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Biomedical subjects

J E Schmidt

Publications and source records attributed to J E Schmidt.

At least 19 recordsLinked to original sources
PubMed2005

Hydraulics of laboratory and full-scale upflow anaerobic sludge blanket (UASB) reactors.

Laboratory-scale upflow anaerobic sludge blanket (UASB) reactors are often used as test platforms to evaluate full-scale applications. However, for a given volume specific hydraulic loading rate and geometry, the gas and liquid flows increase proportionally with the cube root of volume. In this communication, we demonstrate that a laboratory-scale reactor had plug-flow hydraulics, while a full-scale reactor had mixed flow hydraulics. The laboratory-scale reactor could be modeled using an existing biochemical model, and parameters identified, but because of computational speed with plug-flow hydraulics, mixed systems are instead recommended for parameter identification studies. Because of the scaling issues identified, operational data should not be directly projected from laboratory-scale results to the full-scale design.

Anaerobiosis↗
PubMed2005

Semi-automated digital image analysis of joint space width in knee radiographs.

OBJECTIVE: To design a semi-automated program to measure the minimum tibiofemoral joint space width (JSW) of knee radiographs. DESIGN: Bilateral knee radiographs were obtained twice within a 2 week period from 34 asymptomatic research participants. Radiographic images were analyzed to report both the variability of the image analysis program and the reproducibility of JSW measurements within a 2 week period. In addition, the results were compared with minimum JSW measurements read manually by an experienced musculoskeletal radiologist. RESULTS: The variability of the image analysis program was shown to be within one pixel. The results showed that reproducibility was better with the automated method. In addition, the manual method measured a greater minimum JSW than the automated method. There was no significant difference in between-day measurements. There was a significant difference reported between the automated and manual minimum JSW measurements. CONCLUSION: A novel semi-automated method for measurement of JSW has been developed.

Adult↗
PubMed2005

Strategies for changing temperature from mesophilic to thermophilic conditions in anaerobic CSTR reactors treating sewage sludge.

Thermophilic anaerobic digestion presents an advantageous way for stabilization of sludge from wastewater treatment plants. Two different strategies for changing operational process temperature from mesophilic (37 degrees C) to thermophilic (55 degrees C) were tested using two continuous flow stirred tank reactors operated at constant organic loading rate of 1.38 g VS/l reactor/day and hydraulic retention time of 20 days. In reactor A, the temperature was increased step-wise: 37 degrees C-->42 degrees C-->47 degrees C-->51 degrees C-->55 degrees C. While in reactor B, the temperature was changed in one-step, from 37 degrees C to the desired temperature of 55 degrees C, The results showed that the overall adaptation of the process for the step-wise temperature increment took 70 days in total and a new change was applied when the process was stabilized as indicated by stable methane production and low volatile fatty acids concentrations. Although the one-step temperature increase caused a severe disturbance in all the process parameters, the system reached a new stable operation after only 30 days indicating that this strategy is the best in changing from mesophilic to thermophilic operation in anaerobic digestion plants.

Bacteria, Anaerobic↗
PubMed2004

Psychological and sleep quality differences between chronic daily headache and temporomandibular disorders patients.

The aim of this study was to investigate whether chronic daily headache (CDH) and temporomandibular disorders (TMD) patients present with different psychological and sleep quality characteristics. Sixty-seven patients diagnosed with CDH, according to classification criteria from Silberstein et al., were matched by age and sex with 67 patients who had a primary diagnosis of myofascial pain (MP) and 67 patients with a primary diagnosis of TMJ intracapsular pain (IC) according to the Research Diagnostic Criteria for TMD. The CDH group was comprised of three mutually exclusive diagnostic groups: chronic migraine (n = 35); chronic tension-type headache (n = 26); 'other CDH' (n = 6). All patients completed a battery of psychological and sleep quality questionnaires. All CDH subgroups showed similar psychological and sleep quality profiles. Pain intensity and duration were controlled in the multivariate analyses (Mancova) by treating them as covariates. The CDH and MP groups revealed higher levels of psychological distress than the IC group on most psychological domains. The MP group also revealed numerically higher levels of psychological distress in most psychological domains than the CDH group, although these differences were generally not significant. We did not find significant differences between the three groups on post traumatic stress symptoms either. Sleep quality was significantly worse in the MP group than in the CDH and IC groups. These results are discussed in the context of multimodal patient evaluation and treatments that are often necessary for successful clinical management.

Adolescent↗
PubMed2004

Anaerobic bioprocessing of sewage sludge, focusing on degradation of linear alkylbenzene sulfonates (LAS).

Anaerobic degradation of sludge amended with linear alkylbenzene sulfonates (LAS) was tested in a one stage continuous stirred tank reactor (CSTR) and a two stage reactor system consisting of a CSTR as first step and upflow anaerobic sludge bed (UASB) reactor as the second step. Anaerobic removal of LAS was only observed at the second step but not at the first step. Removal of LAS in the UASB reactors was approx. 80% where half was due to absorption and the other half was apparently due to biological removal as shown from the LAS mass balance. At the end of the experiment the reactors were spiked with 14C-LAS which resulted in 5.6% 14CO2 in the produced gas. Total mass balance of the radioactivity was however not achieved. In batch experiments it was found that LAS at concentrations higher than 50 mg/l is inhibitory for most microbial groups of the anaerobic process. Therefore, low initial LAS concentration is a prerequisite for successful LAS degradation. The results from the present study suggest that anaerobic degradation of LAS is possible in UASB reactors when the concentration of LAS is low enough to avoid inhibition of microorganisms active in the anaerobic process.

Absorption↗
PubMed2004

Improved nitrogen removal in upflow anaerobic sludge blanket (UASB) reactors by incorporation of Anammox bacteria into the granular sludge.

Upflow anaerobic sludge blanket reactors may offer a number of advantages over conventional mixed-tank, SBR, and biofilm reactors, including high space-loading, low footprint, and resistance to shocks and toxins. In this study, we assessed the use of upflow anaerobic sludge blanket (UASB) reactor technology as applied to anaerobic ammonia removal, or Anammox. Four 200 ml UASB reactors were inoculated with 50% (by volume) anaerobic granular sludge and 50% flocular sludge from different sources (all with the potential for containing Anammox organisms). Tools used to assess the reactors included basic analyses, fluorescent in-situ hybridisation, and mathematical modelling, with statistical non-linear parameter estimation. Two of the reactors showed statistically identical Anammox activity (i.e., identical kinetic parameters), with good ammonia and nitrite removal (0.14 kgNHx m(-3) reactor day(-1), with 99% ammonia removal). The third reactor also demonstrated significant Anammox activity, but with poor identifiability of parameters. The fourth reactor had no statistical Anammox activity. Modelling indicated that poor identifiability and performance in the third and fourth reactors were related to an excess of reduced carbon, probably originating in the inoculum. Accumulation of Anammox organisms was confirmed both by a volume loading much lower than the growth rate, and response to a probe specific for organisms previously reported to mediate Anammox processes. Overall, the UASB reactors were effective as Anammox systems, and identifiability of the systems was good, and repeatable (even compared to a previous study in a rotating biological contactor). This indicates that operation, design, and analysis of Anammox UASB reactors specifically, and Anammox systems in general, are reliable and portable, and that UASB systems are an appropriate technology for this process.

Ammonia↗
PubMed2004

Removal of polycyclic aromatic hydrocarbons (PAHs) from sewage sludge by anaerobic degradation.

Due to the hydrophobic nature of the polyaromatic hydrocarbons (PAHs) they are mostly bound to the sludge and escape aerobic treatment in a wastewater treatment plant. They therefore proceed directly to the anaerobic post treatment, terminate in the sludge, and can be released to the environment if land spreading is used. PAH degradation in anaerobic methanogenic systems has only recently been shown to occur. In this study we have assessed several factors of anaerobic PAH degradation by evaluating thermodynamic feasibility of degradation, assessing degradation at different temperatures, and investigating the enriched cultures using fluorescent in-situ hybridization (FISH). Thermodynamic calculations indicated that PAH degradation was possible under methanogenic conditions, in the presence of hydrogen utilizing methanogens. Removal of naphthalene and 1-methyl naphthalene depended both on temperature and the initial inoculum. Inocula sourced from contaminated land sites were the most effective. The enrichments were all a mixture of Bacteria, and Archaea, and the Archaea were generally identified as Methanobacteriales, using an order-specific probe. The bacteria were not specifically identified. The results indicate a syntrophic culture, with the bacteria oxidizing the naphthalene, and the Archaea converting the hydrogen produced by oxidation, to methane.

Bacteria, Anaerobic↗
PubMed2004

Use of an anaerobic sequencing batch reactor for parameter estimation in modelling of anaerobic digestion.

The model structure in anaerobic digestion has been clarified following publication of the IWA Anaerobic Digestion Model No. 1 (ADM1). However, parameter values are not well known, and uncertainty and variability in the parameter values given is almost unknown. Additionally, platforms for identification of parameters, namely continuous-flow laboratory digesters, and batch tests suffer from disadvantages such as long run times, and difficulty in defining initial conditions, respectively. Anaerobic sequencing batch reactors (ASBRs) are sequenced into fill-react-settle-decant phases, and offer promising possibilities for estimation of parameters, as they are by nature, dynamic in behaviour, and allow repeatable behaviour to establish initial conditions, and evaluate parameters. In this study, we estimated parameters describing winery wastewater (most COD as ethanol) degradation using data from sequencing operation, and validated these parameters using unsequenced pulses of ethanol and acetate. The model used was the ADM1, with an extension for ethanol degradation. Parameter confidence spaces were found by non-linear, correlated analysis of the two main Monod parameters; maximum uptake rate (k(m)), and half saturation concentration (K(S)). These parameters could be estimated together using only the measured acetate concentration (20 points per cycle). From interpolating the single cycle acetate data to multiple cycles, we estimate that a practical "optimal" identifiability could be achieved after two cycles for the acetate parameters, and three cycles for the ethanol parameters. The parameters found performed well in the short term, and represented the pulses of acetate and ethanol (within 4 days of the winery-fed cycles) very well. The main discrepancy was poor prediction of pH dynamics, which could be due to an unidentified buffer with an overall influence the same as a weak base (possibly CaCO3). Based on this work, ASBR systems are effective for parameter estimation, especially for comparative wastewater characterisation. The main disadvantages are heavy computational requirements for multiple cycles, and difficulty in establishing the correct biomass concentration in the reactor, though the last is also a disadvantage for continuous fixed film reactors, and especially, batch tests.

Acetates↗
PubMed2002

Anaerobic biodegradation of spent sulphite liquor in a UASB reactor.

Anaerobic biodegradation of fermented spent sulphite liquor, SSL, which is produced during the manufacture of sulphite pulp, was investigated. SSL contains a high concentration of lignin products in addition to hemicellulose and has a very high COD load (173 g COD l(-1)). Batch experiments with diluted SSL and pretreated SSL indicated a potential of 12-22 l methane per litre SSL, which corresponds to 0.13-0.22 l methane (g VS)(-1) and COD removal of up to 37%. COD removal in a mesophilic upflow anaerobic sludge blanket, UASB. reactor ranged from 10% to 31% at an organic loading rate, OLR, of 10-51 g (1 d)(-1) and hydraulic retention time from 3.7 to 1.5 days. The biogas productivity was 3 1 (l(reactor d)(-1), with a yield of 0.05 l gas (g VS)(-1). These results suggest that anaerobic digestion in UASB reactors may provide a new alternative for the treatment of SSL to other treatment strategies such as incineration. Although the total COD reduction achieved is limited, bioenergy is produced and readily biodegradable matter is removed causing less load on post-treatment installations.

Anaerobiosis↗
PubMed2002

Anaerobic digestion of olive oil mill effluents together with swine manure in UASB reactors.

Combined anaerobic digestion of olive oil mill effluent (OME) with swine manure, was investigated. In batch experiments was shown that for anaerobic degradation of OME alone nitrogen addition was needed. A COD:N ratio in the range of 65:1 to 126:1 was necessary for the optimal degradation process. Furthermore, it was found that methane productions rates during digestion of either swine manure alone or OME alone were much lower than the rates achieved when OME and manure were digested together. Admixing OME with manure at a concentration of 5 to 10% OME resulted in the highest methane production rates. Using upflow anaerobic sludge blanket (UASB) reactors, it was shown that codigestion of OME with swine manure (up to 50% OME) was successful with a COD reduction up to 75%. The process was adapted for degradation of OME with stepwise increase of the OME load to the UASB reactor. The results showed that the high content of ammonia in swine manure, together with content of other nutrients, make it possible to degrade OME without addition of external alkalinity and without addition of external nitrogen source. Anaerobic treatment of OME in UASB reactors resulted in reduction of simple phenolic compounds such as mequinol, phenyl ethyl alcohol and ethyl methyl phenol. After anaerobic treatment the concentration of these compounds was reduced between 75 and 100%. However, the concentration of some degradation products such as methyl phenol and ethyl phenol were detected in significantly higher concentrations after treatment, indicating that the process has to be further optimised to achieve satisfactory removal of all xenobiotic compounds.

Agriculture↗
PubMed2001

The EUVAC-NET survey: national pertussis surveillance systems in the European Union, Switzerland, Norway, and Iceland.

A questionnaire was mailed out to member states of the European Union (EU) plus Switzerland, Norway, and Iceland, to inquire about the type of information routinely recorded in national pertussis surveillance systems. Information was requested on surveillance methods, type of information recorded for cases of pertussis, vaccination schedule, type of vaccine used, and methods for estimating vaccination coverage. Local surveillance methods, vaccination strategies, and methods to estimate vaccination coverage were found to differ widely across the participating countries. The results of the questionnaire survey show, however, that there are comparable subsets of variables common to many countries. Future activities of the EUVAC-NET project will include defining the homogeneous elements in national systems and to group appropriately those countries with common surveillance features.

Data Collection↗
PubMed2001

The EUVAC-NET survey: national measles surveillance systems in the EU, Switzerland, Norway, and Iceland.

The EUVAC-NET network undertook a questionnaire study on measles surveillance systems in EU member countries, Switzerland, Norway and Iceland. All questionnaires were completed. Surveillance systems for measles are implemented in 16 of the 18 countries. Most countries have some case based data and in all countries the shift is towards case based surveillance for measles, though there are differences between countries concerning case definitions and classifications. A two-dose MMR vaccination schedule is implemented in all the EUVAC-NET countries but methods used for estimation of vaccination coverage are diverse.

Data Collection↗
PubMed2000

Requesting information about and obtaining reversal after tubal sterilization: findings from the U.S. Collaborative Review of Sterilization.

OBJECTIVE: To determine the cumulative probabilities over 14 y of requesting information on sterilization reversal and of obtaining a reversal and to identify risk factors observable at sterilization for both measures of regret. DESIGN: The U.S. Collaborative Review of Sterilization, a prospective cohort study. SETTING: Fifteen medical centers in 9 cities. PATIENT(S): 11,232 women. MAIN OUTCOME MEASURE(S): Cumulative probabilities of requesting information on reversal and undergoing reversal. RESULT(S): The 14-y cumulative probability of requesting reversal information was 14.3% (95% confidence interval [CI], 12.4%-16.3%). Among women aged 18 to 24 y at sterilization, the cumulative probability was 40.4% (95% CI, 31.6%-49.2%). Women aged 18 to 24 y were almost 4 times as likely to request reversal information as were women > or = 30 years of age (adjusted rate ratio [RR], 3.5; 95% CI, 2.8-4.4). Number of living children was not associated with requesting reversal information. The overall cumulative probability of obtaining reversal was 1.1% (95% CI, 0.5-1.6). Younger women (18 to 30 y) were more likely to obtain reversal (RR, 7.6; 95% CI, 3.2-18.3). CONCLUSION(S): Women who were sterilized at a young age had a high chance of later requesting information about reversal, regardless of their number of living children.

Adult↗
PubMed2000

Acetate conversion in anaerobic biogas reactors: traditional and molecular tools for studying this important group of anaerobic microorganisms.

Different methods were applied to study the role of aceticlastic methanogens in biogas reactors treating solid waste and wastewater. We used traditional microbiological methods, immunological and 16S rRNA ribosomal probes for detection of the methanogens. Using this approach we identified the methanogenic spp. and their activity. In biofilm systems, such as the UASB reactors the presence of the two aceticlastic methanogens could be correlated to the difference in the kinetic properties of the two species. In biogas reactors treating solid wastes, such as manure or mixture of manure and organic industrial waste, only Methanosarcina spp. were identified. Methanosarcina spp. isolated from different plants had different kinetics depending on their origin. Relating the reactor performance data to measurement of the activity by conventional microbiological methods gave a good indication of the microbial status of specific trophic groups. 16S rRNA probing confirmed these observations and gave a more detailed picture of the microbial groups present.

Acetates↗
PubMed1999

[A survey of forensic psychiatric resources. Trends in the flow of patients to a new unit of forensic psychiatry, Sygehus Fyn, December 31, 1985 to December 31, 1995].

The study covered 163 patients sentenced to special measures. All of them were from the county of Funen, which is a representative part of Denmark regarding forensic psychiatry. On the cross-sectional date 31st December each year the total number of patients treated in the unit was the recorded. The number of patients sectioned to psychiatric treatment in hospital increased by 150% during the observation period. The recorded rise covered both offenders sentenced according to the section 16 and section 69 of the Danish penal code and reflected an increasing number of schizophrenic patients and to lesser-extent patients with personality disorder. The increasing number of beds occupied by forensic patients was in accordance with the development in the total number of patients treated in the unit.

Bed Occupancy↗