Analysis of cases with co-infection of COVID-19 and pulmonary aspergillosis.

The objective of this study was to investigate the risk factors and diagnosis measure of COVID-19-associated pulmonary aspergillosis (CAPA). This study included 201 COVID-19 patients from December 1, 2022, to January 31, 2023; 7 (3.5%) were diagnosed with CAPA. The main risk factors were age, MV, ICU admission and COPD, and the presence of comorbidities such as ARDS and hypoproteinemia in COVID-19 patients, more susceptible to Aspergillus infection. In addition to specimen culture in the lower respiratory tract, the 1,3-ß-D-glucan antigen test can serve as an important screening indicator for early CAPA diagnosis in non-granulocytopenia patients.

The regulation of intestinal flora on host's genes may play an essential role in the development of endometrial hyperplastic processes in yang deficiency individuals.

Yang-deficiency constitution (YADC) is linked to a higher vulnerability to various diseases, such as cold coagulation and blood stasis (CCBS) syndrome and infertility. Endometrial hyperplastic processes (EHPs) are a leading cause of infertility in women and are characterized by CCBS. However, it remains unclear whether YADC is related to the development of EHPs. METHODS: We recruited 202 EHPs patients including 147 with YADC (YEH group) and 55 with non-YADC (NYEH group). Fecal samples were collected from 8 YEH patients and 3 NYEH patients and analyzed using 16S rRNA V3-V4 sequencing for gut microbiota analysis. We obtained constitution survey data and a differential gut microbiota dataset from the literature for further analysis. Bioinformatics analysis was conducted using gut microbiota-related genes from public databases. RESULTS: YADC was significantly more prevalent in EHPs than non-YADC (P < 0.001), suggesting it as a potential risk factor for EHPs occurrence (ORpopulation survey = 13.471; ORhealthy women = 5.173). The YEH group had higher levels of inflammation, estrogen, and tamoxifen-related flora compared to NYEH and healthy YADC groups. There was an interaction between inflammation, estrogen, differential flora, and EHPs-related genes, particularly the TNF gene (related to inflammation) and the EGFR gene (related to estrogen), which may play a crucial role in EHPs development. CONCLUSION: YEH individuals exhibit significant changes in their gut microbiota compared to NYEH and healthy YADC. The interaction between specific microbiota and host genes is believed to play a critical role in the progression of EHPs.

Gut microbiome changes in mouse, Mongolian gerbil, and hamster models following Clostridioides difficile challenge.

Introduction: Clostridioides difficile infection (CDI), as well as its etiology and pathogenesis, have been extensively investigated. However, the absence of suitable CDI animal models that reflect CDI symptoms and the associated gut microbiome changes in humans has limited research progress in this field. Thus, we aimed to investigate whether Mongolian gerbils, which present a range of human pathological conditions, can been used in studies on CDI. Methods: In this study, we infected Mongolian gerbils and two existing CDI model animals, mice and hamsters, with the hypervirulent ribotype 027 C. difficile strain, and comparatively analyzed changes in their gut microbiome composition via 16S rRNA gene sequencing. Methods: In this study, we infected Mongolian gerbils and two existing CDI model animals, mice and hamsters, with the hypervirulent ribotype 027 C. difficile strain, and comparatively analyzed changes in their gut microbiome composition via 16S rRNA gene sequencing. Results: The results obtained showed that C. difficile colonized the gastrointestinal tracts of the three rodents, and after the C. difficile challenge, C57BL/6J mice did not manifest CDI symptoms and their intestines showed no significant pathological changes. However, the hamsters showed explosive intestinal bleeding and inflammation and the Mongolian gerbils presented diarrhea as well as increased infiltration of inflammatory cells, mucus secretion, and epithelial cell shedding in their intestinal tissue. Further, intestinal microbiome analysis revealed significant differences with respect to intestinal flora abundance and diversity. Specifically, after C. difficile challenge, the Firmicutes/Bacteroidetes ratio decreased for C57BL/6J mice, but increased significantly for Mongolian gerbils and hamsters. Furthermore, the abundance of Proteobacteria increased in all three models, especially in hamsters, while that of Verrucomicrobia only increased significantly in C57BL/6J mice and Mongolian gerbils. Our results also indicated that differences in the relative abundances of Lactobacillaceae and Akkermansia were primarily responsible for the observed differences in response to C. difficile challenge. Conclusion: Based on the observed responses to C. difficile challenge, we concluded for the first time that the Mongolian gerbil could be used as an animal model for CDI. Additionally, the taxa identified in this study may be used as biomarkers for further studies on CDI and to improve understanding regarding changes in gut microbiome in CDI-related diseases.

GLUT1-mediated microglial proinflammatory activation contributes to the development of stress-induced spatial learning and memory dysfunction in mice.

BACKGROUND: Stress is a recognized risk factor for cognitive decline, which triggers neuroinflammation involving microglial activation. However, the specific mechanism for microglial activation under stress and affects learning and memory remains unclear. METHODS: The chronic stress mouse model was utilized to explore the relationship between microglial activation and spatial memory impairment. The effect of hippocampal hyperglycemia on microglial activation was evaluated through hippocampal glucose-infusion and the incubation of BV2 cells with high glucose. The gain-and loss-of-function experiments were conducted to investigate the role of GLUT1 in microglial proinflammatory activation. An adeno-associated virus (AAV) was employed to specifically knockdown of GLUT1 in hippocampal microglia to assess its impact on stressed-mice. RESULTS: Herein, we found that chronic stress induced remarkable hippocampal microglial proinflammatory activation and neuroinflammation, which were involved in the development of stress-related spatial learning and memory impairment. Mechanistically, elevated hippocampal glucose level post-stress was revealed to be a key regulator of proinflammatory microglial activation via specifically increasing the expression of microglial GLUT1. GLUT1 overexpression promoted microglial proinflammatory phenotype while inhibiting GLUT1 function mitigated this effect under high glucose. Furthermore, specific downregulation of hippocampal microglial GLUT1 in stressed-mice relieved microglial proinflammatory activation, neuroinflammation, and spatial learning and memory injury. Finally, the NF-κB signaling pathway was demonstrated to be involved in the regulatory effect of GLUT1 on microglia. CONCLUSIONS: We demonstrate that elevated glucose and GLUT1 expression induce microglia proinflammatory activation, contributing to stress-associated spatial memory dysfunction. These findings highlight significant interplay between metabolism and inflammation, presenting a possible therapeutic target for stress-related cognitive disorders.

Hippocampal Lactate-Infusion Enhances Spatial Memory Correlated with Monocarboxylate Transporter 2 and Lactylation.

Lactate has emerged as a key player in regulating neural functions and cognitive processes. Beyond its function as an energy substrate and signal molecule, recent research has revealed lactate to serve as an epigenetic regulator in the brain. However, the molecular mechanisms by which lactate regulates spatial memory and its role in the prevention of cognitive disorders remain unclear. Herein, we injected L-lactate (10 µmol/kg/d for 6 d) into the mouse's hippocampus, followed by the Morris water maze (MWM) test and molecular analyses. Improved spatial memory performances were observed in mice injected with lactate. Besides, lactate upregulated the expression of synaptic proteins post-synaptic density 95 (PSD95), synaptophysin (SYP), and growth associated protein 43 (GAP43) in hippocampal tissues and HT22 cells, suggesting a potential role in synaptic transmission and memory formation. The facilitative role of monocarboxylate transporter 2 (MCT2), a neuron-specific lactate transporter, in this process was confirmed, as MCT2 antagonists attenuated the lactate-induced upregulation of synaptic proteins. Moreover, lactate induced protein lactylation, a post-translational modification, which could be suppressed by MCT2 inhibition. RNA sequencing of lactated-injected hippocampal tissues revealed a comprehensive gene expression profile influenced by lactate, with significant changes in genes associated with transcriptional progress. These data demonstrate that hippocampal lactate injection enhances spatial memory in mice, potentially through the upregulation of synaptic proteins and induction of protein lactylation, with MCT2 playing a crucial role in these processes. Our findings shed light on the multi-faceted role of lactate in neural function and memory regulation, opening new avenues for therapeutic interventions targeting cognitive disorders.

Effect of Starch Types on the Textural and Rehydration Properties of Extruded Peanut Protein Pore Gel Particles.

In this study, the effect of different starches from corn, potato and pea containing varying amylose/amylopectin ratios on the textural and rehydration properties of extruded peanut protein gel particles were investigated. Results showed that textural and rehydration properties of peanut protein extruded with corn starch, potato starch and amylopectin are slightly inferior to those of peanut protein with pea starch extrudates. The addition of pea starch led to an increase in the pore structure of the peanut protein extrudates and improved their water absorption index, simultaneously reducing the hardness and density. Pea starch, as a natural water-absorbing expansion material, helped peanut protein to form cross-linked gel polymers that bind more water molecules, in addition to further polymerization with peanut protein, which made the protein secondary structure became disordered. These changes directly affected the textural properties of the extrudates. In addition, the blended system of starches and peanut protein tended to form more elastic solids, which affected the expansion of the extrudates. These findings indicate that starch can effectively improve the poor expansion of proteins, making it suitable for use in the production of plant protein-based foods.

Circadian changes of autonomic function in patients with zoster-associated pain: A heart rate variability analysis.

OBJECTIVE: To investigate the circadian changes of the autonomic function in patients with zoster-associated pain (ZAP). METHODS: A total of 37 patients with ZAP from April 2022 to October 2022 were enrolled as the observation group, and 37 normal volunteers at the same time were selected as the control group. All participants were required to wear a 24-h Holter, which was used to compare the heart rate variability (HRV) between the two groups. HRV analysis involved time- and frequency-domain parameters. RESULTS: There was no statistically significant difference in general information between two groups. Patients with ZAP had an increased mean heart rate and decreased the standard deviation of normal-to-normal (SDNN) R-R interval, the root mean square of the differences (RMSSD) in successive RR interval, low frequency (LF), and high frequency (HF) compared with control groups in all periods (p < .05). The ratio of LF/HF between two groups had no significant difference (p = .245). SDNN had no significant difference between day and night in the control group (p > .05), whereas SDNN of ZAP patients in night period was reduced than that in day period (p < .001). The level of RMSSD during the day was lower than those at night in the control group (p < .05), whereas no significant difference of RMSSD between two periods was observed in patients with ZAP (p > .05). CONCLUSION: The results of this study indicated that ZAP contributes to the decline of autonomic nervous system (ANS) function, especially parasympathetic components. The patients with ZAP lost parasympathetic advantage and had a worse ANS during the night.

Dopamine-Modified Chitosan Patterning Hydrogel with Dynamic Information Storage Ability.

The storage of dynamic information in hydrogels has aroused considerable interest regarding the multiple responsiveness of soft matter. Herein, we propose an electrical writing methodology to prepare dopamine (DA)-modified chitosan hydrogels with a dynamic information storage ability. A pH-responsive chitosan hydrogel medium was patterned by cathodic writing to in situ generate OH- in the writing area, at which dopamine underwent an auto-oxidation reaction in the locally alkaline environment to generate a dark color. The patterned information on the hydrogel can be encoded simply by electrical signals. The speed of information retrieval is positively correlated with the charge transfer during the electrical writing process, and the hiding of information is negatively correlated with the environmental stimulus (i.e., dopamine concentration, pH value, etc.). To showcase the versatility of this medium for information storage and the precision of the pattern, a quick response (QR) code is electronically written on dopamine-modified chitosan hydrogel and can be recognized programmably by a standard mobile phone. The results show that electrical regulation is a novel means to program the information storage process of hydrogels, which inspires future research on structural and functional information storage using stimulus-responsive hydrogels.

Preventive and Therapeutic Effects of Crocetin in Rats with Heart Failure.

Gardenia is both a food and medicine plant. It is widely used for cardiovascular protection, and its main bioactive ingredient is crocetin. This study aims to observe the therapeutic effects of crocetin on chronic heart failure in rats induced by various etiologies. It further compares the efficacy differences between preventative and treatment administration, varying dosages, and treatment durations, to provide improved guidance for medication in heart failure rats and determine which categories of chronic heart failure rats might benefit most from crocetin. Chronic heart failure models induced by abdominal aorta constriction, renal hypertension, and coronary artery ligation were constructed. By examining cardiac function, blood biochemistry, and histopathology, the study assessed the preventive and therapeutic effects of crocetin on load-induced and myocardial ischemia-induced heart failure. The results showed that in all three models, both treatment and preventative administration of crocetin significantly improved chronic heart failure in rats, especially in preventative administration. The results indicate crocetin may be beneficial for improving symptoms and functional capacity in rats with heart failure. Furthermore, long-term administration was more effective than short-term administration across all three rat models, with therapeutic onset observed over 6 weeks.

Doping Ferrocene-Based Conjugated Microporous Polymers with 7,7,8,8-Tetracyanoquinodimethane for Efficient Photocatalytic CO2 Reduction.

The design and synthesis of organic photocatalysts remain a great challenge due to their strict structural constraints. However, this could be mitigated by achieving structural flexibility by constructing permanent porosity into the materials. Conjugated microporous polymers (CMPs) are an emerging class of porous materials with an amorphous, three-dimensional network structure, which makes it possible to integrate the elaborate functional groups to enhance photocatalytic performance. Here, we report the synthesis of a novel CMP, named TAPFc-TFPPy-CMP, constructed by 1,1'3,3'-tetra(4-aminophenyl)ferrocene (TAPFc) and 1,3,6,8-tetrakis(4-formylphenyl)pyrene (TFPPy) monomers. The integration of the p-type dopant 7,7,8,8-tetracyanoquinodimethane (TCNQ) into the TAPFc-TFPPy-CMP improved the light adsorption performance, leading to a decrease in the optical bandgap from 2.00 to 1.43 eV. The doped CMP (TCNQ@TAPFc-TFPPy-CMP) exhibited promising catalytic activity in photocatalytic CO2 reduction under visible light, yielding 546.8 µmol g-1 h-1 of CO with a selectivity of 96% and 5.2 µmol g-1 h-1 of CH4. This represented an 80% increase in the CO yield compared to the maternal TAPFc-TFPPy-CMP. The steady-state photoluminescence (PL) and fluorescence lifetime (FL) measurements reveal faster carrier separation and transport after the doping. This study provides guidance for the development of organic photocatalysts for the utilization of renewable energy.

Characteristics of Pickering emulsions stabilized by microgel particles of five different plant proteins and their application.

Pickering emulsions stabilized by protein particles are of great interest for use in real food systems. This study was to investigate the properties of microgel particles prepared from different plant proteins, i.e., soybean protein isolate (SPI), pea protein isolate (PPI), mung bean protein isolate (MPI), chia seed protein isolate (CSPI), and chickpea protein isolate (CPI). MPI protein particles had most desirable Pickering emulsion forming ability. The particles of SPI and PPI had similar particle size (316.23 nm and 294.80 nm) and surface hydrophobicity (2238.40 and 2001.13) and emulsion forming ability, while the CSPI and CPI particle stabilized emulsions had the least desirable properties. The MPI and PPI particle stabilized Pickering emulsions produced better quality ice cream than the one produced by SPI particle-stabilized emulsions. These findings provide insight into the properties of Pickering emulsions stabilized by different plant protein particles and help expand their application in emulsions and ice cream.

Forsythoside A protects against Zearalenone-induced cell damage in chicken embryonic fibroblasts via mitigation of endoplasmic reticulum stress.

Zearalenone (ZEA) is a non-steroidal estrogenic mycotoxin that exerts its toxic effects through various damage mechanisms such as oxidative stress, endoplasmic reticulum stress (ERS), mitochondrial damage, cell cycle arrest, and apoptosis. At present, there are few studies on drugs that can rescue ZEA-induced chicken embryonic fibroblasts damage. Forsythoside A (FA) is one of effective ingredients of traditional Chinese medicine that plays a role in various biological functions, but its antitoxin research has not been investigated so far. In this study, in vitro experiments were carried out. Chicken embryo fibroblast (DF-1) cells was used as the research object to select the appropriate treatment concentration of ZEA and examined reactive oxygen species (ROS), mitochondrial membrane potential, ERS and apoptosis to investigate the effects and mechanisms of FA in alleviating ZEA-induced cytotoxicity in DF-1 cells. Our results showed that ZEA induced ERS and activated the unfolded protein response (UPR) leading to apoptosis, an apoptotic pathway characterized by overproduction of Lactate dehydrogenase (LDH), Caspase-3, and ROS and loss of mitochondrial membrane potential. We also demonstrated that FA help to prevent ERS and attenuated ZEA-induced apoptosis in DF-1 cells by reducing the level of ROS, downregulating GRP78, PERK, ATF4, ATF6, JNK, IRE1, ASK1, CHOP, BAX expression, and up-regulating Bcl-2 expression. Our results provide a basis for an in-depth study of the mechanism of toxic effects of ZEA on chicken cells and the means of detoxification, which has implications for the treatment of relevant avian diseases.

Spatial and temporal analysis of HIV clinical outcomes in Florida reveals counties with persistent racial and ethnic disparities during 2012-2019.

BACKGROUND: Racial/ethnic disparities in the HIV care continuum have been well documented in the US, with especially striking inequalities in viral suppression rates between White and Black persons with HIV (PWH). The South is considered an epicenter of the HIV epidemic in the US, with the largest population of PWH living in Florida. It is unclear whether any disparities in viral suppression or immune reconstitution-a clinical outcome highly correlated with overall prognosis-have changed over time or are homogenous geographically. In this analysis, we 1) investigate longitudinal trends in viral suppression and immune reconstitution among PWH in Florida, 2) examine the impact of socio-ecological factors on the association between race/ethnicity and clinical outcomes, 3) explore spatial and temporal variations in disparities in clinical outcomes. METHODS: Data were obtained from the Florida Department of Health for 42,369 PWH enrolled in the Ryan White program during 2008-2020. We linked the data to county-level socio-ecological variables available from County Health Rankings. GEE models were fit to assess the effect of race/ethnicity on immune reconstitution and viral suppression longitudinally. Poisson Bayesian hierarchical models were fit to analyze geographic variations in racial/ethnic disparities while adjusting for socio-ecological factors. RESULTS: Proportions of PWH who experienced viral suppression and immune reconstitution rose by 60% and 45%, respectively, from 2008-2020. Odds of immune reconstitution and viral suppression were significantly higher among White [odds ratio =2.34, 95% credible interval=2.14-2.56; 1.95 (1.85-2.05)], and Hispanic [1.70 (1.54-1.87); 2.18(2.07-2.31)] PWH, compared with Black PWH. These findings remained unchanged after accounting for socio-ecological factors. Rural and urban counties in north-central Florida saw the largest racial/ethnic disparities. CONCLUSIONS: There is persistent, spatially heterogeneous, racial/ethnic disparity in HIV clinical outcomes in Florida. This disparity could not be explained by socio-ecological factors, suggesting that further research on modifiable factors that can improve HIV outcomes among Black and Hispanic PWH in Florida is needed.

Monoclonal neutralizing antibodies against SARS-COV-2 S protein.

Novel coronavirus pneumonia, also known as coronavirus disease 2019 (COVID-19), is caused by sub-severe acute respiratory syndrome type 2 coronavirus (SARS-CoV-2) infection. The spike (S) protein of SARS-CoV-2 binds to angiotensin-converting enzyme 2 (ACE2) receptors widely expressed on the surface of human cells leading to life-threatening respiratory infections. A serious hazard to human health is posed by the lack of particular treatment medications for this virus infection. We advocate the creation of high-affinity antibodies using the receptor binding domain (RBD) of S protein as a specific antigenic epitope to develop a drug that can precisely target therapy COVID-19 because SARS-CoV-2 infection of the host cells is dependent on S protein binding to ACE2. Finally, we obtained high-affinity antibodies 14F4HL and 14E3HL that have high affinity with RBD and well-drug-forming properties, suitable for further humanization studies. Thus, monoclonal antibodies that neutralize the S protein were identified in our study, which may provide new insights for the development of COVID-19 therapeutic drugs.

Long-lived nitric oxide molecular tagging velocimetry with 1 + 1 REMPI.

The successful demonstration of long-lived nitric oxide (NO) fluorescence for molecular tagging velocimetry (MTV) measurements is described in this Letter. Using 1 + 1 resonance-enhanced multiphoton ionization (REMPI) of NO at a wavelength near 226 nm, targeting the overlapping Q1(7) and Q21(7) lines of the A-X (0, 0) electronic system, the lifetime of the NO MTV signal was observed to be approximately 8.6 µs within a 100-Torr cell containing 2% NO in nitrogen. This is in stark contrast to the commonly reported single photon NO fluorescence, which has a much shorter calculated lifetime of approximately 43 ns at this pressure and NO volume fraction. While the shorter lifetime fluorescence can be useful for molecular tagging velocimetry with single laser excitation within very high-speed flows at some thermodynamic conditions, the longer lived fluorescence shows the potential for an order of magnitude more accurate and precise velocimetry, particularly within lower speed regions of hypersonic flow fields such as wakes and boundary layers. The physical mechanism responsible for the generation of this long-lived signal is detailed. Furthermore, the effectiveness of this technique is showcased in a high-speed jet flow, where it is employed for precise flow velocity measurements.

[Virulence genes and antimicrobial resistance of Bacillus cereus in prepackaged pastries sold in Taizhou from 2020 to 2022].

OBJECTIVE: To investigate the virulence genes and antimicrobial resistance of Bacillus cereus from the pre-packaged pastries in Taizhou city. METHODS: 500 pre-packaged patries were collected in taizhou city market. 97 Bacillus cereus strains were detected from them by GB 4789.14-2014 method and identified with 4 houseking genes, then 13 virulence genes were detected by polymerase chain reaction(PCR)method and the antimicrobial resistance of Bacillus cereus to 19 antibiotics was detected by paper diffusion method. RESULTS: The result showed that the contamination rate of Bacillus cereus was 19.4% in 500 pre-packaged pastries. The detection rate of four housekeeping genes groEL, gyr B, rpoB and Vrr were 100%, 94.8%, 97.9% and 96.9%, respectively, and 89.7% at the same time. The virulence gene test result showed that the detection rate of nheABC, entFM, bceT, cytK and hblABCD were 91.8%, 88.7%, 61.9%, 51.6% and 25.8%, emetic virulence genes had the lowest detection rate, ces and EMl were 4.1%, cer was 5.2%. 97 Bacillus cereus strains show different degrees of drug resistance to 14 antimicrobials, the resistance rates to penicillin, ampicillin, cefotaxime and cotrimoxazole were higher than 95%, but they were completely sensitive to streptomycin, vancomycin and chloramphenicol. CONCLUSION: There is a risk of contamination by diarrhea-type Bacillus cereus and vomiting-type Bacillus cereus in prepackaged pastries in Taizhou. The isolated and identified Bacillus cereus has multiple-drug resistance.

Synergistic oxidation of toluene through bimetal/cordierite monolithic catalysts with ozone.

Toluene treatment has received extensive attention, and ozone synergistic catalytic oxidation was thought to be a potential method to degrade VOCs (violate organic compounds) due to its low reaction temperature and high catalytic efficiency. A series of bimetal/Cord monolithic catalysts were prepared by impregnation with cordierite, including MnxCu5-x/Cord, MnxCo5-x/Cord and CuxCo5-x/Cord (x = 1, 2, 3, 4). Analysis of textural properties, structures and morphology characteristics on the prepared catalysts were conducted to evaluate their performance on toluene conversion. Effects of active component ratio, ozone addition and space velocity on the catalytic oxidation of toluene were investigated. Results showed that MnxCo5-x/Cord was the best among the three bimetal catalysts, and toluene conversion and mineralization rates reached 100 and 96% under the condition of Mn2Co3/Cord with 3.0 g/m3 O3 at the space velocity of 12,000 h-1. Ozone addition in the catalytic oxidation of toluene by MnxCo5-x/Cord could efficiently avoid the 40% reduction of the specific surface area of catalysts, because it could lower the optimal temperature from 300 to 100 °C. (Co/Mn)(Co/Mn)2O4 diffraction peaks in XRD spectra indicated all the four MnxCo1-x/Cord catalysts had a spinel structure, and diffraction peak intensity of spinel reached the largest at the ratio of Mn:Co = 2:3. Toluene conversion rate increased with rising ozone concentration because intermediate products generated by toluene degradation might react with excess ozone to generate free radicals like ·OH, which would improve the toluene mineralization rate of Mn2Co3/Cord catalyst. This study would provide a theoretical support for its industrial application.

Observation and quantification of the pseudogap in unitary Fermi gases.

The microscopic origin of high-temperature superconductivity in cuprates remains unknown. It is widely believed that substantial progress could be achieved by better understanding of the pseudogap phase, a normal non-superconducting state of cuprates1,2. In particular, a central issue is whether the pseudogap could originate from strong pairing fluctuations3. Unitary Fermi gases4,5, in which the pseudogap-if it exists-necessarily arises from many-body pairing, offer ideal quantum simulators to address this question. Here we report the observation of a pair-fluctuation-driven pseudogap in homogeneous unitary Fermi gases of lithium-6 atoms, by precisely measuring the fermion spectral function through momentum-resolved microwave spectroscopy and without spurious effects from final-state interactions. The temperature dependence of the pairing gap, inverse pair lifetime and single-particle scattering rate are quantitatively determined by analysing the spectra. We find a large pseudogap above the superfluid transition temperature. The inverse pair lifetime exhibits a thermally activated exponential behaviour, uncovering the microscopic virtual pair breaking and recombination mechanism. The obtained large, temperature-independent single-particle scattering rate is comparable with that set by the Planckian limit6. Our findings quantitatively characterize the pseudogap in strongly interacting Fermi gases and they lend support for the role of preformed pairing as a precursor to superfluidity.