A short overview of bubbles in foods and chocolate.

The incorporation of bubbles in foods has created a positive market response from consumers since their first introduction over 70 years ago and has resulted in an expanding market over this period. However, although the physics and chemistry of most ingredients in commercial food products are reasonably well understood, the behaviour of bubbles in foods are much less established and their behaviour not fully appreciated. In fact, bubbles are perhaps the least studied of all food ingredients even though aeration is still one of the fastest growing unit operations in processing. Although many of these manufactured aerated food products are perceived as lighter with lower calorific values, problems in manufacturing remain even today and it is generally difficult to optimize the size, the size distribution, the deviation the from spherical shapes and the stability of the bubbles during the different stages of the processing. In this review, we discuss the dispersion of the various food ingredients and the different processes involved in introducing bubbles into the melt, producing well dispersed multiphase systems. The second part of this review focusses on aerated chocolate and the above aspects are particularly important and are discussed in some detail since it has been well established that the bubble size and size distribution can influence the texture, the mouthfeel, the crispness, the melting temperature, and the brittleness of the product. Understanding the science involved in the transformation from the liquid state containing dispersed bubbles to a solid chocolate foam, stabilization of the bubbles and the control of the bubble size are highlighted. Although CO2 is usually used to generate bubbles in chocolate, several different gases including N2O, Ar and N2 have also been evaluated. One of the research aims of food companies is to improve control over the stability of the systems. This has been investigated with respect to drainage, by carrying out experiments under zero gravity conditions.

Long-term trends in critical care admissions in Wales*.

As national populations age, demands on critical care services are expected to increase. In many healthcare settings, longitudinal trends indicate rising numbers and proportions of patients admitted to ICU who are older; elsewhere, including some parts of the UK, a decrease has raised concerns with regard to rationing according to age. Our aim was to investigate admission trends in Wales, where critical care capacity has not risen in the last decade. We used the Secure Anonymised Information Linkage Databank to identify and characterise critical care admissions in patients aged ≥ 18 years from 1 January 2008 to 31 December 2017. We categorised 85,629 ICU admissions as youngest (18-64 years), older (65-79 years) and oldest (≥ 80 years). The oldest group accounted for 15% of admissions, the older age group 39% and the youngest group 46%. Relative to the national population, the incidence of admission rates per 10,000 population in the oldest group decreased significantly over the study period from 91.5/10,000 in 2008 to 77.5/10,000 (a relative decrease of 15%), and among the older group from 89.2/10,000 in 2008 to 75.3/10,000 in 2017 (a relative decrease of 16%). We observed significant decreases in admissions with high comorbidity (modified Charlson comorbidity index); increases in the proportion of older patients admitted who were considered 'fit' rather than frail (electronic frailty index); and decreases in admissions with a medical diagnosis. In contrast to other healthcare settings, capacity constraints and surgical imperatives appear to have contributed to a relative exclusion of older patients presenting with acute medical illness.

Reliability of frailty assessment in the critically ill: a multicentre prospective observational study.

Demand for critical care among older patients is increasing in many countries. Assessment of frailty may inform discussions and decision making, but acute illness and reliance on proxies for history-taking pose particular challenges in patients who are critically ill. Our aim was to investigate the inter-rater reliability of the Clinical Frailty Scale for assessing frailty in patients admitted to critical care. We conducted a prospective, multi-centre study comparing assessments of frailty by staff from medical, nursing and physiotherapy backgrounds. Each assessment was made independently by two assessors after review of clinical notes and interview with an individual who maintained close contact with the patient. Frailty was defined as a Clinical Frailty Scale rating > 4. We made 202 assessments in 101 patients (median (IQR [range]) age 69 (65-75 [60-80]) years, median (IQR [range]) Acute Physiology and Chronic Health Evaluation II score 19 (15-23 [7-33])). Fifty-two (51%) of the included patients were able to participate in the interview; 35 patients (35%) were considered frail. Linear weighted kappa was 0.74 (95%CI 0.67-0.80) indicating a good level of agreement between assessors. However, frailty rating differed by at least one category in 47 (47%) cases. Factors independently associated with higher frailty ratings were: female sex; higher Acute Physiology and Chronic Health Evaluation II score; higher category of pre-hospital dependence; and the assessor having a medical background. We identified a good level of agreement in frailty assessment using the Clinical Frailty Scale, supporting its use in clinical care, but identified factors independently associated with higher ratings which could indicate personal bias.

Short course antibiotic therapy for Gram-negative hospital-acquired pneumonia in the critically ill.

Hospital-acquired pneumonia (HAP) is a common cause of morbidity and mortality in the critically ill, yet the optimal duration of antibiotic therapy is unknown. Too short a course may lead to treatment failure, whereas too long a course may lead to increased antibiotic resistance, antibiotic-related morbidity and increased costs. Standard duration of antibiotic therapy for Gram-negative (GN-)HAP at our institution is 5 days, significantly shorter than advocated in many current guidelines. We performed a retrospective review of all cases of GN-HAP on our critical care unit fulfilling clinical and microbiological criteria to investigate recurrence rate and mortality following short course antibiotic therapy. Seventy-nine eligible patients with GN-HAP were identified. Of these, 79% were receiving mechanical respiratory support at diagnosis; 42% had GN-HAP due to non-fermenting Gram-negative bacilli (NF-GNB) and 72% were treated with the recommended 5 day course of antibiotics. Two patients had clear evidence of non-resolution of pneumonia after 5 days of therapy. Overall recurrence rate was 14%, with relapse rates significantly higher among patients with NF-GNB when compared to patients with other Gram-negative organisms (17% vs 2%; P=0.03). The overall recurrence rate was no higher than rates reported in earlier studies (17-41%). Critical care mortality (34.2%) was also not in excess of previously reported values (18-57%). In this limited study, use of a 5 day course of appropriate antibiotics for GN-HAP does not appear to increase risk of recurrence or mortality when pneumonia resolution has been achieved prior to the cessation of therapy.

Foaming in chemical surfactant free aqueous dispersions of anatase (titanium dioxide) particles.

Steady-state dynamic aqueous foams were generated from surfactant-free dispersion of aggregated anatase nanoparticles (in the micrometer size range). In order to tune the particle surfaces, to ensure a critical degree of hydrophobicity (so that they disperse in water and generate foam), the particles were subjected to low-temperature plasma treatment in the presence of a vapor-phase silane coupling agents. From ESCA it was shown that hydrophobization only occurred at a small number of surface sites. Foamability (foam generation) experiments were carried out under well-defined conditions at a range of gas flow rates using the Bikermann Foaming Column.1 The volume of the steady-state foams was determined under constant gas flow conditions, but on removing the gas flow, transient foams with short decay times (<5 s) were observed. The foamability of the steady-state foams was found to be dependent on (a) the time of plasma treatment of the particles (surface hydrophobicity), (b) the particle concentration in the suspension, and (c) the state of dispersion of the particles. High foamability was promoted in the neutral pH regions where the charged particles were highly dispersed. In the low and high pH regions where the particles were coagulated, the foamability was considerably reduced. This behavior was explained by the fact that the large coagula were less easily captured by the bubbles and more easily detached from the interface (during the turbulent foaming conditions) than individual dispersed particles.

The role of the surfactant head group in the emulsification process: binary (nonionic-ionic) surfactant mixtures.

Dilute emulsions of dodecane in water were prepared under constant flow rate conditions with binary surfactant systems. The droplet size distribution was measured as a function of the mixed surfactant composition in solution. The systems studied were (a) the mixture of anionic sodium dodecyl sulfate (SDS) with nonionic hexa(ethyleneglycol) mono n-dodecylether (C12E6) and (b) the mixture of cationic dodecyl pyridinium chloride (DPC) with C12E6. At a constant concentration of SDS or DPC surfactant in solution (below the CMC) the mean emulsion droplet size decreases with the increase in the amount of C12E6 added to the solution. However, a sharp break of this droplet size occurs at a critical concentration and beyond this point the mean droplet size did not significantly change upon further increase of the C12E6. This point was found to corresponded to the CMC of the mixed surfactant systems (as previously determined from microcalorimetry measurements) and this result suggested the mixed adsorption layer on the emulsion droplet was similar to the surfactant composition on the mixed micelles. The emulsion droplet size as a function of composition at the interface was also studied. The mean emulsion droplet size in SDS-C12E6 solution was found to be lower than that in DPC-C12E6 system at the equivalent mole fraction of ionic surfactant at interface. This was explained by the stronger interactions between sulphate and polyoxyethylene head groups at the interface, which facilitate the droplet break-up. Counterion binding parameter (beta) was also determined from zeta-potential of dodecane droplets under the same conditions and it was found that (beta) was independent of the type of the head group and the mole fraction of ionic surfactant at interface.

Experimental techniques for studying the structure of foams and froths.

Several techniques are described in this review to study the structure and the stability of froths and foams. Image analysis proved useful for detecting structure changes in 2-D foams and has enabled the drainage process and the gradients in bubble size distribution to be determined. However, studies on 3-D foams require more complex techniques such as Multiple-Light Scattering Methods, Microphones and Optical Tomography. Under dynamic foaming conditions, the Foam Scan Column enables the water content of foams to be determined by conductivity analysis. It is clear that the same factors, which play a role in foam stability (film thickness, elasticity, etc.) also have a decisive influence on the stability of isolated froth or foam films. Therefore, the experimental thin film balance (developed by the Bulgarian Researchers) to study thinning of microfilms formed by a concave liquid drop suspended in a short vertical capillary tube has proved useful. Direct measurement of the thickness of the aqueous microfilm is determined by a micro-reflectance method and can give fundamental information on drainage and thin film stability. It is also important to consider the influence of the mineral particles on the stability of the froth and it have been shown that particles of well defined size and hydrophobicity can be introduced into the thin film enabling stabilization/destabilization mechanisms to be proposed. It has also been shown that the dynamic and static stability can be increased by a reduction in particle size and an increase in particle concentration.

The LH1-RC core complex of Rhodobacter sphaeroides: interaction between components, time-dependent assembly, and topology of the PufX protein.

Mutant strains of the photosynthetic bacterium Rhodobacter sphaeroides, lacking either LH1, the RC or PufX, were analysed by mild detergent fractionation of the cores. This reveals a hierarchy of binding of PufX in the order RC:LH1 > LH1 > RC. The assembly of photosynthetic membranes was studied by switching highly aerated cells to conditions of low aeration in the dark. The RC-H subunit appears before other components, followed by the pufBALMX then pufBA transcripts. Synthesis of the PufX polypeptide precedes that of LH1alpha and beta, which suggests that PufX associates with a limited amount of LH1alpha, beta and the RC, and prior to the encirclement of the RC by the rest of the LH1 complex. The topology of PufX within the intracytoplasmic membrane was determined by proteolytic treatment of membrane vesicles followed by protein sequencing; PufX is N-terminally exposed on the cytoplasmic surface of the photosynthetic membrane.

Fatal bleeding from gastric ulceration during first day of life--possible association with social stress.

Death from haemorrhage is described in a 21-hour-old baby boy with acute gastric ulceration. Particular note is made of the very high level of psychosocial maternal stress during the last trimester of pregnancy. A causal relationship of this stress and the peptic ulceration is suggested, with gastrin as the mediator.

Pyridoxol metabolism in vitamin B6-responsive convulsions of early infancy.

As there is uncertainty about the nature of the metabolic defect in vitamin B6-responsive convulsion, certain aspects of pyridoxol metabolism were studied in 3 patients who were believed on clinical grounds to have the condition. The findings were compared with those in healthy children and adults, and in children with mental handicap. The magnitude of the initial rise and the subsequent fall in plasma pyridoxal phosphate (PALP) concentrations after a load of pyridoxol suggested that the vitamin B6-responsive patients were able to synthesise PALP normally but were unable to maintain the prolonged high levels normally found in plasma. The urinary excretion of 4-pyridoxic acid was within normal limits, but the excretion of pyridoxol after the load was raised. It is suggested that there may be an instability of the PALP-albumin complex in this condition. Some of the biochemical features were also observed in an infant presenting with convulsions soon after birth but without evidence of clinical B6-dependency.

Poliomyelitis-like illness after acute asthma.

Two children had pain in one arm, followed by weakness and wasting, after an acute exacerbation of bronchial asthma. Similar cases in which a poliomyelitis-like illness was associated with acute asthma have been reported, but the relationship between the two remains conjectural.