Liquid-liquid phase separation in mixed organic/inorganic single aqueous aerosol droplets.

Direct measurements of the phase separation relative humidity (RH) and morphology of aerosol particles consisting of liquid organic and aqueous inorganic domains are presented. Single droplets of mixed phase composition are captured in a gradient force optical trap, and the evolving size, refractive index (RI), and morphology are characterized by cavity-enhanced Raman spectroscopy. Starting at a RH above the phase separation RH, the trapped particle is dried to lower RH and the transition to a phase-separated structure is inferred from distinct changes in the spectroscopic fingerprint. In particular, the phase separation RHs of droplets composed of aqueous solutions of polyethylene glycol (PEG-400)/ammonium sulfate and a mixture of C6-diacids/ammonium sulfate are probed, inferring the RH from the RI of the droplet immediately prior to phase separation. The observed phase separation RHs occur at RH marginally higher (at most 4%) than reported in previous measurements made from studies of particles deposited on hydrophobic surfaces by brightfield imaging. Clear evidence for the formation of phase-separated droplets of core-shell morphology is observed, although partially engulfed structures can also be inferred to form. Transitions between the different spectroscopic signatures of phase separation suggest that fluctuations in morphology can occur. For droplets that are repeatedly cycled through the phase separation RH, the water activity at phase separation is found to be remarkably reproducible (within ±0.0013) and is the same for the 1-phase to 2-phase transition and the 2-phase to 1-phase transition. By contrast, larger variation between the water activities at phase separation is observed for different droplets (typically ±0.02).

A framework for the organization and delivery of systemic treatment.

BACKGROUND: Increasing systemic treatment and shortages of oncology professionals in Canada require innovative approaches to the safe and effective delivery of intravenous (IV) cancer treatment. We conducted a systematic review of the clinical and scientific literature, and an environmental scan of models in Canada, the United Kingdom, Australia, and New Zealand. We then developed a framework for the organization and delivery of IV systemic treatment. METHODS: The systematic review covered the medline, embase, cinahl, and HealthStar databases. The environmental scan retrieved published and unpublished sources, coupled with a free key word search using the Google search engine. The Systemic Treatment Working Group reviewed the evidence and developed a draft framework using evidence-based analysis, existing recommendations from various jurisdictions, and expert opinion based on experience and consensus. The draft was assessed by Ontario stakeholders and reviewed and approved by Cancer Care Ontario. RESULTS: The poor quantity and quality of the evidence necessitated a consensus-derived model. That model comprises four levels of care determined by a regional systemic treatment program and three integrated structures (integrated cancer programs, affiliate institutions, and satellite institutions), each with a defined scope of practice and a specific organizational framework. INTERPRETATION: New models of care are urgently required beyond large centres, particularly in geographically remote or rural areas. Despite limited applicable evidence, the development and successful implementation of this framework is intended to create sustainable, accessible, quality care and to measurably improve patient outcomes.

Clinical photography: a guide for the clinician.

Clinicians might not always have available the services of a professional medical photographer, but if a standardised approach is followed those who take their own clinical photographs can achieve acceptable results. This article offers guidance to the clinician on consistent lighting, exposure, patient positioning, linear scale, perspective, depth of field, and background. Advice is given on equipment and materials, including digital and conventional cameras, flash (strobe), films, and processing choices. Consistency of approach is emphasised - it is not acceptable to use photographic tricks to enhance the appearance of clinical outcomes. Rather, care should be taken to ensure that the only changes among clinical photographs taken over time are in the patient. Photographs should be stored and presented appropriately for their use and images for publication should be prepared according to the instructions to authors. Digital images for publication should be sized appropriately for the final reproduction size.

Managing digital clinical photographs.

Digital cameras have been used for clinical photography in the Medical Illustration Department at Great Ormond Street Hospital NHS Trust for eight years. In that time methods have evolved to take advantage of both technological advances and experiences gained in operating a routine digital photographic service. The management of a large number of digital images requires assiduous attention to all stages of production. Current techniques are described for: controlling quality and exposure in the acquisition of images with a digital camera; temporary and permanent storage, backing up and archiving procedures; and cataloguing of clinical images. Planning for network delivery, the Electronic Patient Record and the management of images in teaching collections are discussed.

A clinical image library using photo CD.

In a move to update a collection of medical slide images and improve access to high-quality medical images for postgraduate teachers at the Institute of Child Health and Great Ormond Street Hospital for Children, a new collection of scanned slide images was created on Kodak Photo CD discs. Each image was available in five different resolutions. The images were catalogued in an image database by diagnosis, date, patient registration number, and anatomical view. Images could be accessed using simple search protocols and output to digital files, slides or prints.

Semi-synthetic approaches to novel penicillins.

The first part of this account of the discovery of penicillin, published in last month's issue of TIBS, concluded with the detection of 6-beta-amino-penicillanic acid (6-APA), the nucleus of the penicillin structure. The exploitation of 6-APA led to the preparation of a range of clinically important semi-synthetic penicillins, which is described in this article.

Early discoveries in the penicillin series.

It is now 50 years since the therapeutic potential of penicillin was first demonstrated. This first antibiotic and the series of compounds derived from it have been of immense importance in modern medicine. This article describes the early search for more potent penicillin derivatives, culminating with the discovery of an intermediate of penicillin biosynthesis, 6-beta-amino penicillanic acid (6-APA). A companion article in next month's TIBS will chart the subsequent exploitation of 6-APA and the preparation of a range of clinically important semi-synthetic penicillins.

The CPHA's ICD-9.CM as a coding source for medical slide filing.

A system is described for the coding of medical photographs using the Commission for Professional and Hospital Activities' 'International Classification of Diseases with Clinical Modification'; ICD-9.CM. Methods of indexing, cross-indexing and the application of coding criteria are discussed with reference to examples. Some atypical coding situations are discussed.

Antibacterial halogenoacetyl derivatives of amino acids and simple peptides.

The vital role of D-alanine and L-lysine in the peptidoglycan crosslinking process in the bacterial cell wall prompted preparation of various small peptides incorporating these amino acids. N-Iodoacetyl or -bromoacetyl derivatives of the peptides were then prepared in the hope that they would serve as active-site-directed irreversible inhibitors of cell wall transpeptidases. Certain of the halogenoacetyl dipeptide esters, but not the corresponding free acids, showed slight antistaphylococcal activity. Subsequent structural variation showed that inclusion of C-alanine or L-lysine was not necessary, since antibacterial activity was at least as good when the dipeptide unite was replaced by glycylglycine or by an omega-aminoalkanoic acid. It was concluded that the observed antibacterial activity was probably not due to specific inhibition of a cell wall transpeptidase.

Structure--activity relationships in cephalosporins prepared from penicillins. 1. 7beta-Acylamino derivatives of 3-benzyl- and 3-(3-pyridylmethyl)ceph-3-em-4-carboxylic acids.

tert-Butyl 7beta-aminoceph-3-em-4-carboxylates carrying either benzyl or 3-pyridylmethyl substituents at position 3 have been prepared by a multistep modification of the penicillin nucleus. Acylation of either amine, followed by deprotection, gave a range of new cephalosporins. The relationship between structure and antibacterial activity is discussed. D-Phenylglycine proved to be a preferred side chain in both series.

Structure--activity relationships in cephalosporins prepared from penicillins. 2. Analogues of cephalexin substituted in the 3-methyl group.

A previously outlined general procedure for preparing various 3-substituted cephalosporins from the penicillin nucleus has been used, with modifications where required, to prepare a series of analogues of cephalexin with various substituents in the 3-methyl group. The 3-substituents most conducive to broad-spectrum antibacterial activity were 3-pyridylmethyl and m- or p-carboxybenzyl. The compounds were only poorly absorbed by the oral route in mice, but the 3-(carboxybenzyl) compounds gave more prolonged useful serum levels than the usual cephalosporins.