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1.
World J Microbiol Biotechnol ; 39(3): 76, 2023 Jan 13.
Article in English | MEDLINE | ID: mdl-36637547

ABSTRACT

In this study, microstructural improvement of cementitious composites was achieved by bacterial CaCO3 precipitation using three bacterial species, namely Sporosarcina pasteurii, Bacillus cereus, and Actinobacteria sp. M135-3, respectively. The final product was comparatively investigated regarding the physical effects of urease activity of different cells on the mortar in the long term.Microstructural improvement was determined by evaluating the pore structure by determining the increase in strength, decrease in water absorption, and capillary water absorption rate of the cement mortars having different microorganism concentrations (106-109 bacteria/ml). These measurements were taken on bacteria-containing and control samples on the 2nd, 7th, 28th, and 56th days, respectively. In addition, calcite and vaterite as calcium carbonate polymorphs formed by the precipitation of calcium carbonate by three types of bacteria were identified by Scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM/EDS), X-ray diffraction (XRD) and Thermogravimetric analysis - Differential scanning calorimetry (TGA-DSC) analyzes.The bacteria-containing mortar samples showed that bacterial species and concentrations directly affect cementitious composites' mechanical and physical properties. Composite samples containing bacteria resulted in statistically significant microstructural improvements measured by higher mechanical strength, lower water absorption value, and capillary water absorption rate compared to control samples, especially at early ages. However, the effect of microbial calcite formation diminishes at later ages, especially at 56-days, attributed to the bacteria cells losing their vitality and integrity and forming spaces inside the mortars.


Subject(s)
Actinobacteria , Calcium Carbonate , Calcium Carbonate/chemistry , X-Ray Diffraction , Bacillus cereus , Microscopy, Electron, Scanning , Chemical Precipitation
2.
J Diabetes Complications ; 19(3): 160-4, 2005.
Article in English | MEDLINE | ID: mdl-15866062

ABSTRACT

AIM: The main aim was to evaluate balance and physical fitness in diabetic neuropathic patients. METHODS: Sixty voluntary adults of both sexes from Kutahya, Turkey, were divided into two groups: a Type 2 diabetic neuropathic group (DG), mean age 57.6+/-3.9 (50-65; n=30); and a nondiabetic control group (CG), mean age 55.6+/-6.1 (51-64; n=30). The CG was selected to match the diabetic group characteristics, such as age, body mass, and sex. Standing on dominant and nondominant leg, functional reach and physical fitness tests were used for assessment. RESULTS: Static and dynamic standings on one leg test were significantly lower in DG (P<.01). Considering CG results, maximal balance reduction in DG was found in the dynamic test on the dominant leg with the eyes open and head rotation (63.1%) and the lowest was on the static test on dominant leg with eyes open (19.7%). The result of the functional reach test was determined to be significantly lower in DG, with 21.3% balance reduction (P<.01). In all physical fitness tests, DG made significantly lower repetitions in 1 min (P<.01). Functional reach (34 cm) and one-leg standing (42 s) test results had shown our participants' low-risk falling, considering literature studies (15 cm and 30 s). CONCLUSION: The data show that the diabetic neuropathy disturbed especially the balance on the dominant leg and decrease physical fitness. In this situation, further studies that show the difference between dominant and nondominant leg balance and new risk of falling profile in diabetic neuropathic participants are needed.


Subject(s)
Diabetes Mellitus, Type 2/physiopathology , Diabetic Neuropathies/physiopathology , Physical Fitness , Postural Balance/physiology , Aged , Dominance, Cerebral , Exercise , Female , Humans , Male , Middle Aged , Physical Endurance , Posture , Reference Values , Supine Position
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