Reliability of feedback fechanism based on root cause defect analysis - case study

The case study presented in this article focuses on the common pitfall in which many defect prevention activities fall, caused by inconsistency of data. Before any collected Root Cause Defect Analysis (RCA) data can be used reliably, an analysis of the variation due to the measurement system itself such as a Gauge R&R study, should be performed. This allows to understand of the integrity of the data in terms of data consistency and validity. The RCA data collection process chosen for this case study concentrates on the RCA assessment performed by engineers independently

On Unbounded Composition Operators in L2L^2-Spaces

Fundamental properties of unbounded composition operators in $L^2$-spaces are studied. Characterizations of normal and quasinormal composition operators are provided. Formally normal composition operators are shown to be normal. Composition operators generating Stieltjes moment sequences are completely characterized. The unbounded counterparts of the celebrated Lambert's characterizations of subnormality of bounded composition operators are shown to be false. Various illustrative examples are supplied

Tritolylporphyrin dimer as a new potent hydrophobic sensitizer for photodynamic therapy of melanoma

We report the synthesis, photochemical and photophysical properties and preliminary studies on biological effect of a new tritolylporphyrin dimer (T-D). Absorption and emission properties of T-D suggest its possible use in photodynamic therapy. T-D is capable of singlet oxygen production with 0.8 quantum yield. It also has a high photostability. The photodynamic properties of the dimer were examined following the growth of SKMEL 188 (human melanoma) cells irradiated with red light (cut off vs. non-irradiated cells) for an 81 J/cm2 dose. Our results suggest that tritolylporphyrine dimer T-D may be an interesting hydrophobic sensitizer for photodynamic therapy

A moment problem for pseudo-positive definite functionals

A moment problem is presented for a class of signed measures which are termed pseudo-positive. Our main result says that for every pseudo-positive definite functional (subject to some reasonable restrictions) there exists a representing pseudo-positive measure. The second main result is a characterization of determinacy in the class of equivalent pseudo-positive representation measures. Finally the corresponding truncated moment problem is discussed.Comment: 23

Photoredox Reactions of Hg(CN)₂/[Fe(CN)₆]⁴⁻ and [HgCo₂(CN)₁o]⁶⁻ induced by Inner-Sphere Metal to Metal Charge Transfer Excitation

In complexes of the type [(NC)2HgIINCFeII(CN)5]4- which are formed in aqueous mixtures of Hg(CN)2 and [Fe(CN)6]4- both metals are weakly coupled. Optical metal to metal charge transfer (MMCT) excitation from FeII to HgII leads to the reduction of HgII to Hg0 and the oxidation of [Fe(CN)6]4- to [Fe(CN)6]3-. In the complex [(NC)5CoI-HgII-CoI(CN)5]6- the metals are strongly coupled by direct but polar metal metal bonds. MMCT (CoI -> HgII) excitation induces the photoredox reaction: [HgCo2(CN)10]6- -> Hg0 + 2[Co(CN)5]3-

Technical Debt Prioritization in Telecommunication Applications: Why the Actual Refactoring Deviates from the Plan and How to Remediate It? Case Study in the COVID Era

This paper focuses on application of a technical debt prioritisation technique in telecommunication software managing a fleet of devices for a video surveillance system. Technical debt for this application was gathered, categorised and prioritised according to the Continuous Debt Valuation Approach (CoDVA), previously proposed by the authors. The following research question was posed: Is prioritising technical debt reduction based on CoDVA effective (i.e., executed as per plan, bringing tangible benefits)? The outbreak of COVID-19 pandemic caused unprecedented disturbance to the engineering organisations worldwide, therefore the technical debt identification phase had to be adapted to cope with a switch to forced working-from-home mode. This was achieved by applying the Wisdom of Crowds method, ensuring broad participation of engineers, and providing a fairly complete picture of the accrued technical debt. Nevertheless, the actual technical debt reduction activities did not follow exactly the expected guidelines. The three main causes of this phenomenon were discovered: continuous refactoring approach, sizing of technical debt items, and the broadened scope of refactoring activities. Therefore, as a result of this case study we propose to adopt a specific broadened definition of technical debt and follow a few rules for defining its scope and granularity

Technical Debt Prioritization in Telecommunication Applications: Why the Actual Refactoring Deviates from the Plan and How to Remediate It? Case Study in the COVID Era

This paper focuses on application of a technical debt prioritisation technique in telecommunication software managing a fleet of devices for a video surveillance system. Technical debt for this application was gathered, categorised and prioritised according to the Continuous Debt Valuation Approach (CoDVA), previously proposed by the authors. The following research question was posed: Is prioritising technical debt reduction based on CoDVA effective (i.e., executed as per plan, bringing tangible benefits)? The outbreak of COVID-19 pandemic caused unprecedented disturbance to the engineering organisations worldwide, therefore the technical debt identification phase had to be adapted to cope with a switch to forced working-from-home mode. This was achieved by applying the Wisdom of Crowds method, ensuring broad participation of engineers, and providing a fairly complete picture of the accrued technical debt. Nevertheless, the actual technical debt reduction activities did not follow exactly the expected guidelines. The three main causes of this phenomenon were discovered: continuous refactoring approach, sizing of technical debt items, and the broadened scope of refactoring activities. Therefore, as a result of this case study we propose to adopt a specific broadened definition of technical debt and follow a few rules for defining its scope and granularity

A combination of access to preassociation sites and local accumulation tendency in the direct vicinity of G-N7 controls the rate of platination of single-stranded DNA

Adduct formation between cationic reagents and targets on DNA are facilitated by the ability of DNA to attract cations to its surface. The electrostatic interactions likely provide the basis for the documented preference exhibited by cisplatin and related compounds for nuclear DNA over other cellular constituents. As an extension of a previous communication, we here present an investigation illustrating how the rate of adduct formation with the naturally occuring base guanine (G-N7) can be modulated by i) bulk solvent conditions, ii) local nature and size of the surrounding DNA and, iii) increasing DNA concentration. A series of single-stranded DNA oligomers of the type d(TnGTm); n= 0, 2, 4, 6, 8, 10, 12, 14, 16 and m= 16 –n or n=m= 4, 6, 8, 12, 16, 24 were allowed to react with the active metabolite of a potential orally active platinum(IV) drug, cis-[PtCl(NH3)(c-C6H11NH2)(OH2)]+ in the presence of three different bulk cations; Na+, Mg2+, and Mn2+. For all positions along the oligomers, a change from monovalent bulk cations to divalent ones results in a decrease in reactivity, with Mn2+ as the more potent inhibitor as exemplified by the rate constants determined for interaction with d(T8GT8): 103×kobs/s–1= 6.5 ± 0.1 (Na+), 1.8 ± 0.1 (Mg2+), 1.0 ± 0.1 (Mn2+) at pH 4.2 and 25 °C. Further, the adduct formation rate was found to vary with the exact location of the binding site in the presence of both Na+ and Mg2+, giving rise to reactivity maxima at the middle position. Increasing the size of the DNA-fragments was found to increase the reactivity only up to a total length of ca. 20 bases. The influence from addition of further bases to the reacting DNA was found to be salt dependent. At [Na+]= 0.5 mM a retardation in reactivity was observed whereas [Na+] 4.5 mM give rise to length independent kinetics. Finally, for the first time we have here been able to evaluate the influence from an increasing concentration of non-reactive DNA bases on the adduct formation process. The latter data were successfully fitted to an inhibition model suggesting that non-productive association of the platinum complex with sites distant from G-N7 competes with productive ones in the vicinity of the G-N7 target. Taken together, the kinetics support a reaction mechanism in which access to suitable association sites in the direct vicinity of the target site controls the rate of platination