Hasil untuk "Chemical engineering"

Eun-Kyung Lim, Taekhoon Kim, S. Paik et al.

Shaowen Cao, Jiaguo Yu

Ying Yang, M. Urban

M. Galizia, Won Seok Chi, Z. Smith et al.

Toktam Nezakati, A. Seifalian, A. Tan et al.

Research pertaining to conductive polymers has gained significant traction in recent years, and their applications range from optoelectronics to material science. For all intents and purposes, conductive polymers can be described as Nobel Prize-winning materials, given that their discoverers were awarded the Nobel Prize in Chemistry in 2000. In this review, we seek to describe the chemical forms and functionalities of the main types of conductive polymers, as well as their synthesis methods. We also present an in-depth analysis of composite conductive polymers that contain various nanomaterials such as graphene, fullerene, carbon nanotubes, and paramagnetic metal ions. Natural polymers such as collagen, chitosan, fibroin, and hydrogel that are structurally modified for them to be conductive are also briefly touched upon. Finally, we expound on the plethora of biomedical applications that harbor the potential to be revolutionized by conductive polymers, with a particular focus on tissue engineering, regenerative medicine, and biosensors.

Elbay Malikmammadov, T. E. Tanir, A. Kiziltay et al.

C. Hoyle, A. Lowe, C. Bowman

R. Jayakumar, D. Menon, K. Manzoor et al.

Tiffany Abitbol, A. Rivkin, Yifeng Cao et al.

A. Basso, S. Serban

Abstract The use of immobilized enzymes is now a routine process for the manufacture of many industrial products in the pharmaceutical, chemical and food industry. Some enzymes, such as lipases, are naturally robust and efficient, can be used for the production of many different molecules and have a wide range of industrial applications thanks to their broad selectivity. As an example, lipase from Candida antarctica (CalB) has been used by BASF to produce chiral compounds, such as the herbicide Dimethenamide-P, which was previously made chemically. The use of the immobilized enzyme has provided significant advantages over a chemical process, such as the possibility to use equimolar concentration of substrates, obtain an enantiomeric excess > 99%, use relatively low temperatures ( 1 ]. Some more specific enzymes, like transaminases, have required protein engineering to become suitable for applications in production of APIs (Active Pharmaceutical Ingredients) in conditions which are extreme for a wild type enzyme. The process developed by Merck for sitagliptin manufacture is a good example of challenging enzyme engineering applied to API manufacture. The previous process of sitagliptin involved hydrogenation of enamine at high pressure using a rhodium-based chiral catalyst. By developing an engineered transaminase, the enzymatic process was able to convert 200 g/l of prositagliptin in the final product, with e.e. >99.5% and using an immobilized enzyme in the presence of DMSO as a cosolvent [ 2 ]. For all enzymes, the possibility to be immobilized and used in a heterogeneous form brings important industrial and environmental advantages, such as simplified downstream processing or continuous process operations. Here, we present a series of large-scale applications of immobilized enzymes with benefits for the food, chemical, pharmaceutical, cosmetics and medical device industries, some of which have been scarcely reported on previously. In general, all enzymatic reactions can benefit from the immobilization, however, the final choice to use them in immobilized form depends on the economic evaluation of costs associated with their use versus benefits obtained in the process. It can be concluded that the benefits are rather significant, since the use of immobilized enzymes in industry is increasing.

S. Mitragotri, J. Lahann

Lin Yu, Jiandong Ding

Weikang Hu, Zijian Wang, Yu-Xiu Xiao et al.

Biomedical hydrogels as sole repair matrices or combined with pre-seeded cells and bioactive growth factors are extensively applied in tissue engineering and regenerative medicine. Hydrogels normally provide three dimensional structures for cell adhesion and proliferation or the controlled release of the loading of drugs or proteins. Various physiochemical properties of hydrogels endow them with distinct applications. In this review, we present the commonly used crosslinking method for hydrogel synthesis involving physical and chemical crosslinks and summarize their current progress and future perspectives.

Ng Niels Deen, V. S. Annaland, van der M.A. Hoef et al.

Min Xue, Yong Yang, Xiaodong Chi et al.

Hans Swenson, N. Stadie

The 100th anniversary of Langmuir's theory of adsorption is a significant landmark for the physical chemistry and chemical engineering communities. Despite its simplicity, the Langmuir adsorption model captures the key physics of molecular interactions at interfaces and laid the foundation for further progress in understanding interfacial phenomena, developing new adsorbent materials, and designing engineering processes. The Langmuir model has had an exceptional impact on diverse fields within the chemical sciences (ranging from chemical biology to materials science), an impact that became clearer with the development of modified adsorption theories and continues to be relevant today.

V. Aravindan, J. Gnanaraj, Yun‐Sung Lee et al.

R. Warner

CHEN Daiqi, CHEN Daiqi, YU Jing

Abstract Objective To investigate the effect and underlying mechanisms of curcumin (CUR) on small intestinal injuries associated with severe traumatic infections after combined treatment of ciprofloxacin (CIP) and indomethacin (IND). Methods Adult male C57BL/6 mice (8 weeks old) were randomly divided into (10 animals for survival rate observation, 10 for other indicators) control group, model group [hemorrhage+ fracture+Pseudomonas aeruginosa (PA) infection], IND+CIP treatment group, and IND+ CIP+CUR treatment group. The survival rates within 72 h post-modelling were observed across all groups. At 24 h post-modelling, peripheral blood samples, small intestinal tissues and mesenteric lymph nodes (MLN) were harvested. Small intestinal length, hemorrhagic status, and adhesions were also observed grossly in each group. Bacterial load was determined via dilute plating. HE staining was used to observe histopathological alterations in intestinal tissues across groups. ELISA was employed to measure the contents of inflammatory cytokines, IL-1β, IL-6, IL-10 and TNF-α in the serum and small intestinal homogenate of each group. Liver, renal, and cardiac functions were evaluated by measuring key biochemical indicators. Flow cytometry was applied to measure the percentages of IFN-γ, IL-4, TGF-β, and IL-17 positive cells within CD4+ T cells in the MLN. Real-time quantitative polymerase chain reaction (qPCR) was performed to detect the mRNA expression of forkhead box protein P3 (FOXP3) and retinoic acid receptor-related orphan receptor gamma (RORγ)-t in each group. Results Both the IND+CIP treatment group and the IND+CIP+CUR treatment group significantly improved survival rates in mice with severe traumatic infections (P<0.05). CUR addition reduced bacterial load in the mice (P<0.01). The IND+CIP treatment group exhibited small intestinal injury, which worsened over time, manifested by elevated contents of TNF-α (P<0.01), IL-6 (P<0.05), and IL-1β (P<0.05) and decreased IL-10 (P<0.01) in the small intestine tissues, accompanied with pathological damage in the small intestine. The IND+CIP+CUR treatment group had significantly reversed small intestinal injury, reduced inflammatory factor levels (P<0.01), and restored normal small intestinal structure, showing no significant differences in relevant blood biochemical indicators when compared to the IND+CIP treatment group. The expression of FOXP3 was increased and that of RORγ-t was decreased in CD4+ T cells from the IND+CIP+CUR treatment group than the IND+CIP treatment group (both P<0.01). Conclusion The combination of CUR with IND and CIP can effectively alleviate severe traumatic infections, while antagonize small intestinal damage observed in IND and CIP therapy, with no significant adverse effects on vital organ functions. This mechanism may be related to the balance between regulatory T (Treg) cells and T helper 17 (Th17) cells.

Jianan He, Joshua D. Butson, Ruijia Gu et al.

Abstract MXenes, a novel member of the 2D material family, shows promising potential in stabilizing isolated atoms and maximizing the atom utilization efficiency for catalytic applications. This review focuses on the role of MXenes as support for single‐atom catalysts (SACs) for various electrochemical reactions, namely the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), oxygen reduction reaction (ORR), carbon dioxide reduction reaction (CO2RR), and nitrogen reduction reaction (NRR). First, state‐of‐the‐art characterization and synthesis methods of MXenes and MXene‐supported SACs are discussed, highlighting how the unique structure and tunable functional groups enhance the catalytic performance of pristine MXenes and contribute to stabilizing SAs. Then, recent studies of MXene‐supported SACs in different electrocatalytic areas are examined, including experimental and theoretical studies. Finally, this review discusses the challenges and outlook of the utilization of MXene‐supported SACs in the field of electrocatalysis.