Factors affecting the longevity of sub-surface horizontal flow systems operating as tertiary treatment for sewage effluent

Compared with other forms of domestic wastewater treatment, reed beds require very little in the way of operational and maintenance input. This is even more markedly the case with tertiary treatment systems (than with secondary treatment systems) where the necessary maintenance amounts to only a few days/year. Unfortunately, in practice this frequently results in them receiving little or no attention at all. Tertiary treatment reed beds are not a "fit and forget" solution but they are often treated this way because they are very forgiving and abuse-tolerant. After a number of years a few of these tertiary reed beds have deteriorated to an extent whereby they are close to failing to comply with the regulator's requirements. Severn Trent Water Ltd has recognised this situation and has committed a budget for a programme of reed bed maintenance. This work has started with a survey of the condition of their beds and particularly to determine the common problems and hence the maintenance regime required. Five main problems occurred either singly or in combination namely: (a) sludge deposition; (b) above surface flooding (partially caused by (a), (c), and (d)); (c) inlet flow distributor problems/clogging; (d) outlet collector problems/incorrect level; (e) weed infestation.

The performance of vertical flow constructed wetland systems with special reference to the significance of oxygen transfer and hydraulic loading rates

The paper reviews the development of the vertical flow (VF) reed beds/constructed wetlands over the past 20 years. The performance of VF systems (and their use within hybrid systems) is analysed by reference to a number of brief case studies. The oxygen transfer rate (OTR) achieved is absolutely critical to the sizing of the systems. The author reviews the reported OTRs and comments on the existing design equations proposed for calculation of the area of beds. The 1st generation of VF systems used a set of parallel beds that were dosed one at a time in rotation and then rested for a period of days because there was considerable concern (based on early experience) that they would become clogged. In the past 10 years a number of new designs of 2nd generation VF beds have been built which make use of a single bed and hence operate without any resting periods. The hydraulic loading rate and the selection of the bed media, which are critical to the design and hence successful operation of these 2nd generation compact VF beds, are described. It is now possible to produce a very high quality of effluent from VF beds alone sized at 2 m2/pe when treating domestic sewage.

Physiologic responses in healthy Labrador Retrievers during field trial training and competition

Ten healthy Labrador Retrievers (4 females and 6 males aged 3-6.5 years [mean, 4.5 years]) training with a professional trainer were studied. The dogs were in training during the entire study. Dogs were monitored within 5 minutes after retrieving birds on land and in water on 2 consecutive days during training and on 2 consecutive days at the Atlanta Retriever Club Fall Field Trial. Baseline samples were taken in the morning on a separate day before the dogs were loaded onto a truck. Venous samples were analyzed with a portable blood analyzer. Measurements included hematocrit, sodium, potassium, chloride, blood urea nitrogen (BUN), glucose, lactate, blood pH, Pco2, Po2, HCO3, and TCO2 plus rectal temperature, pulse rate, and respiratory rate. Ambient temperatures were recorded. Distances and times were estimated. Compared to baseline, significant increases occurred in rectal temperature, pulse rate, respiratory rate, chloride, lactate, and pH postexercise (P < .05): sodium, potassium, BUN, Pco2, and TCO2 were significantly decreased postexercise. Blood pH was markedly higher after retrieves on land than after retrieves in water. Estimated mean speeds were 11.4 mph (18.3 km/h) during a triple retrieve on land and 5.6 mph (9.0 km/h) during a retrieve in water. Maximal ambient temperatures were 84-86 degrees F (29-30 degrees C). In summary, Labrador Retrievers training with a professional trainer had evidence of hyperthermia, respiratory alkalosis, hypocapnia, and mild metabolic acidosis monitored within 5 minutes postexercise during training and field trial competition when maximal ambient temperatures were 85 degrees F (29 degrees C). The results provide a baseline against which physiologic responses of dogs with poor performance can be compared.

Delineation of brain metastases on CT images for planning radiosurgery: concerns regarding accuracy

Conformal radiotherapy requires confidence that the images used for target delineation accurately reflect the pathological dimensions of the target. Radiosurgery, which is a conformal radiotherapy technique, is often used to treat brain metastases. The images of brain metastases can be affected by the method of image acquisition. A prospective study was undertaken to evaluate the effect of delay on CT images of brain metastases selected for radiosurgical treatment. A median delay from contrast administration of 65 min resulted in an increase in the volume of the metastases in 86% of cases when compared with the volumes of the same metastases determined from CT images acquired immediately following the administration of contrast medium. The magnitude of the increase in volume was sufficient to cause radiosurgery planners to select larger collimator sizes for radiosurgery plans based on the delayed CT images in 92% of cases. No significant intraobserver or interobserver variation was found in the group of radiosurgery planners. Differences in image acquisition may account in part for the differences in local control reported in the radiosurgical treatment of brain metastases.

Mental health of parents caring for infants

The postpartum period is a sensitive time due to the presence and demands of the developing infant. The care provided by a mother to her infant during this period may be compromised if she is suffering from postnatal depression or postpartum psychosis. Evidence has been emerging which suggests that postnatal depression and postpartum psychoses have adverse effects on the quality of the mother-infant relationship and also on the infant's subsequent cognitive and emotional development. Presented is a review of the literature relating to how these conditions impact on parenting and infant outcomes, what measures are in place to detect these conditions and evidence-based models of best clinical practice are proposed.

Tracheomalacia, timing of symptoms, and thymic enlargement: cause or coincidence?

The authors report a case of severe primary tracheomalacia in a 3-month-old boy. The left lobe of the enlarged thymus was resected at operation to facilitate aortopexy. The authors suggest a possible role for the enlarging thymus contributing to the delayed onset of the symptoms of tracheomalacia, despite the presence of the tracheal lesion from birth.

Gut-focused hypnotherapy normalizes disordered rectal sensitivity in patients with irritable bowel syndrome

BACKGROUND

We have previously shown that hypnotherapy alters rectal sensitivity in some patients with irritable bowel syndrome. However, this previous study used incremental volume distension of a latex balloon, which might be susceptible to subject response bias and might compromise the assessment of compliance. In addition, the study group was symptomatically rather than physiologically defined.

AIM

To assess the effect of hypnotherapy on rectal sensitivity in hypersensitive, hyposensitive and normally sensitive irritable bowel syndrome patients using a distension technique (barostat) that addresses these technical issues.

METHODS

Twenty-three irritable bowel syndrome (Rome I) patients (aged 24-72 years) were assessed before and after 12 weeks of hypnotherapy in terms of rectal sensitivity, symptomatology, anxiety and depression. Normal values for sensitivity were established in 17 healthy volunteers (aged 20-55 years).

RESULTS

Compared with controls, 10 patients were hypersensitive, seven hyposensitive and six normally sensitive before treatment. Following hypnotherapy, the mean pain sensory threshold increased in the hypersensitive group (P = 0.04) and decreased in the hyposensitive group, although the latter failed to reach statistical significance (P = 0.19). Normal sensory perception was unchanged. Sensory improvement in the hypersensitive patients tended to correlate with a reduction in abdominal pain (r = 0.714, P = 0.07).

CONCLUSION

Hypnotherapy improves abnormal sensory perception in irritable bowel syndrome, leaving normal sensation unchanged.

Ketogenic diet for epilepsy

BACKGROUND

The ketogenic diet is a diet high in fat but low in carbohydrate and it is suggested that this diet reduces seizure frequency. Currently, this diet is used mainly for children who continue to have seizures despite treatment with antiepileptic drugs.

OBJECTIVES

To overview the evidence from randomized controlled trials regarding the effects of ketogenic diets.

SEARCH STRATEGY

We searched the Cochrane Epilepsy Group trials register (26 March 2003), the Cochrane Central Register of Controlled Trials (The Cochrane Library issue 1, 2003), MEDLINE (January 1966 to March 2003) and EMBASE (1980 to March 2003).

SELECTION CRITERIA

Randomized controlled trials of ketogenic diets for people with epilepsy.

DATA COLLECTION AND ANALYSIS

We planned for two reviewers to independently apply inclusion criteria and extract data.

MAIN RESULTS

No randomized controlled trials were found.

REVIEWER'S CONCLUSIONS

There is no reliable evidence from randomized controlled trials to support the use of ketogenic diets for people with epilepsy. There are large observational studies, some prospective, suggesting an effect on seizures. These effects need validating in randomized controlled trials. For those with a difficult epilepsy on multiple antiepileptic drugs, we consider the ketogenic diet a possible option.

Paediatric flexible bronchoscopy

Flexible bronchoscopy is an emerging diagnostic, therapeutic and supportive procedure used in paediatric respiratory medicine. Despite the improvements in instruments and anaesthetic support for this procedure, supervised training, strict quality-control measures and ongoing research are essential to ensure standards of safe practice and judicial use of the procedure.

Visceral sensation and emotion: a study using hypnosis

BACKGROUND AND OBJECTIVES

We have previously shown that hypnosis can be used to study the effect of different emotions on the motility of the gastrointestinal tract. These studies demonstrated that both anger and excitement increased colonic motility while happiness led to a reduction. The purpose of this study was to investigate the effect of hypnotically induced emotion on the visceral sensitivity of the gut.

METHODS

Sensory responses to balloon distension of the rectum and compliance were assessed in 20 patients with irritable bowel syndrome (IBS) (aged 17-64 years; 17 female) diagnosed by the Rome I criteria. Patients were studied on four separate occasions in random order either awake (control) or in hypnosis, during which anger, happiness, or relaxation (neutral emotion) were induced.

RESULTS

Hypnotic relaxation increased the distension volume required to induce discomfort (p=0.05) while anger reduced this threshold compared with relaxation (p<0.05), happiness (p<0.01), and awake conditions (p<0.001). Happiness did not further alter sensitivity from that observed during relaxation. There were no associated changes in rectal compliance or wall tension.

CONCLUSIONS

Further to our previous observations on motility, this study shows that emotion can also affect an IBS patient's perception of rectal distension and demonstrates the critical role of the mind in modulating gastrointestinal physiology. These results emphasise how awareness of the emotional state of the patient is important when either measuring visceral sensitivity or treating IBS.

cDNA cloning of a salivary chymotrypsin-like protease and the identification of six additional cDNAs encoding putative digestive proteases from the green mirid, Creontiades dilutus (Hemiptera: Miridae)

RT-PCR with degenerate primers was used to amplify partial cDNA fragments for one serine protease gene and three cysteine protease genes from poly(A) RNA isolated from the midgut of the green mirid, Creontiades dilutus. The serine protease amplicon showed homology to insect trypsin-like protease genes, and all three cysteine protease amplicons showed homology to cathepsin L-like protease genes.RT-PCR was also used to amplify fragments of three serine protease genes from salivary gland poly(A) RNA. One of these salivary gland serine protease amplicons was used to screen a whole organism cDNA library to isolate a full length cDNA clone, designated CdSp1 (Accession AY055753), which encodes a putative chymotrypsin-like protease. CdSp1 codes for a 293 amino acid protein that contains a signal peptide and activation peptide, as well as the catalytic triad present in all serine proteases and several of the binding pocket residues characteristic of chymotrypsins. In situ hybridisation showed that the transcript is expressed in the posterior lobe of the principal salivary gland, but not in the anterior lobe of the principal salivary gland, the accessory salivary gland or the midgut.

Indexing artefacts using a tertiary collimator and a method to avoid them

A tertiary, slotted grid collimator has been proposed as a method by which the spatial resolution of radiation fields shaped using a multileaf collimator (MLC) may be improved. The prototype device previously reported in the literature allowed each slot in the grid to be aligned with each pair of opposing leaves in the MLC. Irradiation through the collimator resulted in a regular pattern of high dose strips, with the width of each strip defined by the width of the slot and the length by the relative separation of the MLC leaf pair. To complete the field, the patient must be indexed relative to the collimator, with the number of sub-fields required determined by the width of the slots and the spacing between them. This indexing is achieved by rotation of the collimator along a radius centred on the radiation source, thus avoiding the effects of beam divergence on the uniformity of delivered composite beams. However, rotation of the tertiary collimator has been shown to result in artefacts in field definition. The source of such artefacts is the proximity of the long edge of a slot to the junction between two MLC leaves, if one leaf is withdrawn with respect to the next. A simple cause for such artefacts was identified as a small misalignment between the slot edge and the leaf junction. Another source of such effects is the finite size of the radiation source, which allows for partial shielding effects beyond the leaf edge. Finally, the effect of the leaf edge penumbra was identified as the cause of potential areas of underdose within the field boundary. Measurements were performed using a mini-diode of the potential magnitude of the last two effects for slot widths of 2.5 and 5.0 mm beneath a single open MLC leaf. For both slot widths, the unwanted overdose due to partial shielding by neighbouring leaves did not exceed 8% of the dose with the slot at the centre of the single open leaf. The potential for underdose within the field was a much more significant effect, especially for the narrower slot, with the peak intensity through the 2.5 mm slot positioned just inside the open leaf only reaching 41% of that measured with it positioned centrally. Such an arrangement of slots and leaves is unavoidable if the separation between neighbouring slots is identical to that of the MLC leaves (1 cm at isocentre). An alternative arrangement is proposed, and has been demonstrated to avoid the generation of the artefacts detailed above.

Optimizing the indexing of a resolution-enhancing tertiary collimator for radiotherapy

A method for improving the resolution of multileaf collimator (MLC) defined radiotherapy fields using a tertiary, slotted grid collimator has been investigated and developed further. The original concept was for each slot to be aligned with each leaf pair of opposing MLC leaves. The total treated area is composed of a series of sub-fields, a pattern of irradiated strips, with the width of each strip defined by the width of the slot and the length by the relative separation of the MLC leaf pair. To complete the field, the patient must be indexed relative to the collimator, with the number of sub-fields required determined by the width of the slots and the spacing between them. Two methods were considered by which this indexing could be achieved: movement of the patient while holding the tertiary collimator fixed, or rotating the grid with the point of rotation defined as the radiation source. Consideration of the movement resolution and precision required for the patient support system for non-cardinal gantry, collimator and table angles cast doubt on the practicality of the use of such a strategy. To assess the effect of divergence on the abutting sub-fields, measurements were also performed to assess the uniformity of single fields generated by the tertiary collimator in planes above and below the isocentre using both methods of indexing. As expected, rotation of the collimator resulted in a similar degree of non-uniformity for any plane chosen, whereas significant dose heterogeneities were introduced to treatment planes within 5 cm above and below the isocentre if the patient support system was used. Therefore, the rotation strategy will be implemented with all future versions of the device.

The safest surgical incisions and amputations applying the angiosome principles and using the Doppler to assess the arterial-arterial connections of the foot and ankle

Knowing the arterial anatomy of the foot and ankle in addition to understanding the angiosome concept provides the basis for careful and safe planning of incisions. The Doppler allows the surgeon to map out the actual vascular anatomy that exists preoperatively and therefore allows for appropriate adjustment to the planned incisions. If the vascular flow is inadequate for the planned surgery, then the vascular surgeon has to intervene to improve the existing blood flow. If the vascular tree is so compromised that successful revascularization of the affected angiosome is impossible, then the revascularization is likely to fail. Serious consideration to a below-knee amputation should then enter the decision tree at that time. Most of the time, however, the blood flow is adequate or can be sufficiently augmented with vascular surgery. The foot and ankle surgeon can then perform preoperative mapping of the arterial blood supply with the Doppler. By making the necessary adjustments to the planned incision, surgery can proceed safely with uneventful healing.

Cognitive vulnerability to depression in 5-year-old children of depressed mothers

Studies of cognitive vulnerability to depression in young children have, in the main, relied on self-report questionnaires (e.g. of self-esteem, attributional style). They have failed to produce convincing evidence of a cognitive vulnerability to depression in children under 8 years. In the current study latent depressive cognitions were investigated in the 5-year-old children (N = 94) of depressed and well mothers in a situation of mild stress, that is, the threat of losing a card deal in a modified version of the competitive children's card game "Snap"'. In the context of "losing", but not "winning", deals, children who had been exposed to maternal depression, either in the previous 12 months or at any other time during their lifetime, were more likely than nonexposed children to express depressive cognitions (hopelessness, pessimism, and low self-worth). The association between depressive cognitions and recent exposure to maternal depression was in part accounted for by current maternal hostility to the child. The results of this study stand in contrast to those of studies which have used questionnaire methods to assess vulnerability to depressive cognitions in this age group. They suggest that it might be important to employ ecologically realistic situations to access latent self-cognitions in young children; and they underscore the importance. increasingly evident in research with adults and older children, of employing methods that involve the induction of low mood in order to elicit cognitions relevant to depression.

Influence of psychiatric disorder on the controlling behaviour of mothers with 1-year-old infants. A study of women with maternal eating disorder, postnatal depression and a healthy comparison group

BACKGROUND

Certain styles of parental controlling behaviour influence child development. Work with mothers with eating disorders suggests that they may be particularly controlling of their infants.

AIMS

To examine the nature and specificity of maternal controlling behaviour in mothers with eating disorders compared with mothers who had experienced postnatal depression and a healthy comparison group.

METHOD

Mothers with eating disorders (n=34), postnatal depression (n=39) and a healthy comparison group (n=61) and their 12-month-old infants were observed during play and mealtimes, and blind ratings made of verbal and non-verbal control exerted by the mother.

RESULTS

Mothers in the eating disorder group used more verbal control, especially strong control. There were no differences between the groups on gentle verbal control and physical contact. Maternal dietary restraint was the one feature of eating disorder psychopathology associated with the use of verbal control. Marital criticism was also associated with the extent of verbal controlling behaviour.

CONCLUSIONS

Aspects of maternal control of infants were found to be specific to maternal eating disorder psychopathology.

The measurement of kappach factors for application with the IPEMB very low energy dosimetry protocol

In 1996. the IPEMB issued a new code of practice detailing the procedures by which the output of therapeutic kilovoltage x-ray devices are to be determined. For x-ray beam qualities in the range 0.035-1.0 mm Al half-value thickness (HVL), the equation for converting the instrument reading into absorbed dose to water contained a factor named kch. This was included to account for the change in response of the parallel plate chamber from its calibration conditions free in air to those in the user's measurement phantom. As no data were available with which to quantify this factor at very low energies, the code advised that the user take a value of unity until sufficient data became available upon which to base an addendum. In this work, kch values have been determined for four chambers: two PTW 23344 large volume soft x-ray chambers, one PTW 23342 small volume soft x-ray chamber and a Markus electron chamber. Variations in the value of kch were investigated for changes in FSD, applicator size and beam quality. The water equivalence of the Mix-D phantom used for these measurements was also verified. A comparison of the results for the two PTW 23344 chambers showed no significant differences for any experimental situation, indicating that kch is a factor of chamber design rather than variations in construction. No variation in kch was identified with changes in FSD. A small dependence on applicator size was identified for larger applicators, and this was found to be dependent upon chamber design. The measured values of kch were found to increase with energy and again differences were seen between chamber designs. Overall, the values of kch recorded during these measurements ranged from 1.01 to 1.08. These results highlight a significant underestimation of doses calculated using the very low energy code of practice. This supports the need for further work to confirm these results. and the production of an addendum to the code in its present form.