Simple Suspension Research Articles

Comparative Analysis of Verapamil Pharmacokinetics: Evaluating the Impact of Simple Suspension and Crushing Administration Methods

Background/Objective: It is not uncommon for elderly patients to experience difficulties with feeding and swallowing. In the simple suspension method, tablets are dissolved and suspended in warm water without prior crushing or decapsulation, and then administered via a tube. Despite the prevalence of this method, the pharmacokinetics of suspended tablet dosage forms remain poorly understood. Methods: Verapamil was employed in dissolution tests following both the simple suspension and crushing methods. A pharmacokinetics study was conducted on healthy adult males. Results: The resultant dissolution profiles from the two methods exhibited notable dissimilarities. Drug release from the crushed product commenced earlier than that from the simple suspension and intact tablet. Furthermore, the area under the curve for verapamil during the initial 24 h period was 1.7 and 1.3 times greater in the crushed and simple suspension groups, respectively, than in the tablet group. Conclusions: The crushing and simple suspension methods are safe techniques for administering medications to patients with dysphagia, thereby preventing aspiration. Nevertheless, the processing of medications may result in an increased frequency of adverse effects. It is recommended that the processing of medicines prior to administration be avoided.

A Case of Esophagogastric Junction Cancer Treated with Pain Control by Administering Methadone Tablets Through a Gastrostomy.

Introduction: Methadone is used to treat intractable cancer pain when other opioid analgesics are ineffective. Methadone tablets may be difficult to administer in cases of gastrointestinal passage obstruction. However, changing the route of methadone tablet administration is possible. Case Description: The patient, diagnosed with esophagogastric junction cancer with multiple metastases, continued to receive methadone tablets even after not being longer able to take oral medication. Method: Methadone tablets were administered using a simple suspension method via gastrostomy. We measured the respiratory rate during sleep daily. We also measured weekly QTc values using a 12-lead electrocardiogram and methadone blood concentration periodically. No side effects were observed. Conclusion: Using a simple suspension method to administer methadone is a safe pain management method when accompanied by careful monitoring. To date, no study has examined the tube administration safety of methadone tablets. Thus, this case report is of important clinical significance.

Evaluation of the Simple Suspension Method for Oral Anticancer Drugs.

The simple suspension method (SSM) involves administering tablets or capsules using a tube after disintegration and suspension in hot water without crushing or opening the capsule. Particularly, for anticancer drugs, it is an excellent method of administration that reduces the risk of exposure during dispensing. In contrast, information on SSM for individual drugs is insufficient. Anticancer drugs present a therapeutic challenge because their information is limited. We investigated whether SSM is possible with 36 anticancer drugs. Furthermore, we examined the pH of the suspension of these drugs, for which no information on SSM is available. We found that suspension was possible for 24 of the 36 drugs. Furthermore, the pH of the suspension was measured, which provided important information when considering dissolution solutions other than hot water. Little changes in the pH were observed before or after passing through the tube. The results of this study may improve medication adherence in patients with cancer experiencing dysphagia.

Upcycling waste derived glass into high-performance photocatalytic scaffolds by alkali activation and direct ink writing

Novel and eco-friendly solutions are extensively needed for wastewater treatment. This work capitalizes on the combination of waste vitrification and additive manufacturing to produce an efficient photocatalyst for the specific purpose. Fine powders of waste-derived glass, containing Fe3O4 inclusions, by simple suspension (for a solid loading of 65 wt %) in alkaline solution (5 M NaOH), were transformed into pastes for direct ink writing. 3D-printed reticulated scaffolds were stabilized by the progressive hardening of a zeolite-like gel, formed by glass/solution interaction, at nearly room temperature. The printed scaffolds were successfully tested for the removal of methylene blue, realized by combining the high sorption capacity of the gel with the catalytic activity of magnetite inclusions, under UV light. A complete degradation of methylene blue is achieved by 90 min exposure, comparing favorably with other reported photocatalytic materials, requiring from 60 to 360 min. The photocatalytic activity was tested for several cycles, with no significant degradation. In other words, a waste-derived material can be reused for multiple times, to remediate wastewaters, with evident benefits on waste minimization.

Development and Assessment of a New Oral Selenium Fast-disintegrating Tablets

Selenium is an essential trace element and its deficiency causes myositis, myocardial damage, and other symptoms. Patients receiving long-term intravenous nutrition or tube-feeding in particular are deficient in essential trace elements, including selenium, and require regular supplementation. In Japan, injectable selenium-containing products are listed on the National Health Insurance drug price list, and oral solutions are prepared and used in hospitals. However, these formulations have problems related to preservation and require complicated administration procedures. In this study, we developed a new fast-disintegrating tablet formulation of selenium, using SmartEx® (D-mannitol·low substituted hydroxypropylcellulose (L-HPC)·fully hydrolyzed polyvinyl alcohol (PVA) mixture) as a coprocessing additive, that can be administered orally or by feeding tube. The tablet formulation had excellent disintegrable capability, sufficient hardness, and did not cause tube blockage when administered in the simple suspension method. In addition, the tablet formulation showed no changes in properties in an accelerated test without packaging for 42 d, indicating that it could be stored for a long period. Fast-disintegrating tablets prepared with SmartEx® are expected to improve the adherence and quality of life of patients who require selenium supplementation.

A study on the chemical stability of cholesterol-lowering drugs in concomitant simple suspensions with magnesium oxide

BackgroundDifficulty in taking solid medicines is a common issue particularly for the elderly because of a decline in swallowing function, also known as dysphagia. For patients with such a dysfunction, a simple suspension method, in which solid medicines are disintegrated and suspended using warm water, has been developed and widely used in Japanese clinical settings. However, there is little information on drug stability in the simple co-suspension of multiple formulations especially including acidic or alkaline ones. In this study, the chemical stability of typical cholesterol-lowering drugs was investigated in a simple co-suspension with alkaline magnesium oxide (MgO) which is frequently used as a laxative or antacid in Japan.MethodsA cholesterol-lowering drug (one tablet) was soaked with or without MgO in warm water (55°C), and the vessel was left at room temperature for 10 min or 5 h. The suspensions prepared were then analyzed by high-performance liquid chromatography. Degradation products were analyzed by nuclear magnetic resonance spectroscopy and mass spectrometry for the structural elucidation.ResultsIn the simple co-suspension with MgO, no significant degradation was observed for atorvastatin or pravastatin, while a significant decrease of the recovery from the co-suspension was observed for rosuvastatin after 5 h. On the other hand, simvastatin and ezetimibe co-suspended with MgO were partially degraded to simvastatin acid and a pyran compound, respectively.ConclusionsA simple co-suspension with MgO is feasible for atorvastatin, pravastatin, and rosuvastatin, although the rosuvastatin tablet should not be left soaking for a long time. Further it is inadvisable to suspend simvastatin or ezetimibe together with MgO because of their partial degradation.

Analysis of the curative effect and prognostic factors in patients with scapular fracture with surgical indications after conservative treatment: a case series and clinical outcomes.

The choice of treatment for scapular fractures is a topic worth discussing. The type of scapular fracture is often complex, and more and more scholars prefer surgical treatment to obtain better shoulder joint function. In addition, because of the rich blood supply and muscles of the scapula, some scholars believe that simple suspension can also achieve satisfactory clinical effects. The aim of this study was to investigate the curative effect and prognostic factors of patients with scapular fracture with indications for surgery after receiving conservative treatment. Patients with scapular fracture who did not receive surgical treatment from July 2016 to May 2021 were recruited from the orthopedic trauma database of Nanjing Gulou Hospital, and the data from patients with indications for surgery were screened out for a retrospective analysis. The data were obtained from the database of orthopaedic trauma patients in Nanjing Drum Tower Hospital. The relevant data were recorded during telephone and video follow-up visits. Linear regression was used to analyze the factors associated with disabilities of the arm, shoulder and hand (DASH) score after receiving conservative treatment. A total of 21 patients were included in the final statistical analysis. All patients were followed up for 31.0±20.3 (range, 6-63) months, aged 52.9±12.7 (range, 27-71) years. All fractures had clinical healing with a 100% recovery satisfaction rate. Outcome measures of efficacy [both DASH scores and visual analogue scale (VAS) scores], were correlated with whether the fracture involved the superior border of the scapular, were not associated with the following variables: age (P=0.18), Injury Severity Score (ISS) score (P=0.10), the glenopolar angle (GPA) value (P=0.76), superior shoulder suspensory complex (SSSC) injury (P=0.82), and glenoid fracture (P=0.84). The range of motion of the affected shoulder was significantly reduced compared to the healthy shoulder (P<0.01), but the range of forward flexion and elevation was not significantly different from that of the healthy shoulder (P>0.05). Patients with fractures not involving the superior border of the scapula had a much lower range of motion in the affected shoulder than in the healthy shoulder during abduction (P<0.05). The range of surgical indications for scapular fractures with scapular fractures involving the lower margin of the scapular can be appropriately narrowed. Some patients with scapular fracture who have surgical indications can regain satisfactory shoulder function after receiving conservative treatment.

Optimal Administration of Phosphorus Adsorbents When Using Medical Nutritional Supplements for Tube-fed Patients.

All medical enteral nutrition products contain phosphorus and when administered to patients with chronic kidney disease (CKD) and on dialysis, they lead to the risk of elevated serum phosphorus levels. Thus, serum phosphorus levels should be monitored, and phosphorus adsorbents should be used in cases of high serum phosphorus levels. In this study, we investigated the effect of phosphorus adsorbents on enteral nutrition, using Ensure Liquid®, a medical nutritional formula, for patients with CKD and those on dialysis. Additionally, we compared the effects of the simple suspension method, in which various phosphorus-adsorbing agents are suspended and mixed directly with the nutritional formula for tube administration (hereafter referred to as the "pre-mix method"), and the conventional method, in which only the phosphorus-adsorbing agents are administered separately from the nutritional formula for tube administration (hereafter referred to as the "normal administration method"). The administration of various phosphorus adsorbents using the pre-mix technique resulted in a phosphorus removal rate of 8-15% (approximately 12% on average). Therefore, through the pre-mix method, maintaining the phosphorus content of Ensure Liquid® below the daily phosphorus intake standard was possible for patients on dialysis. The pre-mix method via the simple suspension method of administering phosphorus adsorbent with Ensure Liquid® resulted in less drug adsorption to the injector and tube and a higher phosphorus removal rate than the normal administration method.

Preclinical modeling of intravitreal suspensions

There are a number of obstacles that complicate the development of intravitreal delivered small molecules therapies. One serious complication is the potential need for complex polymer depot formulations early in the drug discovery process. The development of such formulations often requires substantial investment of time and material which may not be readily available in preclinical development. Herein I present a diffusion limited pseudo-steady state model to provide prediction of drug release from an intravitreally administered suspension formulation. By using such a model, a preclinical formulator may be able to more confidently determine if development of a complex formulation is required or if a simple suspension may work to support a study design. In this report, the model is used to predict the intravitreal preformance of two different molecules (triamcinolone acetonide and GNE-947) at multiple dose levels in rabbit eyes as well as provide a prediction for the performance of a marketed formulation of Trimacinolone Acetonide in humans.

Preventing bank panics: The role of the regulator's preferences

AbstractHow do the preferences of a banking authority affect its decision making in periods of distress and thus financial stability? We study this question in a version of Diamond and Dybvig (1983) with a monopolistic bank and a time‐consistent policy response by a banking authority. We show that limited commitment on the part of the banking authority may induce fragility but the banking authority's incentives are also an important determining factor in the degree of financial stability. In particular, under a simple suspension scheme, delegating a banking authority who places sufficient weight on a banker's welfare acts as a commitment device and prevents runs, in analogy with how a Rogoff (1985) “conservative” central banker helps reduce inflation bias. In contrast, once interventions take the form of payment rescheduling, the scope for the bank's susceptibility to a panic increases should the banking authority put more weight on monopoly rents. Identifying such an aspect of vulnerability suggests that appointing a banking authority whose objective function deviates from that of depositors may have unintended consequences.

In-situ generated Ni/Ni3Si to enhance electromagnetic wave absorption properties of Ni/PDCs/biomass ceramic composites

In recent years, electromagnetic wave (EMW) absorbing materials derived from biomass materials have been widely concerned because of their light weight and high efficiency. Here, Ni/PDCs/biomass ceramic composites absorbing material was prepared by a simple suspension impregnation-in-situ reduction carbonization process and polymer-derived ceramics (PDCs) with peanut shell as the absorbing matrix and NiO doped in polysiloxane as the precursor solution. The synergistic effect of Ni/PDCs could effectively adjust the impedance matching of the composite, and the BET results shown that the prepared Ni/PDCs/biomass ceramic composites had a hierarchical porous structure, which could not only provide a large number of heterogeneous interfaces, but also enhance the interface polarization, dipole polarization and multiple reflection loss of the absorbing material. The sample of NPP-1 possessed good EMW absorbing performance when the content of NiO was 1 % and the filler was 50 %, the minimum reflection loss (RLmin) reached − 66.38 dB at 1.74 mm, and the effective absorption bandwidth (EAB) was 3.54 GHz (14.46–18 GHz) at 1.45 mm. In this work, the electromagnetic parameters of biomass materials were adjusted by polymer conversion ceramics and metal oxides, which provided another feasible scheme for enhancing the absorbing properties of biomass materials.

OPTIMIZATION OF ACYCLOVIR SUSPENSION: FORMULATING DEVELOPMENT USING NA-CMC AND QUALITY CONTROL OF FINISHED PRODUCTS

Objective: Acyclovir is widely used as a potent antiviral drug to treat viral infections of herpes and varicella-zoster families. Unfortunately, the drug has a very poor oral bioavailability character (15-30%). The purpose of this study was to develop a formulation of acyclovir suspension with a simple suspension method using Na-CMC (carboxymethylcellulose sodium), and to carry out quality control of the finished product.&#x0D; Methods: The formulation was developed by designing variations in Na-CMC concentration and quality control, including pH, viscosity, dispersibility, storage stability, microscopic measurement, sedimentation volume, and evaluation of acyclovir levels. Quality control is to evaluate the suspension in order to obtain good and stable physicochemical properties of the suspension.&#x0D; Results: Design variations of Na-CMC concentrations of 1.4%, 1.5%, and 1.6% resulted in a homogeneous suspension and easily dispersed perfectly. The three formulas did not have a significant difference in the value of viscosity, permeability, and sedimentation volume, which were not significant. All formulas have pseudoplastic flow properties, with good particle size uniformity in the range of 0–13 µm. The stability of pH during storage time was shown by the formula with 1.5% Na-CMC.&#x0D; Conclusion: The acyclovir suspension with 1.5% Na-CMC concentration was the best compared to the other formulas in terms of stability and physicochemical properties.

Superporous acrylic acid and HPMC hydrogels of mefenamic acid: Formulation, characterization and optimization by central composite design.

The purpose of the study was to devise the superporous hydrogels (SPHs) of mefenamic acid (MA) to acquire the sustained action of the MA in the body. The superporous hydrogels of mefenamic acid were formulated by employing the gas blowing method. The central composite rotatable design (CCRD) was applied to optimize the effect of independent formulation factors like acrylic acid (AC), HPMC and glycerol (GLY) over dependent variables like porosity, viscosity, drug content and swelling ratio of superporous hydrogels in water, phosphate buffer (pH 6.8) and in 0.1N HCl (pH 1.2). A number of characteristics such as void fraction, surface morphology by Scanning electron microscopy (SEM) and in vitro drug release study were governed along with physico-chemical analysis by Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC) and appraised statistically by employing the ANOVA. The comparative analgesic activity of optimized superporous hydrogel formulation SPH17 was also analyzed by using tail flick method. The Fourier transform infrared spectroscopy and Differential scanning calorimetry studies approved the physical compatibility between the polymers and the drug. The Scanning electron microscopy study specified micrographic insight about the structure of formed formulations comprising presence of pores, fibers and drug-hole aggregates. The superporous hydrogels were detected to be low dense as they expressed density lower than 0.75g/cc. The decrease in concentration of the polymers and cross linker contributed towards the increase in the void fraction of the superporous hydrogel formulations. The optimized formulation SPH 17 exhibited a highly sustained release of MA for up to 10h in the both 0.1N HCl and phosphate buffer (66.6%) media. The non-fickian release of drug revealed the coupling of the diffusion and polymer relaxation mechanism of the drug release from the formulations. The obtained outcomes suggested that analgesic effect of SPH 17 was significantly (p < 0.05) higher than that of simple suspension of mefenamic acid and total analgesic effect duration for superporous hydrogel was also doubled as compared to the duration of analgesic effect produced by drug suspension. The successfully formulated SPH with HPMC K100M as a gelling agent had sustained the action of the mefenamic acid (MF) by improving its poor solubility and permeability. The introduction of inter-penetrating polymeric network (acrylic acid) using glycerol as a cross linker impart increased residence time to superporous hydrogels which ultimately enhanced the feasibility of using superporous hydrogel as oral sustained release devices particularly for gastric retention.

Design and manufacturing a novel screw‐in‐pipe inspection robot with steering capability

AbstractIn this article, a novel in‐pipe inspection robot is designed and manufactured in Kharazmi University KharazmPipeBot. This robot is able to move through any pipeline with a predefined diameter range with a variable pitch rate and report any desired data within the pipe with the aid of the installed camera. To achieve the highest stability of the robot through the pipe, the robot's movement is based on the screw locomotion protocol provided by the aid of its rotor and stator. A simple suspension is designed for three legs of the robot by installing a passive prismatic joint equipped with a spring for each leg to provide a smoother movement for the robot chassis. The main novelty of the robot is adding an extra controlling actuator for the robot which is the steer of the front wheels. This input can control the pitch rate of the robot movement and consequently the spiral track of the wheels can be actively managed. This importance lets us to bypass the probable obstacles attached to the inner wall of the pipes. A brief presentation of the robot model is delivered. Afterward, to verify the claimed novelties of the system, a prototype of the robot is manufactured in Kharazmi University and the efficiency of the robot is demonstrated by conducting some initial experimental tests. It is shown that the robot can move with a variable pitch rate through the wall and pass a detected obstacle accordingly.

Evaluation of Simple Suspension Methods for Preventing Exposure to Hazardous Drugs Administered by Enteral Feeding Tube

Evaluation of Simple Suspension Methods for Preventing Exposure to Hazardous Drugs Administered by Enteral Feeding Tube

Acoustic Levitation for Large Particle Based on Concave Spherical Transducer Arrays

With the advantages of non-contact, compatibility, no chemical effect and safety, acoustic levitation of object has great potential to apply in chemistry, biology, medicine field and micro robots. Suspension to large particle higher than the half wavelength( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.5\lambda $ </tex-math></inline-formula> ) of sound wave, is a challenge technology in micro-nanoscale manipulation. An increased large quantity probes, double sided and four sided phased array with virtual vortex can provide higher capture power, control ability and stability of particle fixation and the manipulation. However, for a limited confined space, the additional probes and sided phased array emission and receiving device is hard to be established and applied. Additional probes and sided ultrasonic phased array requires higher processing ability of MCU (Micro Control Unit) and the quantities of transducers. Further, multiparticles suspension is rare to be reported. In this study, a relatively simple suspension device of one sided concave spherical transducer array is designed, aiming to levitate a large particle and multi-particles. Based on the one sided acoustic field simulation of ultrasonic array, the optimized structure of open spherical sector (OSS) is constructed to establish levitation device. Experimental platform integrating FPGA controller, amplifier and impedance matching is developed to drive the transducer arrays, where a polystyrene particle with 6 mm ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.71\lambda $ </tex-math></inline-formula> ) diameter is successfully levitated. The virtual twin trap sound pressure of transducer array is measured to evaluate the particle stability. Experiments demonstrate the correctness of virtual twin trap acoustic field analysis, the feasibility in the manipulation to the large particle and multi-particles by acoustic trap.

A Case of ALK-positive Lung Cancer That Responded to Brigatinib Administered via Gastrostomy Using a Simple Suspension Method

背景．ALK阻害薬はいずれも内服薬であるため，経口投与困難な症例ではその恩恵を受けることが難しい．そのような症例に対する方策として簡易懸濁法を用いた経管投与が挙げられるが，ブリグチニブをはじめとするALK阻害薬に対する簡易懸濁法や経管投与は確立されたものではない．症例．71歳男性．2015年に当科で多発脳転移，多発肺転移，左癌性胸水などを伴うALK陽性肺腺癌の診断に至った．クリゾチニブで治療を開始したが，約10ヶ月で腫瘍が増大したため，2次治療としてアレクチニブ投与を開始した．その後，約4年9ヶ月にわたり腫瘍は良好に制御されていたが，2021年2月より嚥下時のつかえ感が出現した．同症状は徐々に進行し，2021年3月に水分以外の経口摂取が困難となった．上部消化管内視鏡，CTによる評価の結果，食道傍リンパ節の転移巣による食道狭窄が原因と判明した．ALK阻害薬による治療を行うため，胃瘻を造設し，簡易懸濁法を用いてブリグチニブを投与したところ，食道狭窄の改善を得られ，固形物の再摂取が可能となった．結論．簡易懸濁法を用いて胃瘻から投与したブリグチニブが奏効したALK陽性肺癌の1例を経験した．

Fiber-Tip Fabry–Perot Cavity Pressure Sensor With UV-Curable Polymer Film Based on Suspension Curing Method

We investigate a novel and compact fiber-tip pressure sensor based on Fabry-Perot interferometer (FPI). The proposed device is fabricated by welding a Section of hollow silica tube (HST) on the end of single mode fiber (SMF) and then coating with ultraviolet (UV) curable polymer film at the tip of HST. A simple suspension curing method is introduced to control the formation of the UV curable polymer layer. Therefore, different thicknesses of the polymer film can be easily controlled. The pressure sensing mechanism is based on the cavity length change induced by ambient pressure. The sensor characteristics are studied theoretically and experimentally. The proposed fiber-tip pressure sensor with polymer film thickness of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5.7\,\, \mu \text{m}$ </tex-math></inline-formula> exhibits a pressure sensitivity of 396 pm/kPa in the range of 0–30 kPa based on wavelength shift of the interference dip. Moreover, temperature crosstalk is measured, and the thermal-induced deformation of the polymer film is simulated using the Finite Element Analysis method. The proposed fiber-tip Fabry-Perot cavity pressure sensor has advantages of high sensitivity, fast response, excellent repeatability, compact size, cost effectiveness and easy fabrication, which makes it suitable for high sensitivity pressure detection in a limited space.

Revisit soil organic matter

<p indent="0mm">The accurate and comprehensive understanding of the molecular composition, source, and stabilization mechanism of soil organic matter (SOM) is vital for soil management and the preservation of organic carbon. Currently, a series of key scientific issues concerning the formation and stabilization of SOM is highly contentious. This review summarized the advances in the sources and molecular structure of SOM, and presented a systematic analysis of the different views, conflicts, and problems concerning soil humic substances in the past decades. The traditional view of soil science believes that SOMs are mainly composed of humic substances which are macromolecular compounds and are derived from plant and animal residues through a series of mineralization and humification processes. Soil enzymes and minerals, including phenol oxidase, laccase, peroxidase, iron oxide, manganese oxide, promote the polymerization of organic molecules through additive nucleophilic reactions and free radical catalyzation. ¹³C-NMR and FT-ICR-MS analyses supported the existence of humic substances in soils based on the structure and the molecular composition of SOM. However, with the application of biomarker analysis, high-resolution mass spectrometry, spatial resolution spectroscopy, and other advanced techniques, there is an emergence of new perspectives on the source and the structure of SOM. HPLC-SEC showed the average molecular weight of Aldrich humic acid was significantly smaller than previously thought and the aggregation of humic substances was affected by acetic acid, pH and ionic strength. These evidences suggest that humic substances are aggregates of small organic compounds with a molecular weight of hundreds to thousands of Daltons, rather than macromolecules of tens to hundreds of thousands of Daltons. Furthermore, <italic>in situ</italic> observation of soil particles by STXM revealed significant heterogeneity of SOM at <sc>50 nm</sc> spatial resolution. In terms of the origin of SOM, model calculations and biomarker analysis have indicated that microbial necromass is the major constituent of SOM which accounts for ~33%–62% of SOM in different ecosystems. Collectively, microbial residues may contribute predominantly to the SOM pool and traditional concept “humification” may not occur in the soil. These new findings are contrary to the traditional theory of soil chemistry and soil biochemistry and subvert our understanding of SOM. Therefore, it is imperative to perform further in-depth studies to fill the knowledge gaps regarding the sources, formation processes, and molecular structures of humus. However, further intensive investigations on SOM are restricted by the lack of efficient and reliable extraction procedures. In addition, the conversion coefficients from biomarker to necromass are not accurate and mass spectrometry could not provide a comprehensive analysis on the whole organic molecules in the soil. The studies on enzymatic reactions and microbial synthesis were mainly performed in simple suspension systems, which could not simulate the complex soil matrix. Consequently, future studies are needed to improve the efficiency and accuracy of the extraction and analysis of SOM and to develop a real-time study platform for the interfacial reactions among minerals, organic matters and microorganisms. Meanwhile, <italic>in situ</italic> characterization techniques and modeling should be employed and combined to clarify the sources and the underlying mechanisms of SOM stabilization at molecular level.

Photocatalytic CO2 Reduction Using Water as an Electron Donor under Visible Light Irradiation by Z-Scheme and Photoelectrochemical Systems over (CuGa)0.5ZnS2 in the Presence of Basic Additives.

We demonstrated photocatalytic CO2 reduction using water as an electron donor under visible light irradiation by a Z-scheme photocatalyst and a photoelectrochemical cell using bare (CuGa)0.5ZnS2 prepared by a flux method as a CO2-reducing photocatalyst. The Z-scheme system employing the bare (CuGa)0.5ZnS2 photocatalyst and RGO-(CoOx/BiVO4) as an O2-evolving photocatalyst produced CO of a CO2 reduction product accompanied by H2 and O2 in a simple suspension system without any additives under visible light irradiation and 1 atm of CO2. When a basic salt (i.e., NaHCO3, NaOH, etc.) was added into the reactant solution (H2O + CO2), the CO formation rate and the CO selectivity increased. The same effect of the basic salt was observed for sacrificial CO2 reduction using SO32– as an electron donor over the bare (CuGa)0.5ZnS2 photocatalyst. The selectivity for the CO formation of the Z-schematic CO2 reduction reached 10–20% in the presence of the basic salt even in an aqueous solution and without loading any cocatalysts on the (CuGa)0.5ZnS2 metal sulfide photocatalyst. It is notable that CO was obtained accompanied by reasonable O2 evolution, indicating that water was an electron donor for the CO2 reduction. Moreover, the present Z-scheme system also showed activity for solar CO2 reduction using water as an electron donor. The bare (CuGa)0.5ZnS2 powder loaded on an FTO glass was also used as a photocathode for CO2 reduction under visible light irradiation. CO and H2 were obtained on the photocathode with 20% and 80% Faradaic efficiencies at 0.1 V vs RHE, respectively.