abstract
The analysis of energy use patterns for India has shown the continued dominance of biomass, particularly in rural areas. Biomass use is usually characterized by low efficiency of use and lower quality of life. In order to promote development it is necessary to provide quality fuels (liquid and gaseous fuels) and electricity in a sustainable, equitable, and affordable way. The main focus of this book is on exploring the potential of bioenergy in meeting the energy needs of developing countries such as India. This is attempted here by defining the goals of development, the services requiring energy, the forms of energy required, and analysing the potential of bioenergy in comparison with other options.
Environmental and socio-economic benefits of bioenergy
Authors: Ravindranath N H , Hall D O 
Published: November 2023

Abstract
The current trends of energy provision and use based on commercial energy were shown to be non-sustainable, environmentally damaging, and leading to inequities. It will be useful first to understand the socio-economic and environmental implications of continuing with the existing patterns (business as usual, BAU) and the possible implications of adopting the proposed bioenergy options. Major environmental problems such as deforestation, submergence of forest (from hydroelectric projects), acid rain, global warming, and local air pollution are all linked in various ways to the extraction, processing, and use of energy. Environmental considerations have, however, rarely determined decisions on energy in the past. Now, due to local and global pressure, there is a change in the attitude of developing as well as industrialized countries, and environmental considerations are frequently included in energy planning. India, for example, has a clear policy to promote renewables on a medium- and long-term basis (Box 6.1). The need for and the potential of bioenergy options in meeting rural energy needs were presented in earlier chapters. In this chapter the social, economic, and environmental implications and opportunities created by adoption of bioenergy options in India are discussed.
Approaches to implementing bioenergy programmes
Authors: Ravindranath N H , Hall D O 
Published: November 2023

Abstract
One of the important aspects to be considered in utilizing the bioenergy potential in India is the feature of dispersed rural human settlements encompassing 75 per cent of the country’s population. Bioenergy options can provide a decentralized village-level, self-reliant energy system to meet village needs in a sustainable and environmentally sound way (Chapters 6 and 8). The next question we should ask is how can this be done. An approach to the implementation of rural bioenergy centre (RBC) schemes (which are at the heart of the proposed biomass-based energy programme) and of the large- scale bioenergy systems is considered in this chapter. Here we suggest an approach based largely on the Indian experience.
Principles and Tools: Questionnaires, Structured Interviews, Diaries, and Calendars
Authors: Jensen R , Bendtsen L 
Published: November 2023

Abstract
Headache is mainly a subjective phenomenon and we urgently need a biological marker, both in the diagnostic process and in the long-term follow-up guiding the physicians in the treatment strategy. In headache, we have to rely on the history of the patients and on a negative workup, where other diseases are excluded. In clinical practice, the efficiency of taking the history can be greatly augmented by the use of various instruments because headache patients, like most other pain patients, tend to report the most recent and the most severe headaches.
Trigeminal Autonomic Cephalalgias
Authors: Goadsby P J 
Published: November 2023

Abstract
The Trigeminal Autonomic Cephalalgias (TACs) is a grouping of headache syndromes recognized in the second edition of the International Headache Society classification. The term was coined to reflect some part of the pathophysiology of these conditions that is a common thread, viz., excessive cranial parasympathetic autonomic reflex activation to nociceptive input in the ophthalmic division of the trigeminal nerve.
A case of Hemicrania Continua Overlapping With Other Forms of Strictly Unilateral Headaches Associated With Autonomic Symptoms
Authors: Nappi G , Tassorelli C , Sances G , Cecchini A P , Guaschino E , Sandrini G 
Published: November 2023

Abstract
At two decades from its first description Hemicrania Continua (HC) remains an enigma in the field of primary headaches in terms of etiology and pathogenesis. In the recently released second edition of the International Classification of Headache Disorders (ICHD-II), HC has been aggregated to the fourth group ‘Other Primary Headaches’, not without a vivacious and prolonged discussion among the members of the Classification Subcommittee.
Hyperhomocysteinemia Due to MTHFR C677T Polymorphism as a Possible Link Between Stroke and Migraine In Young Populations
Authors: Marchione P , Giacomini P , Fortini D , Vento C , Samà D , Corigliano D , Nappi G 
Published: November 2023

Abstract
Increased homocysteine levels are associated with various pathological conditions in humans, including stroke and cardiovascular disorders. A recent study suggests that the MTHFR gene, causing mild hyperhomocysteinemia, may be a genetic risk factor for migraine. Homocysteine acts as an excitatory amino acid in vivo and may influence the threshold of migraine headache. The aim of this study is to evaluate the prevalence of migraine in stroke patients with hyperhomocysteine due to MTHFR polymorphism.
Posttraumatic Migraine Secondary to Organic Lesions
Authors: Pascual A M , Salvador A , Gil R , Láinez M J A 
Published: November 2023

Abstract
Posttraumatic Headache (PTH) is usually, one of the several symptoms of ‘post- concussion syndrome’ and therefore, may be accompanied by additional cognitive, behavioral, or somatic problems. A variety of pain patterns may develop after head injury and may closely resemble primary headache disorders. Tension-type is the most common variety of PTH, followed by cervicogenic headache, migraine, and cluster-like headaches.
National and International Action Plans for Improving Headache Diagnosis
Authors: Steiner T J 
Published: November 2023

Abstract
Headache disorders are ubiquitous, common, and disabling. Migraine alone, according to the World Health Organization (WHO), is nineteenth in the list of all causes of years of healthy life lost to disability (YLDs). There are huge consequential financial costs. Effective healthcare can alleviate much of this illness burden. The problem is that it depends not only on the existence of efficacious therapies, which we have, but also on the allocation of healthcare resources to deliver them to those who need them.
Genetics Of Rheumatoid Arthritis
Authors: Gregersen Peter K , Plenge, Robert M , Gulko Pércio S 
Published: November 2023

Abstract
Over the last five years, it has become apparent that the genetic factors underlying rheumatoid arthritis are more various and more complex than many in the field had originally thought. The major histocompatibility complex (MHC) remains the most important contributor to genetic risk for rheumatoid arthritis (RA), although HLA-DRB1 is clearly not the only locus involved in these MHC associations. The entire field of human genetics, particularly the genetics of complex disease, is currently under-going dramatic change, driven in part by astounding advances in genotyping technology, accompanied by substantial decreases in costs.
Skin infections in the cancer patient
Authors: Hay Roderick J 
Published: November 2023

Abstract
In many parts of the world infections of the skin are the commonest manifestations of skin disease. This is because the major factors determining the risk of infection are the ease of transmission of the organisms and their intrinsic pathogenicity rather than the underlying condition of the host. Many skin pathogens cause disease in a variety of different human hosts irrespective of the host’s underlying immune status. Infections such as bacterial pyoderma (impetigo), dermatophytosis or ringworm, scabies and viral warts (human papillomavirus or HPV infections) are all examples of these common infections (Table 9.1). Their transmission is generally determined by simple risk factors for exposure, such as communal activities including use of public swimming pools, overcrowding, and sometimes, lack of hygiene. Opportunities for spread between individuals under these circumstances are frequent. These infections are also seen in the immunosuppressed patient. Generally in such individuals their prevalence is no commoner, and sometimes less frequent, than that seen in the healthy population. The reasons for reduced prevalence may reflect a lower opportunity for spread due, for example, to reduction of communal activities. However, in immunologically predisposed patients skin infections may present with clinical manifestations that are either similar to those seen in normal individuals or more widespread, atypical in presentation or recalcitrant to therapy. For instance the lesions of furunculosis (staphylococcal boils) in the neutropenic patient may be widely distributed rather than clustered in one region or there may be an abnormal evolution of infection such as occurs in disseminated Fusarium infections originating from an infected toenail in the severely neutropenic patient. In short the presence of immunosuppression does not affect the prevalence of the infection but may alter its clinical expression (Chren et al 1995).
The Biology of Alpine Habitats
Authors: Nagy Laszlo , Grabherr Georg 
Published: November 2023

Abstract
This book is unique in providing a global overview of alpine (high mountain) habitats that occur above the natural (cold-limited) tree line, describing the factors that have shaped them over both ecological and evolutionary timescales. The broad geographic coverage helps synthesise common features whilst revealing differences in the world’s major alpine systems from the Arctic to the Tropics. The words “barren” and “wasteland” have often been applied to describe landscapes beyond the treeline. However, a closer look reveals a large diversity of habitats, assemblages and individual taxa, largely connected to topographic diversity within individual alpine regions. The book considers habitat-forming factors (landforms, energy and climate, hydrology, soils, and vegetation) individually, as well as their composite impacts on habitat characteristics. Evolution and population processes are examined in the context of the responsiveness / resilience of alpine habitats to global change. Finally, a critical assessment of the potential impacts of climate change, atmospheric pollutants and land use is made and related to the management and conservation options available for these unique habitats.