Highly efficient phosphorus recovery from sludge and manure biochars using potassium acetate pre-treatment.

Pyrolysis converts nutrient-rich residues (e.g., sewage sludge and manures) into biochar with low levels of organic contaminants and high nutrient contents. However, the availability of phosphorus (P) as one of the key nutrients in such biochar tends to be low and new approaches are needed to enhance P-availability. In this work we tested and optimised one such method, doping biomass prior to pyrolysis with potassium (K) as potassium acetate. The treatment worked effectively in both pyrolysis units tested (microscale and lab-scale, continuous unit) and all three feedstocks (two types of sewage sludges and swine manure). The most dramatic effect was observed in the microscale pyrolysis unit at 400 °C where 5% K doping increased the water-extractable P content 700-fold to 43% of total P. Of the added K, on average 90% was retained in biochar after pyrolysis of which ∼50% was water-extractable. The proposed method enables conversion of low-value residues into valuable resources with agronomically relevant total and available P and K levels. This approach does not require specialised equipment or process modifications and is therefore easy to implement and relatively cheap (∼US$ 60-80 t-1 treated feedstock). It can present an urgently required solution to fulfil regulatory requirements for P-recovery.

Waste timber pyrolysis in a medium-scale unit: Emission budgets and biochar quality.

Pyrolysis of organic waste or woody materials yields a stable carbonaceous product that can be mixed into soil and is often termed "biochar". During pyrolysis carbon-containing gases are emitted, mainly volatile organic carbon species, carbon monoxide and aerosols. In modern pyrolysis units, gases are after-combusted, which reduces emissions substantially. However, emission data for medium- to large-scale pyrolysis units are scant, both regarding gases, aerosols, heavy metals and polycyclic aromatic hydrocarbons (PAH). Making biochar from lightly contaminated waste timber (WT) is a promising waste handling option as it results in the potential valorization of such residues into e.g. sorbents for contaminant stabilization. For this process to be environmentally sustainable, emissions during the process need to be low and the resulting biochar of sufficient quality. To investigate both issues, we pyrolyzed three batches of WT and one reference batch of clean wood/leaves in a representative medium-scale pyrolysis unit (Pyreg-500, 750 t/year) with after-combustion of the pyrolysis gases, and measured the gas, aerosol, metal and PAH emissions, as well as the characteristics and contamination levels of the resulting biochar, including contaminant leaching. Mean emission factors for the WT were (g/kg biochar); CO = 7 ±â€¯2, non-methane volatile organic compounds (NMVOC) = 0.86 ±â€¯0.14, CH4 = 0, aerosols (PM10) = 0.6 ±â€¯0.3, total products of incomplete combustion (PIC) = 9 ±â€¯3, PAH-16 = (2.0 ±â€¯0.2) ·â€¯10-5, As (most abundant metal) = (2.3 ±â€¯1.9) ·â€¯10-3 and NOX = 0.65 ±â€¯0.10. There were no significant differences in emission factors between the pyrolysis of WT and the reference respectively, except for PM10, NMVOC, and PAH-16, which were significantly lower for WT than for the clean wood/leaves. The WT biochar did not satisfy premium or basic European Biochar Certificate criteria due to high levels of zinc and PAH. However, leachable metal contents were <0.1% of total contents. Still, use of the WT-biochar without further improvement or investigation would be limited to ex situ use, not improving soil fertility or in situ remediation.

Tensile strength decreases and perfusion pressure of 3-holed polyamide epidural catheters increases in long-term epidural infusion.

BACKGROUND AND OBJECTIVES: Epidural analgesia is an established method for pain management. The failure rate is 8% to 12% due to technical difficulties (catheter dislocation and/or disconnection; partial or total catheter occlusion) and management. The mechanical properties of the catheters, like tensile strength and flow rate, may also be affected by the analgesic solution and/or the tissue environment. METHOD: We investigated the tensile strength and perfusion pressure of new (n=20), perioperatively (n=30), and postoperatively (n=73) used epidural catheters (20-gauge, polyamide, closed tip, 3 side holes; Perifix [B. Braun]). To prevent dislocation, epidural catheters were taped (n=5) or fixed by suture (n=68) to the skin. After removal, mechanical properties were assessed by a tensile-testing machine (INSTRON 4500), and perfusion pressure was measured at flow rates of 10, 20, and 40 mL/h. RESULTS: All catheters demonstrated a 2-step force transmission. Initially, a minimal increase of length could be observed at 15 N followed by an elongation of several cm at additional forces (7 N). Breakage occurred in the control group at 23.5±1.5 N compared with 22.4±1.6 N in perioperative and 22.4±1.7 N in postoperative catheters (P<0.05). Duration of catheter use had no effect on tensile strength, whereas perfusion pressure at clinically used flow rates (10 mL/h) increased significantly from 19±1.3 to 44±72 mm Hg during long-term (≥7 days) epidural analgesia (P<0.05, analysis of variance). Fixation by suture had no influence on tensile strength or perfusion pressure. CONCLUSIONS: Epidural catheter use significantly increases the perfusion pressure and decreases the tensile strength.

A Swiss anaesthesiology closed claims analysis: report of events in the years 1987-2008.

BACKGROUND AND OBJECTIVE: In 1999, the Swiss Society of Anaesthesiology and Reanimation (SSAR) initiated an analysis of closed malpractice claims filed against anaesthetists in a project intended to improve patient safety. This article discusses the results of a review of closed claims between 1987 and 2008 and filed up to the end of 2009. METHODS: Records of closed claims were provided by Swiss professional medical liability insurance companies and the Office for Extrajudicial Expert Review of the Swiss Medical Association. Data were collected by an onsite reviewer, converted into a standardised format and sent to the SSAR Closed Claims Study Group.Assessment criteria employed by the committee were level of care (standard or substandard); severity of injury; appropriateness of patient information; and consent. RESULTS: The records of 171 events leading to anaesthesia-related injuries were entered into the database. These injuries occurred within the period 1987-2008. The majority of claims (54%) were related to regional anaesthesia, with general anaesthesia accounting for 28% and other anaesthesia-related procedures for 18%. The quality of care was judged by the committee to be substandard in 55% of cases, and liability was accepted in 46% of all claims. Negative outcomes were death in 12% and permanent injury in 63% of the patients. CONCLUSION: The closed claims analysis project enabled the SSAR to identify areas of high medicolegal risks to gain an insight into the causes of infrequent but potentially harmful events leading to anaesthesia-related injuries and, based on these data, to develop preventive strategies.

Tetrahydrocannabinol (Delta 9-THC) Treatment in Chronic Central Neuropathic Pain and Fibromyalgia Patients: Results of a Multicenter Survey.

Central neuropathic pain is difficult to treat, but delta 9-Tetrahydrocannabinol (delta 9-THC) may be a promising therapeutic agent. We administered in 172 patients on average 7.5 mg delta 9-THC over 7 months. Of these, 48 patients prematurely withdrew due to side effects, insufficient analgesia, or expense of therapy. Thus, 124 patients were assessed retrospectively in a multicenter telephone survey. Reported changes in pain intensity, recorded on a numeric rating scale (NRS), Pain Disability Index (PDI), Medical Outcomes Short-Form (SF-12), Quality of Life Impairment by Pain (QLIP), Hospital Anxiety Depression Scale (HADS), and amount of concomitant pain medication were recorded. Psychometric parameters (PDI, SF-12, QLIP, HADS) and pain intensity improved significantly during delta 9-THC treatment. Opioid doses were reduced and patients perceived THC therapy as effective with tolerable side effects. About 25% of the patients, however, did not tolerate the treatment. Therapy success and tolerance can be assessed by a transient delta 9-THC titration and its maintained administration for several weeks. The present survey demonstrates its ameliorating potential for the treatment of chronic pain in central neuropathy and fibromyalgia. A supplemental delta 9-THC treatment as part of a broader pain management plan therefore may represent a promising coanalgesic therapeutic option.

Duration of effects of aspirin on platelet function in healthy volunteers: an analysis using the PFA-100.

STUDY OBJECTIVE: The aim of the study was to determine the duration and effects of aspirin on platelet function. STUDY DESIGN: Prospective investigation. SETTING: Blood samples from volunteers. PATIENTS AND MONITORING: Ten healthy male volunteers took part in this investigation. After having measured baseline hemostatic parameters, 2000-mg aspirin was taken orally. Subsequently, the hemostatic profile had been compiled daily for a duration of 4 days after ingestion. MEASUREMENTS AND MAIN RESULTS: Platelet function was analyzed (1) after 3 hours and (2) daily for 4 days by the platelet function analyzer (PFA-100, Dade Co, Miami, Fla), which represents a sensitive investigation method for measuring platelet function and dysfunction. Routine hemostatic parameters were investigated. Three hours after ingestion of aspirin, abnormal PFA-100 values could be detected. Further detectable elevated values were found during the following 3 days. CONCLUSION: Effects of single-dose aspirin 2000 mg on platelet function were detected after 3 hours and had been lasting for the following 3 days. This result shows that PFA-100 may help by evaluating hemostasis during the preoperative period.

Intrathecal morphine for chronic benign pain.

In the treatment of chronic benign pain, the administration of an intrathecal opioid produces a potent analgesia without interfering with the motor and sensory functions of the lower extremities. An intrathecal opioid should be considered only when pain control with conventional oral and systemic administration is inadequate or is associated with unmanageable side effects. A trial period and a psychological evaluation are mandatory prior to implantation of a permanent device. About 40% of the patients need surgical revision for various complications. Hormonal changes may influence sexual behaviour. Catheter granulomas can form with high concentrations of morphine. Adjuvant drugs such as bupivacaine, clonidine and ketamine might be necessary to deal with the development of tolerance to morphine. The sophistication of available technology for intrathecal infusion today far exceeds our knowledge of the potential neurological effects of this treatment modality.