Phyto-dewatering of sewage sludge using Panicum repens L.

Experiments in the field environment have been conducted to study the growth of Panicum repens L., an aquatic plant, in the sewage sludge matrix. The experiments were also carried out to investigate the ability of this plant to dewater sewage sludge to increase the capacity of conventional drying beds. In addition, the ability of Panicum repens L. to reduce the sludge contents of certain elements (copper (Cu), Iron (Fe), Sodium (Na), lead (Pb), and Zinc (Zn)) was also investigated. All experiments were carried out in batch reactors. Different plant coverage densities were tested (0.00 to 27.3 kg/m2). The liquid sewage sludge was collected from a wastewater treatment plant in Helwan city, Cairo Governorate, Egypt. The collected sludge represents a mixture of the primary sludge and waste activated sludge before discharging into drying beds.

The outcomes of the elderly in acute care general surgery.

INTRODUCTION: Elderly patients form a growing subset of the acute care surgery (ACS) population. Older age may be associated with poorer outcomes for some elective procedures, but there are few studies focusing on outcomes for the elderly ACS population. Our objective is to characterize differences in mortality and morbidity for acute care surgery patients >80 years old. METHODS: A retrospective review of all ACS admissions at a large teaching hospital over 1 year was conducted. Patients were classified into non-elderly (<80 years old) and elderly (≥80 years old). In addition to demographic differences, outcomes including care efficiency, mortality, postoperative complications, and length of stay were studied. Data analysis was completed with the Student's t test for continuous variables and Fisher's exact test for categorical variables using STATA 12 (College Station, TX, USA). RESULTS: We identified 467 non-elderly and 60 elderly patients with a mean age-adjusted Charlson score of 3.2 and 7.2, respectively (p < 0.001) and a mortality risk of 1.9 and 11.7 %, respectively (p < 0.001). The elderly were at risk of longer duration (>4 days) hospital stay (p = 0.05), increased postoperative complications (p = 0.002), admission to the ICU (p = 0.002), and were more likely to receive a non-operative procedure (p = 0.003). No difference was found (p = NS) for patient flow factors such as time to consult general surgery, time to see consult by general surgery, and time to operative management and disposition. CONCLUSIONS: Compared to younger patients admitted to an acute care surgery service, patients over 80 years old have a higher risk of complications, are more likely to require ICU admission, and stay longer in the hospital.

Issues in potential organ donor management.

The shortage of organ donors has become a serious problem in modern medicine. Room for improvement exists in our ability to convert potential donors to actual donors based on the available numbers and a significant amount of recent research. A significant percentage of the potential donors represent head-injured patients, so a significant amount of responsibility falls on surgeons to optimize the opportunity for donation. There are clear steps along the pathway from potential to actual donor where physicians can have a significant effect on the rate of successful donation: 1. Identify all potential donors and institute a review system to verify that all potential donors are being identified in your area. 2. Establish an acceptable method to rapidly and accurately determine brain death in potential donors using the local available services. 3. Approach all potential donor families for consent, decouple death notification and consent request, use a member of the hospital team and an OPO representative to approach the family, and make the request in a private setting. 4. Use an aggressive, proactive approach to the medical management of the potential donor using the techniques described to limit the number of medical failures and maximize the number of organs donated per donor. Institute a review process to evaluate any medical failures that occur. Given the difference between the numbers of potential versus actual donors, the authors' significant contact with potential donors, and the clear opportunities for improvement in their approach, the surgical community must address these issues surrounding the optimal management of potential donors and their families.

Selective measurement of chromium(VI) by fluorescence quenching of ruthenium.

A flow injection method is described for the selective measurement of chromium(VI) in aqueous solutions. This method is based on the dynamic quenching of ruthenium(II) fluorescence. The detection limit is 0.43 ppm and 40 samples can be analyzed per hour. Selectivity is demonstrated over ferrous, nickel, cupric and zinc cations and no effect is observed from sulfate, chloride, borate and phosphate. Some interference quenching was measured for cyanide and nitrate, but the method is more responsive to chromium(VI) by factors of 10.2 and 82, respectively. The effects of solution pH, carrier stream flow rate and ruthenium concentration are demonstrated. Results indicate the method is suitable for measuring chromium(VI) in effluents from electroplating baths.

Optical sensor for sulfur dioxide based on fluorescence quenching.

A series of potential indicator dyes is evaluated for use in the development of optical sensors for measuring sulfur dioxide in gaseous samples. Rhodamine B isothiocyanate is selected on the basis of relative sensitivity to dynamic quenching by sulfur dioxide and oxygen. A solid-state fluorometer is described for monitoring the sulfur dioxide induced fluorescence quenching of sensing membranes composed of silicone and rhodamine B isothiocyanate. A modulated blue LED is coupled with the lock-in detection of a photodiode detector to provide high signal-to-noise ratios. The limit of detection is 0.114+/-0.009% for sulfur dioxide in a carrier stream of nitrogen gas. Selectivity measurements indicate no interference from several common gases (HCl, NH(3), NO, and CO(2)). Oxygen alters the sensor response when comparing signals for sulfur dioxide in 0, 20 and 100% oxygen environments.

Posterior mediastinal hematoma after a fall from standing height: a case report.

Posterior Mediastinal Hematomas (PMHs) secondary to a fall from standing height are uncommon, with only one previous case reported in the literature. We describe a case of a 78-year-old male with multiple medical comorbidities, who was transferred to Montreal General Hospital (MGH) with a posterior mediastinal hematoma (PMH) after sustaining a fall from standing height. On initial assessment, the patient was hemodynamically stable and complained of mild chest pain, dyspnea, fatigue, and diaphoresis. The patient's airway was secured via endotracheal intubation fearing impending respiratory compromise secondary to an enlarging PMH. The patient was admitted to ICU where over the next 3 days he was managed conservatively via careful monitoring of his hemodynamic and hematologic indices. Repeat CT scanning indicated reduction in size of the PMH. The patient was discharged on hospital day eight. This case describes the assessment, evaluation, and conservative management of PMH in a complicated patient receiving prior anticoagulation. A review of the literature regarding the epidemiology of PMH and the management of both unstable and stable PMHs is also presented.

Assessing the need for reintubation: a prospective evaluation of unplanned endotracheal extubation.

OBJECTIVE: Unplanned endotracheal extubation (UEE) is a common complication in medical intensive care units but very little data about UEE in surgical populations are available. Our hypothesis is that the surgical intensive care unit (SICU) population requires reintubation less frequently compared with the medical intensive care unit population. We prospectively gathered data on patients in a SICU in an attempt to identify the incidence of UEE and to study the need for reintubation after UEE. METHODS: During an 18-month period, we prospectively identified SICU patients from a quality improvement database who required ventilatory support. All patients who self-extubated were included in the study. RESULTS: Fifty-eight of 1,178 intubated patients experienced unplanned extubation 61 times during the 18-month period. A total of 22 patients (36%) required reintubation, whereas 39 patients (64%) did not. Thirty-three patients self-extubated while being actively weaned from ventilatory support. Of these, only 5 patients (15%) required reintubation and 28 patients (85%) did not (p < 0.01). CONCLUSION: A total of 85% of patients who self-extubate during the weaning process did not require reintubation in our study. Those who have an FiO2 >50%, a lower PaO2/FiO2 ratio, had UEE occur by accident, or were not being weaned when UEE occurred required reintubation more frequently. These data suggest that some of our SICU patients are intubated longer than necessary, which may translate into more ventilator related complications, longer ICU stays and increased cost.

Characterization of a heparin binding site on the heavy chain of factor XI.

The glycosaminoglycan heparin enhances several reactions involving coagulation factor XI (FXI) including activation of FXI by factor XIIa, thrombin, and autoactivation; and inactivation of activated FXI (FXIa) by serine protease inhibitors. We examined the effect of heparin on inhibition of FXIa by the inhibitors C1-inhibitor (C1-INH) and antithrombin III (ATIII). Second order rate constants for inhibition in the absence of heparin were 1.57 x 10(3) and 0.91 x 10(3) M-1 s-1 for C1-INH and ATIII, respectively. Therapeutic heparin concentrations (0.1-1.0 units/ml) enhanced inhibition by ATIII 20-55-fold compared with 0.1-7.0-fold for C1-INH. For both inhibitors, the effect of heparin over a wide range of concentrations (10(-1) to 10(5) units/ml) produced bell-shaped curves, demonstrating that inhibition occurs by a template mechanism requiring both inhibitor and protease to bind to heparin. This implies that FXI/XIa contains structural elements that interact with heparin. Human FXI contains a sequence of amino acids (R250-I-K-K-S-K) in the apple 3 domain of the heavy chain that binds heparin (Ho, D., Badellino, K., Baglia, F., and Walsh, P. (1998) J. Biol. Chem. 273, 16382-16390). To determine the importance of this sequence to heparin-mediated reactions, recombinant FXI molecules with alanine substitutions for basic amino acids were expressed in 293 fibroblasts, and tested in heparin-dependent assays. Inhibition of FXIa by ATIII in the presence of heparin was decreased 4-fold by alanine substitution at Lys253 (A253), with smaller effects noted for mutants A255 and A252. FXI undergoes autoactivation to FXIa in the presence of heparin. The rate of autoactivation was decreased substantially for A253 with modest decreases for A255 and A252. Substituting all four charged residues in the sequence resulted in a profound decrease in autoactivation, significantly greater than for any single substitution. Relative affinity for heparin was tested by determining the concentration of NaCl required to elute FXIa from heparin-Sepharose. Wild type FXIa eluted from the column at 320 mM NaCl, whereas FXIa with multiple substitutions (A252-254 or A250-255) eluted at 230 mM NaCl. All proteins with single substitutions in charged amino acids eluted at intermediate NaCl concentrations. The data indicate that FXI/XIa must bind to heparin for optimal inhibition by ATIII and for autoactivation. Lys253 is the most important amino acid involved in binding, and Lys255 and Lys252 also have roles in interactions with heparin.

Garlic prevents hypoxic pulmonary hypertension in rats.

Hypoxic pulmonary vasoconstriction underlies the development of high-altitude pulmonary edema. Anecdotal observations suggest a beneficial effect of garlic in preventing high-altitude symptoms. To determine whether garlic influences pulmonary vasoconstriction, we assessed the effect of garlic on pulmonary pressures in rats subjected to alveolar hypoxia and on vasoconstriction in isolated pulmonary arterial rings. Garlic gavage (100 mg/kg body wt) for 5 days resulted in complete inhibition of acute hypoxic pulmonary vasoconstriction compared with the control group. No difference in mean arterial pressure or heart rate response to hypoxia was seen between the groups. Garlic solution resulted in a significant dose-dependent vasorelaxation in both endothelium-intact and mechanically endothelium-disrupted pulmonary arterial rings. The administration of NG-nitro-L-arginine methyl ester (a nitric oxide synthase inhibitor) inhibited the vasodilatory effect of garlic by 80%. These studies document that garlic blocks hypoxic pulmonary hypertension in vivo and demonstrate a combination of endothelium-dependent and -independent mechanisms for the effect in pulmonary arterial rings.