Specific Influence of Solvents on the Infrared Spectra of Alcohols

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70532/2/JCPSA6-21-6-1115-1.pd

The Effect of Hydrogen Bonding on the Hindered Rotation of the Hydroxyl Group in Alcohols

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/69594/2/JCPSA6-20-12-1977-1.pd

Effect of Hydrogen Bonding on the Deformation Frequencies of the Hydroxyl Group in Alcohols

The effects of hydrogen bonding on the infrared spectra of aliphatic alcohols have been studied in the range 4000 to 350 cm—1. Twenty‐six alcohols were investigated of which 10 were primary, 7 were branched primary, 6 were secondary, and 3 were tertiary. Attention was concentrated on the region of the spectrum between 1500 cm—1 and 350 cm—1 where the deformation vibrations of the OH group occur. Spectra were obtained of the alcohols (a) in dilute solution in nonpolar solvents, (b) in the liquid state, and (c) in the vapor state, the degree of association being followed by observation of the well‐known effect of hydrogen bonding in the OH stretching vibration near 3.0μ. Methanol, ethanol, and hexanol‐1 were also investigated after deuteration of the OH group. All the alcohols exhibited a broad diffuse association band with a maximum near 650 cm—1. This has been assigned to the out‐of‐plane deformation vibration of the H atom in the COH group. All the alcohols also exhibited a broad association band which usually had 2 maxima near 1410 cm—1 and 1330 cm—1. This band (which appears to have been missed by previous workers) is assigned to the in‐plane deformation vibration of the H atom in the COH group. The corresponding monomeric band varies between 1200 cm—1 and 1330 cm—1 in undeuterated alcohols and between 870 cm—1 and 930 cm—1 in deuterated alcohols. There is in addition a very narrow association band which lies near 1100 cm—1 in primary and secondary alcohols and near 1165 cm—1 in tertiary alcohols. This is assigned to the effect of hydrogen bonding on the skeletal vibrations, which involve stretching of the CO bond. It appears that the effects of hydrogen bonding on the deformation motions of the OH group are quite complex and that steric effects, rotational isomerism, and interaction with C ☒ H deformation frequencies may all be involved to some extent.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71317/2/JCPSA6-24-3-559-1.pd

Scheepvaartbeweging

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Evolving information systems: meeting the ever-changing environment

To meet the demands of organizations and their ever-changing environment, information systems are required which are able to evolve to the same extent as organizations do. Such a system has to support changes in all time-and application-dependent aspects. In this paper, requirements and a conceptual framework for evolving information systems are presented. This framework includes an architecture for such systems and a revision of the traditional notion of update. Based on this evolutionary notion of update (recording, correction and forgetting) a state transition-oriented model on three levels of abstraction (event level, recording level, correction level) is introduced. Examples are provided to illustrate the conceptual framework for evolving information systems

De bescherming van de burgerbevolking in gewapend conflict: over gebaande paden en nieuwe wegen

Criminal Justice: Legitimacy, accountability, and effectivit

Children with multiple endocrine neoplasia type 2B: Not tall and marfanoid, but short with normal body proportions

Objective: Multiple endocrine neoplasia 2B (MEN2B) is characterised by early-onset medullary thyroid carcinoma (MTC), pheochromocytoma and several nonendocrine manifestations. Unfortunately, MEN2B is often diagnosed late, after the development of clinically significant MTC. Marfanoid habitus is considered an important related feature, which may lead to the assumption that patients with MEN2B have tall stature. Here, we describe the longitudinal growth and body proportions of eight MEN2B patients during childhood. Design: It is a retrospective case series. Methods: Patients were under the care of a Dutch MEN expertise centre. Growth patterns were assessed and interpreted in relation to body mass index (BMI), age at diagnosis and at thyroidectomy, extensiveness of disease manifestations and parental height. Results: Seven patients were short during childhood, of whom four showed growth below target height range (THR) and three at the lowest margin of THR. Only one patient grew well within THR. All patients who attained final height (n = 4) ended within THR, despite short stature during childhood. Arm span/height ratio was not increased and upper segment/lower segment ratio was not reduced in any patient. Short stature in childhood in this study did not seem to be associated with age at diagnosis, age at thyroidectomy, extensiveness of MTC, endocrine deficiencies or BMI. Conclusions: This study shows that children with MEN2B may well present with short rather than tall stature. Thereafter, final height within THR was attained in those who already reached adulthood, but none had tall stature. Finally, body proportions were normal in all children and adults in this case series, not underlining a ‘marfanoid’ body habitus

The protection of civilians in armed conflicts: well-trodden paths and new ways forward

Criminal Justice: Legitimacy, accountability, and effectivit