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1.
Sci Rep ; 14(1): 14770, 2024 Jun 26.
Article in English | MEDLINE | ID: mdl-38926594

ABSTRACT

The core and surface structure, and magnetism of mechano-synthesized LaFeO3 nanoparticles (30-40 nm), Eu3+-doped (La0.70Eu0.30FeO3), and Eu3+/Cr3+ co-doped (La0.70Eu0.30Fe0.95Cr0.05O3) are reported. Doping results in a transition from the O'-type to the O-type distorted structure. Traces of reactants, intermediate phases, and a small amount of Eu2+ ions were detected on the surfaces of the nanoparticles. The nanoparticles consist of antiferromagnetic cores flanked by ferromagnetic shells. The Eu3+ dopant ions enhance the magnetization values relative to those of the pristine nanoparticles and result in magnetic susceptibilities compatible with the presence of Eu3+ van Vleck paramagnetism of spin-orbit coupling constant (λ = 363 cm-1) and a low temperature Curie-Weiss like behavior associated with the minority Eu2+ ions. Anomalous temperature-dependent magnetic hardening due to competing magnetic anisotropy and magnetoelectric coupling effects together with a temperature-dependent dopant-sensitive exchange bias, caused by thermally activated spin reversals at the core of the nanoparticles, were observed.

2.
Cureus ; 14(5): e25445, 2022 May.
Article in English | MEDLINE | ID: mdl-35774661

ABSTRACT

Granulomatosis with polyangiitis (GPA) is a rare, autoimmune, antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis of uncertain etiology. The incidence of autoimmune complications following stem cell transplant is around 2-5%, with autoimmune cytopenia reported most frequently. We present a case of a 65-year-old male patient who presented to the hospital with productive cough, dyspnea, and fever for five months after haploidentical stem cell transplantation. On presentation, he was febrile, tachypneic, and mildly hypoxic. Chest radiograph showed bilateral pulmonary infiltrates. An initial diagnosis of pneumonia was made, and the patient was started on antibiotics. The patient did not respond to initial management, and all his initial infectious workups came back negative. On further evaluation, cytoplasmic antineutrophil cytoplasmic antibodies (c-ANCA) resulted positive in high titers. The patient was diagnosed with GPA, and IV methylprednisolone and rituximab were started. He responded well to treatment and was eventually discharged home. The classical form of GPA is characterized by the involvement of the upper respiratory tract, sinuses, lungs, and kidneys. Autoimmune disorders may develop secondary to hematopoietic stem cell transplant (HSCT). In our case, the patient was diagnosed with GPA, which is likely one of the autoimmune complications after HSCT.

3.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120442, 2022 Feb 05.
Article in English | MEDLINE | ID: mdl-34601368

ABSTRACT

Carbon nanoparticles (CNPs) are getting wide attention due to their fluorescence and low level of toxicity compared to other semiconducting photoluminescent materials. CNPs show strong 'solvatochromism', and the emission mechanism is still under discussion. Florescent carbon in the form of films would tremendously increase its potential for applications. In this work, we report for the first time the fluorescent emission characteristics of carbon films formed by aggregation of CNPs. Films of carbon were grown on glass substrates by using a novelCold Vapour Deposition System. We have performed a detailed comparative study of the emission spectra of film and CNPs (prepared using the microwave synthesis method) in various solvents. A qualitative model based on solvatochromism of CNPs is used to understand the emission pathways in the film.


Subject(s)
Carbon , Nanoparticles , Fluorescence , Microwaves , Solvents
4.
Cell Stress Chaperones ; 25(1): 73-80, 2020 01.
Article in English | MEDLINE | ID: mdl-31734892

ABSTRACT

Induction of heat shock protein expression and the heat shock (stress) response are seen in exercise. This exercise-induced response is thought protective against cellular stress through the expression of heat shock proteins. The highly inducible heat shock protein 72 (HSP72) has been shown to be expressed in a number of stress-related conditions, but not investigated in women with polycystic ovary syndrome (PCOS). Twenty-one women (10 controls, 11 with PCOS) concluded an 8-week supervised, moderate-intensity exercise programme. Monocytes and lymphocytes were analysed by flow cytometry for HSP72 expression from blood samples prior to, mid-way and at the completion of the programme. The monocyte HSP72 expression showed an increase from baseline values through mid-way (p = 0.025), and at the completion of the programme (p = 0.011) only in the control group, the PCOS group showed no significant change. This pattern was similar for lymphocyte HSP72 expression where a significant increase was found at the completion of the programme (p = 0.01) only in the control group. The magnitude of increased HSP72 expression following completion of the programme was linked to baseline values only in the control group. In conclusion, increased HSP72 expression to exercise over an 8-week period was seen in control but not in PCOS women, suggesting that there is an impairment of HSP72 expression in response to exercise in these women.


Subject(s)
Exercise Therapy , HSP72 Heat-Shock Proteins/metabolism , Polycystic Ovary Syndrome/metabolism , Polycystic Ovary Syndrome/therapy , Adult , Female , Heat-Shock Response/physiology , Humans , Lymphocytes/metabolism , Monocytes/metabolism
5.
Article in English | MEDLINE | ID: mdl-30984117

ABSTRACT

Purpose: Endothelial dysfunction is a known comorbidity in women with polycystic ovary syndrome (PCOS). The aim was to assess if supervised, moderate intensity exercise could potentially impact markers of endothelial disruption; endothelial cell derived microparticles (EMP). Methods: The current study investigated the effects of a supervised 8-week moderate intensity exercise programme on EMP in women with PCOS (n = 11) and control women free from any known disease (n = 10). EMP were enumerated via specific antibody (CD105, CD106) labeling and flow cytometry. Results: CD105+MP significantly reduced in women with PCOS from pre to post-exercise programme, with CD105+ MP reducing from 2114 CD105+ MP per µl platelet free plasma (PFP) to 424 CD105+ MP per µl PFP (p = 0.025). Control women showed no significant change in CD105+ MP (p = 0.25) after completing the same exercise programme. CD106+ MP showed no change in either PCOS (p = 0.95) or control groups (p = 0.99). No significant correlations existed with the changes in EMP compared to body composition changes as a result of exercise. Conclusion: Supervised, moderate intensity exercise independent of substantial weight loss reduced circulating CD105+ MP, likely reflecting an improvement in endothelial function in women with PCOS compared to healthy control women. Additionally, EMP may be a useful marker for physical improvement in exercise programmes for clinical populations.

6.
Cureus ; 10(7): e3041, 2018 Jul 24.
Article in English | MEDLINE | ID: mdl-30258740

ABSTRACT

Rhabdomyolysis is characterized by muscle necrosis and leakage of toxic intracellular contents into the circulatory system. It is most commonly caused by trauma, physical exertion, drugs, toxins, and a variety of infections; only rarely is it associated with acute human immunodeficiency virus (HIV) infection alone. The severity of illness ranges from asymptomatic elevations in serum muscle enzymes to life-threatening electrolyte imbalances and acute kidney injury. High HIV viral load is associated with higher muscle breakdown that increases the incidence of severe acute kidney injury and sometimes the need for renal replacement therapy. The introduction of highly active antiretroviral therapy (HAART) revolutionized the treatment of HIV infection and increased the life expectancy of such patients by suppressing viral replication. Myopathy is one of the neuromuscular manifestations of HIV. It can occur either as a result of a complication of HIV itself or as a result of medicines used to control HIV. Muscle involvement of HIV infection ranges from asymptomatic muscle enzyme elevation to severe, HIV-associated polymyositis or pyomyositis. Here we report a case of acute retroviral syndrome presenting as severe non-traumatic rhabdomyolysis.

7.
Drug Healthc Patient Saf ; 6: 55-67, 2014.
Article in English | MEDLINE | ID: mdl-24812526

ABSTRACT

Diabetes is a lifelong condition requiring ongoing medical care and patient self-management. Exogenous insulin therapy is essential in type 1 diabetes and becomes a necessity in patients with longstanding type 2 diabetes who fail to achieve optimal control with lifestyle modification, oral agents, and glucagon-like peptide 1-based therapy. One of the risks that hinders insulin use is hypoglycemia. Optimal insulin therapy should therefore minimize the risk of hypoglycemia while improving glycemic control. Insulin degludec (IDeg) is a novel basal insulin that, following subcutaneous injection, assembles into a depot of soluble multihexamer chains. These subsequently release IDeg monomers that are absorbed at a slow and steady rate into the circulation, with the terminal half-life of IDeg being ~25 hours. Thus, it requires only once-daily dosing unlike other basal insulin preparations that often require twice-daily dosing. Despite its long half-life, once-daily IDeg does not cause accumulation of insulin in the circulation after reaching steady state. IDeg once a day will produce a steady-state profile with a lower peak:trough ratio than other basal insulins. In clinical trials, this profile translates into a lower frequency of nocturnal hypoglycemia compared with insulin glargine, as well as an ability to allow some flexibility in dose timing without compromising efficacy and safety. Indeed, a study that tested the extremes of dosing intervals of 8 and 40 hours showed no detriment in either glycemic control or hypoglycemic frequency versus insulin glargine given at the same time each day. While extreme flexibility in dose timing is not recommended, these findings are reassuring. This may be particularly beneficial to elderly patients, patients with learning difficulties, or others who have to rely on health-care professionals for their daily insulin injections. Further studies are required to confirm whether this might benefit adherence to treatment, reduce long-term hypoglycemia or reduce diabetes-related complications.

8.
Vet Pathol ; 50(5): 738-48, 2013 Sep.
Article in English | MEDLINE | ID: mdl-23444036

ABSTRACT

Canine lymphoma is the neoplasm most often treated by chemotherapy, yet there are few data to correlate response to therapy with its different subtypes. This study is based on biopsy specimens from 992 dogs for which lymphoma was the clinical diagnosis. All cases were phenotyped by immunohistochemistry for CD3 and CD79alpha. Cases with histiocytic proliferation were evaluated immunohistochemically for CD18. Clonality was verified in 12 cases by polymerase chain reaction (PCR). Survival (event time) data and complete survival information (cause of death or time to last follow-up) were available on 456 dogs. Additional covariate information when available included size, age, sex, phenotype, stage and grade of lymphoma, mitotic index, and treatment protocol. Because of the many subtypes of B- and T-cell lymphoma, the cases were grouped into 7 diagnostic categories: (1) benign hyperplasia; (2) low-grade B-cell; (3) high-grade B- and T-cell; (4) low-grade T-cell; (5) centroblastic large B-cell of all mitotic grades (subdivided by clinical stage); (6) immunoblastic large B-cell of all mitotic grades, and (7) high-grade peripheral T-cell. Grouping was determined by histological grade (based on mitotic rate/400× field, with low-grade 0-5, intermediate 6-10, and high-grade >10) and stage for survival function estimation. No association with survival was found for size (based on breed of dog) or sex. All diagnostic categories of indolent or low-grade type had low mitotic rates, whereas those with clinically high grades had high mitotic rates. The diagnostic category with the most cases was centroblastic large B-cell lymphoma. Compared with dogs in this largest represented group of lymphomas, dogs with high-grade lymphomas had significantly higher mortality rates, and dogs with low-grade T-cell lymphomas had significantly lower mortality rates. Treatments for high-, intermediate-, and low-grade lymphomas were divided into 4 groups: absence of treatment, chemotherapy with or without hydroxydaunorubicin, and only prednisone. Dogs with low-grade T-cell (T-zone) lymphomas had the longest median survival (622 days), whereas the shortest median survival was in dogs with T-cell high-grade (peripheral T-cell) subtype (162 days). The dogs with centroblastic large B-cell lymphomas had a median survival of 127 days with low stage, 221 days with intermediate stage, and 215 days with advanced stage. Dogs with T-zone lymphoma were probably diagnosed in later stages of disease because of the lack of signs associated with progression. As with human lymphomas, a histological diagnosis with immunophenotyping is a minimal requirement for diagnosis of a specific subtype.


Subject(s)
Dog Diseases/diagnosis , Dog Diseases/drug therapy , Dog Diseases/pathology , Lymphoma/veterinary , Phenotype , Age Factors , Animals , CD18 Antigens/genetics , CD3 Complex/genetics , CD79 Antigens/genetics , Dog Diseases/classification , Dogs , Immunohistochemistry/veterinary , Lymphoma/classification , Lymphoma/diagnosis , Lymphoma/drug therapy , Lymphoma/pathology , Neoplasm Grading/veterinary , Neoplasm Staging/veterinary , Polymerase Chain Reaction/veterinary , Regression Analysis , Sex Factors , Survival Rate
9.
Vet Pathol ; 50(1): 86-93, 2013 Jan.
Article in English | MEDLINE | ID: mdl-22700849

ABSTRACT

Lymphoma is the most common malignant neoplasm in the horse. Single case reports and small retrospective studies of equine lymphomas are reported infrequently in the literature. A wide range of clinical presentations, tumor subtypes, and outcomes have been described, and the diversity of the results demonstrates the need to better define lymphomas in horses. As part of an initiative of the Veterinary Cooperative Oncology Group, 203 cases of equine lymphoma have been gathered from 8 institutions. Hematoxylin and eosin slides from each case were reviewed and 187 cases were immunophenotyped and categorized according to the World Health Organization classification system. Data regarding signalment, clinical presentation, and tumor topography were also examined. Ages ranged from 2 months to 31 years (mean, 10.7 years). Twenty-four breeds were represented; Quarterhorses were the most common breed (n = 55), followed by Thoroughbreds (n = 33) and Standardbreds (n = 30). Lymphomas were categorized into 13 anatomic sites. Multicentric lymphomas were common (n = 83), as were skin (n = 38) and gastrointestinal tract (n = 24). A total of 14 lymphoma subtypes were identified. T-cell-rich large B-cell lymphomas were the most common subtype, diagnosed in 87 horses. Peripheral T-cell lymphomas (n = 45) and diffuse large B-cell lymphomas (n = 26) were also frequently diagnosed.


Subject(s)
Horse Diseases/classification , Lymphoma/veterinary , Animals , Female , Horse Diseases/pathology , Horses , Immunophenotyping/veterinary , Lymphoma/classification , Lymphoma/pathology , Male , Mitosis , Retrospective Studies , Skin/pathology , World Health Organization
10.
Water Sci Technol ; 63(9): 1855-63, 2011.
Article in English | MEDLINE | ID: mdl-21902023

ABSTRACT

Species, dose, and mean ion resident time (MIRT(c)) in the concentrate of electro-dialysis reversal (EDR) desalination are analysed. In the classical EDR, dimensions, flow, and velocity of dilute and concentrate are equal; Langelier saturation index (LSI) and CaSO4 saturation are used to control the scaling and fouling processes in concentrate, as such LSI < + 2.16 for preventing CaCO3 from fouling and CaSO4 saturation level < 200 for averting CaSO4 from precipitation. If LSI is more than allowable limit, acid is added in concentrate to keep CaCO3 continuously dissolving; if CaSO4 saturation level in concentrate is more than the allowable limit, sodium hexametaphosphate (SHMP) is added in concentrate to maintain CaSO4 dissolving. EDR, however, was successfully modernised to operate with the higher water recovery rate (R) without any anti-scalant and without acid; this new EDR operated with LSI at 2.29 and CaSO4 saturation level 358.9% at lower dose and lower MIRT(c). Dose and MIRT(c) are proposed to address the controlling process. Monographs for the acids and SHMP requirements, and for the desalting cost including desalting power, membrane surface area, and chemicals usage, are developed. By lowering R and polar reversal interval, EDR can be operated at MIRT(c) < 130 min; at MIRT(c0 < 130 min, desalting cost/ energy can be minimised by eliminating chemicals requirement.


Subject(s)
Dialysis/methods , Electrochemical Techniques/methods , Sodium Chloride/chemistry , Water Purification/methods , Water/chemistry , Models, Theoretical , Time Factors , Water Supply
11.
Vet Pathol ; 48(1): 198-211, 2011 Jan.
Article in English | MEDLINE | ID: mdl-20861499

ABSTRACT

A study was carried out to test the accuracy and consistency of veterinary pathologists, not specialists in hematopathology, in applying the World Health Organization (WHO) system of classification of canine lymphomas. This study represents an initiative of the ACVP Oncology Committee, and the classification has been endorsed by the World Small Animal Veterinary Association (WASVA). Tissue biopsies from cases of canine lymphoma were received from veterinary oncologists, and a study by pathologists given only signalment was carried out on 300 cases. Twenty pathologists reviewed these 300 cases with each required to choose a diagnosis from a list of 43 B and T cell lymphomas. Three of the 20 were hematopathologists who determined the consensus diagnosis for each case. The 17 who formed the test group were experienced but not specialists in hematopathology, and most were diplomates of the American or European Colleges of Veterinary Pathology. The overall accuracy of the 17 pathologists on the 300 cases was 83%. When the analysis was limited to the 6 most common diagnoses, containing 80% of all cases, accuracy rose to 87%. In a test of reproducibility enabled by reintroducing 5% of cases entered under a different identity, the overall agreement between the first and second diagnosis ranged from 40 to 87%. The statistical review included 43,000 data points for each of the 20 pathologists.


Subject(s)
Dog Diseases/classification , Lymphoma/veterinary , Animals , Dogs , Lymph Nodes/pathology , Lymphoma/classification , Observer Variation , Pathology, Veterinary/standards , Veterinarians/standards , World Health Organization
12.
Environ Sci Technol ; 44(21): 8248-53, 2010 Nov 01.
Article in English | MEDLINE | ID: mdl-20929262

ABSTRACT

Ozonation is very effective in eliminating micropollutants that react fast with ozone (k > 10(3) M(-1) s(-1)), but there are also ozone-refractory (k < 10 M(-1) s(-1)) micropollutants such as X-ray contrast media, organic phosphates, and others. Yet, they are degraded upon ozonation to some extent, and this is due to (•)OH radicals generated in the reaction of ozone with organic matter in wastewater (DOM, determined as DOC). The elimination of tri-n-butyl phosphate (TnBP) and tris-2-chloroisopropyl phosphate (TCPP), added to wastewater in trace amounts, was studied as a function of the ozone dose and found to follow first-order kinetics. TnBP and TCPP concentrations are halved at ozone to DOC ratios of ∼0.25 and ∼1.0, respectively. The (•)OH rate constant of TCPP was estimated at (7 ± 2) × 10(8) M(-1) s(-1) by pulse radiolysis. Addition of 1 mg H(2)O(2)/L for increasing the (•)OH yield had very little effect. This is due to the low rate of reaction of H(2)O(2) with ozone at wastewater conditions (pH 8) that competes unfavorably with the reaction of ozone with wastewater DOC. Simulations based on the reported (Nöthe et al., ES&T 2009, 43, 5990-5995) (•)OH yield (13%) and (•)OH scavenger capacity of wastewater (3.2 × 10(4) (mgC/L)(-1) s(-1)) confirm the experimental data. Based on a typically applied molar ratio of ozone and H(2)O(2) of 2, the contribution of H(2)O(2) addition on the (•)OH yield is shown to become important only at high ozone doses.


Subject(s)
Hydrogen Peroxide/chemistry , Ozone/chemistry , Phosphates/chemistry , Waste Disposal, Fluid/methods , Water Pollutants, Chemical/chemistry , Hydroxyl Radical , Phosphates/analysis , Water/chemistry , Water Pollutants, Chemical/analysis
13.
Lett Appl Microbiol ; 51(2): 196-204, 2010 Aug.
Article in English | MEDLINE | ID: mdl-20565574

ABSTRACT

AIMS: Escherichia coli has emerged as a viable heterologous host for the production of complex, polyketide natural compounds. In this study, polyketide biosynthesis was compared between different E. coli strains for the purpose of better understanding and improving heterologous production. METHODS AND RESULTS: Both B and K-12 E. coli strains were genetically modified to support heterologous polyketide biosynthesis [specifically, 6-deoxyerythronolide B (6dEB)]. Polyketide production was analysed using a helper plasmid designed to overcome rare codon usage within E. coli. Each strain was analysed for recombinant protein production, precursor consumption, by-product production, and 6dEB biosynthesis. Of the strains tested for biosynthesis, 6dEB production was greatest for E. coli B strains. When comparing biosynthetic improvements as a function of mRNA stability vs codon bias, increased 6dEB titres were observed when additional rare codon tRNA molecules were provided. CONCLUSIONS: Escherichia coli B strains and the use of tRNA supplementation led to improved 6dEB polyketide titres. SIGNIFICANCE AND IMPACT OF THE STUDY: Given the medicinal potential and growing field of polyketide heterologous biosynthesis, the current study provides insight into host-specific genetic backgrounds and gene expression parameters aiding polyketide production through E. coli.


Subject(s)
Biosynthetic Pathways/genetics , Erythromycin/analogs & derivatives , Escherichia coli/genetics , Escherichia coli/metabolism , Anti-Bacterial Agents/metabolism , Codon , Erythromycin/metabolism , Escherichia coli/enzymology , Genetic Engineering , Humans , Plasmids , RNA Stability , Recombinant Proteins/biosynthesis , Recombination, Genetic
14.
Singapore Med J ; 51(2): e40-2, 2010 Feb.
Article in English | MEDLINE | ID: mdl-20358142

ABSTRACT

We report a unique variation in the origin and branches of both the left and right external carotid artery (ECA) found during the dissection of a human cadaver. Knowledge of the possible anatomical variations of the ECA is especially important in facio-maxillary and neck surgeries. Surgeons need to be aware of the possibility of encountering such variations, as they may lead to difficulties in differentiating between the external and internal carotid arteries, and in identifying the branches and origins. This knowledge is also important for radiologists in the image interpretation of the face and neck regions.


Subject(s)
Carotid Artery, External/abnormalities , Carotid Artery, External/anatomy & histology , Cadaver , Carotid Artery, Common/abnormalities , Carotid Artery, Common/anatomy & histology , Humans , Neck/anatomy & histology , Neck/blood supply
15.
Water Sci Technol ; 59(8): 1479-85, 2009.
Article in English | MEDLINE | ID: mdl-19403960

ABSTRACT

The rate constants of the reactions of O(3) with some typical wastewater pollutants (tributyltin, the macrolide antibiotic clarithromycin, the beta blocker metoprolol and the analgesic diclofenac) were determined and some mechanistic aspects were elucidated. Except for tributyltin compounds that react only slowly with O(3) (k=4-7 M(-1) s(-1)), the compounds react fast (k>10(4) M(-1) s(-1)) and can be eliminated at low O(3) doses. Clarithromycin reacts at its dimethylamino group and yields the corresponding N-oxide that is no longer biologically active. The nitrogen is also the major site of O(3) attack in diclofenac and in metoprolol. This gives rise to *OH radicals and these are the precursors of hydroxylated products and markedly contribute to chloride release in diclofenac.


Subject(s)
Clarithromycin/chemistry , Diclofenac/chemistry , Metoprolol/chemistry , Ozone/chemistry , Trialkyltin Compounds/chemistry , Waste Disposal, Fluid , Water Pollutants, Chemical/chemistry , Kinetics , Molecular Structure , Oxidation-Reduction , Tropical Climate
16.
Bioresour Technol ; 100(4): 1695-9, 2009 Feb.
Article in English | MEDLINE | ID: mdl-18977134

ABSTRACT

In this study, it is hypothesized that anaerobic hydrolysis of organic solid wastes (OSWs) in leachbed reactors can be enhanced by two approaches: (1) by increasing the porosity of the leachbed; and (2) by seeding the bed with brown-rot fungi or anaerobically digested residues. The hypothesis is verified using cattle manure as a model OSW and pistachios-half-shell as an inert additive to increase the porosity of the leachbed. The enhancement was quantified in terms of volatile fatty acid (VFA) generation and soluble COD generation. Results of this study showed that 15% more VFAs and 8% more soluble COD can be obtained at higher bed porosities and with brown-rot fungi or digested residues as the seed. Compared to a leachbed without any recirculation, porosity enhancement, nor seed addition, the VFA yield (g VFA/g manure) in a leachbed with pistachios-half-shell as porosity enhancers was 193% higher; that in a leachbed with leachate recirculation (of 4 L/day), pistachios-half-shell as porosity enhancers, and brown-rot fungi or digested sludge as seed was 230% higher.


Subject(s)
Bioreactors , Manure , Ammonia/analysis , Anaerobiosis , Animals , Cattle , Fatty Acids, Volatile/analysis , Fungi/metabolism , Hydrogen-Ion Concentration , Hydrolysis , Methane/analysis , Oxygen , Sewage
18.
Water Res ; 41(2): 323-32, 2007 Jan.
Article in English | MEDLINE | ID: mdl-17141822

ABSTRACT

A mathematical model for the hydrolysis and acidogenesis reactions in anaerobic digestion of cattle manure is presented. This model is based on the premise that particulate hydrolysable fraction of cattle manure is composed of cellulose and hemicellulose that are hydrolyzed at different rates according to a surface-limiting reaction; and, that the respective soluble products of hydrolysis are utilized by acidogens at different rates, according to a two-substrate, single-biomass model. Batch experimental results were used to identify the sensitive parameters and to calibrate and validate the model. Results predicted by the model agreed well with the experimentally measured data not used in the calibration process, with correlation coefficient exceeding 0.91. These results indicate that the most significant parameter in the hydrolysis-acidogenesis phase is the hydrolysis rate constant for the cellulose fraction.


Subject(s)
Bacteria, Anaerobic/metabolism , Cellulose/metabolism , Fermentation/physiology , Manure/microbiology , Refuse Disposal/methods , Acids/metabolism , Anaerobiosis/physiology , Animals , Bioreactors , Cattle , Hydrolysis , Kinetics , Manure/analysis , Models, Biological
19.
Food Microbiol ; 23(6): 599-604, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16943057

ABSTRACT

Salmonella spp. are the leading cause of foodborne illness worldwide. Conventional culture techniques for the detection of Salmonella spp. are labor intensive and time consuming. Several rapid detection methods have been developed over the past few years. However, standard methods for sample handling and preparation have not been established and limited data are available on the sensitivity and specificity of these methods for detection of Salmonella in naturally contaminated retail meat. Using culture as the gold standard for Salmonella detection in naturally contaminated raw poultry products, the sensitivity and specificity of a polymerase chain reaction (PCR) detection method was determined under varying enrichment protocols. Chicken meat samples (ground, boneless/skinless breast meat, and bone-in breast meat with skin) from retail grocery stores were pre-enriched in buffered peptone water (BPW) and Salmonella specific primers ST 11 and ST 15 were used to amplify a 429 bp region of random fragment target specific to all Salmonella spp. There was a significant decrease (P-value<0.001) in the sensitivity of the PCR test when BPW pre-enrichment alone (85%) was used compared to the sensitivity achieved after both BPW enrichment and selective enrichment with RV and TT-H (100%). PCR failed to detect any positive samples when no pre-enrichment was conducted. A minimum of 12h pre-enrichment was required for detection of Salmonella by PCR at a limit of 100 colony forming unit (cfu)/1 ml of sample. No detectable amplification product was seen in those naturally contaminated meat samples testing negative by culture methods.


Subject(s)
DNA, Bacterial/analysis , Food Contamination/analysis , Polymerase Chain Reaction/methods , Poultry Products/microbiology , Salmonella/isolation & purification , Animals , Chickens , Colony Count, Microbial/methods , Consumer Product Safety , Food Microbiology , Humans , Reproducibility of Results , Salmonella Food Poisoning/prevention & control , Sensitivity and Specificity , Species Specificity , Time Factors
20.
Chemosphere ; 65(1): 17-23, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16631229

ABSTRACT

Macrolide antibiotics are widely used (in the order of 1g per person per year). They pass the body largely unchanged and are also not degraded in wastewater treatment plants. With not too much effort, they may be eliminated from their effluents by ozonation. The macrolide antibiotics have all a dimethylamino group at one of the carbohydrate residues in common. This functional group is the target of the ozone reaction, and clarithromycin has been selected here for a more detailed study. Since only the free amine reacts with ozone, the rate of reaction is pH dependent (at pH 7: k = 4 x 10(4) M(-1) s(-1)). In analogy to the ozonolysis of trimethylamine, the main reaction is a transfer of an O-atom yielding the N-oxide (identified by HPLC/MS-MS). A minor product (10%, based on formaldehyde yields) is demethylated clarithromycin (identified by HPLC/MS-MS). The dimethylamino group is thought to be essential for the binding of the macrolide antibiotics to their target. As a consequence, chemical changes of this functional group, notably the formation of the N-oxide that is no longer a proton acceptor, inactivates these drugs as assayed by the suppression of the growth of Pseudomonas putida. This is most important for wastewater treatment, as mineralization of clarithromycin by ozone would require 100 times as much ozone.


Subject(s)
Anti-Bacterial Agents/analysis , Clarithromycin/analysis , Ozone/chemistry , Water Pollutants, Chemical/analysis , Water Purification/methods , Anti-Bacterial Agents/chemistry , Clarithromycin/chemistry , Kinetics , Molecular Structure , Oxidation-Reduction , Pseudomonas putida/drug effects
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