RESUMO
In the real-world, there are various situations when all units are not accessible of the respondent called unit non-response. The effect of unit non-response is a tricky matter for estimating the total number of unit. The present work highlights the interest about subpopulations (domains) in two affairs: i. if domains total of the supportive information is accessible ii. if domains total of the supportive variable does not access. The government needs to be introducing the actual facilities in these small domains. The supportive information is used to find out the estimate of the non respondent information and to apply this information for desired domains. Sometimes, it has been found that the accessible auxiliary variable for the domains might be positive shape. Therefore, it develops an appropriate model that has positive skewness. The present context highlighted the indirect method using a power-based estimation with calibration approach. By combining power based estimation and calibration technique, it is possible to obtain more accurate estimates for intended small domains. Even the supportive information is positively biased. This approach helps us in mitigating the effect of non-respondent and improving the overall reliability of the estimators. The simulation was conducted for different sizes 70 and 90 when nonresponse variable in the study variable. The results show that investigated power-based estimate provides better option over relevant exponential, ratio, and generalized regression estimators for intended domains.
RESUMO
We report on a direct comparison of the separation performance in capillary nano-LC between commercial packed bed columns and the small-domain silica monoliths in applications. Octadecylsilylated monolithic silica capillary columns with a 50 and 100 µm inner diameter (i.d.) were prepared with a procedure providing domain sizes in the sub-2 µm range. The fabricated monolith columns could provide plate heights (H) of 4.0â4.2 µm for hexylbenzene (retention factor (k) = 3.6) at an optimal linear velocity range under an isocratic condition, while showing a column permeability (Kv0 = 1.6â1.8 × 10-14 m2) comparable to that of a column packed with 3â3.5 µm particles. When the peak capacity (np) for a cytochrome C digest was compared for variable gradient times (tG = 15, 30, 60, and 120 min) and constant gradient steepness (b'), the present monolith columns could show a 30â40% higher np-value than the packed capillary column with 2 µm particles (e.g. np = 180 versus np = 259 at tG = 30 min). The produced monolith columns showed a high chromatographic repeatability for both isocratic and gradient elution (e.g. relative standard deviation (n = 3, RSD (%)) = 0.5% for H, 2,6% for k, and 5.6% for Kv0 in the isocratic mode using the 100 µm i.d.-columns). The present results show that the domain sizes which can now be achieved for capillary silica monoliths are sufficiently small to result in separation efficiencies that can successfully compete with the commercial packed bed columns available for use in nano-LC applications.
Assuntos
Cromatografia Líquida/métodos , Nanotecnologia/métodos , Tamanho da Partícula , Dióxido de Silício/química , Derivados de Benzeno/química , Citocromos c/análiseRESUMO
Antibody-drug conjugates (ADCs) represent an innovative class of biopharmaceuticals, which aim at achieving a site-specific delivery of cytotoxic agents to the target cell. The use of ADCs represents a promising strategy to overcome the disadvantages of conventional pharmacotherapy of cancer or neurological diseases, based on cytotoxic or immunomodulatory agents. ADCs consist of monoclonal antibodies attached to biologically active drugs by means of cleavable chemical linkers. Advances in technologies for the coupling of antibodies to cytotoxic drugs promise to deliver greater control of drug pharmacokinetic properties and to significantly improve pharmacodelivery applications, minimizing exposure of healthy tissue. The clinical success of brentuximab vedotin and trastuzumab emtansine has led to an extensive expansion of the clinical ADC pipeline. Although the concept of an ADC seems simple, designing a successful ADC is complex and requires careful selection of the receptor antigen, antibody, linker, and payload. In this review, we explore insights in the antibody and antigen requirements needed for optimal payload delivery and support the development of novel and improved ADCs for the treatment of cancer and neurological diseases.
Assuntos
Anticorpos Monoclonais/administração & dosagem , Anticorpos Monoclonais/química , Doenças do Sistema Nervoso Central/terapia , Sistemas de Liberação de Medicamentos , Imunoconjugados/administração & dosagem , Imunoconjugados/química , Neoplasias/terapia , Humanos , Imunoconjugados/uso terapêuticoRESUMO
Monolithic silica materials (first unclad monolith rods, then monolithic capillary columns) were prepared using various amounts of polyethylene glycols (PEGs) with different molecular weight (MW). The monolith rods were used to examine the mesoporosity by argon physisorption technique, and the macroporosity by mercury intrusion porosimetry. Subsequently, silica-based monolithic capillary columns with an inner diameter of 100 µm were produced using the same preparation conditions as used for the rods. The results obtained with the monolith rods showed the following important findings: (1) it is feasible to fabricate monolithic silica rods possessing macropore size of 0.5-1.4 µm by tuning the amount of PEGs (independently of the MW), whereas the macropore volume and the mesoporosity remain similar. (2) the smallest macropore size (0.5 µm) rod prepared with PEG having a MW=20,000g/mol provided a narrower macropore size distribution than with PEG with MW=10,000g/mol. The monolithic capillary columns produced with the different PEG type showed similar retention factors for hexylbenzene (k=2.3-2.4) and similar t0-based column permeability (Kv0=2.3-2.4×10(-14)m(2)) in 20:80% (v/v) water:methanol, as expected from the results obtained with the monolith rods. The column prepared with PEG of MW=20,000g/mol gave a plate height of H=4.0 µm for hexylbenzene at an optimal linear velocity of u0=2.6mm/s in 20:80% (v/v) water containing 0.1% formic acid:acetonitrile. To the best of our knowledge, this is the lowest plate height ever recorded for a monolithic column. Comparing the kinetic performance at 30MPa shows that the best monolithic silica column obtained in the present study performs better than the second-generation monolithic silica columns developed up till now in the practically most relevant range of plate numbers (N≤40,000). In this range, the performance is now similar to that of 2.7 µm core-shell particle columns.