Chronic Inflammatory Demyelinating Polyneuropathy (CIDP): Overview, Treatment, and a Case Study.

Chronic inflammatory demyelinating polyneuropathy (CIDP) is an uncommon immune-mediated neuropathy with an often unknown etiology. Patients typically present with gradual muscle weakness, sensory loss, and reduced deep tendon reflexes. Diagnostic challenges persist due to the absence of specific lab findings and definitive criteria. Treatment commonly involves glucocorticoids, IVIG, or plasma exchange, with varied long-term outcomes. We aim to elucidate the diagnostic complexities and treatment modalities associated with chronic CIDP through a comprehensive review of a patient's clinical presentation, diagnostic work-up, and therapeutic interventions. A 70-year-old female with a complex medical history, including dermatomyositis and IgG subclass deficiency, presented with progressive lower extremity weakness and numbness. Initial workup including MRI and CT scans were inconclusive. She was diagnosed with CIDP based on electromyography (EMG)/nerve conduction studies and cerebrospinal fluid (CSF) analysis. Plasma exchange (PLEX) treatment was initiated but led to multifocal cerebral infarcts, complicating her course. Subsequent rounds of PLEX alongside dual antiplatelet therapy showed no adverse neurological events and yielded minimal to moderate improvement in her mobility. The patient was discharged to an inpatient rehabilitation center for continued care. Elevated WBCs and other abnormal lab results were monitored throughout, underscoring the need for a multidisciplinary approach in complex cases like this one. Our comprehensive overview of CIDP and its diagnostic and treatment complexities underscores the challenges clinicians face in both accurate diagnosis and effective management. The multifaceted approach - spanning history-taking, electrodiagnostic studies, and advanced imaging - highlights the necessity for a nuanced, evidence-based practice. The variability in treatment outcomes emphasizes the need for personalized medicine and continuous research to optimize therapeutic strategies. Given the inconclusive nature of some diagnostic tools and the variable treatment responses, there remains a clear need for ongoing study and long-term follow-up to further refine our understanding and management of CIDP.

A Genome-Wide Identification and Expression Pattern of LMCO Gene Family from Turnip (Brassica rapa L.) under Various Abiotic Stresses.

Laccase-like multi-copper oxidases (LMCOs) are a group of enzymes involved in the oxidation of numerous substrates. Recently, these enzymes have become extremely popular due to their practical applications in various fields of biology. LMCOs generally oxidize various substrates by linking four-electron reduction of the final acceptor, molecular oxygen (O2), to water. Multi-copper oxidases related to laccase are extensively distributed as multi-gene families in the genome sequences of higher plants. The current study thoroughly investigated the LMCO gene family (Br-Lac) and its expression pattern under various abiotic stresses in B. rapa L. A total of 18 Br-Lac gene family members located on five different chromosomes were identified. Phylogenetic analysis classified the documented Br-Lac genes into seven groups: Group-I (four genes), Group-II (nine genes), Group-III (eight genes), Group-IV (four genes), Group-V (six genes), and Group-VI and Group-VII (one gene each). The key features of gene structure and responsive motifs shared the utmost resemblance within the same groups. Additionally, a divergence study also assessed the evolutionary features of Br-Lac genes. The anticipated period of divergence ranged from 12.365 to 39.250 MYA (million years ago). We also identified the pivotal role of the 18 documented members of the LMCO (Br-lac) gene family using quantitative real-time qRT-PCR. Br-Lac-6, Br-Lac-7, Br-Lac-8, Br-Lac-16, Br-Lac-17, and Br-Lac-22 responded positively to abiotic stresses (i.e., drought, heat, and salinity). These findings set the stage for the functional diversity of the LMCO genes in B. rapa.

Species distribution modelling of Monotheca buxifolia (Falc.) A. DC.: Present distribution and impacts of potential climate change.

Species distribution modelling (SDM) is an important tool to examine the possible change in the population range and/or niche-shift under current environment and predicted climate change. Monotheca buxifolia is an economically and ecologically important tree species inhabiting Pakistan and Afghanistan in dense patches, and species range is contracting rapidly. This study hypothesize that predicted climate change might remarkably influence the existing distribution pattern of M. buxifolia in the study area. A total of 75 occurrence locations were identified comprising M. buxifolia as a dominant tree species. The Maximum Entropy (MaxEnt) algorithm was utilized to perform the SDM under current (the 1970s-2000s) and two future climate change scenarios (shared socioeconomic pathways: SSPs 245 and 585) of two time periods (the 2050s and 2070s). The optimal model settings were assessed, and simulation precision was assessed by examining the partial area under the receiver operating characteristic curve (pAUC-ROC). The results showed that out of 39 considered bio-climatic, topographic, edaphic, and remote sensing variables which were utilized in the preliminary model, 6 variables including precipitation of warmest quarter, topographic diversity, global human modification of terrestrial land, normalized difference vegetation index, isothermality, and elevation (in order) were the most influential drivers, and utilized in all reduced SDMs. A high predictive performance (pAUC-ROC; >0.9) of all the considered SDMs was recorded. A total of about 67,684 km2 of geographical area was predicted as suitable habitat (p > 0.8) for M. buxifolia, and Pakistan is the leading country (with about 54,975 km2 of suitable land area) under the current climate scenario. Overall, the existing distribution of the tree species in the study area might face considerable loss (i.e. rate of change %; -27 to -107) in future, and simultaneously a northward (high elevation) niche shift is predicted for all the considered future climate change scenarios. Hence, development and implementation of a coordinated conservation program is required on priority basis to save the tree species in its native geographic range.

Assessment of variability in nutritional quality of wild edible fruit of Monotheca buxifolia (Falc.) A. DC. Along the altitudinal gradient in Pakistan.

The fruit of Monotheca buxifolia is among the underutilized wild edible fruits that grows in Hindukush and Suleiman range mountains of Pakistan. Mountain communities consume this wild fruit as a food, medicine and it provides an important source of income. In this study, we aimed to investigate the total yield and the effect that altitude plays on its proximate composition and mineral contents as determined through phytochemical screening of this economically important wild fruit. Our results indicate a significant increase in the total fruit yield with increasing trunk diameter (R2 = 0.98), height (R2 = 0.95) and cover (R2 = 0.92). The proximate composition shows that the crude fat and carbohydrate contents of Monotheca fruit significantly varies (P < 0.05) along the altitudinal gradient. Similarly, ANOVA followed by post hoc Tukey HSD, further confirms the variation (P < 0.01) in moisture contents of the fruit. Dry matter ranged from 95.28 ± 4.64 to 108 ± 3.70 g kg- 1 of the fruit's edible portion, while protein contents varied between 17.16 % and 20.44 %. The fruits were found to be rich in minerals containing sizeable amounts of potassium, iron, phosphorus, sodium, nitrogen, magnesium, and copper. Significant difference was observed in the nitrogen (P < 0.01), potassium (P < 0.05) and sodium (P < 0.05) contents of the fruit along the altitudinal gradient. Similarly, tannins, flavonoids, saponins, reducing sugars, terpenoids, anthraquinones, and cardiac glycosides, were the most prominent chemicals found in Monotheca fruit. It was concluded that Monotheca fruit is a good source of carbohydrates, proteins, macro and micro-nutrients which fluctuated along the altitudinal gradient.

Ecosystem Services and Linkages of Naturally Managed Monotheca buxifolia (Falc.) A. DC. Forests with Local Communities across Contiguous Mountainous Ranges in Pakistan.

The local community of the Suleiman and Hindukush mountain systems in Pakistan has largely depended on the natural resources of the environment since ancient times. The ecosystem of these regions is under huge pressure due to a lack of awareness and the uncontrolled interference of communal, commercial, security, political, and ecological conditions. The present study was designed to illuminate the link between mountain society and the consumption of the benefits from Monotheca phytocoenoses using the ecosystem services concept from the sphere of the socio-ecological system to cultural relations. The use of this approach is very important due to the visible role and dominant status of Monotheca vegetation within the ecological system of the region. M. buxifolia is strongly connected with both local and cultural traditions and is counted as a key species, particularly for high-mountain inhabitants. We report that Monotheca phytocoenoses provide several services including shelter, food, fodder, medicines, and wood, etc., to the indigenous community and is highly valued in the local culture because of the poor economic condition of the society. The concept of this cultural keystone species is crucial for understanding ecosystem services and must be considered for the protection and conservation of these habitats. The results of field and social studies have shown that the stable maintenance of Monotheca phytocoenosis forests ensures the existence of key species as the most important providers of ecosystem services, e.g., provisioning, regulation, maintenance and cultural services, indicating the close relations between society and the protection of mountain areas. According to the results obtained, the mountains community of the studied area believes that tree species like M. buxifolia, F. palmata, O. ferruginea, P. granatum, A. modesta, J. regia, etc., are the key components contributing to the function of both the mountain ecosystem and communities' well-being. This approach will be extremely useful for ensuring an inclusive management of the socio-ecological system of the Hindukush and Suleiman Mountain ranges of Pakistan.

Emerging Fabrication Strategies of Hydrogels and Its Applications.

Recently, hydrogels have been investigated for the controlled release of bioactive molecules, such as for living cell encapsulation and matrices. Due to their remote controllability and quick response, hydrogels are widely used for various applications, including drug delivery. The rate and extent to which the drugs reach their targets are highly dependent on the carriers used in drug delivery systems; therefore the demand for biodegradable and intelligent carriers is progressively increasing. The biodegradable nature of hydrogel has created much interest for its use in drug delivery systems. The first part of this review focuses on emerging fabrication strategies of hydrogel, including physical and chemical cross-linking, as well as radiation cross-linking. The second part describes the applications of hydrogels in various fields, including drug delivery systems. In the end, an overview of the application of hydrogels prepared from several natural polymers in drug delivery is presented.

A Therapeutic Journey of Potential Drugs Against COVID-19.

Coronavirus disease (CoVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) scrambles the world by infecting millions of peoples all over the globe. It has caused tremendous morbidity, mortality and greatly impacted the lives and economy worldwide as an outcome of mandatory quarantines or isolations. Despite the worsening trends of COVID-19, no drugs are validated to have significant efficacy in the clinical treatment of COVID-19 patients in large-scale studies. Physicians and researchers throughout the world are working to understand the pathophysiology to expose the conceivable handling regimens and to determine the effective vaccines and/or therapeutic agents. Some of them re-purposed drugs for clinical trials which were primarily known to be effective against the RNA viruses including MERS-CoV and SARS-CoV-1. In the absence of a proven efficacy therapy, the current management use therapies based on antivirals, anti-inflammatory drugs, convalescent plasma, anti-parasitic agents in both oral and parenteral formulation, oxygen therapy, and heparin support. What is needed at this hour, however, is a definitive drug therapy or vaccine. Different countries are rushing to find this, and various trials are already underway. We aimed to summarize the potential therapeutic strategies as treatment options for COVID-19 that could be helpful to stop further spread of SARS-CoV-2 by affecting its structural components or modulation of immune response and discuss the leading drugs/vaccines, which are considered as potential agents for controlling this pandemic.

Recent progress in the development of potential drugs against SARS-CoV-2.

SARS-CoV-2, a newly emerged and highly pathogenic coronavirus, is identified as the causal agent of Coronavirus Disease (2019) (COVID-19) in the late December 2019, in China. The virus has rapidly spread nationwide and spilled over to the other countries around the globe, resulting in more than 120 million infections and 2.6 million deaths until the time of this review. Unfortunately, there are still no specific drugs available against this disease, and it is very necessary to call upon more scientists to work together to stop a further spread. Hence, the recent progress in the development of drugs may help scientific community quickly understand current research status and further develop new effective drugs. Herein, we summarize the cellular entry and replication process of this virus and discuss the recent development of potential viral based drugs that target bio-macromolecules in different stages of the viral life cycle, especially S protein, 3CLPro, PLPro, RdRp and helicase.

Synthesis and Coordination Properties of a Water-Soluble Material by Cross-Linking Low Molecular Weight Polyethyleneimine with Armed Cyclotriveratrilene.

In this study, a full organic and water-soluble material was synthesized by coupling low molecular weight polyethylenimine (PEI-800) with cyclotriveratrilene (CTV). The water-soluble cross-linked polymer contains hydrophobic holes with a high coordination capability towards different organic drug molecules. The coordinating capability towards hydrophilic drugs (doxorubicin, gatifloxacin and sinomenine) and hydrophobic drugs (camptothecin and celastrol) was analyzed in an aqueous medium by using NMR, UV-Vis and emission spectroscopies. The coordination of drug molecules with the armed CTV unit through hydrophobic interactions was observed. In particular, celastrol exhibited more ionic interactions with the PEI moiety of the hosting system. In the case of doxorubicin, the host-guest detachment was induced by the addition of ammonium chloride, suggesting that the intracellular environment can facilitate the release of the drug molecules.

N-Aryl-3,4-dihydroisoquinoline Carbothioamide Analogues as Potential Urease Inhibitors.

N-Aryl-3,4-dihydroisoquinoline carbothioamide analogues 1-22 were synthesized by a simple one-step reaction protocol and subjected to in vitro urease inhibition studies for the first time. All compounds 1-22 were found active and showed significant to moderate urease inhibitory potential. Specifically, analogues 1, 2, 4, and 7 were identified to be more potent (IC50 = 11.2 ± 0.81-20.4 ± 0.22 µM) than the standard thiourea (IC50 = 21.7 ± 0.34 µM). The structure-activity relationship showed that compounds bearing electron-donating groups showed superior activity. Molecular docking study on the most active derivatives revealed a good protein-ligand interaction profile against the corresponding target with key interactions, including hydrogen bonding, hydrophobic, and π-anion interactions.

Eggshell membranes coated chitosan decorated with metal nanoparticles for the catalytic reduction of organic contaminates.

This study focusses on the effect of chitosan coating with eggshell membranes for the reduction of different organic pollutants. Chickens eggs were collected from the local market and utilized to extract the enrich eggshell membranes (ESM). The chicken eggshell membranes are abundant waste material which is inexpensive and illustrates remarkable physiognomies for many possible applications. Fresh fibers/strips coated by chitosan (CS) were prepared by mixing the eggshell membranes with CS solution (2 wt%/v) in different proportions i.e., 10 %, 30 %, 50 %, 60 %, 70 %, 80 %, and 90 %. These strips were then templated with copper and iron metal nanoparticles by putting them in their metal ions aqueous solution to adsorb the metals ions and were then reduced to zero-valent metal nanoparticles (MNPS) by using NaBH4 aqueous solution. These prepared materials (MNPS@ESM-CS) were characterized by using XRD, XPS, FE-SEM, and EDS to confirm the successful preparation of MNPs over the surface of ESM coated with CS. Afterwards, these prepared materials were investigated as a catalyst for the reduction of different organic pollutants, such as 4-nitroaniline (4-NA), 4-nitrophenol (4-NP) and methylene blue (MB) dye. The catalytic efficiency of ESM was enhanced 5.7-fold by adding only 20 % CS solution. It was observed that Cu@ESM-CS-80 % took 7 min for reduction of 4-NA, 6 min for 4-NP, and 7 min for MB dye. The reusability of the catalytic strip was also investigated for four cycles and found efficient and can be easily recovered by simply pulling it from the reaction mixture.

Insights into uptake, accumulation, and subcellular distribution of selenium among eight wheat (Triticum aestivum L.) cultivars supplied with selenite and selenate.

Selenium (Se)-enriched wheat can be improved by altering Se sources and selecting wheat cultivars. Such improvement can affect subcellular distribution and speciation of Se in wheat. Thus, a pot experiment was conducted to investigate Se uptake and distribution when Se was applied as selenite or selenate at low and high rates (1 and 10 mg kg-1, respectively). Moreover, Se's impact on the grain and biomass yield of eight wheat cultivars was also investigated. The subcellular distribution and speciation of Se were also explored to elucidate Se metabolism and micro-distribution pattern in wheat. Results showed that biomass and grain yield were decreased with the application of both selenite and selenate in almost all the cultivars, regardless of the Se rate. Application high Se rate resulted in a significant (p < 0.05) decrease in grain yield and biomass compared with low rate of Se. Compared with the low rate of selenite application, the grain and the biomass yield of ZM-9023 significantly (p < 0.05) increased by about 15% for low rate of selenate application. In addition, both selenite and selenate treatment increased the uptake of Se in each part of wheat, compared with the control. Selenium was mostly accumulated in the grain and root of wheat under selenite treatment, while more Se accumulation was found in leaves and straw for selenate application. Further investigation on the subcellular distribution of Se showed that the proportion of Se in soluble fraction was significantly (p < 0.05) higher in wheat leaves than that in organelle fraction and cell walls (46%-66%). Meanwhile, Se6+ was the main species found in soluble fraction, whereas SeMet and MeSeCys were the species predominantly stored in organelle fraction. In conclusion, wheat cultivar ZM-9023 is the most Se-rich potential cultivar, and the isolation of Se in the soluble fraction plays an important role in Se tolerance and accumulation.

Boron Chemistry for Medical Applications.

Boron compounds now have many applications in a number of fields, including Medicinal Chemistry. Although the uses of boron compounds in pharmacological science have been recognized several decades ago, surprisingly few are found in pharmaceutical drugs. The boron-containing compounds epitomize a new class for medicinal chemists to use in their drug designs. Carboranes are a class of organometallic compounds containing carbon (C), boron (B), and hydrogen (H) and are the most widely studied boron compounds in medicinal chemistry. Additionally, other boron-based compounds are of great interest, such as dodecaborate anions, metallacarboranes and metallaboranes. The boron neutron capture therapy (BNCT) has been utilized for cancer treatment from last decade, where chemotherapy and radiation have their own shortcomings. However, the improvement in the already existing (BPA and/or BSH) localized delivery agents or new tumor-targeted compounds are required before realizing the full clinical potential of BNCT. The work outlined in this short review addresses the advancements in boron containing compounds. Here, we have focused on the possible clinical implications of the new and improved boron-based biologically active compounds for BNCT that are reported to have in vivo and/or in vitro efficacy.

Lignocellulosic biomass supported metal nanoparticles for the catalytic reduction of organic pollutants.

Lignocellulosic biomass waste is a cheap, eco-friendly, and sustainable raw material for a wide array of applications. In the present study, an easy, fast, and economically feasible route has been proposed for the preparation of different zero-valent metal nanoparticles (ZV-MNPs) based on Cu, Co, Ag, and Ni NPs using empty fruit bunch (EFB) biomass residue as support material. The catalytic efficiency of ZV-MNPs/EFB catalyst was investigated against five model pollutants, such as methyl orange (MO), congo red (CR), methylene blue (MB), acridine orange (AO), and 4-nitrophenol (4-NP) using NaBH4 as a source of hydrogen and electron. Comparative study revealed that among as-prepared ZV-MNPs/EFB catalysts, Cu-NPs immobilized onto EFB (Cu/EFB) exhibited maximum catalytic efficiency towards pollutant abasement. Degradation reactions were highly efficient, and were completed within a short time (4 min) in case of MO, CR, and MB, whilst AO and 4-NP were reduced in less than 15 min. Kinetic investigation revealed that the degradation rate of model pollutants accorded with pseudo-first order model. Furthermore, supported catalysts were easily recovered after the completion of experiment by simply pulling the catalyst from reaction system. Recyclability tests performed on Cu/EFB revealed that more than 97% of the reduction was achieved in case of MO dye for four successive cycles of reuse. The as-prepared heterostructure showed multifunctional properties, such as enhanced uptake of contaminants, high catalytic efficiency, and easy recovery, hence, offers great prospects in wastewater purification.

Understanding boosting selenium accumulation in Wheat (Triticum aestivum L.) following foliar selenium application at different stages, forms, and doses.

There are a lack of systematic studies comparing the effects of foliar-applied selenium (Se) with different Se sources at different growth stages in wheat. Herein, we biofortified wheat via the foliar application of selenite and selenate at different rates and different stages under field conditions. Results showed that foliar-applied selenate and selenite had no significant effect either on wheat biomass or grain yield (p < 0.05). Selenium distribution in different parts of wheat plant ranked decrease as leaf > root > grain > glume > stem with selenite treatment, and it appeared in the decline order as leaf > grain > glume > stem > root with selenate treatment. These results suggested that biofortification with selenate caused, relatively to selenite, a higher accumulation of Se in grains. Foliar application of Se of either selenate or selenite at pre-filling stage was superior in improving the Se concentration of wheat grains than application at pre-flowering stage. Meanwhile, organic Se comprised about 72-93% of total Se in wheat grains, which was reduced by 5.8% at high Se rate (100 g ha-1), irrespective of the forms of Se or stages applied. The organic Se proportion in wheat grains was 9% higher with the selenate treatment than with the selenite treatment. Selenomethionine (SeMet) was the main organic species (67-86%) in wheat grains, followed by selenocysteine (SeCys2). In summary, our results indicate that Se biofortification of wheat is most effective with 20 g ha-1 selenate foliar-applied at pre-filling stage.

Chitosan-coated polyurethane sponge supported metal nanoparticles for catalytic reduction of organic pollutants.

In this research work, polyurethane sponge (PUS) is used as a readily removable substrate for the synthesis of different nanoparticles on the surface and its use in reducing toxic dyes. An aqueous solution of 0.5 wt% chitosan (CH) was coated on PUS to prepare an ionophilic CH-PUS material. The CH-PUS pieces were then kept in 0.05 M concentration of four different salt solutions. After absorbing the metal ions for a 4 h time period, the CH-PUS pieces were treated with 0.2 M NaBH4 solution to convert the adsorbed ions to the analogous metal nanoparticles. The bare PUS, CH-PUS and M/CH-PUS were analyzed by various spectroscopic techniques. After catalytic testing of different M/CH-PUS under similar conditions using a model reaction of 4-nitrophenol (4-NP) reduction by NaBH4, we found that Cu/CH-PUS outperformed among the other M/CH-PUS. The Cu/CH-PUS catalyzed the 4-NP reduction with the fastest reaction rate constant of 0.7923 min-1. We also tested with different factors affecting the reaction rate constant such as different weights of catalyst, various concentrations of 4-NP and NaBH4. Lastly, after testing Cu/CH-PUS catalyst for the reduction of different dyes, its high performance was observed for the congo red dye.

Copper nanoparticles embedded chitosan for efficient detection and reduction of nitroaniline.

In this study, we proficiently designed metal nanoparticles embedded in chitosan biopolymeric matrices, which have the ability to be employed simultaneously for the recognition and complete reduction of 4-nitroaniline. Copper nanoparticles embedded chitosan (CuNPs-CH) were coated on glassy carbon electrode to design an efficient electrochemical sensor for 4-nitroaniline. The sensing ability of CuNPs-CH modified electrode toward 4-nitroaniline was assessed by cyclic voltammetry, amperometry and chronoamperometry at working potential of -0.76 V and pH 7.0, while the complete reduction of 4-nitroaniline was analyzed by UV-visible spectrophotometer. The sensing features of CuNPs-CH modified electrode include a sensitivity of -8.166 µA mM-1 cm-2, and detection limit of 0.37 µM. The catalytic ability of CuNPs-CH for 4-nitroaniline reduction reaction was investigated. The results displayed that 4-nitroaniline completely transformed to diaminobenzene in short contact time with a rate constant of 7.51 × 10-3 s-1. The reduction aptitude of CuNPs-CH was also examined toward 4-nitrophenol and rhodamine B; however, the designed system was more efficient toward 4-nitroaniline. The developed approach offered a new methodology for simultaneous detection and reduction of 4-nitroaniline simply for environmental safety purposes.

Chitosan nanocomposite fibers supported copper nanoparticles based perceptive sensor and active catalyst for nitrophenol in real water.

In this report, copper nanoparticles templated at chitosan-coated graphene oxide (GO) nanocomposite fibers (Cu@CH + GO) were prepared via solution-based fiber formation followed by treatment with a metal salt solution and NaBH4 and utilized for the detection and catalytic reduction of 4-nitrophenol (4-NP). Cu@CH + GO exhibited a high sensitivity of 1.729 ± 0.027 µAmM-1 cm-2 and a detection limit of 3.5 mM toward 4-NP. In addition, high catalytic activity was observed for the reduction of 4-NP with an apparent rate constant of 1.310 ± 0.093 min-1 using 7 mg of Cu@CH + GO catalyst. Besides the good catalytic activities of Cu@CH + GO, it could be easily recovered by simply pulling the fiber from the reaction medium. Moreover, Cu@CH + GO catalyst was also examined in real samples and found to be efficient in the detection and reduction of 4-NP. This novel approach provides a new route for simultaneous detection and reduction of 4-NP and can be a time and cost-effective tool for environmental safety.

Chitosan-titanium oxide fibers supported zero-valent nanoparticles: Highly efficient and easily retrievable catalyst for the removal of organic pollutants.

Different chitosan-titanium oxide (CS-TiO2-x, with x = TiO2 loadings of 1, 5, 10,15 and 20 wt%) nanocomposite fibers were prepared and kept separately in each salt solution of CuSO4, CoNO3, AgNO3 and NiSO4 to adsorb Cu2+, Co2+, Ag+, and Ni+ ions, respectively. The metal ions loaded onto CS-TiO2 fibers were reduced to their respective zero-valent metal nanoparticles (ZV-MNPs) like Cu0, Co0, Ag0 and Ni0 by treating with NaBH4. The CS-TiO2 fibers templated with various ZV-MNPs were characterized and investigated for their catalytic efficiency. Among all prepared ZV-MNPs, Cu0 nanoparticles templated on CS-TiO2-15 fibers exhibited high catalytic efficiency for the reduction of dyes (methyl orange (MO), congo red (CR), methylene blue (MB) and acridine orange (AO)) and nitrophenols (4-nitrohphenol (4-NP), 2-nitrophenol (2-NP), 3-nitrophenol (3-NP) and 2,6-dinitrophenol (2,6-DNP)). Besides the good catalytic activities of Cu/CS-TiO2-15 fibers, it could be easily recovered by simply pulling the fiber from the reaction medium.

Synthesis and characterization of metal nanoparticles templated chitosan-SiO2 catalyst for the reduction of nitrophenols and dyes.

Different metal nanoparticles (MNPs) templated on chitosan-silica (CH-SiO2) nanocomposite fiber were prepared via simple and fast method of the metal ions uptake by fiber and their subseqent reduction using strong reducing agent. The performance difference of CH-SiO2 templated with Cu, Co, Ag and Ni nanoparticles for both reduction of 4-nitroaniline (4-NA) and decolorization of congo red (CR) was investigated. The Cu nanoparticles loaded CH-SiO2 (Cu/CH-SiO2), showed high catalytic efficiencies in the reduction of 4-NA and CR, as compared to other loaded MNP fibers. The apparent rate constants of 6.17 × 10-3 s-1 and 1.68 × 10-2 s-1 and turnover frequencies (TOF) of 4.693 h-1 and 3.965 h-1 were observed for the reduction of 4-NA and CR, respectively. In addition, the catalytic activity of Cu/CH-SiO2 catalyst was also examined and found efficient in the reduction of nitrophenols (2-NP, 3-NP and 4-NP), and other dyes. Thus, Cu/CH-SiO2 with excellent catalytic activity can also be employed for other applications.