7 results on '"Sadrzadeh N"'
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2. Surface Phase Behavior of Poly(tert-butyl methacrylate)−Fatty Acid Glyceride Binary Mixtures as Monolayers at the Air−Water Interface
- Author
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Sadrzadeh, N., Yu, H., and Zografi, G.
- Abstract
Mixtures of poly(tert-butyl methacrylate) (PtBMA) and the lipids monoolein, diolein, and triolein spread as monolayers at the air−water interface have been used as models to examine the surface phase behavior of lipid−polymer mixtures as a function of lipid structure, polymer molecular weight (17K to 3400K), and mixture composition. A measure of miscibility and polymer−lipid interactions was obtained through analysis of surface pressure−area isotherms and by direct observation with fluorescence microscopy. At all molecular weights of PtBMA, for the polymer alone and in mixtures, identical surface pressure−area isotherms were obtained when area was expressed on a per monomer basis, indicating that all monomer segments were located at the interface and equally accessible to the lipid molecules. Through thermodynamic analysis, it was found that monoolein, with two hydroxyl groups, formed nonideal miscible mixed monolayers with PtBMA under what appear to be good solvent conditions. Diolein, with one hydroxyl group, behaved very much as a Θ solvent, forming nearly ideal homogeneous monolayers, while a lack of affinity between triolein and PtBMA due to poor hydrogen bonding led to surface phase separation at higher surface pressures, consistent with poor solvent conditions.
- Published
- 1998
3. Automated monitoring of brush use in dairy cattle.
- Author
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Sadrzadeh N, Foris B, Krahn J, von Keyserlingk MAG, and Weary DM
- Subjects
- Animals, Cattle, Dairying methods, Dairying instrumentation, Radio Frequency Identification Device methods, Female, Algorithms, Animal Welfare, Behavior, Animal, Machine Learning
- Abstract
Access to brushes allows for natural scratching behaviors in cattle, especially in confined indoor settings. Cattle are motivated to use brushes, but brush use varies with multiple factors including social hierarchy and health. Brush use might serve an indicator of cow health or welfare, but practical application of these measures requires accurate and automated monitoring tools. This study describes a machine learning approach to monitor brush use by dairy cattle. We aimed to capture the daily brush use by integrating data on the rotation of a mechanical brush with data on cow identify derived from either 1) low-frequency radio frequency identification or 2) a computer vision system using fiducial markers. We found that the computer vision system outperformed the RFID system in accuracy, and that the machine learning algorithms enhanced the precision of the brush use estimates. This study presents the first description of a fiducial marker-based computer vision system for monitoring individual cattle behavior in a group setting; this approach could be applied to develop automated measures of other behaviors with the potential to better assess welfare and improve the care for farm animals., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Sadrzadeh et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
- Published
- 2024
- Full Text
- View/download PDF
4. The Effect of Placement and Group Size on the Use of an Automated Brush by Groups of Lactating Dairy Cattle.
- Author
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Foris B, Sadrzadeh N, Krahn J, Weary DM, and von Keyserlingk MAG
- Abstract
Mechanical brushes are often provided on dairy farms to facilitate grooming. However, current brush designs do not provide data on their use, and thus little is known about the effects of group size and placement of brushes within the pen. The objectives of this study were to automatically detect brush use in cow groups and to investigate the influence of (1) group size and the corresponding cow-to-brush ratio and (2) brush placement in relation to the lying stalls and the feeding and drinking areas. We measured brush use in groups of 60, 48, 36, and 24 cows, with the brush placed either in the alley adjacent to the feed bunk and water trough or in the back alley. Cows used the brush for longer when it was placed in the feed/water alley compared to when placed in the back alley. Average brush use per cow increased when cows were housed in smaller groups, but the brush was never in use more than 50% of the day, regardless of group size. We conclude that brush use increases when availability is increased and when the brush is placed closer to the feed and water.
- Published
- 2023
- Full Text
- View/download PDF
5. Solid-state stability of spray-dried insulin powder for inhalation: chemical kinetics and structural relaxation modeling of Exubera above and below the glass transition temperature.
- Author
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Sadrzadeh N, Miller DP, Lechuga-Ballesteros D, Harper NJ, Stevenson CL, and Bennett DB
- Subjects
- Drug Stability, Kinetics, Powder Diffraction, Powders, Recombinant Proteins chemistry, Transition Temperature, X-Ray Diffraction, Insulin chemistry
- Abstract
The effect of temperature on the chemical stability of an amorphous spray-dried insulin powder formulation (Exubera) was evaluated in the solid state at constant moisture content. The chemical stability of the powder was assessed using reversed-phase high-performance liquid chromatography (RP-HPLC) and high-performance-size exclusion chromatography (HP-SEC). The major degradants in spray-dried insulin produced during heat stressing were identified as A21-desamidoinsulin (A21) and high molecular weight protein (HMWP). As expected, the rates of formation of A21 and HMWP were observed to increase with temperature. A stretched-time kinetic model (degradation rate is proportional to the square root of time) was applied to the degradant profiles above and below the glass transition temperature (T(g)) and apparent reaction rate constants were determined. Below T(g), isothermal enthalpy of relaxation measurements were used to assess the effect of temperature on molecular mobility. The formation of A21 and HMWP was found to follow an Arrhenius temperature dependence above and below the T(g). Comparison of reaction rate constants to those estimated from structural relaxation experiments suggests that the reaction pathways to form A21 and HMWP below the T(g) may be coupled with the molecular motions involved in structural relaxation.
- Published
- 2010
- Full Text
- View/download PDF
6. Peptide drug delivery strategies for the treatment of diabetes.
- Author
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Sadrzadeh N, Glembourtt MJ, and Stevenson CL
- Subjects
- Amino Acid Sequence, Diabetes Mellitus classification, Dimerization, Disulfides chemistry, Glucagon-Like Peptide 1 administration & dosage, Glucagon-Like Peptide 1 chemistry, Humans, Hypoglycemic Agents chemistry, Hypoglycemic Agents pharmacokinetics, Insulin analogs & derivatives, Insulin chemistry, Insulin pharmacokinetics, Models, Chemical, Molecular Sequence Data, Protein Conformation, Protein Engineering, Protein Structure, Secondary, Zinc chemistry, Diabetes Mellitus drug therapy, Drug Delivery Systems methods, Hypoglycemic Agents administration & dosage, Insulin administration & dosage, Peptides administration & dosage
- Abstract
Drug delivery strategies for diabetes have included a wide range of scientific and engineering approaches, including molecular design, formulation and device design. Molecular engineering has resulted in modified pharmacokinetics, such as rapid-acting or slow-release analogs of insulin. Long-acting insulin formulations are designed to meet the body's basal needs, whereas rapid-acting insulin formulations are designed to cover mealtime glucose spikes. Furthermore, the discovery of new therapeutic biomolecules, which like insulin need to be injected, will drive the need for more flexible and universally applicable delivery systems. Formulation design, such as particle engineering, can be used to modify pharmacokinetic profiles. In general, suspension formulations of insulin commonly demonstrate reduced solubility and result in sustained release. Similarly, depot injections can result in precipitation of insulin at the site of injection, again resulting in lower solubility and sustained release. Particle engineering also has been applied to pulmonary formulations for delivery to the deep lung. The creation of novel drug delivery methods for the treatment of diabetes should remove barriers to insulin therapy and increase patient acceptance and compliance. Eliminating routine injections with needle-free injectors, insulin pumps, inhalation, buccal sprays, intra-nasal delivery, and transdermal patches may offer increasingly attractive alternatives., ((c) 2007 Wiley-Liss, Inc. and the American Pharmacists Association.)
- Published
- 2007
- Full Text
- View/download PDF
7. The design and performance of the exubera pulmonary insulin delivery system.
- Author
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Harper NJ, Gray S, De Groot J, Parker JM, Sadrzadeh N, Schuler C, Schumacher JD, Seshadri S, Smith AE, Steeno GS, Stevenson CL, Taniere R, Wang M, and Bennett DB
- Subjects
- Aerosols, Equipment Design, Humans, Hypoglycemic Agents administration & dosage, Hypoglycemic Agents pharmacokinetics, Hypoglycemic Agents therapeutic use, Insulin administration & dosage, Insulin pharmacokinetics, Thermodynamics, Treatment Outcome, Administration, Inhalation, Insulin therapeutic use, Lung physiology
- Abstract
The Exubera system (Pfizer, New York, NY/Nektar Therapeutics, San Carlos, CA) is an integration of five major new technologies: protein formulation, powder processing, powder filling, drug packaging, and delivery device. The product provides a simple interface, where the patient interacts only with the delivery device and powder packaging. These components were designed together to assure repeatable dosing when used by a wide range of patients under real-world life-style and handling conditions. The device design is purely mechanical, using patient-generated compressed air as the energy source. Upon actuation, a sonic discharge of air through the novel release unit reproducibly extracts, de-agglomerates, and disperses the inhalation powder into a respirable aerosol. A clear holding chamber allows for patient feedback via dose visualization and separates aerosol cloud generation from the inspiratory effort. The Exubera product was tested under a wide range of typical use conditions and potential misuse scenarios and following long-term usage in clinical trials. These comprehensive characterization programs demonstrated robust aerosol and mechanical performance, confirming the design intent of the inhaler. These studies provide assurance of consistent and reliable dose delivery in a real-world use of the product.
- Published
- 2007
- Full Text
- View/download PDF
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