RESUMEN
Since limb bleeding has been well managed by extremity tourniquets, the management of exsanguinating torso hemorrhage (TH) has become a hot issue both in military and civilian medicine. Conventional hemostatic techniques are ineffective for managing traumatic bleeding of organs and vessels within the torso due to the anatomical features. The designation of noncompressible torso hemorrhage (NCTH) marks a significant step in investigating the injury mechanisms and developing effective methods for bleeding control. Special tourniquets such as abdominal aortic and junctional tourniquet and SAM junctional tourniquet designed for NCTH have been approved by FDA for clinical use. Combat ready clamp and junctional emergency treatment tool also exhibit potential for external NCTH control. In addition, resuscitative endovascular balloon occlusion of the aorta (REBOA) further provides an endovascular solution to alleviate the challenges of NCTH treatment. Notably, NCTH cognitive surveys have revealed that medical staff have deficiencies in understanding relevant concepts and treatment abilities. The stereotypical interpretation of NCTH naming, particularly the term noncompressible, is the root cause of this issue. This review discusses the dynamic relationship between TH and NCTH by tracing the development of external NCTH control techniques. The authors propose to further subdivide the existing NCTH into compressible torso hemorrhage and NCTH' (noncompressible but REBOA controllable) based on whether hemostasis is available via external compression. Finally, due to the irreplaceability of special tourniquets during the prehospital stage, the authors emphasize the importance of a package program to improve the efficacy and safety of external NCTH control. This program includes the promotion of tourniquet redesign and hemostatic strategies, personnel reeducation, and complications prevention.
Asunto(s)
Oclusión con Balón , Torso , Humanos , Hemorragia/etiología , Hemorragia/terapia , Extremidades , Aorta AbdominalRESUMEN
A novel in situ chemical upcycling strategy for plastic waste is proposed by the customized diphenylacetylene monomer with dual photo-response. That is, diphenylacetylene reactive monomers are in situ inserted into the macromolecular chain of polyethylene terephthalate (PET) plastics/fibers through one-pot transesterification of slight-depolymerization and re-polymerization. On the one hand, the diphenylacetylene group absorbs short-wave high-energy UV rays and then releases long-wave low-energy harmless fluorescence. On the other hand, the UV-induced photo-crosslinking reaction among diphenylacetylene groups produces extended π-conjugated structure, resulting in a red-shift (due to decreased HOMO-LUMO separation) in the UV absorption band and locked crosslink points between PET chains. Therefore, with increasing UV exposure time, the upcycled PET plastics exhibit reverse enhanced UV resistance and mechanical strength (superior to original performance), instead of serious UV-photodegradation and damaged performance. This upcycling strategy at oligomer-scale not only provides a new idea for traditional plastic recycling, but also solves the common problem of gradual degradation of polymer performance during use.
RESUMEN
PURPOSE: SAM junctional tourniquet (SJT) has been applied to control junctional hemorrhage. However, there is limited information about its safety and efficacy when applied in the axilla. This study aims to investigate the effect of SJT on respiration when used in the axilla in a swine model. METHODS: Eighteen male Yorkshire swines, aged 6-month-old and weighing 55 - 72 kg, were randomized into 3 groups, with 6 in each. An axillary hemorrhage model was established by cutting a 2 mm transverse incision in the axillary artery. Hemorrhagic shock was induced by exsanguinating through the left carotid artery to achieve a controlled volume reduction of 30% of total blood volume. Vascular blocking bands were used to temporarily control axillary hemorrhage before SJT was applied. In Group I, the swine spontaneously breathed, while SJT was applied for 2 h with a pressure of 210 mmHg. In Group II, the swine were mechanically ventilated, and SJT was applied for the same duration and pressure as Group I. In Group III, the swine spontaneously breathed, but the axillary hemorrhage was controlled using vascular blocking bands without SJT compression. The amount of free blood loss was calculated in the axillary wound during the 2 h of hemostasis by SJT application or vascular blocking bands. After then, a temporary vascular shunt was performed in the 3 groups to achieve resuscitation. Pathophysiologic state of each swine was monitored for 1 h with an infusion of 400 mL of autologous whole blood and 500 mL of lactated ringer solution. Tb and T0 represent the time points before and immediate after the 30% volume-controlled hemorrhagic shock, respectively. T30, T60, T90 and T120, denote 30, 60, 90, and 120 min after T0 (hemostasis period), while T150, and T180 denote 150 and 180 min after T0 (resuscitation period). The mean arterial pressure and heart rate were monitored through the right carotid artery catheter. Blood samples were collected at each time point for the analysis of blood gas, complete cell count, serum chemistry, standard coagulation tests, etc., and thromboelastography was conducted subsequently. Movement of the left hemidiaphragm was measured by ultrasonography at Tb and T0 to assess respiration. Data were presented as mean ± standard deviation and analyzed using repeated measures of two-way analysis of variance with pairwise comparisons adjusted using the Bonferroni method. All statistical analyses were processed using GraphPad Prism software. RESULTS: Compared to Tb, a statistically significant increase in the left hemidiaphragm movement at T0 was observed in Groups I and II (both p < 0.001). In Group III, the left hemidiaphragm movement remained unchanged (p = 0.660). Compared to Group I, mechanical ventilation in Group II significantly alleviated the effect of SJT application on the left hemidiaphragm movement (p < 0.001). Blood pressure and heart rate rapidly increased at T0 in all three groups. Respiratory arrest suddenly occurred in Group I after T120, which required immediate manual respiratory assistance. PaO2 in Group I decreased significantly at T120, accompanied by an increase in PaCO2 (both p < 0.001 vs. Groups II and III). Other biochemical metabolic changes were similar among groups. However, in all 3 groups, lactate and potassium increased immediately after 1 min of resuscitation concurrent with a drop in pH. The swine in Group I exhibited the most severe hyperkalemia and metabolic acidosis. The coagulation function test did not show statistically significant differences among three groups at any time point. However, D-dimer levels showed a more than 16-fold increase from T120 to T180 in all groups. CONCLUSION: In the swine model, SJT is effective in controlling axillary hemorrhage during both spontaneous breathing and mechanical ventilation. Mechanical ventilation is found to alleviate the restrictive effect of SJT on thoracic movement without affecting hemostatic efficiency. Therefore, mechanical ventilation could be necessary before SJT removal.
Asunto(s)
Choque Hemorrágico , Enfermedades Vasculares , Masculino , Animales , Porcinos , Choque Hemorrágico/terapia , Torniquetes , Axila , Hemorragia/terapia , RespiraciónRESUMEN
The preparation of room temperature phosphorescent carbon dots still faces great challenges, especially in the case of carbon dots endowed of visible-light excitable room temperature phosphorescence (RTP). To date, a limited number of substrates have been exploited to synthesize room temperature phosphorescent carbon dots, and most of them can emit RTP only in solid state. Here, the synthesis of a composite obtained from the calcination of green carbon dots (g-CDs) blended with aluminum hydroxide (Al(OH)3 ) is reported. The resultant hybrid material g-CDs@Al2 O3 exhibits blue fluorescence and green RTP emissions in an on/off switch process at 365 nm. Notably, this composite manifests strong resistance to extreme acid and basic conditions up to 30 days of treatment. The dense structure of Al2 O3 formed by calcination contributes to the phosphorescent emission of g-CDs. Surprisingly, g-CDs@Al2 O3 can also emit yellow RTP under irradiation with white light. The multicolor emissions can be employed for anti-counterfeiting and information encryption. This work provides a straightforward approach to produce room temperature phosphorescent carbon dots for a wide range of applications.
RESUMEN
OBJECTIVE: Noncompressible torso hemorrhage (NCTH) is a major challenge in prehospital bleeding control and is associated with high mortality. This study was performed to estimate medical knowledge and the perceived barriers to information acquisition among health-care workers (HCWs) regarding NCTH in China. METHODS: A self-administered and validated questionnaire was distributed among 11 WeChat groups consisting of HCWs engaged in trauma, emergency, and disaster rescue. RESULTS: A total of 575 HCWs participated in this study. In the knowledge section, the majority (87.1%) denied that successful hemostasis could be obtained by external compression. Regarding attitudes, the vast majority of HCWs exhibited positive attitudes toward the important role of NCTH in reducing prehospital preventable death (90.4%) and enthusiasm for continuous learning (99.7%). For practice, fewer than half of HCWs (45.7%) had heard of NCTH beforehand, only a minority (14.3%) confirmed they had attended relevant continuing education, and 16.3% HCWs had no access to updated medical information. The most predominant barrier to information acquisition was the lack of continuing training (79.8%). CONCLUSIONS: Knowledge and practice deficiencies do exist among HCWs. Obstacles to update medical information warrant further attention. Furthermore, education program redesign is also needed.
Asunto(s)
Personal de Salud , Hemorragia , Humanos , Hemorragia/terapia , Torso , Hemostasis , Encuestas y Cuestionarios , Conocimientos, Actitudes y Práctica en SaludRESUMEN
BACKGROUND: External hemorrhage control devices (EHCDs) are effective in reducing the death risk of noncompressible torso hemorrhage (NCTH), but the pressurized area is too large to prevent serious organ damage. This study aims to establish the surface localization strategy of EHCDs based on the anatomical features of NCTH-related arteries through CT images to facilitate the optimal design and application of EHCDs. METHODS: Two hundred patients who underwent abdominal CT were enrolled. Anatomical parameters such as the length of the common iliac artery (CIA), the external iliac artery (EIA), and the common femoral artery were measured; positional relationships among the EHCD-targeted arteries, umbilicus, anterior superior iliac spine (ASIS), and pubic tubercle (PT) were determined. The accuracy of surface localization was verified by the 3D-printed mannequins of 20 real patients. RESULTS: Aortic bifurcation (AB) was 7.5 ± 8.6 mm to the left of the umbilicus. The left CIA (left: 46.6 ± 16.0 mm vs. right: 43.3 ± 15.5 mm, P = .038) and the right EIA (left: 102.6 ± 16.3 mm vs. right: 111.5 ± 18.8 mm, P < .001) were longer than their counterparts, respectively. The vertical distance between the CIA terminus and the ipsilateral AB-ASIS line was 19.6 ± 8.2 mm, and the left and right perpendicular intersections were located at the upper one-third and one-fourth of the AB-ASIS line, respectively. The length ratio of EIA-ASIS to ASIS-PT was 0.6:1. The predicted point and its actual subpoint were significantly correlated (P ≤ .002), and the vertical distance between the two points was ≤5.5 mm. CONCLUSION: The arterial localization strategy established via anatomical investigation was consistent with the actual situation. The data are necessary for improving EHCD design, precise hemostasis, and EHCD-related collateral injuries.Trial registration: Ratification no. 2019092. Registered November 4, 2020-retrospectively registered, www.chictr.org.cn.
Asunto(s)
Aorta Abdominal , Arteria Ilíaca , Arteria Femoral , Hemorragia , Humanos , Arteria Ilíaca/diagnóstico por imagen , TorsoRESUMEN
In China, hepatocellular carcinoma (HCC) is considered a malignant tumor with poor prognosis, frequent metastasis, and a high relapse rate. Telocytes (TCs) participate in tumorigenic, invasive, and migratory processes by secreting functional proteins and transmitting cell-to-cell information, but their functions in HCC are still unknown. TC counts and MMP9 expression in liver cancer tissues were measured using immunohistochemistry, western blotting, and RT-PCR. Primary TCs from liver para-cancer tissues were cultured in vitro. To verify the role of TCs in HCC, a metastatic cancer animal model was established using three types of liver cancer cell lines in vivo. TCs promoted HCC cell metastasis by MMP9 expression in vitro and in vivo. Platelet-derived growth factor-alpha (PDGF-α), secreted by HCC cells, activated the Ras/ERK signaling pathway in TCs, thereby increasing MMP9 expression; Moreover, miR-942-3p suppressed MMP9 expression in TCs. Our results reveal the role of TCs in HCC and the mechanisms by which they elicit their effects, and they may serve as novel prognostic markers for HCC.
RESUMEN
With the widespread adoption of advanced tourniquets, the mortality rate of limb wound hemorrhage has decreased significantly, and non-compressible torso hemorrhage has gradually occupied the leading position of potentially preventable death, both in military and civilian circumstances. With the emergence of novel hemostatic devices and materials, strategies for the management of non-compressible torso hemorrhage have changed significantly. This review summarizes the current treatment strategies and types of equipment for non-compressible torso hemorrhage and suggests future research directions, hoping to provide a comprehensive review for the medical personnel and researchers engaging in this field.
Asunto(s)
Hemorragia , Hemostáticos , Hemorragia/etiología , Hemorragia/terapia , Humanos , TorsoRESUMEN
BACKGROUND: Candidal periprosthetic joint infection is a rare and difficult to diagnose complication of total knee arthroplasty. The treatment of such complications is inconclusive and may include prosthesis removal, debridement, arthrodesis, and extensive antifungal therapy to control the infection. CASE SUMMARY: A 62-year-old male with a history of total knee arthroplasty (TKA) in his left knee presented with ipsilateral knee pain and a sinus discharge 20 mo after TKA. The patient was previously evaluated for left knee pain, swelling, and a transient fever one month postoperatively. Prothesis removal and insertion of a cement spacer were performed in a local hospital six months prior to the current presentation. Medical therapy included rifampicin and amphotericin which were administered for 4 wk following prosthesis removal. A second debridement was performed in our hospital and Candida parapsilosis was detected in the knee joint. Fourteen weeks following the latter debridement, the patient suffered a left intertrochanteric fracture and received closed reduction and internal fixation with proximal femoral nail anterotation. Two weeks after fracture surgery, a knee arthrodesis with autograft was performed using a double-plate fixation. The patient recovered adequately and was subsequently discharged. At the two-year follow-up, the patient has a stable gait with a pain-free, fused knee. CONCLUSION: Fungal periprosthetic joint infection following TKA may be successfully and safely treated with prosthesis removal, exhaustive debridement, and arthrodesis after effective antifungal therapy. Ipsilateral intertrochanteric fractures of the affected knee can be safely fixated with internal fixation if the existing infection is clinically excluded and aided by the investigation of serum inflammatory markers.
RESUMEN
Rational materials design for the synthesis of desirable hollow micro- and nanostructures has recently revealed the remarkable potential for high-performance energy storage and conversion devices. Owing to their unique "core-void-shell" structural configurations, yolk-shell-structured electrode materials can achieve intimate contact with the electrolyte and alleviate the volume expansion issue during electrochemical cycling, which is therefore poised to further boost the electrochemical properties of hybrid supercapacitors. Herein, a facile self-templated strategy, consisting of a hydrothermal step and a high-temperature sulfurization process, has been developed for the construction of yolk-shell (NiCo)9S8 spheres in situ coated by graphite carbon ((NiCo)9S8/GC) due to the non-equilibrium thermal treatment of alkali metal alkoxides. The as-synthesized yolk-shelled sphere exhibits a high specific capacitance of 1434.4 F g-1 (179.3 mA h g-1) at a current density of 1 A g-1, and good rate capability and cycling stability with 83.1% capacitance retention at 8 A g-1 over 5000 cycles. To further demonstrate its practical application, a hybrid supercapacitor device was assembled using (NiCo)9S8/GC as the battery-type positive electrode and activated carbon (AC) as the capacitive-type electrode. The as-fabricated device can reach a wide voltage window of up to 1.6 V, deliver a high energy density of 55.6 W h kg-1 at a power density of 800.3 W kg-1 and maintain 90.2% of specific capacitance after 3000 cycles.
RESUMEN
Transition metal oxides have recently been demonstrated as highly attractive anodes for high-capacity lithium ion batteries, whose electrochemical properties could be further improved through rational architecture design and incorporating reliable conductive network. Herein, mesoporous γ-Fe2O3 spheres/graphene aerogel composites were synthesized via a solvothermal pathway followed by suitable annealing. Experimental results reveal the uniform mesoporous structure and well-dispersed γ-Fe2O3 spheres with the size of 300-400 nm embedded in the mesopores of the graphene aerogel network. Compared with α-Fe2O3/graphene aerogel and pure γ-Fe2O3, the as-synthesized composite delivers, at the first cycle, a high discharging capacity of 1080 mAh g-1 at current density of 200 mA g-1. Even at much higher current density of 8000 mA g-1, satisfactory discharging capacities of 421.5 mAh g-1 can still be achieved. Upon 100 charging-discharging cycles, the specific capacity of as high as 890.5 mAh g-1 at 200 mA g-1 is maintained. The enhanced electrochemical properties could be attributed to their favorable three-dimensional graphene aerogel network, which accounts for the improved structural stability and electronic conductivity of γ-Fe2O3 during the lithiation/delithiation process.
RESUMEN
The continuous exploration of advanced electrode materials is of remarkable significance to revolutionize next-generation high-performance energy storage devices towards a green future. Benefiting from their electrochemically active sites and abundant redox centers, bimetallic selenides with desirable nanostructures recently have emerged as promising electrode alternatives for battery-supercapacitor hybrid (BSH) devices which demonstrate enormous potential in bridging the gap between electrochemical properties with high power densities (supercapacitors) and energy densities (batteries). Herein, employing the hydrothermal approach with solid Ni-Co spheres as precursors followed by the selenization process, selenide-rich bimetallic selenide spheres with a core-shell nanostructure were rationally designed and synthesized for use as the cathode electrode in superior BSH devices. The as-obtained (NiCo)9Se8/(NiCo)0.85Se (Ni-Co-Se) exhibits a high specific capacity of 164.44 mA h g-1 at a current density of 1 A g-1 with 85.72% capacity retention even after 5000 cycles at a current density of as high as 8 A g-1, suggesting its great promise in practical applications for BSH devices. By integrating activated carbon as the anode with the as-obtained bimetallic selenides as the cathode, an alkaline aqueous BSH device is fabricated and delivers a high energy density of 37.54 W h kg-1 at a high power density of 842.7 W kg-1. It is found that the excellent electrochemical performances can be ascribed to facile ion and electron transport pathways, high electrical conductivity and reliable structural robustness of the prepared selenides. Moreover, the synthetic strategy presented in this paper opens up an avenue to guide the synthesis of various anion doped bimetallic compounds towards high-performance energy conversion and storage devices.
RESUMEN
Self-assembled Ni(OH)2 nanosheet-decorated hierarchical flower-like MnCo2O4.5 nanoneedles were synthesized via a cost-effective and facile hydrothermal strategy, aiming to realize a high-capacity advanced electrode of a battery-supercapacitor hybrid (BSH) device. It is demonstrated that the as-synthesized hierarchical flower-like MnCo2O4.5@Ni(OH)2-nanosheet electrode exhibits a high specific capacity of 318 mAh g-1 at a current density of 3 A g-1 and still maintains a capacity of 263.5 mAh g-1 at a higher current density of 20 A g-1, with an extremely long cycle lifespan of 87.7% capacity retention after 5000 cycles. Moreover, using the unique core-shell structure as the cathode and hollow Fe2O3 nanoparticles/reduced graphene oxide as the anode, the BSH device delivers a high energy density of 56.53 Wh kg-1 when the power density reaches 1.9 kW kg-1, and there is an extraordinarily good cycling stability with the capacity retention rate of 90.4% after 3000 cycles. It is believed that the superior properties originate from desirable core-shell structures alleviating the impact of volume changes as well as the existence of two-dimensional Ni(OH)2 nanosheets with more active sites, thereby improving the cycle stability and achieving ultrahigh capacity. These results will provide more access to the rational material design of diverse nanostructures toward high-performance energy storage devices.
RESUMEN
BACKGROUND: Intra-abdominal hypertension (IAH) is a disease with high morbidity and mortality among critically ill patients. The study's objectives were to explore the prevalence of IAH and physicians' awareness of the 2013 World Society of Abdominal Compartment Syndrome (WSACS) guidelines in Chinese intensive care units (ICUs). METHODS: A cross-sectional study of four ICUs in Southwestern China was conducted from June 17 to August 2, 2014. Adult patients admitted to the ICU for more than 24 h, with bladder catheter but without obvious intravesical pressure (IVP) measurement contraindications, were recruited. Intensivists with more than 5 years of ICU working experience were also recruited. Epidemiological information, potential IAH risk factors, IVP measurements and questionnaire results were recorded. RESULTS: Forty-one patients were selected. Fifteen (36.59 %) had IVP ≥ 12 mmHg. SOFA (Sequential Organ Failure Assessment) hepatic and neurological sub-scores were utilized as independent predictors for IAH via logistic backward analysis. Thirty-seven intensivists participated in the survey (response rate: 80.43 %). The average score of each center was less than 35 points. All physicians believed the IAH prevalence in their departments was no more than 20.00 %. A significant negative correlation was observed between the intensivists' awareness of the 2013 WSACS guidelines and the IAH prevalence in each center (r = -0.975, P = 0.025). CONCLUSIONS: The prevalence and independent predictors of IAH among the surveyed population are similar to the reports in the literature. Intensivists generally have a low awareness of the 2013 WSACS guidelines. A systematic guideline training program is vital for improving the efficiency of the diagnosis and treatment of IAH.
RESUMEN
OBJECTIVES: To investigate the effect of non-elastic/elastic abdominal binders on intra-vesical pressure (IVP), physiological functions, and clinical outcomes in laparotomy patients at the perioperative stage. METHODS: This prospective study was conducted from May to October 2014 at the Trauma Surgery Department, Daping Hospital, Chongqing, China. Laparotomy patients were randomly divided into non-elastic abdominal binder group (28 patients), and elastic abdominal binder group (29 patients). Binders were applied for 14 days following the operation, or until discharge. Demographic information, Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation II (APACHE-II) scores (prior to the operation, on the first day after operation, the day IVP measurement was stopped, and one day before discharge), and outcomes were recorded. The IVP was measured before the operation to postoperative day 7. RESULTS: There were no significant differences in the demographic information, outcomes, SOFA or APACHE-II scores between the 2 groups. Initial out-of-bed mobilization occurred earlier in the elastic binder group (3.2 ± 2.0 versus 5.0 ± 3.7 days, p=0.028). A greater increase in IVP was observed in the non-elastic binder group than in the elastic binder group (2.9 ± 1.1 versus 1.1 ± 0.7 mm Hg, p=0.000). CONCLUSION: Elastic binders have relatively little effect on IVP and are more helpful at promoting postoperative recovery than non-elastic binders. Therefore, elastic binders are more suitable for clinical use.
Asunto(s)
Abdomen , Vendajes de Compresión , Laparotomía , Cuidados Posoperatorios/métodos , Presión , Adulto , Anciano , Vendajes , Catéteres de Permanencia , Femenino , Humanos , Masculino , Persona de Mediana Edad , Vejiga Urinaria , Catéteres UrinariosRESUMEN
PURPOSE: To investigate the prevalence and diagnosis rate of intra-abdominal hypertension (IAH) in a mixed-population intensive care unit (ICU), and to investigate the knowledge of ICU staff regarding the guidelines published by the World Society of Abdominal Compartment Syndrome (WSACS) in 2013. METHODS: A one-day cross-sectional study based on the WSACS 2013 guidelines was conducted in the general ICU of a tertiary teaching hospital in Chongqing, China. The included patients were divided into intravesical pressure (IVP) measured group and IVP unmeasured group. The epidemiologic data were recorded, and potential IAH risk factors (RFs) were collected based on the guidelines. IVP measurements were conducted by investigators every 4 h and the result was compared to that measured by the ICU staff to evaluate the diagnosis rate. Besides, a questionnaire was used to investigate the understanding of the guidelines among ICU staff. RESULTS: Thirty-two patients were included, 14 in the IVP measured group and 18 in the IVP unmeasured group. The prevalence of IAH during the survey was 15.63% (5/32), 35.71% (5/14) in IVP measured group. Only one case of IAH had been diagnosed by the ICU physician and the diagnosis rate was as low as 20.00%. Logistic regression analysis showed that sequential organ failure assessment (SOFA) score was an independent RF for IAH (OR: 1.532, 95% CI: 1.029-2.282, p=0.036. Fourteen doctors and 5 nurses were investigated and the response rate was 67.86%. The average scores of the doctors and nurses were 27.14±20.16 and 16.00±8.94 respectively. None of them had studied the WSACS 2013 guidelines thoroughly. CONCLUSION: Patients with a higher SOFA score has a higher incidence of IAH. The IAH prevalence in 14 ICU patients with indwelling catheter was 35.71%. Strengthening the wide and rational use of WSACS guideline is important to improve the diagnosis of IAH.
Asunto(s)
Enfermedad Crítica/epidemiología , Hipertensión Intraabdominal/diagnóstico , Hipertensión Intraabdominal/epidemiología , Anciano , China/epidemiología , Estudios Transversales , Femenino , Humanos , Unidades de Cuidados Intensivos , Masculino , Persona de Mediana Edad , Prevalencia , Factores de Riesgo , Índice de Severidad de la Enfermedad , Encuestas y CuestionariosRESUMEN
The technology of non-water-soluble mediator anaerobic biological catalysis has attracted more and more attention in the field of environment technology. In this study, five kinds of quinonly compounds were grafted on the chloromethylation polystyrene macromolecular carrier by Friedel-Crafts reaction. Reaction factors of temperature and molar ratio for the 1,4-naphthoquinone grafting carrier were optimized, and the optimal temperature was 78 degreesC while the optimal molar ratio of 1, 4-naphthoquinone and chloromethylation polystyrene was 2: 1. Fourier infrared spectrum analysis confirmed that the quinone groups were successfully grafted on the macromolecular backbone chloromethylation polystyrene. Catalysis using the five kinds of quinonly materials as non-water-soluble redox mediators enhanced the biological denitrification rate and the decoloration of azo dyes, meanwhile these materials showed good reusability in the biodegradation of azo dye. This study developed a new method for the preparation of quinonly materials and revealed a new field in the technology of mediator catalysis.
Asunto(s)
Compuestos Azo/química , Colorantes/química , Poliestirenos/química , Eliminación de Residuos Líquidos/métodos , Aguas Residuales/química , Biodegradación Ambiental , Catálisis , Naftoquinonas/química , Oxidación-ReducciónRESUMEN
Large-scale nanopatterned sapphire substrates were fabricated by annealing of patterned Al thin films. Patterned Al thin films were obtained by soft UV-nanoimprint lithography and reactive ion etching. The soft mold with 550-nm-wide lines separated by 250-nm space was composed of the toluene-diluted polydimethylsiloxane (PDMS) layer supported by the soft PDMS. Patterned Al thin films were subsequently subjected to dual-stage annealing due to the melting temperature of Al thin films (660°C). The first comprised a low-temperature oxidation anneal at 450°C for 24 h. This was followed by a high-temperature annealing in the range of 1,000°C and 1,200°C for 1 h to induce growth of the underlying sapphire single crystal to consume the oxide layer. The SEM results indicate that the patterns were retained on sapphire substrates after high-temperature annealing at less than 1,200°C. Finally, large-scale nanopatterned sapphire substrates were successfully fabricated by annealing of patterned Al thin films for 24 h at 450°C and 1 h at 1,000°C by soft UV-nanoimprint lithography.
RESUMEN
Taking Chinese pine in Qianshan Mountains as a sample, the tree ring width chronology including standard, residual, and Arstan chronologies was established. The results showed that the tree ring width of Chinese pine had a higher correlation with the temperature in May - July and in September - November, and significant positive correlations were observed between the tree ring width and the extreme minimum temperature in July and mean minimum temperature in September. The chronology had significant or very significant correlations with the extreme minimum temperature in December and next January, mean minimum temperature in January, annual precipitation, and the precipitation in April, May and last December. Chinese pine had stronger responses to the monthly/yearly water vapor pressure and relative humidity. The yearly and most monthly evaporation had negative effects on the growth, being most significant for the evaporation in April - July. The narrowed tree rings recorded by the chronology demonstrated the 30 times of extreme drought since 1 800. The growth of Chinese pine in Qianshan Mountains was also affected by the climate changes on global and hemisphere scales. There existed 11-, 23- and 50- year- common periodicity between the chronology and solar activity, and 10-, 20- and 45- year- common periodicity between the chronology and geomagnetic activity.