Dual channel chemosensor for successive detection of environmentally toxic Pd2+ and CN- ions and its application to cancer cell imaging.

BACKGROUND: Detecting and neutralizing Pd2+ ions are a significant challenge due to their cytotoxicity, even at low concentrations. To address this issue, various chemosensors have been designed for advanced detection systems, offering simplicity and the potential to differentiate signals from different analytes. Nonetheless, these chemosensors often suffer from limited emission response and complex synthesis procedures. As a result, the tracking and quantification of residual palladium in biological systems and environments remain challenging tasks, with only a few chemosensing probes available for commercial use. RESULTS: In this paper, a straightforward approach for the selective detection of Pd2+ ions is proposed, which involves the design, synthesis, and utilization of a propargylated naphthalene-derived probe (E)-N'-((2-(prop-2-yn-1-yloxy)naphthalen-1-yl)methylene)benzohydrazide (NHP). The NHP probe exhibits sensitive dual-channel colorimetry and fluorescence Pd2+ detection over other tested metal ions. The detection process is performed through a catalytic depropargylation reaction, followed by an excited state intramolecular proton transfer (ESIPT) process, the detection limit is as low as 11.58 × 10-7 M under mild conditions. Interestingly, the resultant chemodosimeter adduct (E)-N'-((2-hydroxynaphthalen-1-yl)methylene)benzohydrazide (NHH) was employed for the consecutive detection of CN- ions, exhibiting an impressive detection limit of 31.79 × 10-8 M. Validation of both detection processes was achieved through 1H nuclear magnetic resonance and density functional theory calculations. For real-time applications of the NHP and NHH probes, smartphone-assisted detection, and intracellular detection of Pd2+ and CN- ions within HeLa cells were studied. SIGNIFICANCE: This research presents a novel naphthalene derivative for visually detecting environmentally toxic Pd2+ and CN- ions. The synthesized probe selectively binds to Pd2+, forming a chemodosimeter. It successfully detects CN- ions through colorimetry and fluorimetry, offering a low detection limit and quick response. Notably, it's the first naphthalene-based small molecule to serve as a dual probe for toxic analytes - palladium and cyanide. Moreover, it effectively detects Pd2+ and CN- intracellularly in cancer cells.

Thin colorimetric film array for rapid and selective detection of v-type nerve agent mimic in potentially contaminated areas.

The expeditious detection and quantification of V-series nerve agents (VX) on potentially contaminated surfaces are crucial for the prevention of regional conflict incidents, acts of terrorism, or illicit activities. However, the low volatility and high toxicity of VX make these tasks challenging. Herein, we designed two novel colorimetric thin polymeric films to rapidly and sensitively detect demeton-S, a VX mimic, in contaminated areas. The polymeric films were specifically engineered to include a coordination site for Au (III) ions. Initially, these films were coordinated with Au (III), causing a discernible alteration in color due to enhancement in intramolecular charge transfer process. In the presence of demeton-S, the Au (III) ligands in the films are displaced with demeton-S, resulting in the restoration of the original color of the film, as the enhanced intramolecular charge transfer process is inhibited and thereby serving as an indicator of the presence of demeton-S. The polymeric films exhibit remarkable selectivity toward demeton-S compared to G-type nerve agents and other interference. The reusability of the polymeric films for demeton-S detection was achieved owing to the reversibility of the films during the alternative exposure of Au (III) and demeton-S. The polymeric films demonstrated their applicability for demeton-S detection and quantification in several contaminated areas, including different water, soil, and skin, rendering them highly suitable for on-site measurements.

How Do Two Types of Exercise Habits Predict Physical Activity with Intention?

This manuscript investigates how conscious intention and unconscious exercise habits influence physical activity behavior. While prior research has predominantly focused on conscious decision-making, this study applied a dual-process model to explore the impact of intention and habit on physical activity engagement. Out of the 300 questionnaires distributed to students from one university, 282 questionnaires were utilized for data analysis after excluding insincere responses. Intention was measured using a 7-point scale, while exercise habits were assessed using the Self-Report Behavioral Automaticity Index. In addition, physical activity was measured using the Weekly Leisure-Time Exercise Questionnaire. The validity and reliability of measurement tools were confirmed. Data were analyzed using SPSS and AMOS, including correlation analysis, multiple regression, and moderation analysis. Intention, exercise preparation habit, and exercise performance habit were all found to influence physical activity levels significantly. Intention demonstrated the strongest impact, followed by exercise preparation habit and exercise performance habit. This suggests that the research efforts regarding intention conducted before the emergence of the dual process model, which proposes the importance of unconscious thinking patterns, were not in vain. The analysis revealed a statistically significant moderating effect of exercise preparation habit, but not exercise performance habit, in the relationship between intention and physical activity. Exercise preparation habit was identified as a significant moderator, enhancing the relationship between intention and physical activity. This study underscores the importance of considering both conscious intention and unconscious exercise habits in promoting physical activity. The findings challenge the prevailing emphasis on conscious decision-making and highlight the need for a more comprehensive understanding of unconscious behavior in health behavior interventions. This study is expected to arouse academic interest in the often-neglected area of unconscious behavior.

Transparent nanocellulose paper-based biodegradable colorimetric nerve agent detectors.

Transparent cellulose nanofiber (t-CNF) films were prepared by succinylation and an aqueous collision counter system treatment, and used for the colorimetric detection of diethyl chlorophosphate (DCP), a nerve agent mimic in the vapor phase. DCP receptor with an oxime residue was anchored on the surface of succinylated CNF films, resulting in the target probe (CNF-Azo films). CNF-Azo films exhibited selective detection behavior toward DCP in the vapor phase. The oxime groups of CNF-Azo film reacted with DCP upon exposure to DCP vapor, which was accompanied by a color change from yellow to purple. Significantly, the film's transparency was preserved throughout the detection process, allowing it to identify objects behind the film during DCP detection. This property could apply to any detection system in which the color change caused by detection does not interfere with the film's transparency. The CNF-based film sensor was biodegradable, allowing it to be disposable after use.

Background color dependent photonic multilayer films for anti-counterfeiting labeling.

A new concept for anti-counterfeiting security films that utilize the humidity from human breath to reveal a QR code on color-tunable one-dimensional (1D) PC films is presented. The 1D PC film was fabricated on a transparent polyethylene terephthalate (PET) substrate via sequential alternate layer deposition of photo-crosslinkable poly(2-vinylnaphthalene-co-benzophenone acrylate) (P(2VN-co-BPA)) and quaternized poly(4-vinylpyridine-co-benzophenone acrylate) (P(4VP-co-BPA)) (P4QP-51%). The films exhibited remarkable color transitions with reliable reversibility and reproducibility. Films placed on a black background exhibited the full visible spectrum color in a high humidity environment. Additionally, films placed on a white background displayed three different composite colors, including yellow, magenta, and cyan. These films with vivid color transitions in a high humidity environment can be applied as anti-counterfeiting films. A hidden QR code was also laser printed on the initial PC film to enhance the film's anti-counterfeiting security capabilities. These colorimetric 1D PC films can be used as anti-counterfeiting labels and for information storage.

Recyclable macromolecular thermogels for Hg(II) detection and separation via sol-gel transition in complex aqueous environments.

The sensitive detection and quantitative separation of toxic heavy metal ions in aqueous media are of great importance. In this study, a thermogelling poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL) triblock copolymer (P1) was synthesized, and difluoroboron dipyrromethene (BODIPY) fluorophore integrated with thiosemicarbazide units was attached to the chain ends of P1 through consecutive post-polymerization modifications, leading to P4. P4 exhibited rapid and selective detection of Hg(II) in 100% aqueous media via turn-on fluorescence emission with a limit of detection (LOD) of as low as 0.461 µM. This turn-on emission behavior is attributed to the suppression of CË­N isomerization caused by the formation of a coordination complex between P4 and Hg(II) ions. The selective and quantitative removal of Hg(II) among various metal ions was achieved by trapping chelated Hg(II) ions inside the dehydrated P4 gel via thermo-controlled sol-gel-dehydrated gel transitions. Treating the Hg(II) ion-trapped dehydrated gels with sodium sulfide (Na2S) in acetone/water at room temperature led to HgS precipitates, and P4 in solution was dried and recycled. This recyclable thermoresponsive macromolecular probe is promising for not only Hg(II) detection but also its separation and removal from complex aqueous environments.

A Reusable Polymeric Film for the Alternating Colorimetric Detection of a Nerve Agent Mimic and Ammonia Vapor with Sub-Parts-per-Million Sensitivity.

Thin polymeric films were developed for the vapor-phase sequential colorimetric detection of a nerve agent mimic and ammonia with high sensitivity. N-(4-Benzoylphenyl)acrylamide (BPAm), N,N-dimethylacrylamide (DMA), and (E)-2-(methyl(4-(pyridine-4yldiazenyl)phenyl)amino)ethyl acrylate (MPDEA, M1) were copolymerized via free radical polymerization (FRP) to yield p(BPAm-co-DMA-co-MPDEA), hereafter referred to as P1. P1 exhibits selective sensing properties toward diethyl chlorophosphate (DCP), a nerve agent mimic, in pure aqueous media. Upon the addition of DCP, the pyridine groups of P1 were quaternized with DCP, accompanied by a color change from yellow to pink due to the enhancement of the intramolecular charge transfer (ICT) effect. In situ generated quaternized P1, hereafter referred to as P2, after DCP sensing was used to selectively detect ammonia via dequaternization in an aqueous medium. Ammonia detection was indicated by a color change in the solution from pink back to yellow. A surface-immobilized P1 film was prepared and employed for the vapor-phase detection of DCP, demonstrating that an amount of as low as 2 ppm was detectable. Ammonia vapor was also successfully detected by the P2 film via the ammonia-triggered removal of the quaternized phosphates. Alternating exposure of the film to DCP and ammonia resulted in the corresponding color changes, thereby demonstrating the reversibility of the system. The reusability of the polymeric film for detecting DCP and ammonia in the vapor phase was confirmed by performing four sequential colorimetric detection cycles.

Use of Core-Cross-Linked Polymeric Micelles Induced by the Selective Detection of Cu(II) Ions for the Sustained Release of a Model Drug.

A well-defined amphiphilic phenylthiosemicarbazone-based block copolymer was successfully synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization, followed by postpolymerization modification. Poly( N,N-dimethylacrylamide) (pDMA) was synthesized via RAFT polymerization of N,N-dimethylacrylamide (DMA). The resulting pDMA macrochain transfer agent was further extended using 3-vinylbenzaldehyde (VBA) to yield the poly[( N,N-dimethylacrylamide)- b-(3-vinylbenzaldehyde)] [p(DMA- b-VBA)] block copolymer. The aldehyde groups of p(DMA- b-VBA) were then made to react with 4-phenylthiosemicarbazide to yield the target block copolymer poly{ N,N-dimethylacrylamide- b-[ N-phenyl-2-(3-vinylbenzylidene)hydrazine carbothioamide]} [p(DMA- b-PVHC)]. p(DMA- b-PVHC) self-assembled in aqueous solution to yield polymeric micelles that comprise a pDMA block that forms a hydrophilic shell and a pPVHC block that forms a hydrophobic core. p(DMA- b-PVHC) micelles can detect Cu(II) ions which can be determined by a color change from colorless to yellow induced by the formation of coordination complexes between Cu(II) ions and the phenylthiosemicarbazone units of p(DMA- b-PVHC). As Cu(II) ions slowly penetrated the core of p(DMA- b-PVHC) micelles, these cores cross-linked with each other, which in turn resulted in the micelle particles swelling in water. Upon the addition of Cu(II) ions to a solution of p(DMA- b-PVHC) micelles encapsulating the hydrophobic model drug coumarin 102, this drug was released from the micelles in a sustained manner due to the gradual swelling of the cross-linked micelle cores caused by the slow penetration of Cu(II) ions.

BODIPY-Derived Polymeric Chemosensor Appended with Thiosemicarbazone Units for the Simultaneous Detection and Separation of Hg(II) Ions in Pure Aqueous Media.

Developing a simple and cheap analytical method for the selective detection and quantitative separation of toxic ions present in aqueous media is the biggest challenge faced by the chemosensing research community. Here, a 5,5-difluoro-1,3,7,9-tetramethyl-10-phenyl-5 H-dipyrrolo-diazaborinine-derived water-soluble polymer integrated with thiosemicarbazone units was rationally designed and synthesized for the simultaneous detection and separation of Hg(II) ions in pure aqueous solution. The water-soluble polymer scaffold poly( N, N'-dimethyl acrylamide- co-5,5-difluoro-1,3,7,9-tetramethyl-10-phenyl-5 H-dipyrrolo-diazaborinine-2-carbaldehyde) was synthesized by reversible addition-fragmentation chain transfer polymerization, followed by post-polymerization modification with thiosemicarbazide, leading to the formation of the target probe, P1. The nonemitting P1 exhibited bright yellow emission upon exposure to Hg(II) ions, with a limit of detection as low as 0.37 µM. This turn-on emission behavior triggered by Hg(II) ions might originate from the suppression of isomerization around the C═N bond of the thiosemicarbazone moiety caused by the formation of a coordination complex between P1 and Hg(II) ions. In addition, P1 displayed excellent selectivity toward Hg(II) ions over other metal cations. Finally, the selective removal of Hg(II) ions from an aqueous solution containing various metal ions was achieved by precipitation, which is probably caused by the fact that coordination complexes whereby Hg(II) ions acted as bridgeheads between P1 molecules had formed.

Recyclable Polymeric Thin Films for the Selective Detection and Separation of Picric Acid.

Thin-film probes have been developed for the reversible detection and separation of picric acid (PA) with extreme sensitivity in aqueous media. The free radical copolymerization of dimethylacrylamide (DMA), benzophenone acrylamide (BPAM), and glycidyl methacrylate (GMA) with a feed ratio of 95:1:4 yielded [p(DMA- co-BPAM- co-GMA)] (P1). P1 was transformed to the final polymeric probe, P2, by a subsequent ring-opening reaction between N-(pyren-1-yl-methyl)propan-1-amine (Py-PA) with the epoxide unit of P1. P2 exhibited rapid and selective sensing properties toward PA in aqueous media via turn-off fluorescence emission. The detection sensitivity was tuned precisely by varying the pH of the solution. After the immobilization of P2 on a quartz slide by spin-coating, followed by exposure to UV light, the resulting film exhibited an attogram-level detection limit toward PA. The photoinduced electron transfer together with an energy-transfer process between PA and the pyrene units of P2 were maximized by the strong π-π stacking of pyrene units of P2, which, in turn, induced rapid exciton energy diffusion. Furthermore, the separation of PA from the mixture of the various nitroaromatic compounds by the P2 film was achieved. Whereas the detection process of PA was reversible and repeatable over multiple cycles, the P2 film could be recycled.

Polymeric Micelles Based on Light-Responsive Block Copolymers for the Phototunable Detection of Mercury(II) Ions Modulated by Morphological Changes.

Polymeric micelles based on light-responsive block copolymers were prepared and used for the phototunable detection of mercury(II) ions. 2-Nitrobenzyl acrylate (NBA) and ( E)-2-((4-((4-formylphenyl)diazenyl)phenyl)(methyl)amino) ethyl acrylate (FPDEA) were copolymerized from a poly(ethylene oxide) (PEO) macroinitiator via atom transfer radical polymerization (ATRP), leading to a well-defined block copolymer of PEO113- b-[p(NBA10- co-FPDEA3)] with a low polydispersity index (PDI = 1.16). After polymerization, the aldehyde groups of PEO- b-[p(NBA- co-FPDEA)] were converted to aldoxime groups by reacting with hydroxylamine, leading to the formation of a final oxime-containing polymeric probe, PEO- b-[p(NBA- co-HPDEA)], P1. The resulting block copolymer, P1, was self-assembled in water to yield spherical micelles that consist of a PEO block forming a hydrophilic shell and a copolymer of light-responsive NBA and a mercury(II) ion-detecting HPDEA block forming a hydrophobic core. Upon the addition of mercury(II) ions to this micellar solution, no detection was observed since water-soluble mercury(II) ions have limited accessability to the oxime units of P1, which are located in the hydrophobic core. After UV light irradiation, however, the photolabile 2-nitrobenzyl moieties were cleaved, and hydrophobic PNBA was transformed to hydrophilic poly(acrylic acid) (PAA), leading to the photoinduced dissociation of micelles to unimers. As a result, the oxime units of P1 were exposed to a hydrophilic environment and could react with mercury(II) ions to form nitrile groups, resulting in the turn-on detection of mercury(II) ions by UV light irradiation.

Alumina-coated graphene nanosheet and its composite of acrylic rubber.

A graphene was coated with a thin alumina layer to prepare a novel nanosheet which had high thermal conductivity but low electrical conductivity. The nanosheet with minimal aggregation was prepared effectively by first coating it with aluminum tri-sec-butoxide in anhydrous dimethylformamide, followed by rapid calcination in an inert atmosphere after the hydrolysis of the alkoxide. The morphology observed by scanning electron microscopy and elemental mapping by energy-dispersive X-ray spectrometry showed that the alumina layer coated on the graphene surface was uniform and ultra-thin. Thermogravimetry demonstrated that the uniformly coated alumina protective layer substantially improved the thermal stability of the graphene and that the electrically-insulative alumina layer effectively reduced the electrical conductivity of the graphene. The enhanced polar nature of surface as well as the increased surface roughness due to the coated alumina improved the dispersion of the graphene in the polar acrylic rubber matrix and the interaction at the interface. This led to an effective improvement of the thermal conductivity but marginal increase in electrical conductivity by the filler. Tensile modulus increased drastically to as high as 470% for the composite reinforced with the 5 phr (about 2.5 vol%) loading of the alumina-coated graphene.

Triazole-containing hydrogels for time-dependent sustained drug release.

The purpose of this study is to develop novel triazole-containing hydrogels (TGs) as drug carrier and to investigate the sustained drug release accomplished by their time-dependent swelling behavior. The synthetic pathway of TGs includes: (1) DCC-coupling on hydroxyethyl methacrylate (HEMA) to prepare HEMA-alkyne (HA), (2) click-coupling to prepare a triazole-ring-containing monomer (TM), and (3) the synthesis of a series of TGs. The aggregation between triazole rings is found to be responsible for drug release controllability. Rhodamine 6G is studied as a model anticancer drug for release experiments. The effects of pH and temperature on the properties of sustained drug release are also studied.

Properties of Graphene/Shape Memory Thermoplastic Polyurethane Composites Actuating by Various Methods.

Shape memory behavior of crystalline shape memory polyurethane (SPU) reinforced with graphene, which utilizes melting temperature as a shape recovery temperature, was examined with various external actuating stimuli such as direct heating, resistive heating, and infrared (IR) heating. Compatibility of graphene with crystalline SPU was adjusted by altering the structure of the hard segment of the SPU, by changing the structure of the graphene, and by changing the preparation method of the graphene/SPU composite. The SPU made of aromatic 4,4'-diphenylmethane diisocyanate (MSPU) exhibited better compatibility with graphene, having an aromatic structure, compared to that made of the aliphatic hexamethylene diisocyanate. The finely dispersed graphene effectively reinforced MSPU, improved shape recovery of MSPU, and served effectively as a filler, triggering shape recovery by resistive or IR heating. Compatibility was enhanced when the graphene was modified with methanol. This improved shape recovery by direct heating, but worsened the conductivity of the composite, and consequently the efficiency of resistive heating for shape recovery also declined. Graphene modified with methanol was more effective than pristine graphene in terms of shape recovery by IR heating.

Tuning LCST with thiol-responsiveness of thermoresponsive copolymers containing pendant disulfides.

A new approach that centers on modulating the hydrophobic-hydrophilic balance by conversion of pendant disulfides to thiols and further to sulfides enables facile tuning of the thermoresponsive properties of thiol-responsive copolymers.

Activation of cholera toxin production by anaerobic respiration of trimethylamine N-oxide in Vibrio cholerae.

Vibrio cholerae is a gram-negative bacterium that causes cholera. Although the pathogenesis caused by this deadly pathogen takes place in the intestine, commonly thought to be anaerobic, anaerobiosis-induced virulence regulations are not fully elucidated. Anerobic growth of the V. cholerae strain, N16961, was promoted when trimethylamine N-oxide (TMAO) was used as an alternative electron acceptor. Strikingly, cholera toxin (CT) production was markedly induced during anaerobic TMAO respiration. N16961 mutants unable to metabolize TMAO were incapable of producing CT, suggesting a mechanistic link between anaerobic TMAO respiration and CT production. TMAO reductase is transported to the periplasm via the twin arginine transport (TAT) system. A similar defect in both anaerobic TMAO respiration and CT production was also observed in a N16961 TAT mutant. In contrast, the abilities to grow on TMAO and to produce CT were not affected in a mutant of the general secretion pathway. This suggests that V. cholerae may utilize the TAT system to secrete CT during TMAO respiration. During anaerobic growth with TMAO, N16961 cells exhibit green fluorescence when stained with 2',7'-dichlorofluorescein diacetate, a specific dye for reactive oxygen species (ROS). Furthermore, CT production was decreased in the presence of an ROS scavenger suggesting a positive role of ROS in regulating CT production. When TMAO was co-administered to infant mice infected with N16961, the mice exhibited more severe pathogenic symptoms. Together, our results reveal a novel anaerobic growth condition that stimulates V. cholerae to produce its major virulence factor.

The effect of oxidation on properties of graphene and its polycaprolactone nanocomposites.

A functionalized graphene sheet (FGS), which was prepared by the thermal reduction of graphite oxide, was modified by oxidation with H2O2. Elemental analysis, X-ray photoelectron spectroscopy, and Fourier transform infrared (FTIR) spectroscopy showed that additional oxygen functional groups, either doubly or singly bound to carbon, were created by the oxidation. The size and electrical conductivity of the FGS were reduced by the oxidation. During FGS/Polycaprolactone (PCL) nanocomposite preparation by an in situ polymerization method, PCL was grafted onto a FGS by chain growth from a functional group on FGS such as hydroxyl. Thermogravimetry and FTIR spectra demonstrated that the amount of grafted polycaprolactone (PCL) was decreased by the oxidation of FGS, suggesting that PCL chain growth from the FGS surface was inhibited by the neighboring carboxylic acid group on the FGS. Enhanced compatibility between the oxidized FGS and the PCL matrix was observed by optical microscopy and scanning electron microscopy. The reinforcing effect on tensile properties was also enhanced by the oxidized FGS in the FGS/PCL nanocomposites. This suggests that the surface coverage by the grafted PCL chains on the oxidized FGS is higher than that on a pristine FGS, although the grafted PCL chain length is shorter and the amount grafted is smaller.

Interleukin-15:Interleukin-15 receptor α scaffold for creation of multivalent targeted immune molecules.

Human interleukin-15 (hIL-15) and its receptor α (hIL-15Rα) are co-expressed in antigen presenting cells allowing trans-presentation of the cytokine to immune effector cells. We exploited the high-affinity interactions between hIL-15 and the extracellular hIL-15Rα sushi domain (hIL-15RαSu) to create a functional scaffold for the design of multispecific fusion protein complexes. Using single-chain T cell receptors (scTCRs) as recognition domains linked to the IL-15:IL-15Rα scaffold, we generated both bivalent and bispecific complexes. In these fusions, the scTCR domains retain the antigen-binding activity and the hIL-15 domain exhibits receptor binding and biological activity. As expected, bivalent scTCR fusions exhibited improved antigen binding due to increased avidity, whereas fusions comprising two different scTCR domains were capable of binding two cognate peptide/MHC complexes. Bispecific molecules containing scTCR and scCD8αß domains also exhibit enhanced binding to peptide/MHC complexes, demonstrating that the IL-15:IL-15Rα scaffold displays flexibility necessary to support multi-domain interactions with a given target. Surprisingly, functional heterodimeric molecules could be formed by co-expressing the TCR α and ß chains separately as fusions to the hIL-15 and hIL-15RαSu domains. Together, these properties indicate that the hIL-15 and hIL-15RαSu domains can be used as versatile, functional scaffold for generating novel targeted immune molecules.

Ubiquitous-severance hospital project: implementation and results.

OBJECTIVES: The purpose of this study was to review an implementation of u-Severance information system with focus on electronic hospital records (EHR) and to suggest future improvements. METHODS: Clinical Data Repository (CDR) of u-Severance involved implementing electronic medical records (EMR) as the basis of EHR and the management of individual health records. EHR were implemented with service enhancements extending to the clinical decision support system (CDSS) and expanding the knowledge base for research with a repository for clinical data and medical care information. RESULTS: The EMR system of Yonsei University Health Systems (YUHS) consists of HP integrity superdome servers using MS SQL as a database management system and MS Windows as its operating system. CONCLUSIONS: YUHS is a high-performing medical institution with regards to efficient management and customer satisfaction; however, after 5 years of implementation of u-Severance system, several limitations with regards to expandability and security have been identified.