Microfluidic Study of the Electrocoalescence of Aqueous Droplets in Crude Oil

In electrocoalescence, an electric field is applied to a dispersion of conducting water droplets in a poorly conducting oil to force the droplets to merge in the direction of the field. Electrocoalescence is used in petroleum refining to separate water from crude oil and in droplet-based microfluidics to combine droplets of water in oil and to break emulsions. Using a microfluidic design to generate a two-dimensional (2D) emulsion, we demonstrate that electrocoalescence in an opaque crude oil can be visualized with optical microscopy and studied on an individual droplet basis in a chamber whose height is small enough to make the dispersions two dimensional and transparent. From reconstructions of images of the 2D electrocoalescence, the electrostatic forces driving the droplet merging are calculated in a numerically exact manner and used to predict observed coalescence events. Hence, the direct simulation of the electrocoalescence-driven breakdown of 2D emulsions in microfluidic devices can be envisioned.

Predicting HBsAg clearance in genotype A chronic hepatitis B using HBsAg epitope profiling: A biomarker for functional cure

BACKGROUND AND AIM

Functional cure is the major goal of chronic hepatitis B (CHB) therapy though few biomarkers predict this outcome. HBsAg epitope occupancy can be influenced by therapeutic and immune pressure. The aim of this study was to map the HBsAg epitope profiles during long-term nucleos(t)ide analogue therapy in patients with genotype A CHB, in the context of HBsAg loss (SL)/seroconversion.

METHODS

We evaluated 25 genotype A CHB patients in the GS-US-174-0103 trial of HBeAg-positive CHB patients treated with tenofovir or adefovir for 4 years, 14 who achieved SL whilst 11 had no change. We epitope mapped the major domains of HBsAg to identify those patients with HBsAg clearance profile (CP) (loss of binding at both loops 1 and 2 epitopes of the 'a' determinant) vs non-clearance profile (no change in epitope recognition, or loss of epitope binding at one loop only), correlating this to on-treatment HBsAg responses. Complexed anti-HBs was also measured.

RESULTS

Analysis of the HBsAg epitope profiles of the 25 patients at baseline identified no predictive correlation with SL. In contrast, analysis at week 48 and end of study (week 192) or prior to SL identified significant predictive associations between development of HBsAg CPs and outcome of functional cure. The detection of a CP also correlated with the development of an alanine aminotransferase flare and detection of anti-HBs complexed with HBsAg.

CONCLUSION

The detection of HBsAg CPs by epitope mapping represents a novel viral biomarker, reflecting an emerging anti-HBs selection pressure prior to functional cure.

An ultra-sensitive Abbott ARCHITECT® assay for the detection of hepatitis B virus surface antigen (HBsAg)

BACKGROUND

Critical to the identification of HBV infection and the prevention of transfusion transmitted disease is the sensitive and accurate detection of Hepatitis B virus surface antigen (HBsAg). Improvements in HBsAg assay sensitivity approaching the performance of nucleic acid testing (NAT) are essential to further reduce the detection window for acute HBV infection in regions where NAT is not widely available.

OBJECTIVES AND STUDY DESIGN

An improved HBsAg assay on the fully-automated Abbott ARCHITECT^® platform was developed to improve sensitivity, mutant and genotype detection.

RESULTS

The analytical sensitivity of the improved prototype assay is 5.2 mIU/ml, which is 3.86- to 14.54-fold more sensitive than comparator assays based on the WHO International Reference Standard. The enhanced sensitivity was also demonstrated with 27 HBV seroconversion panels, detecting more panel members (191 of 364) vs. the ARCHITECT^® Qual I (144), Qual II (160) and PRISM^® (148) HBsAg assays. Further, the assay detected 7 of 12 HBV DNA positive/HBsAg negative samples, and detected all evaluated mutants and genotypes with higher sensitivity than the comparator assays. The improvement in sensitivity did not diminish assay specificity, attaining 100% (95% CI, 99.97-100%) on 10,633 blood donors.

CONCLUSIONS

An Abbott ARCHITECT^® HBsAg assay with clinical performance approaching that of mini-pool NAT (approximately 100 copies/ml was developed. The assay has superior HBsAg mutant and genotype detection and specificity, all of which are important for the diagnosis and management of HBV infection.

Interpersonal circumplex

The social and intellectual climate of the late 1940s and early 1950s in America helped nourish humanistic, person-centered views of human behavior. During that time, psychologists such as Gordon Allport, Abraham Maslow, David McClelland, Harry Murray, and Carl Rogers emphasized the positive growth potential in human character. The psychiatrist Harry Stack Sullivan proposed that personality can best be understood within the context of interpersonal transactions, and he provided a practical, street-smart understanding of psychiatric symptoms that was quite an advance over the traditional medical and psychoanalytic viewpoints. These ideas, along with the concept of dimensionalizing traits rather than categorizing them, inspired my colleagues and I to conduct our cooperative work on the interpersonal circumplex, which culminated in the publication of my monograph. Interpersonal Diagnosis of Personality (Leary, 1957).

Impact of an outreach team on re-admissions to a critical care unit

Re-admissions have been cited as a measure of critical care quality and outreach teams have recently been introduced to improve critical care delivery. The aim of this study was to examine whether the number, causes and sequence of re-admissions to critical care altered as a result of the introduction of an outreach team. Re-admissions between April 2000 and November 2001 were examined. The reasons for re-admission were classified as (i) same pathology or disease process; (ii) new, but related, pathology; (iii) new and unrelated pathology; (iv) exacerbation of other comorbidities. During the two-year period, a total of 2546 patients were admitted to critical care of which 100 were re-admitted (49 before outreach and 51 after outreach). The reasons for re-admission did not vary before or after the introduction of the outreach team (same pathology 15 vs. 15; new, but related, pathology 17 vs. 23; new, but unrelated, 14 vs. 9; exacerbation of comorbidity 3 vs. 4, respectively, Chi-squared = 2.07, df = 3, p = 0.56). There was also no difference between the duration of stay on the general ward in between the critical care unit admissions before (median 2.93 [interquartile range 1.32-6.05] days) or after (median 2.25 [interquartile range 1.06-6.32] days) the introduction of an outreach team. As we could not detect any change in patterns of re-admissions as a result of the introduction of an outreach team, we would suggest that although outreach is an important development for critical care, its performance should be measured by other parameters.

Assessing critical care unit performance: a global measure using graphical analysis

Outcome measurement in critical care is difficult because of the wide variety of patients treated and the diverse therapeutic options and pathways available. Individual outcome measures for critical care are available but are naturally limited to only a single aspect of performance. Most importantly, better performance in one aspect of care may compromise the standard of care in another. A global measure of performance would be helpful. For the year 1999-2000, the five hospitals in the East Anglian Critical Care Network provided data on capacity, workload and performance. The data was transformed and displayed graphically on a radar chart so that the area of the polygon within the radar chart was proportional to each unit's overall performance. The results from the five hospitals suggest that there is little overall difference in the units' global performance but the graphical representation highlighted some individual deficiencies. Graphical analysis of complex processes such as critical care delivery may facilitate performance assessment, providing that the measures chosen, weightings assigned and scales used are standardised with care.

Justification of pulse oximeter costs for paramedic prehospital providers

OBJECTIVE

To assess the potential cost savings of decreasing prehospital oxygen utilization by using pulse oximetry to identify those patients who do not require supplemental oxygen.

METHODS

A prospective, controlled trial was performed comparing rates of oxygen utilization by paramedics with and without access to pulse oximetry. Consecutive patient encounters over a ten-week period were randomized by day of presentation. Pulse oximeters were made available on alternate days. On those days, patients whose oxygen saturations were less than 95% were treated with supplemental oxygen.

RESULTS

The use of pulse oximeters incurred a saving of 0.14 "D"-size oxygen cylinders per call. For the authors' service, this translates to a potential saving of $2,324 (C)/vehicle/year.

CONCLUSION

For regions with patient demographics similar to the authors', the initial cost of providing paramedics with pulse oximeters may be offset by savings in oxygen consumption. A formula is provided to allow individual ambulance services to calculate the potential savings for their service.

Acute injury incidence in professional county club cricket players (1985-1995)

BACKGROUND

There is a dearth of evidenced based research into sports injury in professional cricket.

AIM

To investigate the incidence, nature, and site of acute injuries sustained by professional cricketers at one English county club over the period 1985-1995.

METHODS

Injuries in a sample of 54 cricketers who had played in the first team for the same county cricket club in any or all seasons between 1985 and 1995 were investigated. Injury was defined as the onset of pain or a disability resulting from either training for or playing cricket, which caused the player to seek medical attention.

RESULTS

An acute injury rate of 57.4 injuries per 1000 days of cricket played was found, with most injuries sustained during April, the month in which the least number of days were played. The lower limb was the region most vulnerable to injury, accounting for 44.9% of all injuries, followed by the upper limb (29.4%), the trunk (20.0%), and the head and neck (5.7%). No significant difference in injury incidence among player positions was found.

CONCLUSION

There is a need for a system of epidemiological data collection and development of a national cricket injury database to help predict, reduce, and prevent injury at all levels of the game.

Convulsions and respiratory arrest in association with desmopressin administration for the treatment of a bleeding tonsil in a child with borderline haemophilia

Desmopressin (DDAVP) may be used to augment the action of factor VIII in mild haemophilia. Its use has been associated with serious adverse effects. We report a case of a three-year-old child with a family history of haemophilia who suffered complications due to severe acute hyponatraemia following the administration of this drug for post-tonsillectomy bleeding.

Management of splenic artery aneurysm rupture during trial of scar with epidural analgesia

We report a case of ruptured splenic artery aneurysm during labor in which the clinical signs were masked by epidural analgesia. A high index of clinical suspicion must be maintained in cases of atypical epidural breakthrough pain, and attending clinicians must be prepared for the unexpected when faced with a maternal collapse.

Epidermal keratinocyte self-renewal is dependent upon dermal integrity

The epidermis is a major site of self-renewal in which there is constant replacement by cell division in the basal layers of cells lost by desquamation in the superficial layers. Such a tissue is therefore likely to contain stem cells and in this study we have examined the role of the dermis in the maintenance of epidermal self-renewal. We have developed a mouse model to address the question of whether the maintenance of epidermal self-renewal is dependent, as in the hemopoietic system, upon a heterologous cell type. Intact epidermis separated from dermis at the dermo-epidermal junction or epidermis derived from disaggregated epidermal cells, can reconstitute a stratified squamous epithelium when grafted onto the lumbo-dermal fascia of the mouse or onto an experimentally induced granulation tissue bed. However, we have shown that, after grafting, the clonogenic capacity of the keratinocytes declines sharply and the colonies that are produced are incapable of self-renewal in vitro. Although initially hyperplastic, these epidermal grafts assume an atrophic appearance after 40-70 d and this may be related to the loss of self-renewal observed in vitro. With both experimental murine grafts and clinical grafts the failure of keratinocytes to self-renew can be alleviated, partially, by the presence of the dermis in full-thickness or split-thickness grafts, which implies that the dermis has a functional role in epidermal stem cell maintenance. The relevance of these observations to the clinical experience with cultured autologous keratinocyte sheets as wound dressings to patients is discussed.

Movement Patterns of the White-Footed Dunnart, Sminthopsis Leucopus (Marsupialia: Dasyuridae), in a Logged, Burnt Forest on the South Coast of New South Wales

The study was carried out between June 1980 and Dec. 1984 in the Mumbulla State Forest. Ninety-nine individuals were caught in Eucalyptus forest that had been logged in 1979-80 and burnt in 1980. The population was discrete, occupying an area of about 500 ha near the centre of the forest. The repeated capture of 35 individuals enabled movement patterns to be determined. Females occupied small home ranges, and capture sites did not overlap with those of other females. Males did not have exclusive capture sites and the home ranges overlapped. Their movement patterns fell into two groups: explorer males and resident males. The largest movement of an explorer male was 1025 m in 24 h. With data pooled for all trapping periods, the observed range length was 79.5 plus or minus 8.2 m for females; 104.9 plus or minus 14.5 m for resident males and 720.7 plus or minus 93.5 m for explorer males; the average distance between captures was 49.3 plus or minus 2.8 m for females, 63.4 plus or minus 10.3 m for resident males and 481.8 plus or minus 106.1 m for explorer males. Suitable habitat, such as recently disturbed forest, may occur naturally only as disjunct and temporary patches, hence the ability to travel long distances enables this species to utilize these suddenly abundant and transient resources.