Integrated Network Analysis of Symptom Clusters Across Monkeypox Epidemics From 1970 to 2023: Systematic Review and Meta-Analysis.

BACKGROUND: The worldwide spread of monkeypox (mpox) has witnessed a significant increase, particularly in nonendemic countries. OBJECTIVE: We aimed to investigate the changing clinical symptoms associated with mpox from 1970 to 2023 and explore their interrelations. METHODS: In this systematic review and meta-analysis, 3 electronic databases were searched for English peer-reviewed studies conducted from January 1970 to April 2023 that reported any symptoms among confirmed mpox cases. We categorized the mpox epidemics into 3 periods: 1970-2002 (period 1, within the African region), 2003-2021(period 2, epidemics outside Africa), and 2022-2023 (period 3, worldwide outbreak). Following PRISMA guidelines, a meta-analysis was performed to estimate the pooled prevalence for each symptom. The correlation among symptoms was analyzed and visualized using network analysis. RESULTS: The meta-analysis included 61 studies that reported 21 symptoms in 720 patients from period 1, 39 symptoms in 1756 patients from period 2, and 37 symptoms in 12,277 patients from period 3. The most common symptom among patients from all 3 periods was rash (period 1: 92.6%, 95% CI 78.2%-100%; period 2: 100%, 95% CI 99.9%-100%; and period 3: 94.8%, 95% CI 90.9%-98.8%), followed by lymphadenopathy (period 1: 59.8%, 95% CI 50.3%-69.2%; period 2: 74.1%, 95% CI 64.2%-84.1%; and period 3: 61.1%, 95% CI 54.2%-68.1%). Fever (99%, 95% CI 97%-100%), enlarged lymph nodes (80.5%, 95% CI 75.4%-85.0%), and headache (69.1%, 95% CI 4%-100%) were the main symptoms in period 1, with a significant decrease in period 3: 37.9%, 31.2%, and 28.7%, respectively. Chills/rigors (73.3%, 95% CI 60.9%-85.7%), fatigue (68.2%, 95% CI 51.6%-84.8%), and dysphagia/swallowing difficulty (61.2%, 95% CI 10.5%-100%) emerged as primary new symptoms in period 2 and decreased significantly in period 3. Most other symptoms remained unchanged or decreased in period 3 compared to the former 2 periods. Nausea/vomiting had the highest degree of correlation (with 13 symptoms) and was highly positively correlated with lymphadenopathy (r=0.908) and conjunctivitis (r=0.900) in period 2. In contrast, rash and headache were 2 symptoms with the highest degree of correlation (with 21 and 21 symptoms, respectively) in period 3 and were highly positively correlated with fever (r=0.918 and 0.789, respectively). CONCLUSIONS: The manifestation of symptoms in patients with mpox has become more diverse, leading to an increase in their correlation. Although the prevalence of rash remains steady, other symptoms have decreased. It is necessary to surveil the evolving nature of mpox and the consequential changes in clinical characteristics. Epidemic countries may shift their focus on the potential association among symptoms and the high synergy risk. TRIAL REGISTRATION: PROSPERO Registration: CRD42023403282; http://tinyurl.com/yruuas5n.

Understanding A-site tuning effect on formaldehyde catalytic oxidation over La-Mn perovskite catalysts.

A combination study of density functional theory (DFT) calculation and microkinetic analysis was carried out to investigate A-site tuning effect on formaldehyde (HCHO) oxidation over La-Mn perovskite catalysts (A = Sr, Ag, and Sn). The oxygen mobility of A-doped LaMnO3 catalysts and reaction mechanism of HCHO oxidation on catalyst surfaces were investigated. The microkinetic simulation was performed to quantitatively determine the activity of catalysts toward the HCHO catalytic oxidation. The results indicated that A-site tuning weakens the binding energy of Mn-O bond of LaMnO3 surface and facilitates the formation of surface oxygen vacancy. The presence of dopants can significantly reduce the activation energy of O2 dissociation, which ascribes to the facilitation of electron transfer between oxygen species and catalyst surfaces. The reaction cycle of HCHO oxidation contains seven steps: HCHO adsorption, HCHO* dehydrogenation, CHO* dehydrogenation, CO2 desorption, H2O desorption, O2 adsorption and oxygen vacancy recovery. The dopants promote HCHO adsorption and reduce the activation energy of HCHO oxidation. Two elementary steps control the overall reaction rate of HCHO oxidation. CHO* dehydrogenation step has the largest degree of rate control value at low temperature and O2 adsorption step controls the whole reaction at high temperature.

Mercury/oxygen reaction mechanism over CuFe2O4 catalyst.

CuFe2O4 is regarded as a promising candidate of catalyst for Hg0 oxidation in industrial flue gas. However, the microcosmic reaction mechanism governing mercury oxidation on CuFe2O4 remains elusive. Herein, experiments and quantum chemistry calculations were conducted for understanding the chemical reaction mechanism of oxygen-assisted mercury oxidation on CuFe2O4. CuFe2O4 shows the optimal catalytic activity towards mercury oxidation at 150 ºC. The reactivity difference of different lattice oxygen species is associated with its atomic coordination environment. The lattice oxygen coordinating with two octahedral Cu atoms and a tetrahedral Fe atom shows higher catalytic activity towards mercury oxidation than other lattice oxygen atoms. The inverse spinel structure of CuFe2O4 is favorable for O2 activation due to the Jahn-Teller effect, thereby promoting mercury oxidation. O2 molecule preferably adsorbs on iron active site and dissociates into active oxygen species. Hg0 oxidation is a three-step reaction process: Hg0 adsorption, Hg(ads) → HgO(ads), and HgO desorption. The energy barrier of mercury oxidation by chemisorbed oxygen is lower than that of mercury oxidation by lattice oxygen. The chemisorbed oxygen preserves higher reactivity towards mercury oxidation than lattice oxygen. Hg(ads) → HgO(ads) is the rate-determining step of mercury oxidation by chemisorbed oxygen because of the higher energy barrier of 116.94 kJ/mol. This work could provide the theoretical guidance for the diversified structure design of highly-efficient catalysts used for elemental mercury oxidation.

Nanosized Cu-In spinel-type sulfides as efficient sorbents for elemental mercury removal from flue gas.

Mercury emitted from human activities has received increasing attention because of its extreme toxicity, persistence and bioaccumulation. The development of highly-efficient sorbent with abundant active sites that exhibit high affinity toward Hg0 is the key challenge for elemental mercury capture at low temperature. Herein, Cu-In spinel-type sulfides were synthesized through a hydrothermal synthesis. The Hg0 removal performance of CuxIn2-xS2 sorbents was evaluated in the temperature range of 75 °C to 175 °C. The synthesized CuxIn2-xS2 sorbents showed excellent performance for Hg0 removal at low temperatures, which perfectly matches the optimal temperature of flue gas at the downstream of desulfurization system. Hg0 removal efficiency of CuxIn2-xS2 sorbents significantly improved as the Cu proportion increased. CuInS2 sorbent showed superior mercury removal performance, the mercury removal efficiency reached 99.6% at 125 °C. O2 and NO showed a slight inhibition on Hg0 capture. The coexistence of SO2 and H2O showed no obvious negative effects on Hg0 removal. The CuInS2 sorbent displayed a superior tolerance to SO2 and H2O. TPD and XPS analyses demonstrated that the adsorbed mercury mainly existed in the form of mercuric sulfides (HgS). Hg0 adsorption over CuInS2 sorbent occurred via the Mars-Maessen mechanism. In this mechanism, Hg0 vapor was physically adsorbed on CuInS2 sorbent and then converted to HgS. This study provides future potential for applying CuxIn2-xS2 sorbents to capture gaseous mercury at low temperature.

Insights into the mechanism of lead species adsorption over Al2O3 sorbent.

Al2O3 is regarded as an effective sorbent to capture lead from flue gas. The adsorption behaviors of different species of lead (Pb, PbO, PbCl and PbCl2) on the Al2O3 surfaces were explored based on density functional theory. The results show that the chemisorption mechanism is responsible for the adsorption of lead species on the Al2O3 surface. The high reactivity of Pb adsorption on the α-Al2O3 (110) surface is mainly attributed to the existence of unsaturated Al atoms. The Al hollow sites are identified as the effectively active sites for Pb adsorption on the (110) surface. The adsorption energies of different species of lead on the Al-terminated (110) surface are in the range of - 4.20 to - 6.30 eV. PbO adsorption at the Al hollow site of the Al-terminated (110) surface shows the highest adsorption energy (- 6.30 eV), suggesting that Al2O3 prefers to capture PbO among different species of lead. The strong interactions of PbO, PbCl and PbCl2 molecules with the unsaturated Al atoms of the α-Al2O3 (110) surface are responsible for PbO, PbCl and PbCl2 capture by Al2O3. Al2O3 has a good ability to capture different species of lead, and the adsorption capacity follows the order: PbO > Pb > PbCl > PbCl2.

Reaction mechanism of dichloromethane oxidation on LaMnO3 perovskite.

The reaction mechanism of dichloromethane (CH2Cl2) oxidation on LaMnO3 catalyst was investigated using density functional theory calculations. The results showed that CH2Cl2 dechlorination proceeds via CH2Cl2 → CH2ClO → HCHO. The adsorbed Cl∗ and formaldehyde (HCHO) are identified as the important intermediates of CH2Cl2 dechlorination process. The dissociated Cl atoms prefer to adsorb on the surface Mn sites. Surface hydroxyl groups are not directly involved in the CH2Cl2 dechlorination process, but react with the adsorbed Cl∗ to form HCl. The energy barrier of HCl formation is lower than that of Cl2 formation, indicating that hydroxyl groups facilitate the removal of adsorbed Cl∗ species. Three possible pathways of HCHO oxidation with the assist of lattice oxygen, active oxygen atom and hydroxyl groups were investigated. HCHO catalytic oxidation contains four steps: HCHO → CHO → CO → H2O desorption → CO/CO2 desorption. Compared with the HCHO oxidation by lattice oxygen and hydroxyl groups, HCHO oxidation assisted with activated oxygen atom is more thermodynamically favorable. A complete catalytic cycle was proposed to understand the preferable reaction pathway for CH2Cl2 oxidation on LaMnO3 catalyst. The catalytic cycle includes CH2Cl2 dechlorination, HCl formation and HCHO oxidation. The microkinetic analysis indicates that there are four steps controlling the reaction cycle: CH2Cl2∗ + ∗ → CH2Cl∗ + Cl∗, CH2OCl∗ + Cl∗ → CH2O∗ + Cl∗, O2∗ + ∗ → 2O∗, and CHO2∗ + OH∗ → CO2 + H2O∗.

Charge-distribution modulation of copper ferrite spinel-type catalysts for highly efficient Hg0 oxidation.

Hg0 catalytic oxidation is an attractive approach to reduce mercury emissions from industrial activities. However, the rational design of highly active catalysts remains a significant challenge. Herein, the charge distribution modulation strategy was proposed to design novel catalysts: copper ferrite spinel-type catalysts were developed by introducing Cu2+ cations into octahedral sites to form electron-transfer environment. The synthesized catalysts with spinel-type stoichiometry showed superior catalytic performance, and achieved > 90 % Hg0 oxidation efficiency in a wide operation temperature window of 150-300 °C. The superior catalytic performance was closely associated with the mobile-electron environment of copper ferrite. Hg0 oxidation by HCl over copper ferrite followed the Eley-Rideal mechanism, in which physically adsorbed Hg0 reacted with active chlorine species. Density functional theory calculations revealed that octahedral Cu atom is the most active site of Hg0 adsorption on copper ferrite surface. Both direct oxidation pathway (Hg* → HgCl2*) and HgCl-mediated oxidation pathway (Hg* → HgCl* → HgCl2*) played important role in Hg0 oxidation over copper ferrite. HgCl2* formation was identified as the rate-limiting step of Hg0 oxidation. This work would provide a new perspective for the development of admirable catalysts with outstanding Hg0 oxidation performance.

Insights into the catalytic behavior of LaMnO3 perovskite for Hg0 oxidation by HCl.

LaMnO3-based catalysts with perovskite structure have gained increasing interest for Hg0 oxidation owing to their excellent catalytic activity, high thermal stability and unique redox behavior. Understanding the Hg0 oxidation behavior on LaMnO3 will broaden the application of LaMnO3-based perovskites in Hg0 removal field. Density functional theory (DFT) calculations were conducted to examine the catalytic mechanism of Hg0 oxidation by HCl on LaMnO3 surface. The results indicate that Mn-terminated LaMnO3(010) surface is more active and stable than La-terminated surface. Hg0 and HgCl2 are chemisorbed on LaMnO3(010) surface. HgCl can be molecularly chemisorbed on LaMnO3(010) and serve as an intermediate in Hg0 oxidation reaction. HCl dissociatively adsorbs on LaMnO3(010) and generates surface active chlorine complexes. Langmuir-Hinshelwood mechanism, where the chemisorbed Hg0 reacts with the dissociatively adsorbed HCl, is responsible for Hg0 oxidation by HCl on LaMnO3(010). Catalytic Hg0 oxidation over the surface contains four-steps: Hg0 → Hg(ads) → HgCl(ads) → HgCl2(ads) → HgCl2, and the second step (Hg(ads) → HgCl(ads)) is the rate-determining step because of its relatively larger energy barrier (0.74 eV).

AMn2O4 (A=Cu, Ni and Zn) sorbents coupling high adsorption and regeneration performance for elemental mercury removal from syngas.

AMn2O4 (A= Cu, Ni and Zn) spinel sorbents synthesized by a low-temperature sol-gel auto-combustion method were for the first time used to eliminate elemental mercury (Hg0) from syngas. CuMn2O4 sorbent exhibits the highest Hg0 adsorption performance under simulated syngas, higher than 95 % Hg0 capture efficiency is obtained at 200 °C. Adsorption-regeneration experiments demonstrate that the regenerability of CuMn2O4 is excellent. The influences of syngas compositions on Hg0 elimination over CuMn2O4 were examined. H2S plays the most important role in Hg0 removal from syngas, which can be adsorbed on CuMn2O4 surface and transformed into active sulfur species to react with Hg0 to form surface-bonded HgS. X-ray photoelectron spectroscopy (XPS) and temperature-programmed desorption (TPD) experiments prove that HgS is formed on the spent sorbent. The surface Cu2+ cations and chemisorbed/lattice oxygens participate in Hg0 adsorption and transformation. HCl promotes Hg0 removal by forming surface active chlorine species. H2, CO, and H2O inhibit Hg0 removal under N2 atmosphere. However, they exhibit no obvious effect on Hg0 removal with the assistance of H2S. The excellent Hg0 capture performance, good regenerability and H2O resistance of CuMn2O4 make it to be a very promising sorbent for Hg0 removal from syngas at higher temperature.

Cost-Effective Manganese Ore Sorbent for Elemental Mercury Removal from Flue Gas.

Mercury capture from flue gas remains a challenge for environmental protection due to the lack of cost-effective sorbents. Natural manganese ore (NMO) was developed as a cost-effective sorbent for elemental mercury removal from flue gas. NMO sorbent showed excellent Hg0 removal efficiency (>90%) in a wide temperature window (100-250 °C) under the conditions of simulated flue gas. O2, NO, and HCl promoted Hg0 removal due to the surface reactions of Hg0 with these species. SO2 and H2O slightly inhibited Hg0 removal under the conditions of simulated flue gas. O2 addition could also weaken the inhibitory effect of SO2. NMO sorbent exhibited superior regeneration performance for Hg0 removal during ten-cycle experiments. Quantum chemistry calculations were used to identify the active components of NMO sorbent and to understand the atomic-level interaction between Hg0 and sorbent surface. Theoretical results indicated that Mn3O4 is the most active component of NMO sorbent for Hg0 removal. The atomic orbital hybridization and electrons sharing led to the stronger interaction between Hg0 and Mn3O4 surface. Finally, a chemical looping process based on NMO sorbent was proposed for the green recovery of Hg0 from flue gas. The low cost, excellent performance, superior regenerable properties suggest that the natural manganese ore is a promising sorbent for mercury removal from flue gas.

A complete catalytic reaction scheme for Hg0 oxidation by HCl over RuO2/TiO2 catalyst.

RuO2-based catalysts have attracted great attention in mercury emission control region due to their outstanding catalytic activity and long-term stability. Quantum chemistry calculation was performed to uncover the atomic-scale reaction mechanism of Hg0 oxidation by HCl over RuO2/TiO2 catalyst. The results indicate that Hg0 adsorption on RuO2/TiO2(110) surface is controlled by a weak chemisorption mechanism. The 5-fold coordinated surface Ru atom is identified as the active center for Hg0 adsorption. HgCl molecule serves as an intermediate connecting reactant state to product state. The weak interaction between HgCl2 and catalyst surface is favorable for product desorption. HCl activation is an O-assisted surface reaction process in which HCl is oxidized into active Cl atom for Hg0 oxidation. The heterolytic cleavage of HCl molecule occurs without noticeable activation energy barrier. Hg0 oxidation by HCl over RuO2/TiO2 catalyst proceeds through two independent reaction channels. The dominant reaction channel of Hg0 oxidation is identified as a four-step process. Finally, a complete catalytic cycle that can produce the correct stoichiometry was proposed to understand the heterogeneous reaction mechanism of Hg0 oxidation over RuO2/TiO2 catalyst. The catalytic cycle consists of HCl activation, mercury oxidation and surface reoxidation. Mercury oxidation is the rate-determining step of the catalytic cycle.