Capacity optimization and competition with cyclical and lead-time-dependent demands

Capacity acquisition is often capital- and time-consuming for a business, and capacity investment is often partially or fully irreversible and difficult to change in the short term. Moreover, capacity determines the action space for service/production scheduling and lead-time quotation decisions. The quoted lead-time affects the customer’s perceived service quality. Thus, capacity acquisition level and lead-time quotation affect a firm’s revenue/profit directly or indirectly. In this paper, we investigate a joint optimization problem of capacity acquisition, delivery lead-time quotation and service-production scheduling with cyclical and lead-time-dependent demands. We first explore the structural properties of the optimal schedule given any capacity and lead-time. Then, the piecewise concave relationship between the delay penalty cost and the capacity acquisition level is found. Thereby, an efficient and effective polynomial time algorithm is provided to determine the optimal capacity acquisition level, delivery lead-time quotation and service/production schedule simultaneously. Furthermore, a capacity competition game among multiple firms is addressed. The numerical studies show that capacity equilibrium often exists and converges to a unique solution.     

Isotachophoretic determination of phosphate splitting from Amifostine and p-nitrophenyl phosphate in serum and neuroblastoma cells.

Amifostine [WR-2721; H2N-(CH2)3-NH-(CH2)2-S-PO3H2] is used as a protecting agent in the chemotherapy of neuroblastoma. It is supposed that Amifostine will be transformed into its active form, the free thiol (WR-1065), easier by normal cells than by tumour cells. Analytical capillary isotachophoresis was used to determine the dephosphorylation of Amifostine in serum and on neuroblastoma cells and peripheral blood cells. Furthermore, the biological effects of Amifostine and its free thiol, on cell proliferation of neuroblastoma cells were measured in combination with Carboplatin. It was found that neuroblastoma cells did not split phosphate less efficiently than normal peripheral blood cells. Furthermore, neither Amifostine (as expected) nor the free thiol (not expected according to the theory) were able to inhibit the effects of Carboplatin. Therefore, the current hypothesis concerning the mode of action of Amifostine must be questioned.     

Spin-State-Selective TPPI: A New Method for Suppression of Heteronuclear Coupling Constants in Multidimensional NMR Experiments

A novel multidimensional NMR pulse sequence tool, spin-state-selective time-proportional phase incrementation (S(3) TPPI), is introduced. It amounts to application of different TPPIs on the two components of doublets so that their frequencies can be manipulated independently. The chief application is for suppression of large heteronuclear one-bond coupling constants in indirect dimensions of multidimensional experiments without interchanging the two transverse magnetization components of doublets as conventional decoupling does, which is advantageous when they relax at different rates such as by partial compensation of dipolar and CSA relaxation contributions. For experimental confirmation we use a sample of (15)N-labeled neural cell adhesion molecule modules 1 and 2, a protein with a molecular weight of about 20 kDa. The new tool is general and can be combined with many multidimensional NMR experiments for proteins.     

New Multidimensional Editing Experiments for Measurement of Amide Deuterium Isotope Effects on CChemical Shifts inC,N-Labeled Proteins

Novel multidimensional NMR pulse sequences for measurement of the three- and four-bond amide deuterium isotope effect on the chemical shifts of¹³C^βin proteins are presented. The sequences result in editing into two subspectra of a heteronuclear triple resonance spectrum {ω(N), ω(C^β), ω(H^α)} according to there being a deuterium or a proton attached to¹⁵N for the pertinent correlations. The new experiments are demonstrated by an application to the first module of the¹³C,¹⁵N-labeled protein RAP 18-112 (N-terminal module of α₂-macroglobulin receptor associated protein).     

On size and shape of the average meson fields in the semibosonized Nambu & Jona-Lasinio model

We consider the bosonized form of a two-flavor Nambu & Jona-Lasinio model involving scalar-isoscalar and pseudoscalar-isovector quark-quark interaction. Solitonic meson fields are obtained by minimizing the effective Euclidean action. In dependence on the constituent quark mass, which is the only free parameter in the model, we evaluate a series of meson profiles and compare them with a properly parameterized reference profile. We show that the self-consistent fields do in fact practically not depend on the constituent quark mass. Their shape can be very well approximated by this reference profile which interpolates between the correct asymptotic behavior for small and large radii. To demonstrate the accuracy of the approximation we evaluate several static properties like energy, mean square radius, axial-vector constant and delta-nucleon mass splitting using both self-consistent and reference profiles. The agreement is found to be very well in the physically relevant mass region.     

Die jodometrische Dead-stop-Chlorbestimmung und die Chlorcolorimetrie in der Wasserchemie

Zusammenfassung Die Genauigkeit einiger colorimetrischer und volumetrischer Methoden zur Bestimmung von wirksamem freiem Chlor in Wässern wird vergleichend untersucht. Dabei wird festgestellt, daß eine wirklich exakte Methode zur Bestimmung sehr geringer Chlorgehalte in Wasser wegen vorhandener zahlreicher Fehlerquellen bei der Herstellung der Chlorlösungen bestimmten Gehaltes und aus anderen Gründen noch nicht besteht. Es wird eine jodometrische Dead-stop-Mikromethode entwickelt, die es erlaubt, sehr geringe Mengen von Chlor in Wasser unter 0,3 mg/l mit einer Genauigkeit von ±0,004 mg/l zu ermitteln. Ihre Theorie wird dargelegt. Dadurch wird die Möglichkeit geschaffen, Vergleichslösungen und Farbskalen für die colorimetrische Chlorbestimmung sehr genau zu eichen und damit die Empfindlichkeit und Sicherheit dieser in der Wasseruntersuchung verwendeten Methoden zu steigern. Über diesbezügliche Versuche, besonders die colorimetrische Chlorbestimmung mit o-Tolidin und p-Phenylendiamin betreffend, wird berichtet. Die Geschwindigkeit der Farbbildungsreaktion mit o-Tolidin wird untersucht und der Einfluß äußerer Bedingungen bei dieser Methode geprüft. Störungen durch Eisengehalte der zu untersuchenden Wässer bei der Chlorbestimmung werden durch Herabsetzung des p_H-Wertes und Fluoridzusatz ausgeschaltet. Durch die Untersuchungen sind die Grundlagen für eine Normalisierung der Bestimmung des wirksamen Chlors in Trinkwässern geschaffen worden.Herrn Prof. Dr. A. Kurtenacker zum 70. Geburtstage gewidmet.     

Ein neuer Naehweis für Zinn

Analytical and Bioanalytical Chemistry -