Inverse problems for the Sturm-Liouville equation with the discontinuous coefficient

In this study we derive the Gelfand-Levitan-Marchenko type main integral equation of the inverse problem for the boundary value problem $L$ and prove the uniquely solvability of the main integral equation. Further, we give the solution of the inverse problem by the spectral data and by two spectrum.     

Metal-Organic Framework Nanoparticles with Universal Dispersibility through Crown Ether Surface Coordination for Phase-Transfer Catalysis and Separation Membranes

Dispersing metal-organic framework (MOF) solids in stable colloids is crucial for their availability and processibility. Herein, we report a crown ether surface coordination approach for functionalizing the surface-exposed metal sites of MOF particles with amphiphilic carboxylated crown ether (CE^C). The surface-bound crown ethers significantly improve MOF solvation without compromising the accessible voids. We demonstrate that CE^C-coated MOFs exhibit exceptional colloidal dispersibility and stability in 11 distinct solvents and six polymer matrices with a wide range of polarities. The MOF-CE^C can be instantaneously suspended in immiscible two-phase solvents as an effective phase-transfer catalyst and can form various uniform membranes with enhanced adsorption and separation performance, which highlights the effectiveness of crown ether coating.     

Asymmetric Host Molecule Bearing Pyridine Core for Highly Efficient Blue Thermally Activated Delayed Fluorescence OLEDs

In this study, two host materials, pCzBzbCz and pCzPybCz , are synthesized to achieve a high efficiency and long lifetime of blue thermally activated delayed fluorescence organic light-emitting diodes (TADF-OLEDs). The molecular design strategy involves the introduction of a pyridine group into the core structure of pCzPybCz as an electron-withdrawing unit, and an electron-donating phenyl group into the structure of pCzBzbCz . These host materials demonstrate good thermal stability and high triplet energy (T₁=3.07 eV for pCzBzbCz and 3.06 eV for pCzPybCz ) for the fabrication of blue TADF-OLEDs. In particular, pCzPybCz -based OLED devices demonstrate an external quantum efficiency (EQE) of 22.7 % and an operational lifetime of 24 h (LT₉₀, time to attain 90 % of initial luminance) at an initial luminance of 1000 cd m⁻². This superior lifetime could be explained by the C−N bond dissociation energy (BDE) in the host molecular structure. Furthermore, a mixed-host system using the electron-deficient 2,4-bis(dibenzo[b,d]furan-2-yl)-6-phenyl-1,3,5-triazine (DDBFT) is proposed to inhibit the formation of the anion state of our host materials. In short, the device operational lifetime is further improved by applying DDBFT. The carbazole-based asymmetric host molecule containing a pyridine core realizes a high-efficiency blue TADF-OLED showing a positive effect on the operating lifetime, and can provide useful strategies for designing new host materials.     

Self-Tuning GMV Control of Glucose Concentration in Fed-Batch Baker’s Yeast Production

A detailed system identification procedure and self-tuning generalized minimum variance (STGMV) control of glucose concentration during the aerobic fed-batch yeast growth were realized. In order to determine the best values of the forgetting factor (λ), initial value of the covariance matrix (α), and order of the Auto-Regressive Moving Average with eXogenous (ARMAX) model (n _a, n _b), transient response data obtained from the real process wereutilized. Glucose flow rate was adjusted according to the STGMV control algorithm coded in Visual Basic in an online computer connected to the system. Conventional PID algorithm was also implemented for the control of the glucose concentration in aerobic fed-batch yeast cultivation. Controller performances were examined by evaluating the integrals of squared errors (ISEs) at constant and random set point profiles. Also, batch cultivation was performed, and microorganism concentration at the end of the batch run was compared with the fed-batch cultivation case. From the system identification step, the best parameter estimation was accomplished with the values λ?=?0.9, α?=?1,000 and n _a?=?3, n _b?=?2. Theoretical control studies show that the STGMV control system was successful at both constant and random glucose concentration set profiles. In addition, random effects given to the set point, STGMV control algorithm were performed successfully in experimental study.     

Crystallographic report: The crystal structure of bis‐(3,3‐dimethyl‐3,4‐dihydro‐2H‐1‐thia‐4a,9‐diaza‐3‐sila‐fluorene) silver nitrate

The title compound is a silver nitrate complex with two molecules of 2‐mercaptobenzimidazole derivative. The silver atom lies on an inversion centre of the crystal lattice; nitrogen of the nitrate anion is in another inversion centre. Bond length Ag(1)? N(7) is 2.087(3) Å. Copyright © 2005 John Wiley & Sons, Ltd.     

Synthesis and neurotropic activity of silyl propargyl alcohols and sulfides

New silicon derivatives of hetaryl propargyl sulfides and propargyl alcohols were synthesized using phase‐transfer catalytic and organometallic methods. These compounds were tested for acute toxicity and neurotropic activity in the pentylenetetrazole test, and for phenamine hypothermia, phenamine hyperactivity and passive avoidance response tests. We have found that the silyl propargyl alcohols and sulfides are low toxicity compounds, the LD₅₀ being 700–1300 mg kg^?1. In the PAR test, the synthesized compounds exerted some memory‐improving activity. For di‐1‐(3‐methyl‐3‐hydroxybutyn‐1‐yl)methyl(3‐iodopropyl)silane ( 16 ) the effect was statistically significant and amounted to 250% of the control level. In the pentylenetetrazole test, all compounds possessed anticonvulsant activity, the most active compounds being 3‐(benzoxazolylthio)‐1‐propynyl(trimethyl)silane ( 6 ) and di‐[2‐(1‐hydroxycyclohexyl)ethynyl]methyl(3‐iodopropyl)silane ( 17 ). The phenamine‐induced hyperactivity was significantly elevated after treatment with (3‐trimethylsilyl‐2‐propynyl)thiobenzene ( 1 ) or di‐[1‐(3‐methyl‐3‐hydroxybutyn‐1‐yl)diphenylsilane ( 12 ). Our data show that these silicon derivatives of hetaryl propargyl sulfides and propargyl alcohols possess certain memory improving and anticonvulsant activity that should be studied in detail to evaluate the receptor systems involved. Copyright © 2004 John Wiley & Sons, Ltd.     

Synthesis of unsymmetric diynes by palladium and cesium fluoride catalyzed coupling of terminal bromoalkynes with alkynylstannane

The Stille reaction of unsymmetric diynes from terminal bromoalkynes with alkynylstannane in the presence of palladium catalyst and cesium fluoride was studied. The system (bromoalkyne: PhC≡CSnMe₃:Pd₂(dba)₃:PPh₃:CsF:18‐crown‐6) = (1:1:0.015:0.06:2.2:0.1) in toluene at reflux temperature was found to be the most favored. Products were obtained in 31–100% yields. Correlations between calculated electron density, dipole moments and ¹³C NMR spectral data of synthesized bromoacetylenes and diynes have been carried out. Copyright © 2002 John Wiley & Sons, Ltd.     

Parallel synthesis of benzoxazoles via microwave-assisted dielectric heating

A facile route to benzoxazoles has been developed using microwave-assisted dielectric heating. The ease of synthesis and workup allowed the parallel synthesis of a 48-membered library of benzoxazoles quickly and efficiently.     

Synthesis and Evaluation of Novel 5-O-(4-C-Aminoalkyl-β-D-ribofuranosyl) Apramycin Derivatives for the Inhibition of Gram-Negative Pathogens Carrying the Aminoglycoside Phosphotransferase(3′)-Ia Resistance Determinant

We report the synthesis and evaluation of two new apramycin 5-O-β-d -ribofuranosides, or apralogs, carrying aminoalkyl branches at the ribofuranose 4-position. This novel modification conveys excellent activity for the inhibition of protein synthesis by wild-type bacterial ribosomes and correspondingly high antibacterial activity against several Gram-negative pathogens. Notably, these new modifications overcome the reduction of antibacterial activity in other 2-deoxystreptamine-type aminoglycosides carrying a 5-O-ribofuranosyl moiety when challenged by the presence of an aminoglycoside phosphotransferase enzyme capable of acting on the ribose 5-position.     

Poly(p‐phenylene) with Poly(ethylene glycol) Chains and Amino Groups as a Functional Platform for Controlled Drug Release and Radiotherapy

Conventional cancer treatments such as chemotherapy, radiotherapy, or combination of these two result in side effects, which lower the quality of life of the patients. To overcome problems with these methods, altering the drug properties by conjugating them to carrier polymers has emerged. Such polymeric carriers also hold the potential to make tumor cells more sensitive to radiation therapy. Herein, poly(p‐phenylene) (PPP) polymer with poly(ethylene glycol) (PEG) chains and primary amino groups (PPP‐NH₂‐g‐PEG) is synthesized and conjugated with anticancer drug Doxorubicin (DOX). pH dependent drug release experiments are performed at pH 5.3 and pH 7.4, respectively. Cell viability studies on human cervix adenocarcinoma cells show that lower doses of DOX inhibit cell proliferation when conjugated with nontoxic doses of PPP‐NH₂‐g‐PEG polymer. Additionally, PPP‐NH₂‐g‐PEG/Cys/DOX bioconjugate significantly increases radiosensitive properties of DOX. It is possible to use lower doses of DOX when conjugated to PPP‐NH₂‐g‐PEG in combination with radiotherapy.