Reduction Of Ring Research Articles

Biodegradation of 3-methylpyridine by an isolated strain, Gordonia rubripertincta ZJJ

Methylpyridines are a class of highly toxic pyridine derivatives. In this study, a novel degrading bacterium was isolated for 3-methylpyridine (3-MP) degradation (Gordonia rubripertincta ZJJ, GenBank accession NO. OP430847.1; CCTCC M 2022975). The maximum specific degradation rate, half-saturation constant and inhibition constant were fitted to be 0.48 h−1, 88.3 mg L−1 and 924.0 mg L−1, respectively. During 3-MP biodegradation, the lost total organic carbon was transformed into CO2 (67.4 %) and biomass (32.6 %), and ammonia nitrogen was almost the sole inorganic species with a conversion rate of 36.3 %. Three metabolic pathways were possibly involved in 3-MP degradation: I) methyl oxidation followed by ring hydroxylation and hydrogenation; II) rupture of C=C and C–N bonds after ring reduction; III) initial ring hydroxylation. The study not only provides a novel strain for the high-efficient degradation of 3-MP, but also contributes to an in-depth understanding of 3-MP biotransformation.

Stability before and after percutaneous anterior medullary fixation of lateral compression 1 and 2 pelvic ring disruptions: Should surgeons prioritize the anterior ring?

Surgical intervention for lateral compression (LC) 1 and 2 pelvic ring fractures is controversial. Posterior ring stabilization remains the most common mode of initial fixation. However, greater mechanical instability is observed in the anterior component of LC pelvic fractures. This study tested whether reduction and percutaneous superior ramus fixation will decrease the instability of LC pelvic fractures on intraoperative fluoroscopic imaging. All adult patients (≥ 18 years) presenting with either a Young-Burgess LC1 or LC2 pelvic ring disruption treated operatively with percutaneous anterior followed by posterior fixation by a single surgeon from July 2021 to June 2023 were retrospectively reviewed. Displacement of the anterior ring to intraoperative manual internal rotation stress examination under fluoroscopy was compared before and after anterior pelvic ring reduction and fixation and prior to posterior pelvic ring fixation. Pre- and post-operative visual analog scores (VAS) for pain were also compared. Twenty-one patients with a mean age of 48.7 years were included. Fifteen patients (71.4%) presented with an LC1, and six (28.6%) with an LC2 injury patterns. Anterior pelvic fixation alone provided 7.5mm reduction in mean displacement of the anterior pelvic ring (pre-operative = 9.2 mm vs. post-operative = 1.6 mm, p < 0.001). VAS significantly decreased from 7.2 one-day pre-operatively to 2.2 twenty-four h post-operatively (p < 0.001). Reduction and fixation of the anterior pelvic ring prior to posterior fixation for LC1 and LC2 pelvic ring disruptions substantially improves mechanical stability on intraoperative stress examination. Combination of percutaneous anterior and posterior fixation significantly decreased VAS above the MCID 24 h after stabilization.

Switchable and Chemoselective Arene Hydrogenation for Efficient Late Stage Applications.

The incorporation of three-dimensional structures into drug molecules has demonstrated significant improvements in clinical success. Late-stage saturation of drug molecules provides a direct pathway for this transformation. However, achieving selective and controllable reduction of aromatic rings remains challenging, particularly when multiple aromatic rings coexist. Herein, we present the switchable and chemoselective hydrogenation of benzene and pyridine rings. The utility of the protocol has been comprehensively investigated in diversified substrates with the assistance of a fragment-screening technique. This approach provides convenient access to a diverse array of cyclohexane and piperidine compounds, prevalent in various bioactive molecules and drugs. Furthermore, it discloses promising avenues for applications in the late-stage switchable saturation of drugs, facilitating an increase in the fraction of sp3-carbons which holds the potential to enhance the medicinal properties of drugs.

Scalable and Selective Electrochemical Hydrogenation of Polycyclic Arenes.

The reduction of aromatic compounds constitutes a fundamental and ongoing area of investigation. The selective reduction of polycyclic aromatic compounds to give either fully or partially reduced products remains a challenge, especially in applications to complex molecules at scale. Herein, we present a selective electrochemical hydrogenation of polycyclic arenes conducted under mild conditions. A noteworthy achievement of this approach is the ability to finely control both the complete and partial reduction of specific aromatic rings within polycyclic arenes by judiciously varying the reaction solvents. Mechanistic investigations elucidate the pivotal role played by in situ proton generation and interface regulation in governing reaction selectivity. The reductive electrochemical conditions show a very high level of functional-group tolerance. Furthermore, this methodology represents an easily scalable reduction (demonstrated by the reduction of 1 kg scale starting material) using electrochemical flow chemistry to give key intermediates for the synthesis of specific drugs.

The synthesis of highly nonplanar oxidovanadium(IV) porphyrins as robust catalysts for oxidative bromination of phenols in aqueous medium

Two new complexes, oxidovanadium(IV) 2,3,5,10,12,13,15,20-octaphenyl-7,8,17,18-tetrabromoporphyrin V(IV)O(OPP)Br4 (2), and oxidovanadium(IV) 2,3,5,10,12,13,15,20-octaphenyl-7,8,17,18-tetrachloroporphyrin V(IV)O(OPP)Cl4 (3) starting from oxidovanadium(IV) 2,3,5,10,12,13,15,20-octaphenylporphyrin V(IV)O(OPP) (1) have been prepared in good yields and characterized by various spectroscopic techniques. The single-crystal and DFT-optimized structures of these porphyrins showed a highly nonplanar saddle-shape conformation of the porphyrin macrocycle. In the cyclic voltammograms, the first ring oxidation potential and the first ring reduction potential of V(IV)O(OPP)Br4 (2) and V(IV)O(OPP)Cl4 (3) showed anodic shift as compared to V(IV)O(OPP) (1), indicating the electron-deficient nature of both the porphyrins. The oxidation state of vanadium in the synthesized complexes as +4 was confirmed by EPR spectroscopy, and these porphyrins exhibited axially compressed [Formula: see text] configuration. These porphyrins were utilized as catalysts for the oxidative bromination of thymol and other phenol derivatives with excellent conversion ([Formula: see text] 99.9%), good selectivity, and high TOF value (86869 h[Formula: see text].

Bladder Repair With Irrigation and Debridement and Open Reduction Internal Fixation of the Anterior Pelvic Ring Is Safe and Decreases Risk of Infection in Pelvic Ring Injuries With Extraperitoneal Bladder Ruptures.

To determine the incidence of infection in nonoperative versus operative management of extraperitoneal bladder ruptures in patients with pelvic ring injuries. A retrospective cohort study of 2 prospectively collected trauma registries. Two Level 1 trauma centers. Patients with operative pelvic ring injuries, 68 (6%) had extraperitoneal bladder ruptures. The primary outcome was the incidence and associated risk factors of deep pelvic infection requiring return to OR for surgical debridement. Secondary outcomes included quality of reduction, other complications, and radiographic union. Comparisons were made based on the status of any associated bladder injury. Of 1127 patients with operative pelvic ring injuries, 68 patients had extraperitoneal bladder ruptures, 55 had bladder repair and 13 did not. Of those 13 without repair, none had ORIF of the anterior pelvic ring. Patients without bladder repair had an increased odds of infection 17-fold compared to patients who did have a repair performed (OR 16.9, 95% CI 1.75 - 164, P = 0.01). Other associated factors for deep pelvic infection included use of suprapubic catheter ( p < 0.02) and a closed reduction of the anterior ring ( p < 0.01). Patients undergoing anterior ring ORIF and bladder repair had improved reductions and no increased infection risk. Operative repair of extraperitoneal bladder ruptures decreases risk of infection in patients with pelvic ring injuries. Additionally, ORIF of the anterior pelvic ring does not increase the risk of infection and results in better reductions compared to closed reduction. Treatment algorithms for these combined injuries should consider recommending early bladder repair and anterior pelvic ORIF. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Metagenomic insights into phenanthrene biodegradation in electrical field-governed biofilms for groundwater bioremediation

Electrical fields (EFs)-assisted in-situ bioremediation of petroleum-contaminated groundwater, such as polycyclic aromatic hydrocarbons, has drawn increasing attention. However, the long-term stability, the EFs influence, and metabolic pathways are still poorly understood, hindering the further development of robust technology design. Herein, a series of EFs was applied to the phenanthrene-contaminated groundwater, and the corresponding system performance was investigated. The highest removal capacity of phenanthrene (phe) (7.63 g/(m3·d)) was achieved with EF_0.8 V biofilm at a hydrolytic retention time of 0.5 d. All the biofilms with four EFs exhibited a high removal efficiency of phe over 80% during a 100-d continuous-flow operation. Intermediates analysis revealed the main pathways of phe degradation: phthalate and salicylate via hydroxylation, methylation, carboxylation, and ring cleavage steps. Synergistic effects between phe-degraders (Dechloromonas), fermentative bacteria (Delftia), and electroactive microorganisms (Geobacter) were the main contributors to the complete phe mineralization. Genes encoding various proteins of methyl-accepting (mcp), response regulator (cheABDRY), and type IV pilus (pilABCMQV) were dominant, revealing the importance of cell motility and extracellular electron transfer. Metagenomics analysis unveiled phe-degrading genes, including ring reduction enzymes (bamBCDE), carboxylase of aromatics (ubiD), and methyltransferase protein (ubiE, pcm). These findings offered a molecular understanding of refractory organics’ decompositions in EFs-governed biotechnology.

Physical and Electrochemical Properties of Transition Metal Oxides with Hollow Structure As Sulfur Host Material for Lithium-Sulfur Batteries

INTRODUCTION Because of its high theoretical energy density, possibly low cost, and environmental friendliness, lithium-sulfur (Li-S) batteries have received a lot of interest. However, the principal disadvantage impeding the success of Li–S batteries lies in the severe leakage and migration of soluble lithium polysulfide intermediates out of cathodes upon cycling caused “shuttle effect”. The loss of active sulfur species incurs significant capacity decay and poor battery lifespans which has prevented it from commercial realization.Several researches have been conducted with an attempt to improve capacity of batteries while maintaining life of the Li-S cellใ including an introduction of nanostructured cathode host materials. Two main approaches have currently been explored a. chemical confinement and b. physical confinement to anchor the lithium poly-sulfide (LiPSs) reaction products durin the charging process. Transition metal oxides such as TiO2 and SnO2 has been studied with a potential material to anchor polysulfides via Lewis acid–base interactions and thus maybe able to chemically confine LiPSs within or on the transition metal oxide. Physical confinement may also be possible by trapping LiPSs within a transition metal oxide host structure e.g. hollow structure and thus help impedes polysulfide dissolution into the electrolyte. In this study, TiO2 and SnO2 are focused to understand the physical and electrochemical properties of sulfur host material with hollow structures. The in situ XAS is also conducted to understand the behavior of the dissolution and migration of long-chain LiPSs intermediates (Li2S x , 4 ≤ x ≤ 8) in the sulfur cathode upon discharge. EXPERIMENTAL The transition metal oxide, TiO2 and SnO2, were successfully synthesized by a templated method. The synthesis process involved four steps, preparation of SiO2 spheres, synthesis of SiO2@transition metal oxide core-shell structure by coating transition metal oxide shell on SiO2 and crystallization by calcination and etching the SiO2@transition metal oxide to form hollow transition metal oxide spheres. Structural properties of the synthesized samples were studied by X-ray diffraction (XRD) using Cu-Kα (λ=1.5418 Å) radiation. Particle morphologies and size of the resulting compounds were observed using a field emission scanning electron microscope. Composite electrodes for electrochemical studies were prepared by doctor blade coating of a slurry compound onto carbon-coated aluminium foil current-collectors. The transition metal oxide and sulfur composite, conductive carbon and PVDF binder were mixed in the ratio of 80:10:10 by weight. Electrochemical characterizations were performed by in 2032 coin cells and Galvanostatic charge-discharge cycling was done between 1.8-3.0 V at 0.1C using a MACCOR Series 4000 at room temperature. RESULTS AND DISCUSSIONS Based on the XRD results, single phase anatase TiO2 and tetragonal SnO2 were both successfully synthesized by the templated method. SEM images (Fig. 1a and 1b) demonstrate that TiO2 and SnO2 are generally spherical structures with nanometer scale dimensions ranging from 250-350 nm and 450-500 nm, respectively. The interior hollow region can be seen clearly in the images of broken spheres. The shelled surface of the synthesized powders is hierarchically made up of interconnected nanocrystals providing a possibly porous structure. Hence, the hierarchically porous and hollow structure has a large surface area for adsorbing the LiPSs distributed in the electrolyte.Fig. 1c shows the charge and discharge voltage profiles of SnO2 and sulfur composite electrode cathode in the first five cycles. Two discharge plateaus were clearly observed, which might be attributed to the two-step sulfur-lithium reaction process. The initial plateau, centered about 2.30 V, was commonly attributed to the reduction of the S8 ring and the formation of S8 2−. The second discharge plateau at 2.10 V was attributed to further reduction of the higher polysulfides (Li2S n , 4 ≤ n ≤ 8) to the lower polysulfides (Li2S n , n ≤ 3). There exhibited two plateaus in the charge process at about 2.25 and 2.35 V, respectively. Electrochemical performance in relations to capacity retention and the in situ XAS to understand the behavior of the dissolution and migration of LiPSs will be discussed in the meeting. Figure 1

Single Pyrrole Unit Functionalized Electron Deficient Porphyrins and Their Metal Complexes: Synthesis, Structural, Spectral and Electrochemical Properties

AbstractA family of electron‐deficient regioselective β‐disubstituted meso‐tetraphenylporphyrins, H2TPP(R)2 (where R=trifluoromethyl (CF3) and cyano (CN) and its metal complexes (Co(II), Ni(II), Cu(II) and Zn(II)) were synthesized from versatile precursor H2TPPBr2 by palladium‐catalyzed trifluoromethylation and nucleophilic aromatic cyanation respectively. The absorption spectrum of H2TPP(CF3)2 and H2TPP(CN)2 exhibited a notable shift towards longer wavelengths both in the Soret (Δλmax=16–17 nm) and longest wavelength band, Qx(0,0) (Δλmax=34–52 nm) as compared to precursor porphyrin, H2TPPBr2. The first ring reduction potential of H2TPP(CF3)2 and H2TPP(CN)2 are centred at −0.69 and −0.68 respectively which show drastic anodic shift as compared to precursor H2TPPBr2 (−1.01 V) and parent porphyrin H2TPP (−1.25 V). The anodic shift trend for first ring reduction potentials follows as H2TPP(CN)2&gt;H2TPP(CF3)2&gt;H2TPP(Br)2&gt;H2TPP. Introducing two highly electron withdrawing substituents (CN and CF3) at the single pyrrole unit of the porphyrin macrocycle via regioselective substitution has led to a significant reduction in the HOMO‐LUMO energy gap (0.15 V–0.39 V) in comparison to the precursor H2TPPBr2 (2.08 V). The analysis of the crystal structures for ZnTPP(CN)2 and H2TPP(CF3)2 revealed nearly planar and distinct saddle conformations respectively which are further supported by DFT calculations.

Directing Group Strategy for the Isolation of Organoselenium(VI) Benzoselenonates: Metal-Free Catalysts for Hydrogen Evolution Reaction.

The exploration of fourth-period organoelements, particularly organoseleniums in their highest VI oxidation state, is limited owing to their stability and synthesis. Herein, the isolation of a new class of quinolinyl-embedded, hexavalent selenium(VI) benzoselenonates has been discussed and further evaluated for a metal-free electrocatalytic hydrogen evolution reaction (HER). The Se(VI) benzoselenonates exhibited high Faradaic efficiency (F.E.) of metal-free H2 gas production up to 86% with a very good turnover number (TON) up to 43 and moderate overpotential (η) of 500 mV; in the presence of mild acetic acid source in a less deprotonating DMF solvent. Taken together with various (NMR, UV-vis, and EPR) spectroscopic and DFT computation studies, a plausible HER pathway is proposed, which suggests that the electrochemical reduction of quinolinyl ring is the initiation step and Se(VI) acts as the reaction site by involving a hydridic type of intermediate for the electrochemical H2 gas generation.

Computing primitive idempotents in finite commutative rings and applications

In this paper, we compute an algebraic decomposition of black-box rings in the generic ring model. More precisely, we explicitly decompose a black-box ring as a direct product of a nilpotent black-box ring and unital local black-box rings, by computing all its primitive idempotents. The algorithm presented in this paper uses quantum subroutines for the computation of the p-power parts of a black-box ring and then classical algorithms for the computation of the corresponding primitive idempotents. As a by-product, we get that the reduction of a black-box ring is also a black-box ring. The first application of this decomposition is an extension of the work of Maurer and Raub (2007) on representation problem in black-box finite fields to the case of reduced p-power black-box rings. Another important application is an IND-CCA1 attack for any ring homomorphic encryption scheme in the generic ring model. Moreover, when the plaintext space is a finite reduced black-box ring, we present a plaintext-recovery attack based on representation problem in black-box prime fields. In particular, if the ciphertext space has smooth characteristic, the plaintext-recovery attack is effectively computable in the generic ring model.

New insights into the dihydro-mureidomycin biosynthesis controlled by two unusual proteins in Streptomyces roseosporus

BackgroundUridyl peptide compounds are renowned as a subclass of nucleoside antibiotics for their highly specific antibacterial activity against Gram-negative bacteria and the unique target of action. We previously activated the biosynthetic gene cluster of a uridyl peptide antibiotic, mureidomycin, in Streptomyces roseosporus NRRL 15998 by introducing an exogenous positive regulator gene ssaA, and the generated strain was designated as Sr-hA. This study aims to further explore mureidomycin analogs from Sr-hA as well as the collaborative roles of two wide-spread genes, SSGG-02980 and SSGG-03002 encoding putative nuclease/phosphatase and oxidoreductase respectively, in mureidomycin diversification.ResultsIn order to understand how SSGG-02980 and SSGG-03002 contribute to mureidomycin biosynthesis, the gene disruption mutants and complementary strains were constructed. Mass spectrometry analyses revealed that two series of pairwise mureidomycin analogs were synthesized in Sr-hA with a two-dalton difference in molecular weight for each pair. By disruption of SSGG-03002, only mureidomycins with lower molecular weight (MRDs, 1–6) could be specifically accumulated in the mutant (∆03002-hA), whereas the other series of products with molecular weight plus 2 Da (rMRDs, 1ʹ–6ʹ) became dominant in SSGG-02980 disruption mutant (∆02980-hA). Further comprehensive NMR analyses were performed to elucidate the structures, and three MRDs (3, 4, 5) with unsaturated double bond at C5-C6 of uracil group were characterized from ∆03002-hA. In contrast, the paired rMRDs analogs (3ʹ, 4ʹ, 5ʹ) from ∆SSGG-02980 corresponding to 3, 4 and 5 were shown to contain a single bond at this position. The results verified that SSGG-03002 participates in the reduction of uracil ring, whereas SSGG-02980 antagonizes the effect of SSGG-03002, which has been rarely recognized for a phosphatase.ConclusionsOverall, this study revealed the key roles of two wide-spread families of enzymes in Streptomyces. Of them, oxidoreductase, SSGG-03002, is involved in dihydro-mureidomycin biosynthesis of S. roseosporus, whereas nuclease/phosphatase, SSGG-02980, has an adverse effect on SSGG-03002. This kind of unusual regulation model between nuclease/phosphatase and oxidoreductase is unprecedented, providing new insights into the biosynthesis of mureidomycins in Streptomyces. The findings would be of significance for structural diversification of more uridyl peptide antibiotics against Gram-negative bacteria.

Adverse effects of air pollution on human health predicted from tree-ring reductions – A conceptualization of a new ecosystem service

Air pollution adversely affects human health, while trees, conifers in particular, growing in areas affected by air pollution, immediately register pollution by developing rings with decreased width. Some diseases in human population, e.g. lung cancer, develop and are diagnosed with a certain delay in relation to the exposure to air pollution, thus, with a certain delay to ring reductions in trees. Therefore, reductions can be recognized as an early indicator that alerts about forthcoming outbreak of adverse health effects in human population. Based on this phenomenon we propose a new approach and a new methodology for assessing threats to human health and lives resulting from air pollution. In this paper we explain the application of new approach by presenting and describing it step by step. We state that data obtained through the new ecosystem service can be applied for early warning against adverse effects of air pollution on human health. This includes improved prediction of hospitalization patterns and financial costs for the healthcare system. The proposed methodology can be useful for decision makers e.g. local governments, state agencies, private enterprises and other stakeholders interested in controlling local emitters of air pollution and the harmfulness of pollution to human health and lives.

1-Azaspiro[3.3]heptane as a Bioisostere of Piperidine.

1-Azaspiro[3.3]heptanes were synthesized, characterized, and validated biologically as bioisosteres of piperidine. The key synthesis step was thermal [2+2] cycloaddition between endocyclic alkenes and Graf's isocyanate, ClO2S-NCO, into spirocyclic β-lactams. Reduction of the β-lactam ring with alane produced 1-azaspiro[3.3]heptanes. Incorporation of this core into the anesthetic drug Bupivacaine instead of the piperidine fragment resulted in the new patent-free analogue with high activity.

Open Fixation After Preperitoneal Pelvic Packing Is Associated With a High Surgical Site Infection Rate.

To evaluate the incidence of pelvic space surgical site infection (SSI) after preperitoneal pelvic packing (PPP) for persistent hemodynamic instability. Retrospective comparative study. Urban Level 1 trauma center. 83 patients who received PPP and 55 patients who had open reduction and internal fixation (ORIF) of the anterior pelvic ring without PPP. Operative fixation. Pelvic space SSI. The SSI rate in the PPP group was 31.3% (26/83) compared with 10.9% (6/55) in the control group (proportional difference 20.4%, confidence interval (CI) 6.4-32.5, P = 0.007). Patients in the PPP group (n = 43) were 1:1 propensity score matched with patients in the control group to account for differences in Injury Severity Score and American Society of Anesthesiologists score. In this matched cohort, the rate of pelvic space SSI remained higher in the PPP group compared with that in the control group (30.2% vs. 9.3%; proportional difference 20.9%, CI, 3.7-36.3; P = 0.02). On multivariate analysis of the PPP group, anterior ORIF (odds ratio 6.56, CI, 2.00-21.47, P = 0.002) was found to be independently associated with SSI. PPP is an independent risk factor of space SSI. The likelihood of SSI after PPP is increased with anterior ORIF. The morbidity of SSI after PPP must be weighed against the risk of exsanguination. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

New Insights into the Physicochemical and Electrochemical Characterization of Gold Phthalocyanine-Based Materials

Gold phthalocyanine-based materials can allow to combine the unique physical properties of the metallophthalocyanine with gold for numerous applications such as (photo)-electrochemistry or the so-called single atom catalysts (SACs), which require very small amounts of metal. However, there is currently a lack of physico-chemical and electrochemical knowledge to consider such applications. We report the synthesis and the physical characterization of three types of materials, the unsubstituted and the octo-substituted gold phthalocyanines AuPc, AuPc(CN)8 and AuPc(COOH)8, which were successfully synthesized. To interrogate the physicochemical and electrochemical properties of the as-synthesized materials, we have performed a multi-variant study by integrating different methods (UV–vis, FTIRS, TGA-TDA, HR-ESI-MS, SEM-EDX, XRD, XPS, CV). UV–vis confirms the shift towards high wavelengths (bathochromic effect) for the transition Q-band (charge transfer from pyrrolic carbons to neighboring atoms in the macrocycle) of AuPc(CN)8 and AuPc(COOH)8 compared to AuPc. CV in both aqueous and non-aqueous provides the first electrochemical insights into the phthalocyanine ring reduction and oxidation, AuPc/[AuPc]−, [AuPc]−/[AuPc]2− and [AuPc]2−/[AuPc]3−. The results delineate a possible rational pathway for AuPc-based materials or alternatively, their transformation into SACs, where a single Au atom is embedded in a nanostructured carbon-nitrogen scaffold.

Higher pelvic incidence values are a risk factor for trans-iliac trans-sacral screw malposition in sacroiliac complex fracture treatment

BackgroundPercutaneous iliosacral (IS) screw fixation and trans-iliac trans-sacral (TITS) screw fixation are clinically effective treatments of posterior pelvic sacroiliac fractures. In order to accurately assess the sacrum position relative to the pelvis, pelvic incidence (PI) is a commonly utilized radiographic parameter in sagittal view. This study aimed to investigate and compare the surgical outcomes and radiographic parameters of IS or TITS screw fixations for the treatment of posterior sacroiliac complex fractures with different PI values.Materials and methodsThe data on patients with posterior pelvic sacroiliac fractures who underwent percutaneous IS or TITS screw fixations, or both, at a single level I trauma center between January 2017 and June 2020 were reviewed. We documented the patient characteristics and fracture types, reviewed surgical records, and measured the radiographic parameters via plain films and multi-planar computed tomography (mpCT) images. Radiographic variations in PI, sacral slope, pelvic tilt, sacral dysmorphism, pelvic ring reduction quality, screw deviation angles, screw malposition grading, and iatrogenic complications were documented and analyzed.ResultsA total of 85 patients were included, and 65 IS and 70 TITS screws were accounted for. Patients were divided into two groups according to screw fixation method and further divided into four sub-groups based on baseline PI values. The PI cutoff values were 49.85° and 48.05° in the IS and TITS screw groups, respectively, according to receiver operating characteristic analysis and Youden's J statistic. Smaller PI values were significantly correlated with sacral dysmorphism (p = 0.027 and 0.003 in the IS and TITS screw groups, respectively). Patients with larger PI values were at a significantly increased risk of screw malposition in the TITS screw group (p = 0.049), with no association in the IS screw group. Logistic regression confirmed that a larger PI value was a significant risk factor for screw malposition in the TITS screw group (p = 0.010). The post-operative outcomes improved from poor/fair (at 6 months) to good/average (at 12 months) based on the Postel Merle d'Aubigné and Majeed scores, with no significant differences between subgroups.ConclusionsBoth percutaneous IS and TITS screw fixations are safe and effective treatments for posterior pelvic sacroiliac fractures. Due to the higher risk of screw malposition in patients with larger PI values, it is crucial to identify potential patients at risk when performing TITS screw fixation surgery.Level of evidence:Level III.

Advantages of residual phenol in coal chemical wastewater as a co-metabolic substrate for naphthalene degradation by microbial electrolysis cell

The use of co-metabolic substrates is effective for polycyclic aromatic hydrocarbons (PAHs) removal, but the potential of the high phenol concentrations in coal chemical wastewater (CCW) as a co-metabolic substrate in microbial electrolysis cell (MEC) has been neglected. In this study, the efficacy of varying phenol concentrations in comparison to simple substrates for degrading naphthalene in MEC under comparable COD has been explored. Results showed that phenol as a co-metabolic substrate outperformed sodium acetate and glucose in facilitating naphthalene degradation efficiency at 50 mg-COD/L. The naphthalene removal efficiency from RP, RA, and RG was found to be 84.11 ± 0.44 %, 73.80 ± 0.27 % and 72.43 ± 0.34 %, respectively. Similarly, phenol not only enhanced microbial biomass more effectively, but also exhibited optimal COD metabolism capacity. The addition of phenol resulted in a stepwise reduction in the molecular weight of naphthalene, whereas sodium acetate and glucose led to more diverse degradation pathways. Some bacteria with the potential ability to degrade PAHs were detected in phenol-added MEC, including Alicycliphilus, Azospira, Stenotrophomonas, Pseudomonas, and Sedimentibacter. Besides, phenol enhanced the expression of ncrA and nmsA genes, leading to more efficient degradation of naphthalene, with ncrA responsible for mediating the reduction of the benzene ring in naphthalene and nmsA closely associated with the decarboxylation of naphthalene. This study provides guidance for the effective co-degradation of PAHs in CCW with MEC, demonstrating the effectiveness of using phenol as a co-substrate relative to simple substrates in the removal of naphthalene.

Gate Pulsing as a Transient Ringing Reduction Method for Multilevel Supply Modulators

Gate Pulsing as a Transient Ringing Reduction Method for Multilevel Supply Modulators

Anaerobic biodegradation of pyrene and benzo[a]pyrene by a new sulfate-reducing Desulforamulus aquiferis strain DSA

The study of anaerobic high molecular weight polycyclic aromatic hydrocarbons (HMW-PAHs) biodegradation under sulfate-reducing conditions by microorganisms, including microbial species responsible for biodegradation and relative metabolic processes, remains in its infancy. Here, we found that a new sulfate-reducer, designated as Desulforamulus aquiferis strain DSA, could biodegrade pyrene and benzo[a]pyrene (two kinds of HMW-PAHs) coupled with the reduction of sulfate to sulfide. Interestingly, strain DSA could simultaneously biodegrade pyrene and benzo[a]pyrene when they co-existed in culture. Additionally, the metabolic processes for anaerobic pyrene and benzo[a]pyrene biodegradation by strain DSA were newly proposed in this study based on the detection of intermediates, quantum chemical calculations and analyses of the genome and RTqPCR. The initial activation step for anaerobic pyrene and benzo[a]pyrene biodegradation by strain DSA was identified as the formation of pyrene-2-carboxylic acid and benzo[a]pyrene-11-carboxylic acid by carboxylation Thereafter, CoA ligase, ring reduction through hydrogenation, and ring cracking occurred, and short-chain fatty acids and carbon dioxide were identified as the final products. Additionally, DSA could also utilize benzene, naphthalene, anthracene, phenanthrene, and benz[a]anthracene as carbon sources. Our study can provide new guidance for the anaerobic HMW-PAHs biodegradation under sulfate-reducing conditions.