Colloidal Solution Research Articles

Effect of crystalloidsolution co-loading infusion rate on the dose requirements of prophylactic phenylephrine for preventing hypotension following combined spinal-epidural anesthesia for cesarean delivery.

Intravenous fluid administration and prophylactic vasopressor infusion are the primary methods for preventing spinal anesthesia-induced hypotension during cesarean delivery. However, evidence regarding the impact of different volumes of crystalloid solution on the phenylephrine infusion dosage for preventing this hypotension remains inconclusive. This study aimed to determine the effect of two IV fluid infusion rates (10 or 20 mL/kg/h) on phenylephrine requirement for preventing spinal anesthesia-induced hypotension. Eighty healthy parturients undergoing elective cesarean delivery under combined spinal-epidural anesthesia were enrolled. Participants were randomly assigned to receive either 10 mL/kg/h (group 10) or 20 mL/kg/h (group 20) of lactated Ringer's solution. The first patient in each group received 0.5µg/kg/min of phenylephrine infusion immediately after intrathecal injection. The phenylephrine dose in subsequent patients was adjusted by increments or decrements of 0.05µg/kg/min based on the previous patient's response. The ED50 of phenylephrine infusion for preventing spinal-induced hypotension for cesarean delivery was estimated using a modified up-down sequential analysis, with probit analysis applied as a backup sensitivity analysis. The ED50 values for preventing spinal anesthesia-induced hypotension were 0.30µg/kg/min (95% CI, 0.29-0.32µg/kg/min) for group 10, and 0.19µg/kg/min (95% CI, 0.16-0.22µg/kg/min) for group 20, respectively. The estimated relative potency for phenylephrine in group 10 compared to group 20 was 1.52 (95%CI, 1.24-1.97), showing a significant difference in the ED50 values between the two groups. This study found that a higher crystalloid co-loading rate significantly reduces prophylactic phenylephrine requirement for preventing spinal anesthesia induced hypotension. https://www.chictr.org.cn/showproj.html?proj=125918 (Trial number: ChiCTR2100048002).

The Efficacy of Andexanet Alfa for the Reversal of Factor Xa Inhibitors Is Not Influenced by Hemodilution with Different Volume Expanders

Background: Andexanet alfa is a specific antidote for factor Xa (FXa) inhibitors. It is licensed to treat patients under FXa inhibitor therapy with life-threatening bleeding. Concomitantly, volume expanders are used to compensate for blood loss and maintain circulation. The competitive binding of andexanet to FXa inhibitors may be disrupted due to hemodilution, as shown by laboratory assays with high sample dilution. This study investigated the efficacy of andexanet for the reversal of FXa inhibitors under hemodilution. Methods: Blood from 10 healthy volunteers was anticoagulated with rivaroxaban and subsequently treated with four different volume expanders (Ringer’s solution, 4% gelatine, 5% and 20% human albumin (HA)) at two dilution levels (20% and 50%). After anticoagulation and hemodilution, andexanet was added according to the high-dose protocol. Blood samples were analyzed using a Russell’s viper venom (RVV) test on a Clot Pro® device, a thrombin generation assay, a fully automated coagulation analyzer and a chromogenic anti-FXa activity assay. Results: After anticoagulation, the median rivaroxaban concentration was 272 ng/mL (IQR 254–353). Anticoagulation with rivaroxaban caused a significant impairment of all coagulation parameters, which was further aggravated by hemodilution. After the administration of andexanet, coagulation parameters in anticoagulated samples were reversed to near baseline in all groups. Andexanet administration decreased the rivaroxaban plasma concentration in all groups to a median of <10 ng/mL. In the anticoagulated, non-hemodiluted samples, anti-FXa activity was reduced by 98%. The anti-FXa activity in the anticoagulated, hemodiluted samples was reduced by approximately 96% in the 20% diluted samples and by about 93% in the 50% diluted samples. Conclusions: Our data indicate that FXa inhibitor reversal with andexanet is about 5% less effective with 50% hemodilution than in non-hemodiluted samples.

Solid-state solvatochromism of oxazolidine in multi-functionalized copolymer nanoparticles: Development of advanced materials with multi-color fluorescence

Investigating the solvatochromism of stimuli-chromic compounds such as oxazolidine in polymer matrices with various polarities or functionalities is a unique approach to developing advanced materials for anticounterfeiting, sensor, optoelectronic, and displayers. In a novel strategy, multi-functionalized copolymer nanoparticles were synthesized by copolymerization of methyl methacrylate (MMA) with various functional comonomers in emulsion media for post-polymerization modification with oxazolidine and investigation of its solvatochromism in both colloidal solution and solid phase. The particle size and morphology of nanoparticles were influenced significantly by the polarity of functional groups, and the morphology evolution from sphere to anisotropic shapes was observed by increasing the polarity of functional groups. Investigation of oxazolidine solvatochromism in colloidal solution and solid polymer powders indicated different mechanisms for solvatochromism, in which the polarity of media is the main effective parameter in colloidal solution and the polarity of functional groups in the polymer structure is the main effective parameter in solid polymer phase. The solvatochromism of oxazolidine was confirmed by observed red shift and blue shift in UV–Vis and fluorescence spectra, in which the intensity of absorbance and emission peaks was changed as a function of the polarity of functional groups. Solvatochromic photoluminescent polymer nanoparticles were used for several advanced applications such as solid anticounterfeiting inks to information encryption, dual-mode visualization of latent fingerprints, and also development of organic light-emitting diodes (OLEDs). For the first time, the results indicate a significant effect of polymer chain local polarity induced by functional groups on the tuning of optical properties of the oxazolidine by the solid-state solvatochromic phenomenon. Solvatochromism of oxazolidine in functionalized polymer nanoparticles is an interesting approach to developing novel intelligent materials that have advanced applications in different fields such as anticounterfeiting and information encryption, optoelectronic, polarity sensor, and visualization of latent fingerprints.

Optical absorption studies of pulsed-laser-engineered silver nanospheres and their enhanced catalytic performance in the degradation of toxic methylene blue dye

Pulsed laser ablation in liquid is an environment-friendly and one of the fastest physical routes to synthesize surfactant-free and stable metal/metal oxide nanoparticles with high purity and no harmful residues. In this study, we report the synthesis of silver nanospheres (AgNSs) using the nanosecond pulsed laser ablation in liquid (PLAL) technique resulting in the formation of a colloidal solution. Investigation of the optical properties using UV–Vis spectroscopy revealed the effects of laser wavelength, frequency, fluence, ablation time, and re-irradiation on the light absorption of the produced silver nanospheres. Physicochemical characterizations included FE-SEM, XRD, DLS, FTIR, and XPS techniques to evaluate the size, morphology, crystal structure, size distribution, zeta potential, and surface chemistry. FE-SEM studies revealed the formation of well-dispersed spherical Ag nanospheres with an average particle size of 209 nm without any agglomeration. DLS measurements showed high stability with a recorded zeta potential value of −38.27 (+/−1.81) mV and a wider size distribution. The XRD analysis indicated a face-centered cubic crystal structure with the formation of an oxide layer over the metallic silver core. The presence of silver and oxygen was confirmed through XPS studies with binding energies at 368.1 eV and 374.1 eV and oxide formation on the surface of Ag NSs. Finally, the catalytic activity of the Ag colloid was examined for the degradation of the toxic methylene blue dye. The results revealed an excellent catalytic response with 90 % of the dye degraded in just 15 min of reaction time. The kinetics of the degradation process were studied with a rate constant of 0.054/min−1 showcasing the effectiveness of the pulsed laser-synthesized silver colloidal nanomaterial as a sustainable approach for environmental remediation.

Colorimetric and fluorimtric microenvironment responsivity of oxazolidine in solvatochromic latex nanoparticles: Versatile intelligent polymeric materials with advanced applications

Oxazolidine, a new category of stimuli-chromic dyes, has displayed a wide range of responsivities, such as halochromism, solvatochromism, ionochromism, and hydrochromism. The optical properties of oxazolidine molecules can be influenced notably by the polarity of solvent, media, and polymer nanoparticles. In this study, multi-functionalized acrylic latex nanoparticles containing different polar functional groups such as amide, amine, acid, hydroxyl, epoxide, and long-chain ester were synthesized by one-pot emulsion copolymerization. Prepared latex nanoparticles have a mean particle size in the range of 45–170 nm and spherical or non-spherical (anisotropic) morphologies depending on the polarity of functional groups. To prepare multi-color photoluminescent latex nanoparticles and investigation of solvatochromism in both colloidal solution and solid phase, as prepared multi-functionalized latex nanoparticles were modified physically with an oxazolidine derivative (5 wt%). Investigation of the solvatochromism of the oxazolidine in colloidal solution and solid phase indicated that the media is the main effective parameter for solvatochromism in colloidal solution. In the case of solid-state solvatochromism, the optical properties of oxazolidine were influenced significantly by the polarity of functional groups, because the interactions of oxazolidine molecules with functional groups of latex nanoparticles is the main parameter that influenced the solvatochromism. The solvatochromic properties of oxazolidine in solid polymer powders are useful for developing multi-color photoluminescent materials with advanced applications in the dual-mode visualization of latent fingerprints (LFPs), anticounterfeiting solid inks, and organic light-emitting diodes (OLEDs). Results displayed potential applications of multi-color polymer powders for the detection of LFPs under visible light and UV-light irradiation, for printing of optical security tags, and construction of OLEDs. The presented study introduces a new category of multi-color solid photoluminescent nanomaterials with multiple applications using solvatochromic properties.

A Comprehensive Review of the Evaluation of in Situ Gels

In situ gels are now among the most widely used and widely available systems. These systems minimize drug administration frequency because of their special sol-to-gel transition properties, increasing patient comfort. Other benefits of these systems include easy production, improved adherence, and ease of use. 'Sol-gel' produces a colloidal suspension or solution by hydrolyzing the precursor and then polymerizing it through condensation. These in situ gelling techniques gel at the accomplishment site because they can be administered as solutions. Recently, several researchers developed liposomes, microspheres, nanoemulsions, nanospheres, and other in situ gelling systems. One of the greatest innovative drug delivery methods to date is the "in situ gel" system, which promotes better patient comfort and compliance as well as a prolonged and regulated release of the medication. With in situ gel formation, a variety of natural and synthetic polymers may find application in oral, ophthalmic, transdermal, buccal, intraperitoneal, parenteral, injectable, rectal, and vaginal routes. Research on the in-situ gel system has a lot of potential to offer cutting-edge methods for medication delivery systems.

Impact of Pre-Silica-Coating on the Luminescence Properties of Silica-Coated Indium Phosphide Nanoparticles

This study examined the impact of silica-coating on the luminescence characteristics of indium phosphide (InP) nanoparticles. Silica-coated InP nanoparticles were prepared using three different techniques. The first method utilized tetraethoxysilane (TEOS) as the silica source, resulting in the encapsulation of multiple InP nanoparticles within silica spheres. This approach caused a red-shift in the luminescence peak wavelength of the InP colloidal solution post-TEOS coating, compared to the original InP colloidal solution. Conversely, the second method employed tetramethoxysilane (TMOS), resulting in the formation of irregularly shaped silica-coatings on multiple InP nanoparticles, which reduced the red-shift in the luminescence peak wavelength of the silica-coated InP colloidal solution. The third method involved pre-coating InP nanoparticles with TMOS, followed by thickening the silica shells using TEOS. This technique successfully encapsulated multiple InP nanoparticles within silica spheres, maintaining the luminescence peak wavelength of the InP colloid solution post-coating with TMOS and TEOS nearly identical to that of the original solution. This method merged the advantageous outcomes of the first two methods. Additionally, silica spheres containing InP nanoparticles synthesized using both TMOS and TEOS exhibited the highest luminescence intensity. In summary, this study introduces a novel approach in nanoparticle engineering, enhancing the functional properties of InP nanoparticles and expanding their potential applications in optoelectronic devices.

Oliguria caused by dehydration in combat trauma (case series)

Background. A combat gunshot wound is significantly different from a civilian trauma. It is characterized by the prevalence of penetrating injuries, which increases the volume of blood loss at the pre-hospital stage, and the destruction of large masses of muscle tissue (rhabdomyolysis), which leads to acute kidney injury. Moreover, combat trauma occurs in conditions of chronic background stress as a result of severe emotional and physical strain, uncomfortable weather conditions, and deprivation of sleep, drinking and food. So, such a phenomenon as voluntary dehydration is common among soldiers in combat conditions. In wounded, oliguria is often considered a result of acute kidney injury, but it can also be a symptom of severe dehydration. The purpose of our work was to analyze three clinical cases of oliguria caused by dehydration in wounded with combat trauma to better understand the severity of the condition of such victims and to improve medical aid for them. Materials and methods. The article describes three cases of men aged 35, 50 and 44 years with combat gunshot wounds to the extremities, who were admitted to the tertiary care hospital on the second day after the injury with oliguria (0.18–0.19 ml/kg/hr) and high creatinine (333 to 457 μmol/L). Results. All three patients were conscious, breathing spontaneously, had stable hemodynamics, and moderate anemia after pre-hospital blood transfusions. Focused ultrasound study revealed hyperdynamic left ventricle and small inferior vena cava with complete inspiratory collapse, which suggested hypovolemia. Upon further investigation of the medical history, patients admitted not drinking any liquid for one to two days prior to injury. Tissue hydrophilicity test was conducted which showed severe dehydration in all three cases. Infusion volume was calculated using P.I. Shelestiuk nomogram (modified by O.V. Kravets et al.) and amounted to 60 ml/kg of balanced crystalloid solutions. Upon starting rehydration, diuresis was restored within two hours and amounted to 0.7–2.1 ml/kg/h in all three patients. Creatinine levels normalized in 2–4 days. Patients were transferred to another hospital in a moderate condition in 4–5 days. Conclusions. Oliguria is a frequent complication of combat gunshot injury. Although it is most often associated with acute kidney injury from rhabdomyolysis, it should also be considered that in a combat environment, soldiers’ access to water may be limited and the injury may be accompanied by dehydration. In the cases presented, the differential diagnosis of the causes of oliguria in the wounded made it possible to detect signs of severe dehydration, abstain from the inappropriate use of saluretics, quickly compensate for the fluid deficit, and to avoid the development of kidney damage and the need for renal replacement therapy.

Effect of Selected Crystalloid and Colloid Solutions on Coagulation Status Evaluated by Rotational Thromboelastometry and Platelet Function Analyser: An in vitro Study

Introduction: Crystalloid and colloid solutions commonly used in intensive and perioperative care can affect haemocoagulation status. This in vitro study assessed the impact of Plasma-Lyte, albunorm 5%, and Gelaspan 4% solutions on primary and secondary haemostasis using rotational thromboelastometry and platelet function analyser. Methods: In this prospective study, we examined blood samples from 20 healthy volunteers using rotational thromboelastometry and platelet function analyser. Simultaneously, we analysed the blood samples subjected to 10% dilution using Plasma-Lyte, albunorm 5%, and Gelaspan 4% solutions. Results: Compared to controls, Plasma-Lyte shortened EXTEM-CT (p = 0.005) and reduced FIBTEM-MCF (p = 0.017). albunorm 5% prolonged EXTEM-CFT (p = 0.001), decreased EXTEM-alpha (p < 0.001) and MCF in EXTEM, INTEM, and FIBTEM tests (p < 0.001, p = 0.038, p = 0.001, respectively), along with MCE in the PLTEM test (p < 0.001). Gelaspan 4% also prolonged EXTEM-CFT (p < 0.001), decreased EXTEM-alpha (p < 0.001) and MCF in EXTEM, INTEM, and FIBTEM tests (p < 0.001, p < 0.001, p = 0.009, respectively), along with MCE in the PLTEM test (p < 0.001). Gelaspan 4% also reduced EXTEM-CT (p = 0.021). All solution prolonged CT in PFA Col/ADP (p = 0.003 for Plasma-Lyte, p < 0.001 for albunorm and Gelaspan) and albunorm 5% also prolonged CT in Col/Epi (p = 0.003). Conclusion: Plasma-Lyte had the least effect on secondary haemostasis, whereas albunorm 5% had the least effect among colloids. Gelaspan 4% adversely affected the propagation phase of coagulation, maximal strength and elasticity of the coagulum, and the level of functional fibrinogen. All solutions adversely affected platelet function in primary haemostasis, with Plasma-Lyte showing the least effect.

Comparative analysis of purity of human albumin preparations for clinical use

BackgroundAlbumin is the most prevalent plasma protein and serves numerous physiological roles, both in body fluid management and in various other capacities. In many diseases, a deficiency of albumin has been observed, and in certain conditions, albumin substitution has been demonstrated to improve outcome in comparison to plasma expansion using crystalloid or other colloid solutions. The favourable effects of using albumin in patients with liver cirrhosis are likely associated with the non-oncotic functions of albumin. Albumin for clinical use is obtained through fractionation of pooled donor plasma. The production procedures are optimized to ensure pure, chemically uncompromised and native protein. ResultsWe have extensively analysed commercial preparations of human albumin for clinical use from six different providers. Parameters that must correspond to the requirements of international pharmacopoeias were assessed (aluminium, ethanol, sodium, the presence of dimers and oligomers) and found to conform in all cases. In addition, we used for the first time nuclear magnetic resonance (NMR) as an additional analytical approach for investigating in greater depth the quality of a biological remedy gained from human plasma. We applied both 1H NMR and 13C-HSQC for confirming the identity of the albumin preparations, which also conformed in all cases. Moreover, we utilized T2-filtered 1H NMR and 13C-HSQC measurements to identify the presence of small molecules in the preparations. This demonstrated similar patterns of additional substances present, but also unveiled certain differences in purity in the products of the different providers. SignificanceOur analyses confirmed that albumin preparations in clinical use conform to the requirements. We furthermore demonstrate that NMR measurements can provide further depth in identity and purity measurements of biologicals. Despite largely standardized protocols in pharmaceutical albumin production, our in-depth analyses revealed differences in purity. Some samples exhibited lower levels of components other than albumin. We discuss possible causes of these observations and their potential implications for clinical therapy.

Synthesis and Characterization of ZnO Nanoparticles by Pulsed Laser Ablation in Liquid Using Different Wavelengths for Antibacterial Application

In this paper, the synthesis of colloidal solution of ZnO nanoparticles by PLAL using an Nd: YAG laser with 1064 nm and 532 nm wavelengths is described. The optical, morphological, structural, wettability and antibacterial activities were studied. The XRD analysis showed the hexagonal wurtzite structure while the UV-vis indicated the blue shift of the absorption peak due to the surface plasmon of the nanoparticle, which showed significant changes in color behavior. The FE-SEM revealed a uniformed spherical shape with a partial size range of 20.50–21.48 nm for ZnO at 1064 and 57.08–59.87 nm for ZnO at 532nm. Also, the concentration measurement indicated that the concentration of ZnO prepared at 1064 nm is 26.7 μg ml-1 and 63 μg ml-1 at 532 nm due to the relevance of high energy to the Zn plate and little distortion in the water and high absorption of short wavelength. Finally, the optical density of the antibacterial activity has been investigated, and both concentrations have good antibacterial activity at 12 h. The ZnO prepared at 532 nm has higher antibacterial activity because it has a high concentration of nanoparticles for both S. aureus and E. coli. Finally, the cell viability for ZnO synthesis with both 1064 nm and 532 nm indicates that this material has high biocompatibility and could be used for medical applications.

Testing Neuroprotective Strategies in Prolonged Field Care Model of Traumatic Brain Injury and Hemorrhagic Shock.

Prolonged Field Care (PFC) is a military adaptation of Tactical Combat Casualty Care providing extended pre-hospital management during delayed extrication. Effects of addition of Valproic Acid (VPA) to Fresh Frozen Plasma (FFP) in a PFC model of hemorrhagic shock and traumatic brain injury (TBI) are not known. We hypothesized that VPA is associated with decreased neurological impairment, and its protective changes are detected at the transcriptomic level. Swine underwent TBI and 40%-blood volume hemorrhage. After 2-hours of shock, they were randomized to: 1)normal saline (NS), 2)NS+250 ml FFP (NS+FFP), or 3)NS+FFP+150 mg/kgVPA(NS+FFP+VPA). At 72-hours, they were transfused packed red blood cells before being euthanized. Intraoperative variables and neurological outcomes were compared. Brain lesion size was measured, and gene expression profiles were analyzed using RNA-sequencing. Pathway and network analyses were performed on differentially expressed genes. Real-time PCR was performed to validate key genes. NS+FFP and NS+FFP+VPA required significantly less crystalloid resuscitation(974 ml-NS+FFP; 1461ml-NS+FFP+VPA vs. 4540 ml-NS, p<0.001), had smaller brain lesion size(2477mm3-NS+FFP; 3018.0mm3-NS+FFP+VPA vs. 4517.0mm3-NS, p<0.01), and less functional neurologic impairment compared to NS. Per pathway analysis of differentially expressed genes, VPA was associated with enrichment of numerous metabolic changes in injured brains, which were not observed with FFP. Network analysis showed enrichment of various gene networks. MT-ATP8 gene was downregulated in VPA-treated animals. The addition of FFP to the resuscitation protocol resulted in a significant reduction in crystalloid requirements. Both, the FFP and FFP+VPA groups showed improved neurological recovery compared to NS alone and had distinctive transcriptomic profiles in injured brains at 72-hours. MT-ATP8, involved in worsening ischemia following brain injury, was down-regulated in VPA-treated animals.

Biogenic silver nanoparticles synthesized using bracken fern inhibits cell proliferation in HCT-15 cells through induction of apoptosis pathway and overexpression of heat shock proteins

BackgroundIn recent years, biosynthesized nanoparticles has shown a promise as alternative avenue for improving the effectiveness of conventional chemotherapy. Despite, there is a significant gap in existing literature concerning the comprehensive study of biogenic silver nanoparticles derived from terrestrial fern species and their potential effects on cancer cells. This study is aiming to investigate effects of biogenic silver nanoparticles synthesized using aqueous extract of bracken fern Pteridium revolutum on inhibiting cell proliferation and inducing apoptosis in HCT-15 cells. MethodsBiogenic silver nanoparticles synthesized using aqueous extract of Pteridum revolutum followed by their characterization (UV–Visible spectroscopy, TEM, XRD and FTIR). The impact on cell proliferation of HCT-15 cells was assessed by MTT assay while induction of apoptosis was demonstrated via DNA fragmentation, caspase-3 assay, cell cycle arrest, FITC V- Annexin assay and evaluation of expression of apoptotic genes using real time PCR and western blotting techniques. ResultsResults of UV–Vis spectrum of colloidal solution of CW-AgNPs showed surface plasmon resonance peak at 430 nm. TEM and XRD results confirmed synthesis of spherical shaped, 20–40 nm sized nanoparticles. The results elucidate cytotoxic effect of PR-AgNPs against HCT-15 cells in time and dose dependent manner with IC50 observed at 5.79 ± 0.58 µg /mL after 24 h of exposure. Furthermore, PR-AgNPs induce significant alterations in cellular morphology, elevate DNA DNA fragmentation and enhance expression of p53 and caspase-3 in HCT10 cells. ConclusionThe findings from this study address the noteworthy antiproliferative effects of PR-AgNPs in cancer cells primarily mediated through activation of intrinsic apoptosis pathway by inducing p53 and caspase-3 genes.

In Situ Crystal Growth and Fusing-Confined Engineering of Quasi-Monocrystalline Perovskite Thick Junctions for X-ray Detection and Imaging.

Metal halide perovskites exhibit great promise for utilization in X-ray detection owing to their excellent optoelectronic properties and high X-ray attenuation capabilities. However, fabricating large-area thick films for high-performance perovskite X-ray detection remains challenging. This study develops an in situ crystal growth and fusing-confined approach to prepare high-quality, large-scale perovskite quasi-monocrystalline thick junctions. The perovskite crystals are grown in situ using a highly concentrated perovskite colloidal solution in 2-methoxyethanol. Introducing methylammonium chloride enhances grain reorganization during in situ growth and fusing-confined processes, effectively reducing grain boundaries and surface defects. This allows for the preparation of quasi-monocrystalline thick junctions of large grains (>100 μm) with high crystallinity, uniform orientation, and vertical penetration across the film thickness. Additionally, the carrier mobility and lifetime of the thick junctions are significantly enhanced. The optimized MAPbI3 detectors demonstrate an X-ray sensitivity of 2.6 × 104 μC Gyair-1 cm-2 and an exceptionally low detection limit of 1 nGyair s-1. Furthermore, inspired by a honeycomb structure, these detectors realize X-ray imaging in 64 × 64 pixels through a pixelated separation design, effectively reducing the charge-sharing effect. This study offers valuable insights into the preparation of large-scale perovskite quasi-monocrystalline thick junctions for highly sensitive X-ray detection and imaging applications.

Acetylacetonate-modified TiO2 nanoparticles coated on the carbon felt as the negative electrode of vanadium redox flow battery for reducing HER and enhancing V3+/V2+ redox reactions

The occurrence of the hydrogen evolution reaction (HER) on the surface of the carbon-based negative electrode of the vanadium redox flow battery (VRFB) causes high charge transfer resistance (RCT) for the desired V3+/V2+ redox reaction leading to irreversible capacity loss. To this effect, we have synthesized acetylacetonate-modified TiO2 (SGTA) and unmodified TiO2 (SGT) coating colloidal solutions as electrocatalysts for enhanced V3+/V2+ redox reaction on the carbon-felt negative electrodes of VRFB. The SGTA particles exhibit significantly higher homogeneity with sizes of ≤15 nm, in comparison to the severely aggregated SGT particles with diameters of ∼23–75 nm in colloidal solution. When coated on the pristine carbon felt (P-CF), the surface morphology of the SGTA@CF electrode exhibits relatively dense, uniformly coated particles, in comparison to the sparse, non-even coating of aggregated particles on the SGT@CF electrode surface. Consequently, the charge transfer for V3+ → V2+ reduction reaction and charge storage capacity are determined to be in the order SGTA@CF > SGT@CF > P-CF, confirming that the competitive and irreversible HER was higher on the surface of non-evenly coated fibers and bare carbon felt, respectively.

The Effect of Evaluating Perfusion with Infrared Fluorescent Angiography on Flap Survival in Head and Neck Free Flap Reconstruction.

Intraoperative fluid management is one of the most important factors affecting optimal perfusion in the microcirculatory area in patients that undergo flap surgery. While insufficient fluid administration in the intraoperative period leads to flap complications and organ dysfunction, volume load can cause complications such as edema in the denervated flap tissue, the opening of the sutures, or fat necrosis. The Infrared Fluorescent Angiography Perfusion Evaluation Device (SPY) is one of the many noninvasive techniques that evaluate the well-being of microcirculation at the tissue level. This device monitors and scores the perfusion distribution in the flap area. This retrospective study aimed to investigate the effect of fluid resuscitation in head and neck free flap transfer surgery on flap quality and patient outcomes according to the change in SPY scores. This study included 39 ASA I-II patients who were aged 18-60 years and underwent simultaneous free flap reconstruction of the head and neck between 2015 and 2021. Patients' blood pressure, body temperature, hemoglobin, pH, and lactate values were recorded at both baseline and end of the operation. Also, the SPY "Infrared Fluorescent Angiography Perfusion Evaluation Device" scores, the amount of intraoperative fluid and transfusion, bleeding and urine output, and the duration of mechanical ventilation, anesthesia and surgery, and the duration and amount of drainage, the length of stay in hospital and intensive care unit, and the presence of flap infection, detachment, necrosis and loss, and re-exploration rate were recorded for the patients. The difference between the first and last measured SPY values was observed to be positively correlated with the length of stay in the hospital and intensive care unit and the duration of drainage. There was a positive correlation between the length of stay in the hospital and intensive care unit and the duration of drainage, the amount of drainage, as well as the duration of anesthesia and the duration of surgery (p < 0.001). A positive correlation was found between the amount of drainage and the amount of crystalloid solution administered (r = 0.36, p < 0.05). In patients with flap infection, the difference between SPYfirst and SPYlast, the duration of anesthesia, and the duration of surgery were significantly higher. The amount of crystalloid solution given and bleeding and the duration of anesthesia and surgery were found to be significantly higher in mechanically ventilated patients (p < 0.05). It has been concluded that SPY-guided fluid management can be beneficial in preventing morbidities, such as extended hospital and intensive care stay, by reducing flap infection, mechanical ventilation duration, and drainage, with early diagnosis of insufficient perfusion.

Intravenous Lipid Emulsion for the Treatment of Ivermectin Toxicity in a Cat: A Case Report

A two-years-old male cat weighing three kg was presented to the Referral Veterinary Polyclinic of ICAR – Indian Veterinary Research Institute (IVRI), Izatnagar with history of anorexia, no water intake, ataxia, head tilting downward, sudden recumbency and loss of vision. While taking history the owner declared about the use of off-label oral ivermectin preparation @ 2.5 mg/kg total dose (5 times the recommended dose) once only. Cat had high rectal temperature (105° F), normal mucus membrane, tachypnoea (70/min), tachycardia(145/min). At the beginning, the patient received 20% lipid emulsion (Intralipid) at 1.5 mL/kg body weight, Diazepam 0.5 mg/kg b. wt. IV once, dexamethasone 0.5 mg/kg b. wt., and 25 mg/kg b. wt. bid of cefotaxime. The patient also received constant rate infusion therapy at 0.25 ml/kg/h, OD, and isotonic crystalloid solution (0.9% NS) at 30 ml/kg body weight for a total of 10 minutes. After three days, the cat's clinical condition returned to normal state. This case reports helps to readers in managing an emergency condition of ivermectin toxicity.

Unveiling the Electrostatically Driven Collapsing and Relaxation of Polyelectrolyte-Colloid Complexes: A Tunable Pathway to Colloidal Assembly.

Polyelectrolyte-colloid (PEC) complexes, ubiquitous across diverse fields, exhibit remarkable phase transitions, mimicking intricate biological assemblies. While the role of electrostatic forces in the PEC complex assembly is undeniable, achieving a holistic comprehension remains an elusive goal. This study unveils a fascinating phenomenon: the formation of highly collapsed coacervate structures in PEC complexes at elevated polyelectrolyte concentrations, followed by the swelling of complexes at even higher concentrations. Employing anionic silica colloids and cationic chitosan as a model system, small-angle X-ray/neutron (SAXS/SANS) elucidates the transition from a bead-on-a-necklace-like phase to a dense packed coacervate state (with volume fraction ∼0.62) until 3 wt % concentration of the polyelectrolyte. However, beyond 3 wt %, swelling of the dense collapsed assembly is observed. This structural evolution of PEC complexes as a function of chitosan concentration is attributed to the interplay of electrostatically driven interactions and the Donnan effect. Notably, the critical concentration for coacervation, Cs*, demonstrates a linear dependence on the initial colloid concentration. Interestingly, a complete expansion of the coacervate is observed at a high polyelectrolyte concentration, particularly for dilute colloid solutions (2 wt %). Furthermore, the addition of an electrolyte sheds light on the delicate interplay of forces. While a low electrolyte concentration partially screens charges, leading to a shift in phase diagram, higher concentrations trigger complete coacervate dissolution beyond the critical electrolyte concentration of 0.2 M, due to the complete screening of electrostatic charges.

Studying the optical properties of assembled silver and gold nanoparticles for the purpose of creating SERS sensors

The optical properties of silver and gold sols with different sizes of nanoparticles and the method of their chemical deposition on the surface of silicon, silicon oxide, glass and aluminum foil were studied in order to obtain SERS substrates – promising platforms for the development of aptamer sensors and immunochemical analysis of various pathogens. It has been established that for operation on lasers with exciting radiation wavelengths of 532, 638 and 785 nm, it is possible to create universal SERS substrates based on colloidal solutions obtained by the liquid-phase chemical method with an average silver particle size of 40 nm and by the Leopold-Lendl method with an average size of 20 nm.

The Sol-Gel Process, a Green Method Used to Obtain Hybrid Materials Containing Phosphorus and Zirconium.

The sol-gel process is a green method used in the last few decades to synthesize new organic-inorganic phosphorus-containing hybrid materials. The sol-gel synthesis is a green method because it takes place in mild conditions, mostly by using water or alcohol as solvents, at room temperature. Therefore, the sol-gel method is, among others, a promising route for obtaining metal-phosphonate networks. In addition to phosphorus, the obtained hybrid materials could also contain titanium, zirconium, boron, and other elements, which influence their properties. The sol-gel process has two steps: first, the sol formation, and second, the transition to the gel phase. In other words, the sol-gel process converts the precursors into a colloidal solution (sol), followed by obtaining a network (gel). By using the sol-gel method, different organic moieties could be introduced into an inorganic matrix, resulting in organic-inorganic hybrid structures (sometimes they are also referred as organic-inorganic copolymers).