RESUMO
BACKGROUND: Surgical stabilization of rib fractures (SSRF) improves outcomes in chest wall trauma. Geriatric patients are particularly vulnerable to poor outcomes; yet, this population is often excluded from SSRF studies. Further delineating patient outcomes by age is necessary to optimize care for the aging trauma population. METHODS: A retrospective cohort study was conducted examining outcomes among patients aged 40+ for whom an SSRF consult was placed between 2017 and 2022 at a level 1 trauma center. Patients were categorized into geriatric (65+) and adult (40-64), as well as 80 years and older (80+) and 79 and younger (40-79). Patient outcomes were assessed comparing non-operative and operative management of chest wall trauma. Propensity matched analysis was performed to evaluate mortality differences between adult and geriatric patients who did and did not undergo SSRF. RESULTS: A total of 543 patients had an SSRF consult. Of these, 227 were 65+, and 73 were 80+. A total of 129 patients underwent SSRF (24 %). The percentage of patients undergoing SSRF did not vary between 40 and 64 and 65+ (23.7 % and 23.6 %, respectively, p = 0.97) or 40-79 and 80+ (24.0 vs 21.9, p = 0.69). Patients undergoing SSRF had higher chest injury burden and were more likely to require mechanical ventilation and ICU level care on admission. Overall, in-hospital mortality rate was 4.6 %. Among patients who underwent SSRF, mortality rate did not significantly differ between 65+ and 40-64 (7.8% vs 2.7 %, p = 0.18) or 80+ and 40-79 (6.3% vs 4.6 %, p = 0.77). This remained true in propensity matched analysis. CONCLUSION: Geriatric and octogenarian patients with rib fractures underwent SSRF at similar rates and achieved equivalent outcomes to their younger counterparts. SSRF did not differentially affect mortality outcomes based on age group in propensity matched analysis. SSRF is safe for geriatric patients including octogenarians.
Assuntos
Pontuação de Propensão , Fraturas das Costelas , Centros de Traumatologia , Humanos , Fraturas das Costelas/cirurgia , Fraturas das Costelas/mortalidade , Feminino , Masculino , Estudos Retrospectivos , Idoso , Idoso de 80 Anos ou mais , Pessoa de Meia-Idade , Resultado do Tratamento , Adulto , Fatores Etários , Mortalidade Hospitalar , Fixação Interna de Fraturas/métodos , Traumatismos Torácicos/cirurgia , Traumatismos Torácicos/mortalidadeRESUMO
BACKGROUND: Unexpected ICU admissions are a key quality metric in trauma care. The purpose of this study is to identify the most common causes of unplanned ICU admissions among trauma patients at an ACS-verified level 1 trauma center. METHODS: A retrospective review was conducted of all trauma patients with unplanned admission to the ICU at a level 1 trauma center between 2019 and 2021. Unplanned ICU admissions were categorized into (1) "bounce-backs," patients previously admitted to the ICU and (2) "upgrades," patients who had not previously been cared for in the ICU. RESULTS: Of 300 unexpected ICU transfers, bounce-backs accounted for 69% and upgrades 31%. The most common injuries were traumatic brain injuries (40%) and rib fractures (41.3%). In-hospital mortality rate was 10% and did not significantly differ between bounce-backs and upgrades (12 vs 5%, P = .92). Respiratory distress was the most common cause of transfer (41.1%), followed by neurologic (29.6%) and cardiovascular decline (21.2%). Patients were on average 928 mL fluid positive 72 hours prior to transfer (t > 0, P < .0001), and 295 mL fluid positive in the 24 hours prior to transfer (t > 0, P .0003). Patients transferred for respiratory distress were no more fluid over-balanced than those transferred for other reasons. CONCLUSION: We found a large percent of unplanned transfers occurring within 48 hours of admission or transfer out of the ICU suggesting under-triage as a leading cause of bounce-backs and upgrades. Respiratory distress was the leading cause of transfer. These findings highlight opportunities for targeted interventions.
Assuntos
Unidades de Terapia Intensiva , Centros de Traumatologia , Ferimentos e Lesões , Humanos , Centros de Traumatologia/estatística & dados numéricos , Estudos Retrospectivos , Unidades de Terapia Intensiva/estatística & dados numéricos , Masculino , Feminino , Pessoa de Meia-Idade , Adulto , Ferimentos e Lesões/terapia , Ferimentos e Lesões/mortalidade , Mortalidade Hospitalar , Admissão do Paciente/estatística & dados numéricos , Transferência de Pacientes/estatística & dados numéricos , Lesões Encefálicas Traumáticas/terapia , Lesões Encefálicas Traumáticas/mortalidade , Idoso , Fatores de TempoRESUMO
INTRODUCTION: Identifying patients who can be safely managed in lower-level trauma centers is critical to avoid overburdening level I centers. This study examines the transfer patterns and outcomes of blunt splenic injury (BSI) patients cared for at 2 regional level III trauma centers as compared to an associated level I center. METHODS: A retrospective cohort study was conducted including all trauma patients with BSI admitted to 2 level III trauma centers (TC3) and a level I center (TC1) between 2012 and 2022. Patients were broken into 3 categories: TC1, TC3, and transfer patients (transferred from TC3 to TC1). RESULTS: A total of 1480 patients were admitted to TC1, 208 patients to TC3, and 128 were transferred. 22.7% of transfer patients were children. No difference in splenic injury grade was seen between patients managed at TC1 and TC3. Patients presenting to TC1 had more severe concomitant injuries. Patients underwent urgent splenectomy at similar rates at TC1 and TC3 (15.1 vs 18.7%, P = .1). Successful nonoperative management was achieved at similar rates (81.3 vs 75.5%, P = .1). When controlling for ISS and ED disposition, there was no significant difference in length of stay (LOS), ICU LOS, and inpatient mortality between TC1 and TC3. CONCLUSION: Level III centers effectively managed BSI achieving comparable outcomes to the level 1 center. Transfers commonly occurred in pediatric and multisystem trauma patients, though high-grade splenic injuries were not predictive of transfer. High-grade BSI can be safely managed at level III centers without need for transfer.
Assuntos
Baço , Centros de Traumatologia , Ferimentos não Penetrantes , Humanos , Ferimentos não Penetrantes/terapia , Ferimentos não Penetrantes/mortalidade , Ferimentos não Penetrantes/diagnóstico , Ferimentos não Penetrantes/cirurgia , Estudos Retrospectivos , Baço/lesões , Masculino , Feminino , Adulto , Escala de Gravidade do Ferimento , Esplenectomia/estatística & dados numéricos , Pessoa de Meia-Idade , Tempo de Internação/estatística & dados numéricos , Transferência de Pacientes/estatística & dados numéricos , Resultado do Tratamento , Criança , Traumatismos Abdominais/terapia , Traumatismos Abdominais/cirurgia , Traumatismos Abdominais/diagnóstico , Traumatismos Abdominais/mortalidadeRESUMO
Introduction: Flat-panel detector C-arms (FCs) are reported to reduce radiation exposure and improve image quality compared with conventional image intensifier C-arms (CCs). The purpose of this study was to compare radiation exposure and image quality between three commonly used FCs. Materials and Methods: A cadaver model was placed in the prone position to simulate percutaneous nephrolithotomy. We compared the following three FCs: OEC Elite CFD from GE HealthCare, Zenition 70 from Philips, and Ziehm Vision RFD from Ziehm Imaging. To measure the radiation dose, optically stimulated luminescence dosimeters (OSLDs) were utilized during five 300-second trials, conducted under three settings: automatic exposure control (AEC), AEC with low dose (LD), and LD with the lowest pulse rate (LDLP). Ten blinded urologists evaluated the image quality. Data were statistically analyzed using the analysis of variance (ANOVA) and Tukey's B post hoc tests. Results: In the AEC setting, the Philips C-arm demonstrated lower ventral OSLD exposure (42,446 mrad) compared with both the GE (51,076 mrad) and Ziehm (83,178 mrad; p < 0.001) C-arms. Similarly, in the LD setting, the Philips C-arm resulted in less ventral OSLD exposure (25,926 mrad) than both the Ziehm (30,956 mrad) and GE (38,209 mrad; p < 0.001) C-arms. Meanwhile, in the LDLP setting, the Ziehm C-arm showed less ventral OSLD exposure (4019 mrad) than both the GE (7418 mrad) and Philips (8229 mrad; p < 0.001) C-arms. All three manufacturers received adequate image quality ratings at the AEC and LD settings. However, at LDLP, the Ziehm C-arm received inadequate ratings in 8% of images, whereas both the GE and Philips C-arms received 100% adequate ratings (p = 0.016). Conclusions: Radiation produced by flat-panel C-arms varies dramatically, with the highest exposure (Ziehm) being almost double the lowest (Philips) in AEC. Improved picture quality at the lowest settings may come at the cost of increased radiation dose. Surgeons should carefully select the machine and settings to minimize radiation exposure while still preserving the image quality.
Assuntos
Doses de Radiação , Humanos , Imagens de Fantasmas , Fluoroscopia/métodosRESUMO
BACKGROUND: Freestanding emergency departments have risen in popularity as a means to expand access to care. Although some evaluation of freestanding emergency department utility in specific patient populations exists, management of surgical patients via remote triage and disposition has not been previously described. We report our experience with remote triage to discharge home, level I trauma center, or community hospital admission for general surgery patients who present to an affiliated freestanding emergency department. METHODS: A retrospective cohort study of patients presenting to freestanding emergency departments requiring surgical consultation between 2016 and 2021 was conducted. Outcomes included disposition, length of stay, surgical intervention, 30-day mortality, and readmission. Undertriage and overtriage rates were calculated and defined as the following: (1) discharge undertriage-discharge home with 30-day emergency department visit/readmission; 2) transfer undertriage-transfers to community hospital requiring transfer to trauma center; and (3) overtriage-admissions <24 hours without surgery. RESULTS: Of 1,105 patients, 15% were discharged home, 27% were transferred to trauma centers, and 58% were transferred to community hospitals. Patients admitted to trauma centers were older and had higher acuity pathology, whereas patients admitted to community hospitals had higher operative rates with shorter lengths of stay, operating room time, 30-day readmission, and mortality. Transfer undertriage was 0.9% (n = 6), with only 1 patient requiring transfer from a community hospital to a trauma center for disease acuity. Discharge undertriage was 12% (n = 20) due to worsening or persistent pathology. Overtriage was 5.5% (n = 52), with most having a partial small bowel obstruction or ambiguous diagnostic imaging requiring observation. CONCLUSION: Remote surgery triage at freestanding emergency departments, without an in-person examination, demonstrated both low undertriage and overtriage rates, reflecting appropriate triage practices.
Assuntos
Triagem , Ferimentos e Lesões , Humanos , Estudos Retrospectivos , Centros de Traumatologia , Hospitalização , Visitas ao Pronto SocorroRESUMO
Early surgical stabilization of rib fracture (SSRF) improves outcomes in patients with flail physiology and severely displaced fractures. We present two cases of patients with severe chest injury and large flail segment who underwent SSRF while on veno-venous extracorporeal membrane oxygenation (VV-ECMO). The patients developed respiratory failure within 24 hours of admission requiring VV-ECMO. The extent of their chest wall injury limited pulmonary mechanics prohibiting transition off VV-ECMO. Therefore, SSRF was performed on hospital days 2 and 3 and while on VV-ECMO support. Stabilizing the chest wall allowed for improved ventilation and successful decannulation from VV-ECMO on postoperative days 3 and 4. Ultimately, both achieved a functional recovery and were discharged home. These cases demonstrate a unique thoracic damage control strategy wherein SSRF is performed while on VV-ECMO. Improving chest stability and pulmonary mechanics with SSRF allowed for safe transition off VV-ECMO and achieved a favorable long-term outcome.
Assuntos
Oxigenação por Membrana Extracorpórea , Tórax Fundido , Fraturas das Costelas , Traumatismos Torácicos , Ferimentos não Penetrantes , Humanos , Fraturas das Costelas/complicações , Fraturas das Costelas/cirurgia , Ferimentos não Penetrantes/complicações , Ferimentos não Penetrantes/cirurgia , Tórax Fundido/etiologia , Tórax Fundido/cirurgia , Estudos RetrospectivosRESUMO
INTRODUCTION: Liposomal bupivacaine (LB) is a depot formulation of bupivacaine, which releases the drug over 72 hours to prolong local pain control. This retrospective study compares the effect of using LB versus plain bupivacaine on postoperative pain control, length of hospital stay and cost among patients undergoing vaginal reconstructive surgery. MATERIALS AND METHODS: Patients who underwent vaginal reconstructive surgery with levatorplasty and received an injection of 20 cc of either plain bupivacaine or LB for pudendal nerve block were included. The primary outcomes included postoperative narcotic use and subjective pain score. The secondary outcome was postoperative length of stay. Comparisons between groups were performed using the T test, Mann Whitney U and Chi-square tests with p < 0.05 considered significant. RESULTS: Between June 2016 and December 2021, 25 patients had received LB as a pudendal nerve block and 25 had received plain bupivacaine. Demographics between groups were similar. There was no difference between postoperative morphine equivalent dose (MED) for plain bupivacaine versus LB (25.3 ± 65.8 vs. 24.9 ± 31.7 MED; p = 0.159) or length of hospital stay (15.8 ± 12.0 hours vs. 23.8 ± 20.0; p = 0.094). Furthermore, subjective pain was also similar between groups (0 vs. 1.6 ± 2.6, p = 0.68), (4.6 ± 2.3 vs. 4.9 ± 2.0 average POD 1 pain, p = 0.534) and (4.3 ± 2.1 for vs. 4.9 ± 2.1 average POD 2 pain, p = 0.373). CONCLUSION: LB is not superior to plain bupivacaine for controlling pain following vaginal reconstructive surgery, and justification for the exponentially greater cost of LB is not supported. Prospective investigations with larger sample sizes are needed to determine the optimal pain management for levatorplasty in vaginal reconstructive surgery.
Assuntos
Bupivacaína , Manejo da Dor , Feminino , Humanos , Anestésicos Locais , Dor Pós-Operatória/tratamento farmacológico , Dor Pós-Operatória/etiologia , Dor Pós-Operatória/prevenção & controle , Estudos Retrospectivos , Estudos Prospectivos , Lipossomos , Analgésicos OpioidesRESUMO
Ferrocene is perhaps the most popular and well-studied organometallic molecule, but our understanding of its structure and electronic properties has not changed for more than 70 years. In particular, all previous attempts of chemically oxidizing pure ferrocene by binding directly to the iron center have been unsuccessful, and no significant change in structure or magnetism has been reported. Using a metal organic framework host material, we were able to fundamentally change the electronic and magnetic structure of ferrocene to take on a never-before observed physically stretched/bent high-spin Fe(II) state, which readily accepts O2 from air, chemically oxidizing the iron from Fe(II) to Fe(III). We also show that the binding of oxygen is reversible through temperature swing experiments. Our analysis is based on combining Mößbauer spectroscopy, extended X-ray absorption fine structure, in situ infrared, SQUID, thermal gravimetric analysis, and energy dispersive X-ray fluorescence spectroscopy measurements with ab initio modeling.
RESUMO
In this study, we present a rapid, cost-effective Python-driven computer vision approach to quantify the prevalent "gloppiness" phenomenon observed in complex fluids and gels. We discovered that rheology measurements obtained from commercial shear rheometers do show some hints, but do not exhibit a strong correlation with the extent of "gloppiness". To measure the "gloppiness" level of laboratory-produced shower gel samples, we employed the rupture time of jetting flow and found a significant correlation with data gathered from the technical insight panelist team. While fully comprehending the "gloppiness" phenomenon remains a complex challenge, the Python-based computer vision technique utilizing jetting flow offers a promising, efficient, and affordable solution for assessing the degree of "gloppiness" for commercial liquid and gel products in the industry.
RESUMO
A small subset of males presenting with cryptorchidism are found to have ectopic testes. The most common location for an ectopic testicle is the superficial inguinal pouch, but there are several other possibilities, necessitating a thorough physical exam. A 4-month-old term male presented for evaluation of a nonpalpable right testicle. Examination revealed an ectopic right testicle located in the perineum. The patient underwent successful right orchiopexy. Ectopic testes are rare but remain in the differential diagnoses for patients with cryptorchidism. Patients should undergo prompt orchiopexy to avoid potential complications and allow maximal preservation of testicular function.
RESUMO
Atomic-level understanding of the gate-opening phenomenon in flexible porous materials is an important step toward learning how to control, design, and engineer them for applications such as the separation of gases from complex mixtures. Here, we report such mechanistic insight through an in-depth study of the pressure-induced gate-opening phenomenon in our earlier reported metal-organic framework (MOF) Zn(dps)2(SiF6) (dps = 4,4'-dipyridylsulfide), also called UTSA-300, using isotherm and calorimetry measurements, in situ infrared spectroscopy, and ab initio simulations. UTSA-300 is shown to selectively adsorb acetylene (C2H2) over ethylene (C2H4) and ethane (C2H6) and undergoes an abrupt gate-opening phenomenon, making this framework a highly selective gas separator of this complex mixture. The selective adsorption is confirmed by pressure-dependent in situ infrared spectroscopy, which, for the first time, shows the presence of multiple C2H2 species with varying strengths of bonding. A rare energetic feature at the gate-opening condition of the flexible MOF is observed in our differential heat energies, directly measured by calorimetry, showcasing the importance of this tool in adsorption property exploration of flexible frameworks and offering an energetic benchmark for further energy-based fundamental studies. Based on the agreement of this feature with ab initio-based adsorption energies of C2H2 in the closed-pore structure UTSA-300a ("a" refers to the activated form), this feature is assigned to the weakening of the H-bond C-H···F formed between C2H2 and fluorine of the MOF. Our analysis identifies the weakening of this H-bond, the expansion of the closed-pore MOF upon successive C2H2 coadsorption until its volume is close to that of the open-pore MOF, and the spontaneous gate opening to energetically favor C2H2 adsorption in the open-pore structure as crucial steps in the gate-opening mechanism in this system.
RESUMO
BACKGROUND: Adult trauma patients are at risk of developing posttraumatic stress disorder (PTSD). Early intervention reduces the development of PTSD, but few trauma patients seek and obtain care. Valid and reliable screening tools are needed to identify patients at risk of developing PTSD. The objective of this review is to identify existing screening tools and evaluate their accuracy for predicting PTSD outcomes. METHODS: PubMed, PsychInfo, and ClinicalTrials.gov were searched for studies evaluating the predictive accuracy of PTSD screening tools among traumatically injured adult civilians. Eligible studies assessed patients during acute hospitalization and at least 1 month following injury to measure PTSD outcome. Eligible outcomes included measures of predictive accuracy, such as sensitivity and specificity. The Quality Assessment of Diagnostic Accuracy Studies 2 tool was used to assess the risk of bias of each study, and the strength of evidence was assessed following the Agency for Healthcare Research and Quality guidelines. RESULTS: Forty-nine studies were included evaluating the predictive accuracy of 38 screening tools. Most tools were assessed in a single study. Questionnaire-style tools had more favorable predictive ability than diagnostic interview assessments. The Injured Trauma Survivor Screen, Posttraumatic Adjustment Screen, the PTSD Checklist for DSM-5, and the Richmond et al. tool demonstrated the most favorable predictive accuracy, with high sensitivity (75-100%) and specificity (67-94%). Common sources of bias were selection bias due to high attrition rate and using nondiagnostic tools to assess PTSD symptoms at follow-up. CONCLUSION: Although sensitivity and specificity of PTSD predictive tools varied widely, several emerged with favorable predictive accuracy. Further research is needed to define the ability of screening and intervention to prevent PTSD in injured trauma survivors. The results of this review can inform screening tool options for screening programs and future intervention studies. LEVEL OF EVIDENCE: Systematic review, level III.
Assuntos
Transtornos de Estresse Pós-Traumáticos , Adulto , Lista de Checagem , Manual Diagnóstico e Estatístico de Transtornos Mentais , Humanos , Programas de Rastreamento/métodos , Transtornos de Estresse Pós-Traumáticos/diagnóstico , Transtornos de Estresse Pós-Traumáticos/etiologia , SobreviventesRESUMO
Fluorosis has been regarded as a worldwide disease that seriously diminishes the quality of life through skeletal embrittlement and hepatic damage. Effective detection and removal of fluorinated chemical species such as fluoride ions (F-) and perfluorooctanoic acid (PFOA) from drinking water are of great importance for the sake of human health. Aiming to develop water-stable, highly selective and sensitive fluorine sensors, we have designed a new luminescent MOF In(tcpp) using a chromophore ligand 2,3,5,6-tetrakis(4-carboxyphenyl)pyrazine (H4tcpp). In(tcpp) exhibits high sensitivity and selectivity for turn-on detection of F- and turn-off detection of PFOA with a detection limit of 1.3 µg L-1 and 19 µg L-1, respectively. In(tcpp) also shows high recyclability and can be reused multiple times for F- detection. The mechanisms of interaction between In(tcpp) and the analytes are investigated by several experiments and DFT calculations. These studies reveal insightful information concerning the nature of F- and PFOA binding within the MOF structure. In addition, In(tcpp) also acts as an efficient adsorbent for the removal of F- (36.7 mg g-1) and PFOA (980.0 mg g-1). It is the first material that is not only capable of switchable sensing of F- and PFOA but also competent for removing the pollutants via different functional groups.
RESUMO
Objective: To review the available literature and identify factors associated with successful outcomes after varicocele repair (VR) in the setting of non-obstructive azoospermia (NOA). Methods: The PubMed and EMBASE databases were searched for relevant articles. Primary outcomes were return of spontaneous spermatogenesis, sperm retrieval rates (SRRs), and unassisted and assisted pregnancy rates. Histopathological subtypes, when available, were used for subgroup analysis. Results: A total of 16 articles were finally included. The average sample size was 43 and average duration of follow-up was 10.5 months. The average rate of primary spermatogenesis after VR was 27.3%. The average SRR, across five studies in men with NOA undergoing microscopic testicular sperm extraction status after varicocelectomy, was 48.9% vs 32.1% for the untreated cohort groups, and the average spontaneous pregnancy rate was 5.24%. Histopathology subtype was a significant contributing factor when analysed. Conclusion: Varicocele repair should be considered in men with NOA, as it may allow some patients to avoid assisted reproductive technologies and improves success rates when utilised.
RESUMO
Some forms of bariatric surgery make patients susceptible to calcium malabsorption, and the parathyroid hormone (PTH) axis is important for maintaining normocalcemia in these patients. Injury to the parathyroid glands due to anterior neck surgery commonly causes PTH axis disruption and can result in severe hypocalcemia in bariatric surgery patients. Herein, we present a case of a patient with a history of stomach intestinal pylorus-sparing bariatric surgery who developed refractory hypocalcemia requiring daily intravenous (IV) calcium 2 years after thyroidectomy. PTH levels were inappropriately normal during episodes of hypocalcemia, and urinary calcium level was <3.0 mg/dL following large oral doses of calcium, suggesting that both inadequate PTH response and malabsorption contributed to her severe hypocalcemia. In order to enhance calcium absorptive capacity while minimizing the risk of weight regain, she was surgically treated with a Roux-en-Y gastric bypass proximal to the prior operation. The surgery successfully improved blood calcium levels; the patient was successfully weaned from IV calcium and was able to maintain normocalcemia with oral supplements. We discuss the case in the context of available literature and provide our recommendations.
Assuntos
Cirurgia Bariátrica/efeitos adversos , Derivação Gástrica/métodos , Hipocalcemia/etiologia , Hipocalcemia/cirurgia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/cirurgia , Tireoidectomia/efeitos adversos , Adulto , Cirurgia Bariátrica/métodos , Feminino , Humanos , Tratamentos com Preservação do Órgão , Piloro , Indução de RemissãoRESUMO
Flexible metal-organic frameworks (MOFs) hold great promise as smart materials for specific applications such as gas separation. These materials undergo interesting structural changes in response to guest molecules, which is often associated with unique adsorption behavior not possible for rigid MOFs. Understanding the dynamic behavior of flexible MOFs is crucial yet challenging as it involves weak host-guest interactions and subtle structural transformation not only at the atomic/molecular level but also in a nonsteady state. We report here an in-depth study on the adsorbate- and temperature-dependent adsorption in a flexible MOF by crystallizing atomic gases into its pores. Mn(ina)2 shows an interesting temperature-dependent response toward noble gases. Its nonmonotonic, temperature-dependent adsorption profile results in an uptake maximum at a temperature threshold, a phenomenon that is unusual. Full characterization of Xe-loaded MOF structures is performed by in situ single-crystal and synchrotron X-ray diffraction, IR spectroscopy, and molecular modeling. The X-ray diffraction analysis offers a detailed explanation into the dynamic structural transformation and provides a convincing rationalization of the unique adsorption behavior at the molecular scale. The guest and temperature dependence of the structural breathing gives rise to an intriguing reverse of Xe/Kr adsorption selectivity as a function of temperature. The presented work may provide further understanding of the adsorption behavior of noble gases in flexible MOF structures.
RESUMO
Combining synthesis, infrared spectroscopy, and ab initio modeling we show that the titanium-based porous framework Ti-MOF-74 has potential as an environmental nitric oxide (NO) scavenger, exhibiting an extraordinarily strong binding affinity and selectivity over other flue-gas components. The robustness upon exposure to water vapor and high flue-gas stack temperatures suggests that this material can perform well in an industrial environment. In-depth analysis of the Ti-NO bond indicates that the NO forms a strong covalent bond with the Ti. The process of this NO bond formation involves a reaction with the OH- capping groups of the Ti to form NOx groups, after which the excess NO binds to the open Ti metal sites. Ti-MOF-74 thus becomes, to the best of our knowledge, the first known porous framework that binds NO significantly stronger than water, providing novel avenues for environmental and physiological scavenging applications.
RESUMO
Modification of the external surfaces of metal-organic frameworks offers a new level of control over their adsorption behavior. It was previously shown that capping of MOFs with ethylenediamine (EDA) can effectively retain small gaseous molecules at room temperature. Reported here is a temperature-induced variation in the capping-layer gate-opening mechanism through a combination of in situ infared experiments and ab initio simulations of the capping layer. An atypical acceleration and increase in the loading of weakly adsorbed molecules upon raising the temperature above room temperature is observed. These findings show the discovery of novel temperature-dependent kinetics that goes beyond standard kinetics and suggest a new avenue for tailoring selective adsorption by thermally tuning the surface barrier.
RESUMO
Inorganic semiconductor materials are best known for their superior physical properties, as well as their structural rigidity and stability. However, the poor solubility and solution-processability of these covalently bonded network structures has long been a serious drawback that limits their use in many important applications. Here, we present a unique and general approach to synthesize robust, solution-processable, and highly luminescent hybrid materials built on periodic and infinite inorganic modules. Structure analysis confirms that all compounds are composed of one-dimensional anionic chains of copper iodide (CumIm+22-) coordinated to cationic organic ligands via Cu-N bonds. The choice of ligands plays an important role in the coordination mode (µ1-MC or µ2-DC) and Cu-N bond strength. Greatly suppressed nonradiative decay is achieved for the µ2-DC structures. Record high quantum yields of 85% (λex = 360 nm) and 76% (λex = 450 nm) are obtained for an orange-emitting 1D-Cu4I6(L6). Temperature dependent PL measurements suggest that both phosphorescence and thermally activated delayed fluorescence contribute to the emission of these 1D-AIO compounds, and that the extent of nonradiative decay of the µ2-DC structures is much less than that of the µ1-DC structures. More significantly, all compounds are remarkably soluble in polar aprotic solvents, distinctly different from previously reported CuI based hybrid materials made of charge-neutral CumXm (X = Cl, Br, I), which are totally insoluble in all common solvents. The greatly enhanced solubility is a result of incorporation of ionic bonds into extended covalent/coordinate network structures, making it possible to fabricate large scale thin films by solution processes.