Calcium Coordination Solids for pH-Triggered Release of Olsalazine

Calcium coordination solids were synthesized and evaluated for delivery of olsalazine (H_4olz), an anti-inflammatory compound used for treatment of ulcerative colitis. The materials include one-dimensional Ca(H_2olz)⋅4 H_2O chains, two-dimensional Ca(H_2olz)⋅2 H_2O sheets, and a three-dimensional metal-organic framework Ca(H_2olz)⋅2DMF (DMF=N,N-dimethylformamide). The framework undergoes structural changes in response to solvent, forming a dense Ca(H_2olz) phase when exposed to aqueous HCl. The compounds Ca(H_2olz)⋅x H_2O (x=0, 2, 4) were each pressed into pellets and exposed to simulated gastrointestinal fluids to mimic the passage of a pill from the acidic stomach to the pH-neutral intestines. All three calcium materials exhibited a delayed release of olsalazine relative to Na_2(H_2olz), the commercial formulation, illustrating how formulation of a drug within an extended coordination solid can serve to tune its solubility and performance

Calcium Coordination Solids for pH-Triggered Release of Olsalazine

Calcium coordination solids were synthesized and evaluated for delivery of olsalazine (H_4olz), an anti-inflammatory compound used for treatment of ulcerative colitis. The materials include one-dimensional Ca(H_2olz)⋅4 H_2O chains, two-dimensional Ca(H_2olz)⋅2 H_2O sheets, and a three-dimensional metal-organic framework Ca(H_2olz)⋅2DMF (DMF=N,N-dimethylformamide). The framework undergoes structural changes in response to solvent, forming a dense Ca(H_2olz) phase when exposed to aqueous HCl. The compounds Ca(H_2olz)⋅x H_2O (x=0, 2, 4) were each pressed into pellets and exposed to simulated gastrointestinal fluids to mimic the passage of a pill from the acidic stomach to the pH-neutral intestines. All three calcium materials exhibited a delayed release of olsalazine relative to Na_2(H_2olz), the commercial formulation, illustrating how formulation of a drug within an extended coordination solid can serve to tune its solubility and performance

Olsalazine-Based Metal–Organic Frameworks as Biocompatible Platforms for H_2 Adsorption and Drug Delivery

The drug olsalazine (H_4olz) was employed as a ligand to synthesize a new series of mesoporous metal–organic frameworks that are expanded analogues of the well-known M_2(dobdc) materials (dobdc^4– = 2,5-dioxido-1,4-benzenedicarboxylate; M-MOF-74). The M_2(olz) frameworks (M = Mg, Fe, Co, Ni, and Zn) exhibit high surface areas with large hexagonal pore apertures that are approximately 27 Å in diameter. Variable temperature H_2 adsorption isotherms revealed strong adsorption at the open metal sites, and in situ infrared spectroscopy experiments on Mg_2(olz) and Ni_2(olz) were used to determine site-specific H_2 binding enthalpies. In addition to its capabilities for gas sorption, the highly biocompatible Mg_2(olz) framework was also evaluated as a platform for the delivery of olsalazine and other encapsulated therapeutics. The Mg_2(olz) material (86 wt % olsalazine) was shown to release the therapeutic linker through dissolution of the framework under simulated physiological conditions. Furthermore, Mg_2(olz) was used to encapsulate phenethylamine (PEA), a model drug for a broad class of bioactive compounds. Under simulated physiological conditions, Mg_2(olz)(PEA)_2 disassembled to release PEA from the pores and olsalazine from the framework itself, demonstrating that multiple therapeutic components can be delivered together at different rates. The low toxicity, high surface areas, and coordinatively unsaturated metal sites make these M_2(olz) materials promising for a range of potential applications, including drug delivery in the treatment of gastrointestinal diseases

Olsalazine-Based Metal–Organic Frameworks as Biocompatible Platforms for H_2 Adsorption and Drug Delivery

The drug olsalazine (H_4olz) was employed as a ligand to synthesize a new series of mesoporous metal–organic frameworks that are expanded analogues of the well-known M_2(dobdc) materials (dobdc^4– = 2,5-dioxido-1,4-benzenedicarboxylate; M-MOF-74). The M_2(olz) frameworks (M = Mg, Fe, Co, Ni, and Zn) exhibit high surface areas with large hexagonal pore apertures that are approximately 27 Å in diameter. Variable temperature H_2 adsorption isotherms revealed strong adsorption at the open metal sites, and in situ infrared spectroscopy experiments on Mg_2(olz) and Ni_2(olz) were used to determine site-specific H_2 binding enthalpies. In addition to its capabilities for gas sorption, the highly biocompatible Mg_2(olz) framework was also evaluated as a platform for the delivery of olsalazine and other encapsulated therapeutics. The Mg_2(olz) material (86 wt % olsalazine) was shown to release the therapeutic linker through dissolution of the framework under simulated physiological conditions. Furthermore, Mg_2(olz) was used to encapsulate phenethylamine (PEA), a model drug for a broad class of bioactive compounds. Under simulated physiological conditions, Mg_2(olz)(PEA)_2 disassembled to release PEA from the pores and olsalazine from the framework itself, demonstrating that multiple therapeutic components can be delivered together at different rates. The low toxicity, high surface areas, and coordinatively unsaturated metal sites make these M_2(olz) materials promising for a range of potential applications, including drug delivery in the treatment of gastrointestinal diseases

Empirical verifi cation of Bogdanowicz-Stachý’s formula for design rainfall intensity calculations

Warunkiem prawidłowego wymiarowania systemów odwadniania terenów jest przyjęcie do obliczeń wiarygodnej wartości natężenia deszczu miarodajnego w funkcji czasu trwania i prawdopodobieństwa przewyższenia, rekomendowanego w normie PN-EN 752:2017. Podstawą ich wyznaczenia jest zastosowanie odpowiedniego modelu opadów, opracowanego na podstawie analizy statystycznej szeregów czasowych lokalnych opadów w wysokiej rozdzielczości czasowej, z co najmniej 30 ostatnich lat. W praktyce inżynierskiej w Polsce, oprócz stosowania nieaktualnego wzoru Błaszczyka, coraz częściej wykorzystuje się probabilistyczny model opadów maksymalnych Bogdanowicz-Stachý, oparty na pomiarach opadów z lat 1960–1990 na 20 stacjach IMGW. Jednak model ten nie zapewnia pełnego pokrycia kraju i opiera się na nieciągłej regionalizacji. Zmieniające się uwarunkowania klimatyczne wymuszają potrzebę sprawdzenia, czy model ten jest aktualny i wiarygodny do stosowania na terenie całego kraju. W artykule dokonano weryfikacji rzeczywistych wartości natężenia deszczu miarodajnego przy zadanym prawdopodobieństwie przewyższenia, wyznaczonych na podstawie 30-letniej serii opadów z lat 1986–2015, względem ich estymat według modelu Bogdanowicz-Stachý. Przeprowadzone analizy podważają zasadność koncepcji prostej regionalizacji opadów w Polsce. Wykazano, że wartości natężenia deszczu miarodajnego, obliczone z modelu Bogdanowicz-Stachý, przy prawdopodobieństwie p=100% i p=50% były najczęściej zaniżone, a przy p=20% i p=10% zawyżone w stosunku do występujących obecnie (1986–2015). Otrzymane wyniki badań dowodzą konieczności zastąpienia modelu Bogdanowicz-Stachý lokalnymi modelami opadów maksymalnych „nowej generacji”, tworzonych w ramach budowy atlasu PANDa (Polski Atlas Natężeń Deszczów), nie tylko w celu uzyskania pełnego pokrycia całego obszaru kraju, lecz także z uwagi na konieczność urealnienia wartości natężenia deszczu miarodajnego do projektowania systemów odwadniania terenów.Accurate dimensioning of drainage systems requires assumption of reliable design rainfall intensities as a function of its duration and probability of exceeding according to PN-EN 752:2017. Design rainfall intensities are determined by application of an adequate rainfall model that is based on statistical analysis of local precipitation time series recorded at high time resolution and covering a period of last 30 years minimum. Beside application of the obsolete Błaszczyk’s formula, the Bogdanowicz-Stachý’s probabilistic maximum precipitation model based on 1960–1990 rainfall records from 20 rain gauges (Institute of Meteorology and Water Management) becomes increasingly popular in Poland. However, this model does not support full coverage of the country and is based on the discontinuous regionalization. Evolving climate conditions demand validation of the model for use throughout the country. This paper presents results of verification of the actual values of rainfall intensities derived from 30-year time series from the period of 1986–2015 for given probabilities of exceeding, in comparison to the estimates delivered by the Bogdanowicz-Stachý’s model. The conducted analysis undermines legitimacy of the simple regionalization concept for precipitation in Poland. Moreover, rainfall intensity values calculated by Bogdanowicz-Stachý’s model for probabilities of p = 100% and p = 50% are mostly understated and for p = 20% and p = 10% are overstated in comparison to actuals (1986–2015). The results of the research confirm the need to replace Bogdanowicz-Stachý’s model with “new generation” local maximum precipitation models developed as part of the PANDa (the Polish Atlas of Rainfall Intensity) atlas, not only to obtain full coverage of the country, but also to make the values of rainfall intensities reliable for design of drainage systems

Empirical verification of Blaszczyk’s formula for design rainfall intensity calculations

Pomimo wyraźnych zastrzeżeń do podstaw teoretycznych oraz ograniczonych i przestarzałych danych opadowych, sformułowana przez Błaszczyka formuła opisująca wartość natężenia deszczu miarodajnego jest w Polsce nadal używana do wymiarowania systemów odwadniania terenów. Podstawą tej formuły (typu IDF – intensity-duration-frequency) jest założenie występowania ścisłej zależności funkcyjnej pomiędzy średnioroczną sumą wysokości opadów a maksymalnymi natężeniami deszczów. Założenie to zostało poddane w artykule weryfikacji na podstawie rzeczywistych maksymalnych wartości natężenia deszczów, wyznaczonych na potrzeby opracowania i wdrożenia Polskiego Atlasu Natężeń Deszczów (PANDa). Maksymalne natężenia deszczów, przy różnych czasach ich trwania, zostały wyszukane z rejestracji opadów w latach 1986–2015, pochodzących z ogólnopolskiej sieci 100 deszczomierzy Instytutu Meteorologii i Gospodarki Wodnej (IMGW-PIB). Wartości te porównano z odpowiadającymi ich estymatami obliczonymi według formuły Błaszczyka. Na podstawie otrzymanych wyników zakwestionowano podstawowe założenie tej formuły mówiące, że wartości maksymalnego natężenia deszczów nie są skorelowane z średniorocznymi sumami wysokości opadów. Ponadto stwierdzono wyraźną tendencję do zaniżania wartości natężenia deszczów obliczanych z formuły Błaszczyka. Wykazano, że wartość średniego błędu względnego pomiędzy rzeczywistymi natężeniami deszczów a ich oszacowaniami wynosiła 33%. Nawet w oryginalnych warszawskich warunkach hydrologicznych stosowanie formuły Błaszczyka okazało się nieakceptowalne, gdyż prowadziło do istotnego zaniżania obecnych natężeń deszczów. Z uwagi na dokonane ustalenia rekomenduje się całkowite wyeliminowanie formuły Błaszczyka z praktyki inżynierskiej projektowania systemów odwadniania terenów w Polsce.Despite serious questions to the theoretical fundamentals as well as the limited and outdated precipitation data, the Blaszczyk’s formula for the design rainfall intensity is still in use for sizing drainage systems in Poland. The assumption of close functional dependence between the average annual precipitation depth and maximum rainfall intensities is the basis for the formula (IDF-type, i.e. intensity-duration-frequency). The assumption was verified against the actual values of maximum rainfall intensity, derived for the purpose of development and implementation of the Polish Atlas of Rainfall Intensity (PANDa rainfall model). The actual maximum rainfall intensities for different duration periods were retrieved from the precipitation records obtained from the nation-wide network of 100 rain gauges of the Polish Institute of Meteorology and Water Management (IMGWPIB) for the period of 1986–2015. These values were compared to the corresponding Blaszczyk formula’s estimates. Based on the results, the basic assumption of the formula was questioned, namely that the maximum rainfall intensity values are not correlated with the normal annual precipitation depth. A clear tendency for the rainfall intensity values to be underestimated by the Blaszczyk’s formula was observed. It was demonstrated that the mean relative error between the actual and estimated rainfall intensities was 33%. Even for the original hydrological Warsaw conditions, the Blaszczyk formula proved unacceptable due to significant underestimation of current rainfall intensities. In view of the findings, a complete elimination of the formula from drainage system engineering in Poland is recommended

Determination of corrosion rates for copper and brass in rolling emulsions Part 1; determination of the effect of de-emulsifiers on the corrosion rate of copper

15.00; Translated from Polish (Ochr. Przed. Koroz. 1985 (5) p. 142-144)SIGLEAvailable from British Library Document Supply Centre- DSC:9022.0602(BISI-NF--190)T / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Gas separations in metal-organic frameworks

Owing to their high surface areas, tunable pore dimensions, and adjustable surface functionality, metal-org. frameworks (MOFs) can offer advantages for a variety of gas storage and gas sepn. applications. In an effort to help curb greenhouse gas emissions from power plants, we are developing new MOFs for use as solid adsorbents in post- and pre-combustion CO2 capture, and for the sepn. of O2 from air, as required for oxy-fuel combustion. In particular, MOFs with open metal cation sites or alkylamine-functionalized surfaces are demonstrated to provide high selectivities and working capacities for the adsorption of CO2 over N2 under dry flue gas conditions. Breakthrough measurements further show compds. of the latter type to be effective in the presence of water, while calorimetry data reveal a low regeneration energy compared to aq. amine solns. MOFs with open metal cation sites, such as Mg2(dobdc) (dobdc4- = 2, 5-dioxido-1,4-benzenedicarboxylate), are highly effective in the removal of CO2 under conditions relevant to H2 prodn., including in the presence of CH4 impurities. Redox-active Fe2+ sites in the isostructural compd. Fe2(dobdc) allow the selective adsorption of O2 over N2 via an electron transfer mechanism. The same material is demonstrated to be effective at 45 ° C for the fractionation of mixts. of C1 and C2 hydrocarbons, and for the high-purity sepn. of ethylene/ethane, propylene/propane, and CO/H2 mixts. Finally, it will be shown that certain structural features possible within MOFs, but not in zeolites, can enable the fractionation of hexane isomers according to the degree of branching or octane no