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S Salem

Publications and source records attributed to S Salem.

At least 19 recordsLinked to original sources
PubMed2006

Determination of the decay rate of nitrifying bacteria.

The growth and decay of nitrifying organisms determines the amount of nitrifying bacteria in activated sludge systems. The growth rate of the nitrifying organisms is reasonable, well defined, and studied, while the decay rate is still rather uncertain. Experiments in previous studies were over periods up to 14 days and obtained results were not confirmed. Contradicting decay rates of nitrifiers in different bacterial communities is reported. No differentiation between ammonia and nitrite oxidizers was made. Therefore, in this studyper day the decay rate of the nitrifying organisms was studied. The starvation condition (aerobic, anoxic, or anaerobic), temperature, type of bacterial community, and the presence of higher organisms are the main aspects that were investigated. A simple and reliable method (adapted from previous studies) for determining the decay rate of nitrifying organisms under different starvation conditions and different temperatures was developed. The test procedure has been used for determining the decay rate of ammonium and nitrite oxidizing bacteria in an enriched nitrifying culture and in activated sludge. The test was successfully applied at starvation periods up to 30 days. The decay rate of the enriched culture of nitrifiers was very low compared to values for nitrifiers in activated sludge. The decay rate of the nitrifiers in activated sludge was found to be to 0.2, 0.1, and 0.06 per day for aerobic, anoxic, and anaerobic conditions, respectively. The decay rate of ammonia oxidizers and nitrite oxidizers was the same at the corresponding conditions.

Ammonia↗
PubMed2006

Biological treatment of sludge digester liquids.

Nitrogen removal in side stream processes offers a good potential for upgrading wastewater treatment plants (WWTPs) that need to meet stricter effluent standards. Removing nutrients from these internal process flows significantly reduces the N-load to the main treatment plant. These internal flows mainly result from the sludge processing and have a high temperature and a high concentration of ammonia. Therefore, the required reactor volumes as well as the required aerobic SRT are small. Generally, biological treatment processes are more economical and preferred over physical-chemical processes. Recently, several biological treatment processes have been introduced for sludge water treatment. These processes are available now on the activated sludge market (e.g. SHARON, ANAMMOX and BABE processes). The technologies differ in concept and in the limitations guiding the application of these processes for upgrading WWTPs. This paper reviews and compares different biological alternatives for nitrogen removal in side streams. The limitations for selecting a technology from the available ones in the activated sludge market are noted and analysed. It is stressed that the choice for a certain process is based on more aspects than pure process engineering arguments.

Aerobiosis↗
PubMed2005

Boosting nitrification with the BABE technology.

Over the past years there has been a growing interest for compact, simple, low cost and robust technologies to upgrade wastewater treatment plants for nitrogen removal. The BABE (Bio Augmentation Batch Enhanced) technology is such a new concept. This patented system for biological treatment of sludge liquor - the effluent produced from digested sludge - uses a new principle, boosting the nitrifying bacteria in a side stream in such a way that the activated sludge in the main process is augmented. This augmentation increases the nitrification capacity of the wastewater treatment plant (wwtp). Experiments on a practical scale have demonstrated the effective and stable operation of the BABE technology. Model studies supported by the results of the full-scale tests showed that the technology can be applied in several situations, i.e. 1) introducing nitrification at high loaded wwtps; 2) enhancing nitrification at wwtps with incomplete nitrification; 3) enlarging denitrification at wwtps with complete nitrification. Most likely this year a full-scale application will be realized in the Netherlands at a wwtp with insufficient nitrification throughout the year.

Ammonia↗
PubMed2004

Full-scale application of the BABE technology.

Bio-augmentation can be used to obtain nitrification in activated sludge processes that operate at sub-optimal solid retention times. A side-stream process, the so-called BABE process that incorporates N-removal and augmentation of nitrifiers has been developed. The principle is to implement a nitrification reactor in the sludge return line, the so-called BABE reactor. This reactor can be fed with an internal N-rich flow (e.g. effluent from the sludge treatment). Hence the nitrification capacity of an activated sludge process can be augmented by the addition of nitrifiers cultivated in the BABE reactor. A full-scale test of the BABE technology has been at the treatment plant Garmerwolde in Groningen, the Netherlands. The set-up allowed comparing between three different lines: with the BABE reactor, without rejectwater and with untreated rejectwater. Based on this, the two important tasks (N-removal and inoculation) performed by the BABE reactor could be quantified. The results of the practical work in Garmerwolde showed a higher nitrification rate in the water line where the BABE reactor was implemented and also lower effluent ammonia. The experiments on a practical scale have demonstrated univocally the effective and stable operation of the BABE technology. In addition, sludge samples in different streams as well as from the BABE reactor were analysed with FISH technique. The FISH results illustrated the augmentation effect of the BABE reactor on the stream with the BABE reactor. A mathematical model, based on ASM1 model and implemented in AQUASIM was developed and used for simulating the treatment plant of Garmerwolde. The simulation results indicated that better effect of the BABE technology is expected at lower ambient temperatures and smaller volume of the BABE reactor. The BABE reactor could also allow for providing more space for de-nitrification in the main water line when nitrification is efficient enough.

Ammonia↗
PubMed2003

Bio-augmentation by nitrification with return sludge.

Bio-augmentation can be used to obtain nitrification in activated sludge processes that operate at sub-optimal solid retention times. In this study, we evaluated the potential of augmenting the endogenous nitrifying bacteria, by implementing a nitrification reactor in the sludge return line. This reactor can be fed with an internal N-rich flow (e.g. effluent from the sludge treatment) or with an external ammonium source. A mathematical model based on ASM1 was developed and used to evaluate the potential of this technique. The bio-augmentation studied here aimed to enhance the nitrification process of highly loaded activated sludge systems. A calibrated simulation model of a high loaded wastewater treatment plant in The Netherlands was used for this study. A side stream process (the named BABE process) was included in the simulation. This process was fed with the ammonia-rich water generated by sludge digestion and subsequent thickening by centrifugation (the so-called rejectwater). An external source (artificial) of ammonium was also considered to evaluate the differences between the two origins of ammonium. The results showed that with the augmentation process, high loaded activated sludge systems can achieve nitrification even at low winter temperatures. The best effect is obtained for systems operating at approximately 50% of the minimal SRT without augmentation. The use of an internal ammonia source is more effective than an external source. The results of this study give a quantitative basis for the design of process internal bio-augmentation processes and the effect on the N-removal capacity of the treatment plant.

Bioreactors↗
PubMed2003

The efficacy and safety of a topical alprostadil cream, Alprox-TD, for the treatment of erectile dysfunction: two phase 2 studies in mild-to-moderate and severe ED.

In two multicenter, placebo controlled, phase 2 studies, patients with mild-to-moderate (n=161, Study 1) or severe (n=142, Study 2) erectile dysfunction (ED) were randomized to receive placebo, 0.05, 0.1, or 0.2 mg (Study 1) or placebo, 0.1, 0.2, or 0.3 mg (Study 2) of topically applied alprostadil (containing a proprietary skin permeation enhancer). The primary efficacy end point in both studies was the change in erectile function (EF) score from baseline to final visit. The changes from baseline for EF scores were -0.8+/-1.1, 1.8+/-1.1, 0.7+/-1.2, and 3.7+/-1.2 (P<0.01; Study 1) and 2.7+/-1.3, 6.29+/-1.4, 6.49+/-1.5, and 9.44+/-1.5 (P<0.001; Study 2) for ascending dose groups in each study. Topical alprostadil was well tolerated with the most common adverse event being urogenital pain. These results suggest this topical alprostadil formulation may be a potentially useful agent for the treatment of ED.

Administration, Topical↗
PubMed2002

Model-based evaluation of a new upgrading concept for N-removal.

Mathematical modelling is considered a time and cost-saving tool for evaluation of new wastewater treatment concepts. Modelling can help to bridge the gap between lab and full-scale application. Bio-augmentation can be used to obtain nitrification in activated sludge systems with a limited aerobic sludge retention time. In the present study the potential for augmenting the endogenous nitrifying population is evaluated. Implementing a nitrification reactor in the sludge return line fed with sludge liquor with a high ammonia concentration leads to augmentation of the native nitrifying population. Since the behaviour of nitrifiers is relatively well known, a choice was made to evaluate this new concept mainly based on mathematical modelling. As an example an existing treatment plant (WWTP Walcheren, The Netherlands) that needed to be upgraded was used. A mathematical model, based on the TUDP model and implemented in AQUASIM was developed and used to evaluate the potential of this bioaugmentation in the return sludge line. A comparison was made between bio-augmentation and extending the existing aeration basins and anoxic tanks. The results of both modified systems were compared to give a quantitative basis for evaluation of benefits gained from such a system. If the plant is upgraded by conventional extension it needs an increase in volume of about 225%; using a bioaugmentation in the return sludge line the total volume of the tanks needs to be expanded by only 75% (including the side stream tanks). Based on the modelling results a decision was made to implement the bioaugmentation concept at full scale without further pilot scale testing, thereby strongly decreasing the scale-up period for this process.

Ammonia↗
PubMed2001

Role of repeated F-18 fluorodeoxyglucose imaging in management of patients with bone and soft tissue sarcoma.

AIM OF THE STUDY: To assess the impact of repeated F-18 FDG studies on the management of patients with bone and soft tissue (B&S) sarcomas. MATERIAL AND METHODS: Twenty patients with B&S tissue tumors (11 M and 9 F age 17-72 years) had 52 F-18 FDG Dual Head Coincidence Imaging (DHCI) studies. 7 patients were followed for 6 months to 2 years clinically after removal of the primary tumor. Thirteen patients were evaluated for suspected recurrences. Patient's preparation, F-18 FDG injection and imaging procedure were done according to department protocol. Attenuation corrected images were interpreted visually by 3 trained physicians. Tumor to background ratios were calculated for all lesions. RESULTS: In 13 patients having both studies, baseline FDG and CT/MRI were concordant in 8 patients, FDG detected more lesions in 3 patients but it did not detect 4 metastatic pulmonary nodules in 2 patients. Follow up studies showed stable disease in 10 patients while 6 patients who showed worsening disease needed to change their chemotherapy. Surgery was avoided in 2 patients and 2 patients showed improved response. CONCLUSION: Repeated F-18 FDG DHCI examinations proved to have an impact on the clinical management of patients with malignant bone and soft tissue sarcoma. It helps to differentiate postoperative changes from local recurrence.

Adolescent↗
PubMed2000

Bone mineral density of the Lebanese reference population.

We determined the bone mineral density (BMD) of normal Lebanese subjects and compared results with US/European reference data. The investigation was conducted at one center, and included 858 women and 165 men aged 20-79 years. Spine, femoral and radial BMD measurements were made using dual-energy X-ray absorptiometry. Age-related changes in BMD were similar in form to those of US/European reference data. However, BMD values of Lebanese were generally lower than US/European values. Spine BMD of Lebanese women was about 8% lower than US/European values between ages 20 and 59 years, and 5-6% lower for ages 60-79 years. Femoral neck BMD values for Lebanese women were 8% lower in the young adult years (age 20-39 years), but only 2-3% lower in the postmenopausal years, compared with US/European women. There were smaller postmenopausal decreases in femoral and radial BMD in Lebanese women compared with US/European women, which led to a convergence of BMD after age 70 years. The BMD of Lebanese men was 5-8% lower than US/European values throughout the age range (20-79 years). The effect of weight on BMD ranged from 0.2% to 0.4% per kilogram. Height was not significantly associated with BMD when both height and weight were entered in multiple regression analyses. The prevalence of osteoporosis appeared to be overestimated if the US/European reference data, rather than Lebanese reference data, were used to calculate T-scores.

Absorptiometry, Photon↗
PubMed2000

Antioxidant status in children with juvenile rheumatoid arthritis (JRA) living in Cairo, Egypt.

The aim of this study was to examine both enzymatic and non-enzymatic antioxidant status in a select group of children with juvenile rheumatoid arthritis (JRA), living in Cairo, Egypt. The plasma concentrations of albumin, ceruloplasmin, vitamin C, vitamin E as well as erythrocyte superoxide dismutase and whole blood glutathione peroxidase activities were all significantly decreased in the presence of JRA compared to those without JRA. Unlike these antioxidant factors, vitamin A and its carrier (e.g. retinol binding protein), which have very little or no antioxidant property, remained unaffected by JRA. These results suggest that the children with JRA are subject to oxidative stress.

Antioxidants↗
PubMed2000

Tc-99m MAG3 scintigraphy in unusually dilated bilateral extrarenal pelves.

The authors report the findings of a radionuclide diuretic renogram in a patient with markedly dilated pelves bilaterally that filled most of the abdominal cavity. With the patient in the sitting position, at the end of the furosemide injection, there was good delineation and filling of the dilated calyces. These findings are unusual because of the extensive pelvicaliceal dilatation, and they emphasize the importance of the sitting position.

Aged↗
PubMed1994

Ultrasonography and ultrasound-guided fine-needle aspiration biopsy of head and neck lesions: a surgical perspective.

A head and neck ultrasound-guided fine-needle aspiration clinic was set up to determine the role of ultrasound and ultrasound-guided fine-needle aspiration in the evaluation of patients with lesions in this region. One hundred ninety-five lesions were biopsied by ultrasound-guided fine-needle aspiration in 203 patients. Ultrasound detected 2 or more lesions in 14 (48%) of 29 patients with a clinically solitary thyroid nodule. Three (8.8%) of 34 lesions thought to be within the parotid gland were determined to be external. A pronounced learning curve was evident in the technique of ultrasound-guided fine-needle aspiration, particularly for nonpalpable disease. Adequacy of sampling for each 3-month period was 71%, 89%, and 94%, respectively. Seventy-four percent of central aspirations were satisfactory compared to 54% of peripheral aspirations. Ultrasound-guided fine-needle aspiration did not alter the clinical staging of metastatic neck disease in 8 patients having 10 neck dissections but proved useful in detecting nodal recurrence in 3 irradiated necks that did not proceed to surgery. The smallest node to harbor malignancy had 4-mm maximal axial diameter. We conclude that ultrasound and ultrasound-guided fine-needle aspiration are valuable adjuncts to the clinical examination.

Biopsy, Needle↗
PubMed1994

Doppler sonography of adnexal masses: the predictive value of the pulsatility index in benign and malignant disease.

OBJECTIVE: The purpose of this study was to determine whether pulsed Doppler sonography can be used to distinguish between benign and malignant adnexal masses on the basis of pulsatility index. SUBJECTS AND METHODS: In an 18-month period, all patients in whom an adnexal mass was detected at sonography had further evaluation of the mass by color and pulsed Doppler sonography. Ninety-nine patients with 102 masses that were surgically removed were included in the study. The pulsatility indexes were calculated from the reproducible spectral waveforms generated from flow centrally or peripherally within or immediately adjacent to the mass. Each lesion was categorized on the basis of its gray scale morphologic features as typically benign or indeterminate/malignant in appearance. RESULTS: Of the 102 adnexal masses, 89 were benign and 13 were malignant. In seven of the 89 benign lesions, no flow could be detected, and these were excluded from analysis. Of the remaining 82 benign lesions, 65 showed pulsatility indexes consistently equal to or greater than 1.0, and 17 showed pulsatility indexes of less than 1.0. Ten of the 13 malignant lesions had pulsatility indexes consistently less than 1.0, and three primary malignant tumors had their lowest pulsatility indexes ranging between 1.1 and 1.8. Sixty-five of the 68 masses with pulsatility indexes equal to or greater than 1.0 were benign, for a positive predictive value of 96% for benign disease. Ten of the 27 masses with pulsatility indexes of less than 1.0 were malignant, for a positive predictive value of 37% for malignant disease. Forty-five masses were detected in perimenopausal and postmenopausal patients. In this group, the pulsatility index had a positive predictive value of 88% for benign disease and 47% for malignant disease. In this study, 45 of 49 masses that had a typically benign sonographic appearance had pulsatility indexes equal to or greater than 1.0. All 49 masses had benign histology. In the remaining 46 masses with an indeterminate/malignant sonographic appearance, 20 of 23 with pulsatility indexes equal to or greater than 1.0 were benign, and 10 of 23 with pulsatility indexes of less than 1.0 were malignant. CONCLUSION: Our results show a high positive predictive value of high-impedance flow in benign adnexal disease and a predominance of low-impedance flow in malignant adnexal disease. However, the pulsatility indexes showed considerable overlap between benign and malignant lesions, indicating that Doppler sonography has severe limitations in the differentiation of benign from malignant adnexal disease on the basis of low-impedance flow (pulsatility index < 1.0).

Adenofibroma↗
PubMed1993

Ultrasound-guided fine-needle aspiration biopsy in the management of thyroid disease.

During a 23-month period, 59 patients were referred for ultrasound (US)-guided fine-needle aspiration biopsy (FNAB) of the thyroid gland because of inadequate orthodox (office) FNAB, a clinically small lesion, or an occult lesion. Seventy percent of the group (41 patients) was referred for surgery, which revealed cancer in 37% of patients, adenoma in 19%, and benign disease in 44%. US-guided FNAB yielded false-positive reports in 0% of patients, false-negative reports in 5% to 12%, and inadequate aspirates in 32%. The US-guided FNAB technique had a sensitivity of 60% to 90%, a specificity of 100%, a positive predictive value of 100%, a negative predictive value of 80%, and an accuracy of 85%. US-guided FNAB provides cytologic information in 60% of patients in whom a diagnosis cannot be established by orthodox (office) means, thus enhancing the diagnostic ability of clinicians who can recommend a treatment program with confidence.

Adenoma↗
PubMed1993

Genotypic Diversity among Strains of Bradyrhizobium japonicum Belonging to Serogroup 110.

Thirty-three strains of Bradyrhizobium japonicum within serogroup 110 were examined for genotypic diversity by using DNA-DNA hybridization analyses. The analysis of the DNA from 15 hydrogen-uptake-negative strains with the bradyrhizobial uptake hydrogenase probe pHU52 showed variation in degree of homology and restriction fragment length polymorphism of EcoRI-restricted DNA. Clustering analysis of the 33 strains on the basis of DNA-DNA hybridization analysis with four restriction enzymes and with the bradyrhizobial nodulation locus, pRJUT10, as probe indicated the existence of four groups of strains, which were less than 70% similar. Restriction digestion of genomic DNA with BamHI and DNA-DNA hybridization with pRJUT10 permitted classification of each of the strains according to a specific fingerprint pattern.

Journal Article↗
PubMed1993

Incidence and types of non-palpable thyroid nodules in thyroids removed for palpable disease.

The purpose of this study was to determine the number, size and types of non-palpable and ultrasound undetected thyroid nodules in thyroid glands removed for a single palpable nodule. Twenty patients undergoing partial (hemi- and subtotal) thyroidectomy and 40 patients having a total thyroidectomy were analyzed. Patients had no more than one palpable nodule, no cervical adenopathy and no history of previous thyroid surgery. An ultrasound was performed routinely within four months of surgery. Forty-six nodules were detected by final pathology in the partial thyroidectomy group but only 42% were detected by palpation and 59% by ultrasound. The median diameter of non-palpable and ultrasound undetected partial thyroidectomy nodules was 0.5 cm and all were benign except for one case of lymphoma. Pathology detected 186 nodules in the total thyroidectomy group although palpation only detected 22% of these and ultrasound 42%. The median diameters of the benign and malignant non-palpable nodules were 0.4 cm and 0.25 cm respectively. Most of the undetected nodules in the total thyroidectomy group were benign but there were 20 non-palpable and 18 ultrasound undetected papillary carcinomas.

Adolescent↗