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61.
Aquatic macrophytes are well known accumulators for heavy metals, the reason why they are used as bioindicators for water quality and in phytoremediaton strategies. This study reports on the elemental concentrations in four free-floating aquatic macrophytes (S. auriculata; P. stratiotes; E. crassipes and E. azurea) growing in two water reservoirs (Santana e Vigário, Rio de Janeiro State, Brazil) of an electric power plant that receive input from the polluted Paraíba do Sul River. Filtered water samples and water suspended solids from these environments were also analysed. Inductively coupled plasma mass spectrometry was used as the principal method, allowing the determination of up to 41 elements, including the rare-earth elements (REEs) and other trace metals not assayed before in these macrophytes. The results show that all elements studied are accumulated by the macrophytes with concentration ratios (CR = [plant]: [water]) varying from about 1,000 to 200,000, based on the dry weight of the plant species. With a few exceptions, highest accumulations were observed in E. crassipes in which CRs increase in the sequence: Cu < Mo < Cr < Pb < Tl < Fe < La < Zn < Ce< Mn. Surprisingly high CRs (e.g. Ce: 74,000) and corresponding mass concentrations were observed for the rare-earth elements (e.g. ∑REE: 112 mg kg?1), also measured in the water suspended particle fraction. The results show that this fraction acts as an effective sink for trace metals in the aquatic system studied and seems to play also an important role in the transfer of metals from water to the plant species.  相似文献   
62.
Supercritical carbon dioxide extraction allowed essential oil of Laurus nobilis to be obtained. Extraction conditions were as follows: pressure, 90 bar; temperature, 50 degrees C; and carbon dioxide flow, Phi = 1.0 kg/h. Waxes were entrapped in the first separator set at 90 bar and -10 degrees C. The oil was recovered in the second separator working at 15 bar and 10 degrees C. The main components were 1,8-cineole (22.8%), linalool (12.5%), alpha-terpinyl acetate (11.4%), and methyleugenol (8.1%). Comparison with the hydrodistilled oil did not reveal any significant difference. Collection of samples at different extraction times during supercritical extraction allowed the change of the oil composition to be monitored. Lighter compounds such as hydrocarbon and oxygenated monoterpenes were extracted in shorter times than the heavier hydrocarbon and oxygenated sesquiterpenes.  相似文献   
63.
The effect of the ripening time on the proteolytic process in cheeses manufactured from mixtures of cow's and ewe's milk during a 167-day ripening period was monitored by capillary electrophoresis of the pH 4.6-insoluble fraction. Totals of 21 and 16 peaks were recognized and matched in the electropherograms obtained with a fused-silica capillary and a neutral capillary (hydrophilically coated), respectively. These peaks corresponded to intact bovine and ovine caseins and their hydrolysis products (e.g., alpha(s1)-casein, gamma-caseins). In 167-day-old cheeses, bovine alpha(s0)-casein (alpha(s1)-casein 9P) had been completely degraded and 6% of the residual bovine alpha(s1)-casein remained intact. Breakdown of the beta-casein fraction was lower than that of the alpha(s)-casein fraction. Finally, partial least-squares regression and principal component regression were used to predict the ripening time in cheeses. The root-mean-square errors in prediction by cross-validation were <7.8 days in all cases.  相似文献   
64.
65.
Eucharis grandiflora Planch. and Linden is a tropical climate Amaryllidacea, commonly known as lily, which develops a bulbous stem and is considered an indoor ornamental plant for its evergreen foliage and inflorescence. The aim of this study was to evaluate the vegetative development of the Lily, in response to the treatment with of the Steiner solution at different concentrations. The plants were acclimated under greenhouse conditions and the bulbs selected by a completely randomized design. Plants were treated with various concentrations of the Steiner solution, to develop the following potential osmotic: ?0.018, ?0.036, ?0.054, ?0.072, and 0 Mpal. The production of bulbils, development and leaf area, stomatal density, chlorophyll quantification, and osmotic potentials were evaluated. The results showed that treatment with solutions of ?0.054 and ?0.072 MPa induced a greater vegetative growth, 29.5% more stomata developed, and synthesized 29% more chlorophyll “b” than the control.  相似文献   
66.
Debranning of wheat affects flour quality, initially by altering the breakage of wheat kernels during first break. The double normalized Kumaraswamy breakage function was applied to model the effect of debranning on wheat breakage during first break milling, in which type 1 breakage describes a relatively narrow distribution of midsized particles, whereas type 2 breakage describes a wide size range of predominantly small particles extending to very large particles. Mallacca (hard) and Consort (soft) wheats were debranned and milled at three roll gaps under sharp‐to‐sharp and dull‐to‐dull dispositions. Type 1 breakage increased at longer debranning times, whereas type 2 breakage decreased, for both wheat varieties under both dispositions. Sharp‐to‐sharp milling tended to produce more type 1 breakage than dull‐to‐dull. A mechanism of wheat breakage is proposed to explain the coproduction of very large and small particles via type 2 breakage and, hence, the effect of debranning. The proposed mechanism is that small particles of endosperm arise from scraping of large flat particles of wheat bran under the differential action of the rolls, such that removal of the bran reduces the production of the large bran particles and thus reduces the opportunity for the scraping mechanism that produces the very small particles.  相似文献   
67.
Experiments were conducted to determine the role of estrogens on endogenous PGF2 alpha secretion and luteolysis following injection of cloprostenol in heifers. In Exp. 1, eight luteal-phase heifers were used to evaluate tamoxifen (T) as an estrogen antagonist. Heifers received T (35 mg i.v.) or ethanol:saline vehicle (ES) every 4 h for 44 h. All received cloprostenol (500 micrograms i.m.) immediately after the start of T or ES, and received estradiol-17 beta (500 micrograms i.m.) 12 h later. Each ES heifer had a surge of luteinizing hormone (LH) within 48 h of estradiol injection, whereas T-treated heifers did not. Estrus was observed in three ES-treated heifers, but not in T-treated heifers. In Exp. 2, 10 heifers received T (35 mg i.v.) or ES every 4 h for 64 h beginning on d 15 postestrus. Cloprostenol (500 micrograms i.m.) was injected 16 h after the start of treatment. Concentrations of LH were similar (P greater than .05) in both groups. In ES heifers, concentrations of 13,14-dihydro-15-keto-prostaglandin F2 alpha (PGFM) increased; in T-treated heifers, PGFM remained at pre-cloprostenol levels. Luteolysis was induced in all heifers. Progesterone (P4) decreased to less than or equal to 1 ng/ml at similar (P greater than .05) rates in ES-treated and T-treated heifers. Mean concentration of P4 288 h post-cloprostenol was greater (P less than .05) in ES-treated than in T-treated heifers. Three ES-treated heifers, but no T-treated heifers, were in standing estrus. We conclude that T effectively antagonizes estrogen in cattle.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
68.
A 6-year-old, spayed, female, domestic shorthair cat was presented for decreased activity. A nodular lesion was found in the skin extending into the subcutaneous tissue of the right abdominal flank. On lateral and ventrodorsal radiographs of the thorax, an opacity involving the entire right caudal lung lobe and pleural effusion were noted. Cytologic evaluation of cells in the thoracic fluid and in the mass revealed a population of atypical epipthelial cells with marked anisocytosis and high N:C ratios, organized in acinar-like clusters. Multinucleated cells and several mitotic figures were found. The cytologic interpretation was carcinoma. Because of the progressive severity of clinical signs, the cat was euthanized. Histologic evaluation of tissues obtained at necropsy indicated a bronchogenic adenocarcinoma in the lung, with metastasis to the skin of the right flank, but no involvement of the digits. Based on immunohistochemical stains, the neoplastic cells strongly co-expressed cytokeratin and vimentin, and were negative for S-100 and actin-specific antigen. Bronchogenic adenocarcinoma is an uncommon neoplasm in cats, and the digits are the most common sites of metastasis. This case was unusual in that the skin of the abdominal wall was the primary site of metastasis, with no involvement of the digits.  相似文献   
69.
OBJECTIVE: To determine milk flow, somatic cell counts (SCCs), and the incidence of clinical mastitis in cows that had undergone theloresectoscopy for treatment of teat stenosis caused by mucosal detachment in the region of the streak canal or Fürstenberg's rosette. DESIGN: Retrospective study. ANIMALS: 52 cows with teat stenosis that were treated via theloresectoscopy. PROCEDURE: Medical records of eligible cows were reviewed. Additional data regarding milking ease, SCC, development of clinical mastitis of the affected gland, and whether the cow remained in the herd were collected via owner-completed questionnaires. RESULTS: 49 of 52 questionnaires were completed. At referral, teat sinusitis was diagnosed in 29 of 52 cows. Milk flow was normal in 38 of 41 treated teats at discharge and in 24 of 40 during the next lactation. Thirteen of 49 cows were culled during the next lactation because of abnormal udder health. High SCC and teat sinusitis at referral and development of clinical mastitis during the 10-day period after surgery resulted in high SCCs in the remainder of the current lactation. The incidence of clinical mastitis during the remainder of the current and during the next lactation was higher in cows that had teat sinusitis at the time of surgery, compared with those that did not. CONCLUSIONS AND CLINICAL RELEVANCE: Teat stenoses resulting from mucosal lesions in the region of the streak canal or Fürstenberg's rosette may be successfully treated via theloresectoscopy. Inflammation of the teat sinus and gland at the time of surgery may adversely affect udder health.  相似文献   
70.
The pathogenesis of equine urticaria is not well understood. In man, urticaria has been associated with immunological and nonimmunological mechanisms leading to the release of various mediators by mast cells. Skin biopsies of 32 horses with a history of urticaria were stained with toluidine blue, a double-labelling method for chymase and tryptase, and immunohistochemistry for immunoglobulin (Ig)E. These horses were compared with horses with pemphigus foliaceus, insect bite hypersensitivity and control horses with healthy skin. Neither formalin fixation time nor biopsy site influenced the staining methods. No chymase-positive cells were found. In all groups of horses, cells staining with toluidine blue and for tryptase and IgE were found in the epidermis and hair follicle papilla and significantly more positively staining cells were observed in the subepidermal dermis compared with the deep dermis. Horses with urticaria had significantly more IgE-bearing cells in the subepidermal dermis than control horses. However, horses with urticaria had significantly fewer toluidine-blue-stained mast cells in both subepidermal and deep dermis compared with the insect bite hypersensitivity and pemphigus foliaceus groups. This study suggests that IgE-mediated reactions play a role in the pathogenesis of urticaria.  相似文献   
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