High-Precision Vital Signs Monitoring Method Using a FMCW Millimeter-Wave Sensor

The method of using millimeter-wave radar sensors to detect human vital signs, namely respiration and heart rate, has received widespread attention in non-contact monitoring. These sensors are compact, lightweight, and able to sense and detect various scenarios. However, it still faces serious problems of noisy interference in hardware, which leads to a low signal-to-noise ratio (SNR). We used a frequency-modulated continuous wave (FMCW) radar sensor operating at 77 GHz in an office environment to extract the respiration and heart rate of a person accustomed to sitting in a chair. Indeed, the proposed signal processing includes novel impulse denoising operations and the spectral estimation decision method, which are unique in terms of noise reduction and accuracy improvement. In addition, the proposed method provides high-quality, repeatable respiration and heart rates with relative errors of 1.33% and 1.96% on average compared with the reference values measured by a reliable smart bracelet.

[Effect of exercise intervention on musculoskeletal disorders in nursing staff]

Objective: To evaluate the effects of exercise intervention on musculoskeletal disorders (MSD) in nursing staff. Methods: In september 2021, we searched the articles on exercise intervention for nurses with musculoskeletal diseases in Embase, PubMed, ClinicalTrails, Wanfang, CNKI and other databases in September 2021, and the search period was from database creation to August 2021. The quality of article was evaluated by Cochrane bias risk assessment tool and MINORS. The systematic review method with narrative synthesis was used to analyze the research results. Results: A total of 7 studies were included, including 6 randomized controlled trials and 1 quasi-experiment. The sample size of the experimental group was 276, and the control group was 273. Depending on the type of exercise intervention, muscle strength training, muscle strength training+stretch/flexibility training, Back School program can reduce the local pain of nursing staff. Among them, muscle strength training can improve the nursing staff's muscle function and quality of life, muscle strength training+stretching/flexibility training can increase muscle strength, range of physical activity and self-efficacy, the Back School program is effective for improving poor posture. Conclusion: Exercise intervention is effective on controlling musculoskeletal disorder symptoms in nursing staff, managers can develop exercise strategies for different MSD symptoms.

Generating Lifetime-Enhanced Microbubbles by Decorating Shells with Silicon Quantum Nano-Dots Using a 3-Series T-Junction Microfluidic Device

Long-term stability of microbubbles is crucial to their effectiveness. Using a new microfluidic device connecting three T-junction channels of 100 μm in series, stable monodisperse SiQD-loaded bovine serum albumin (BSA) protein microbubbles down to 22.8 ± 1.4 μm in diameter were generated. Fluorescence microscopy confirmed the integration of SiQD on the microbubble surface, which retained the same morphology as those without SiQD. The microbubble diameter and stability in air were manipulated through appropriate selection of T-junction numbers, capillary diameter, liquid flow rate, and BSA and SiQD concentrations. A predictive computational model was developed from the experimental data, and the number of T-junctions was incorporated into this model as one of the variables. It was illustrated that the diameter of the monodisperse microbubbles generated can be tailored by combining up to three T-junctions in series, while the operating parameters were kept constant. Computational modeling of microbubble diameter and stability agreed with experimental data. The lifetime of microbubbles increased with increasing T-junction number and higher concentrations of BSA and SiQD. The present research sheds light on a potential new route employing SiQD and triple T-junctions to form stable, monodisperse, multi-layered, and well-characterized protein and quantum dot-loaded protein microbubbles with enhanced stability for the first time.

[The importance of standardized periorbital steroid injections for thyroid-associated ophthalmopathy]

Thyroid-associated ophthalmopathy (TAO) is now the most prevalent orbital disease in adults, with a complex pathophysiology and a wide range of clinical symptoms. In recent years, significant progress has been made in the research on the treatment of TAO. Periorbital steroid injections are considered a precise local treatment and can improve ocular symptoms with minor side effects. However, there is no standardized orbital injection protocol in China, resulting in increased complications. Therefore, it is essential to standardize periorbital steroid injections in treating TAO.

P11.75.B Survival benefit of radiotherapy and surgery in patients with lung cancer brain metastases with poor prognosis factors

Background

Radiotherapy and surgery are the standard treatments for lung cancer brain metastases (BMs). However, limitted studies focused on the treatments for patients with lung cancer BMs with poor prognosis factors. The purpose of this study was to investigate the effects of radiotherapy and surgery in patients with lung cancer BMs with poor prognosis factors, providing reference for clinical strategies.

Material and Methods

We analyzed retrospectively 714 patients with lung cancer BMs. A 1:1 propensity score matching (PSM) was performed to balance potential confounders. Analyses of overall survival (OS) and risk factors for OS were assessed by log-rank test and Cox proportional hazard model.

Results

Age ≥65 years, Karnofsky Performance Scale (KPS) score ≤70, anaplastic large-cell lymphoma kinase (ALK)/epidermal growth factor receptor (EGFR) wild type, extracranial metastases, non-surgery and non-radiotherapy led to poor prognosis. Patients were stratified according to these factors. Radiotherapy and surgery showed no survival benefit in patients with aged ≥65 years or pretreatment KPS score ≤70 before and after PSM. Before PSM, whole brain radiotherapy (WBRT) improved the OS and predicted good prognosis in patients with ALK/EGFR wild type or extracranial metastases. WBRT also predicted good prognosis in patients with non-surgery. Stereotactic radiosurgery (SRS) improved the OS and predicted good prognosis in patients with ALK/EGFR wild type or non-surgery. WBRT plus SRS improved the OS and predicted good prognosis in patients with extracranial metastases or non-surgery. WBRT plus SRS also predicted good prognosis in patients with ALK/EGFR wild type. Surgery improved the OS and predicted good prognosis in patients with non-radiotherapy. After PSM, SRS improved the OS and predicted good prognosis in patients with non-surgery. WBRT plus SRS improved the OS and predicted good prognosis in patients with non-surgery or extracranial metastases. WBRT plus SRS also predicted good prognosis in patients with ALK/EGFR wild type. Surgery improved the OS of patients with non-radiotherapy. We defined that the treatment would provide significant survival benefit if it both prolonged the OS and predicted good prognosis. Meanwhile, the results after PSM were more convincing than the results before PSM.

Conclusion

Radiotherapy has significant survival benefit in patients with lung cancer BMs with poor prognosis factors, including patients with ALK/EGFR wild type or extracranial metastases or non-surgery. Surgery only has significant survival benefit in patients with non-radiotherapy.

Multi-Omics Analysis Reveals that the Antimicrobial Kasugamycin Potential Targets Nitrate Reductase in Didymella segeticola to Achieve Control of Tea Leaf Spot

Because of the lack of effective disease management measures, tea leaf spot-caused by the fungal phytopathogen Didymella segeticola (syn. Phoma segeticola)-is an important foliar disease. The important and widely used agricultural antimicrobial kasugamycin (Ksg), produced by the Gram-positive bacterium Streptomyces kasugaensis, effects high levels of control against crop diseases. The results of this study indicated that Ksg could inhibit the growth of D. segeticola hyphae in vitro with a half-maximal effective concentration (EC₅₀) of 141.18 μg ml^-1. Meanwhile, the curative effect in vivo on the pathogen in detached tea leaves also demonstrated that Ksg induced some morphological changes in organelles, septa, and cell walls as observed by optical microscopy and by scanning and transmission electron microscopy. This may indicate that Ksg disturbs biosynthesis of key metabolites, inhibiting hyphal growth. Integrated transcriptomic, proteomic, and bioinformatic analyses revealed that differentially expressed genes or differentially expressed proteins in D. segeticola hyphae in response to Ksg exposure were involved with metabolic processes and biosynthesis of secondary metabolites. Molecular docking studies indicated that Ksg may target nitrate reductase (NR), and microscale thermophoresis assay showed greater affinity with NR, potentially disturbing nitrogen assimilation and subsequent metabolism. The results indicated that Ksg inhibits the pathogen of tea leaf spot, D. segeticola, possibly by binding to NR, disturbing fungal metabolism, and inducing subsequent changes in hyphal growth and development.

First Measurement of the Z→μ^{+}μ^{-} Angular Coefficients in the Forward Region of pp Collisions at sqrt[s]=13 TeV

The first study of the angular distribution of μ^{+}μ^{-} pairs produced in the forward rapidity region via the Drell-Yan reaction pp→γ^{*}/Z+X→ℓ^{+}ℓ^{-}+X is presented, using data collected with the LHCb detector at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.1  fb^{-1}. The coefficients of the five leading terms in the angular distribution are determined as a function of the dimuon transverse momentum and rapidity. The results are compared to various theoretical predictions of the Z-boson production mechanism and can also be used to probe transverse-momentum-dependent parton distributions within the proton.

Combining Ultrasound and Capillary-Embedded T-Junction Microfluidic Devices to Scale Up the Production of Narrow-Sized Microbubbles through Acoustic Fragmentation

Microbubbles are tiny gas-filled bubbles that have a variety of applications in ultrasound imaging and therapeutic drug delivery. Microbubbles can be synthesized using a number of techniques including sonication, amalgamation, and saline shaking. These approaches can produce highly concentrated microbubble suspensions but offer minimal control over the size and polydispersity of the microbubbles. One of the simplest and effective methods for producing monodisperse microbubbles is capillary-embedded T-junction microfluidic devices, which offer great control over the microbubble size. However, lower production rates (∼200 bubbles/s) and large microbubble sizes (∼300 μm) limit the applicability of such devices for biomedical applications. To overcome the limitations of these technologies, we demonstrate in this work an alternative approach to combine a capillary-embedded T-junction device with ultrasound to enhance the generation of narrow-sized microbubbles in aqueous suspensions. Two T-junction microfluidic devices were connected in parallel and combined with an ultrasonic horn to produce lipid-coated SF₆ core microbubbles in the size range of 1-8 μm. The rate of microbubble production was found to increase from 180 microbubbles/s in the absence of ultrasound to (6.5 ± 1.2) × 10⁶ bubble/s in the presence of ultrasound (100% ultrasound amplitude). When stored in a closed environment, the microbubbles were observed to be stable for up to 30 days, with the concentration of the microbubble suspension decreasing from ∼2.81 × 10⁹/mL to ∼2.3 × 10⁶/mL and the size changing from 1.73 ± 0.2 to 1.45 ± 0.3 μm at the end of 30 days. The acoustic response of these microbubbles was examined using broadband attenuation spectroscopy, and flow phantom imaging was performed to determine the ability of these microbubble suspensions to enhance the contrast relative to the surrounding tissue. Overall, this approach of coupling ultrasound with microfluidic parallelization enabled the continuous production of stable microbubbles at high production rates and low polydispersity using simple T-junction devices.

Roles and Research Trends of Neuroscience on Major Information Systems Journal: A Bibliometric and Content Analysis

Over the past decade, neuroscience has been integrated into information systems as a new methodology and perspective to study and solve related problems. Therefore, NeuroIS has emerged as a new cutting-edge research field. This review aimed to identify, summarize, and classify existing NeuroIS publications through knowledge mapping and bibliometric analysis. To effectively understand the development trend of NeuroIS, this study referred to the journal selection index of the Association of Business Schools in 2021 and journals above three stars in the field of information management as the main selection basis. A total of 99 neuroscience papers and their citation data were included from 19 major information systems journals of SCI/SSCI. This study analyzed bibliometric data from 2010 to 2021 to identify the most productive countries, universities, authors, journals, and prolific publications in NeuroIS. To this end, VOSviewer was used to visualize mapping based on co-citation, bibliographic coupling, and co-occurrence. Keywords with strong citation bursts were also identified in this study. This signifies the evolution of this research field and may reveal potential research directions in the near future. In selecting research methods and analysis tools for NeuroIS, content analysis was used to further conclude and summarize the relevant trends. Moreover, a co-citation network analysis was conducted to help understand how the papers, journals, and authors in the field were connected and related, and to identify the seminal or pioneering major literature. For researchers, network maps visualized mainstream research and provided a structural understanding of NeuroIS. The review concludes by discussing potential research topics in this field.

A mathematical foundation to support bidirectional mappings between digital models: an application of multi-scale modelling in manufacturing

With manufacturing going through the Industry 4.0 revolution, a vast amount of data and information exchange leads to an increase in complexity of digitized manufacturing systems. To tackle such complexity, one solution is to design and operate a digital twin model under different levels of abstraction, with different levels of detail, according to the available information and scope of the model. To support efficient, coherent and stable information flows between models with different levels of detail, a mathematical structure, called a delta lens, has been explored and developed to support rigorous bidirectional transitions between the models. To support different types of abstractions in manufacturing, a hybrid delta lens has been proposed and its formal representation is developed to support the generalization of its structure and properties. Benefits of the proposed hybrid delta lenses are demonstrated through an application to an industrial case to support the modelling of an automatic, high-throughput assembly line.

[Vasohibin-2 promotes proliferation and metastasis of cervical cancer cells by regulating epithelial-mesenchymal transition]

OBJECTIVE

To explore the role of vasohibin-2 (VASH2) in regulation of proliferation and metastasis of cervical cancer cells.

METHODS

We analyzed the differentially expressed genes between cervical cancer cells with flotillin-1 overexpression and knockdown by RNA-seq combined with analysis of public databases. The expression levels of VASH2 were examined in normal cervical epithelial cells (HcerEpic), cervical cancer cell lines (HeLa, C-33A, Ca ski, SiHa and MS751) and fresh cervical cancer tissues with different lymph node metastasis status. We further tested the effects of lentivirus-mediated overexpression and interference of VASH2 on proliferation, migration, invasion and lymphatic vessel formation of the cervical cancer cells and detected the expression levels of key epithelial-mesenchymal transition (EMT) markers and TGF-β mRNA.

RESULTS

RNA-seq and analysis of public databases showed that VASH2 expression was significantly upregulated in cervical cancer cells exogenously overexpressing flotillin-1 (P < 0.05) and downregulated in cells with flotillin-1 knockdown (P < 0.05), and was significantly higher in cervical cancer tissues with lymph node metastasis than in those without lymph node metastasis (P < 0.01). In cervical cancer cell lines Ca Ski, SiHa, and MS751 and cervical cancer tissue specimens with lymph node metastasis, VASH2 expression was also significantly upregulated as compared with HcerEpic cells and cervical cancer tissues without lymph node metastasis (P < 0.05). Exogenous overexpression of VASH2 significantly promoted proliferation, migration, invasion and lymphatic vessel formation of cervical cancer cells, whereas these abilities were significantly inhibited in cells with VASH2 knockdown (P < 0.05). The cervical cancer cells overexpressing VASH2 showed significant down- regulation of e-cadherin and up- regulation of N-cadherin, Vimentin and VEGF-C, while the reverse changes were detected in cells with VASH2 knockdown (P < 0.05). TGF-β mRNA expression was significantly up-regulated in cervical cancer cells overexpressing VASH2 and down-regulated in cells with VASH2 knockdown (P < 0.001).

CONCLUSION

Flotillin-1 may participate in TGF-β signaling pathway-mediated EMT through its down-stream target gene VASH2 to promote the proliferation, migration, invasion and lymphatic vessel formation of cervical cancer cells in vitro.

[Characteristics and risk factors of functional constipation in children aged 0-4 years in Xi 'an]

Objective: To investigate the epidemiology, characteristics and risk factors of functional constipation (FC) in children aged 0-4 years in Xi'an. Methods: From October, 2020 to June, 2021, a prevalence survey was conducted among 2 615 children aged 0-4 years in Xi'an by group sampling. The related factors of FC were investigated by questionnaire designed based on Rome Ⅳ diagnostic criteria.The children were divided into FC group and non-FC group. The prevalence, symptoms and signs of FC were analyzed, and its risk factors were analyzed by multivariate Logistic regression. Results: A total of 2 985 valid questionnaires were handed out, and 2 711 (90.8%) were received back. A total of 2 615 questionnaires were valid, with an effective rate of 96.5%. There were 1 338 males (51.2%) and 1 277 females (48.8%). There were 260 cases in FC group and 2 355 cases in non-FC group. The prevalence of FC in children aged 0-4 years in Xi 'an was 10.6%.There were significant differences in FC prevalence among children of different ages and sex (χ²=14.58,4.39, both P<0.05), but not in urban or rural residence (χ²=3.29, P=0.070). The main symptoms of FC group in the last month were large-diameter feces (73.5%, 191/260), painful defecation or dry and hard defecation (65.8%, 171/260). In the last month, FC group had higher incidences of the Bristol type 1, 2 and 3 stool, fecal retention, prolonged defecation, abdominal pain and incomplete defecation compared with non-FC group, with statistical significance (all P<0.05). Parental history of childhood constipation (OR=2.13, 95%CI 1.55-2.92), fever in the last month (OR=1.86, 95%CI 1.32-2.63), history of constipation (OR=3.24, 95%CI 2.46-4.26) and taking probiotics in the last month (OR=1.45, 95%CI 1.11-1.91) were risk factors of FC in children aged 0-4 years. Stratified with age, the results showed that complementary feeding earlier than 5 months of age or later than 6 months of age (OR=2.42, 95%CI 1.13-5.20), dry stools during the complementary feeding (OR=11.27, 95%CI 5.15-24.66), history of constipation (OR=2.29, 95%CI 1.23-4.29) and taking probiotics in the last month (OR=1.88, 95%CI 1.10-3.23) were risk factors of FC in children aged 0-<1 year, and breastfeeding (OR=0.53, 95%CI 0.29-0.94) was a protective factor of FC in children aged 0-<1 year. Family members' recent constipation history (OR=2.02, 95%CI 1.06-3.85) and past history of constipation (OR=3.06, 95%CI 1.74-5.38) were FC risk factors for children aged 1-<2 years. Parental history of childhood constipation (OR=3.12, 95%CI 2.00-4.85), frequency of eating vegetables less than 3 times per week (OR=3.28, 95%CI 2.00-5.38), history of constipation (OR=3.66, 95%CI 2.42-5.53) and taking antibiotics in the last month (OR=1.65, 95%CI 1.06-2.55) were risk factors for FC in children aged 2-4 years. Conclusions: FC in children aged 0-4 years in Xi'an is mainly manifested with large-diameter feces and painful defecation or dry and hard defecation in the last month. It is associated with a variety of risk factors, which are different in different age groups.

ASSOCIATION BETWEEN THE CTLA-4 EXON 1+49A/G POLYMORPHISM AND THE RELAPSE OF GRAVE'S DISEASE AFTER ATD WITHDRAWAL: A META-ANALYSIS

Background

The cytotoxic T lymphocyte-associated molecules-4 (CTLA-4) is related to the relapse of Graves' disease (GD) after anti-thyroid drugs (ATDs) withdrawal. We performed a meta-analysis to generate large-scale evidence on whether the CTLA-4 exon 1+49A/G polymorphism can predict the relapse of GD after ATDs withdrawal.

Methods and Results

The PubMed, EMBASE,the Cochrane Library and reference lists of relevant studies were searched to identify eligible studies from inception to Jan, 2021. Ten eligible studies consisting of 1450 GD patients with a total of 848 relapsed patients were included in the meta-analysis.In Caucasians patients, the CTLA-4 exon 1+49A/G polymorphism significantly elevated the relapse risk of GD in additive (OR = 2.07, 95% CI: 1.18-3.62, P=0.011), dominant (OR = 2.52, 95% CI: 1.17-5.41, P=0.02), homozygote model(OR = 3.264, 95% CI: 1.25-8.52, P=0.016), except recessive (OR = 2.18, 95% CI = 0.98-4.86, P = 0.062) and heterozygote model (OR = 2.141, 95% CI = 0.958-4.786, P = 0.064). In Asian subgroup, none of these genotypes show any associations with the relapse of GD after ATDs withdrawal.

Conclusion

This meta-analysis suggests that the CTLA-4 exon1 +49A/G polymorphism is associated with the relapse risk of GD after ATDs withdrawal in Caucasians, not Asians. Compared with the AA genotype, Caucasian patients with GG genotype have 3.264 times risk of relapse. A more aggressive treatment such as radioactive iodine or thyroidectomy, or longer periods treatment of ATDs should be recommended in Caucasian patients with the GG genotype.

Angular Analysis of D^{0}→π^{+}π^{-}μ^{+}μ^{-} and D^{0}→K^{+}K^{-}μ^{+}μ^{-} Decays and Search for CP Violation

The first full angular analysis and an updated measurement of the decay-rate CP asymmetry of the D^{0}→π^{+}π^{-}μ^{+}μ^{-} and D^{0}→K^{+}K^{-}μ^{+}μ^{-} decays are reported. The analysis uses proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8, and 13 TeV. The dataset corresponds to an integrated luminosity of 9  fb^{-1}. The full set of CP -averaged angular observables and their CP asymmetries are measured as a function of the dimuon invariant mass. The results are consistent with expectations from the standard model and with CP symmetry.

Stanniocalcin 1 alleviates myocardial ischemia-reperfusion injury through inhibiting inflammation and apoptosis of myocardial cells

OBJECTIVE

Myocardial ischemia-reperfusion injury (MIRI) is the main cause of death from ischemic heart diseases. Stanniocalcin 1 (STC1) has a potential therapeutic effect on MIRI. The purpose of this study is to investigate the effect of STC1 on inflammation and apoptosis of myocardium in MIRI.

MATERIALS AND METHODS

We used rats to make ischemia-reperfusion (I/R) models and determined the efficiency of modeling by 2, 3, 5-triphenyl tetrazolium chloride staining, echocardiography, and lactate dehydrogenase detection. We injected subcutaneously recombinant human STC1 (2.5 μg/kg, 5 μg/kg) into rats daily one week before modeling to detect the effect of STC1 pretreatment on inflammation and apoptosis of rat myocardial cells. In addition, we cultured rat myocardial cell lines (H9c2 cells) to investigate the effect of STC1 on myocardial cells.

RESULTS

The cardiac function and structure of I/R rats were obviously destroyed. After treating rats with STC1, we found that the cardiac function and structure of the rats were significantly improved. In addition, STC1 reduced the expression of inflammatory factors and apoptosis levels in rat myocardium. Stimulation of STC1 also improved the viability of H9c2 cells in vitro.

CONCLUSIONS

Therefore, STC1 can alleviate MIRI by inhibiting inflammation and apoptosis. It indicated that STC1 may have a potential therapeutic effect on MIRI.

Tests of Lepton Universality Using B^{0}→K_{S}^{0}ℓ^{+}ℓ^{-} and B^{+}→K^{*+}ℓ^{+}ℓ^{-} Decays

Tests of lepton universality in B^{0}→K_{S}^{0}ℓ^{+}ℓ^{-} and B^{+}→K^{*+}ℓ^{+}ℓ^{-} decays where ℓ is either an electron or a muon are presented. The differential branching fractions of B^{0}→K_{S}^{0}e^{+}e^{-} and B^{+}→K^{*+}e^{+}e^{-} decays are measured in intervals of the dilepton invariant mass squared. The measurements are performed using proton-proton collision data recorded by the LHCb experiment, corresponding to an integrated luminosity of 9  fb^{-1} . The results are consistent with the standard model and previous tests of lepton universality in related decay modes. The first observation of B^{0}→K_{S}^{0}e^{+}e^{-} and B^{+}→K^{*+}e^{+}e^{-} decays is reported.

Observation of the Decay Λ_{b}^{0}→Λ_{c}^{+}τ^{-}ν[over ¯]_{τ}

The first observation of the semileptonic b-baryon decay Λ_{b}^{0}→Λ_{c}^{+}τ^{-}ν[over ¯]_{τ}, with a significance of 6.1σ, is reported using a data sample corresponding to 3  fb^{-1} of integrated luminosity, collected by the LHCb experiment at center-of-mass energies of 7 and 8 TeV at the LHC. The τ^{-} lepton is reconstructed in the hadronic decay to three charged pions. The ratio K=B(Λ_{b}^{0}→Λ_{c}^{+}τ^{-}ν[over ¯]_{τ})/B(Λ_{b}^{0}→Λ_{c}^{+}π^{-}π^{+}π^{-}) is measured to be 2.46±0.27±0.40, where the first uncertainty is statistical and the second systematic. The branching fraction B(Λ_{b}^{0}→Λ_{c}^{+}τ^{-}ν[over ¯]_{τ})=(1.50±0.16±0.25±0.23)% is obtained, where the third uncertainty is from the external branching fraction of the normalization channel Λ_{b}^{0}→Λ_{c}^{+}π^{-}π^{+}π^{-}. The ratio of semileptonic branching fractions R(Λ_{c}^{+})≡B(Λ_{b}^{0}→Λ_{c}^{+}τ^{-}ν[over ¯]_{τ})/B(Λ_{b}^{0}→Λ_{c}^{+}μ^{-}ν[over ¯]_{μ}) is derived to be 0.242±0.026±0.040±0.059, where the external branching fraction uncertainty from the channel Λ_{b}^{0}→Λ_{c}^{+}μ^{-}ν[over ¯]_{μ} contributes to the last term. This result is in agreement with the standard model prediction.

Enhancing In Vitro Stability of Albumin Microbubbles Produced Using Microfluidic T-Junction Device

Microfluidics is an efficient technique for continuous synthesis of monodispersed microbubbles. However, microbubbles produced using microfluidic devices possess lower stability due to quick dissolution of core gas when exposed to an aqueous environment. This work aims at generating highly stable monodispersed albumin microbubbles using microfluidic T-junction devices. Microbubble generation was facilitated by an aqueous phase consisting of bovine serum albumin (BSA) as a model protein and nitrogen (N₂) gas. Microbubbles were chemically cross-linked using dilute glutaraldehyde (0.75% v/v) solution and thermally cross-linked by collecting microbubbles in hot water maintained at 368 (±2) K. These microbubbles were then subjected to in vitro dissolution in an air-saturated water. Microbubbles cross-linked with a combined treatment of thermal and chemical cross-linking (TC & CC) had longer dissolution time compared to microbubbles chemically cross-linked (CC) alone, thermally cross-linked (TC) alone, and non-cross-linked microbubbles. Circular dichroism (CD) spectroscopy analysis revealed that percent reduction in alpha-helices of BSA was higher for the combined treatment of TC & CC when compared to other treatments. In contrast to non-cross-linked microbubbles where microbubble shell dissolved completely, a significant shell detachment was observed during the final phase of the dissolution for cross-linked microbubbles captured using high speed camera, depending upon the extent of cross-linking of the microbubble shell. SEM micrographs of the microbubble shell revealed the shell thickness of microbubbles treated with TC & CC to be highest compared to only thermally or only chemically cross-linked microbubbles. Comparison of microbubble dissolution data to a mass transfer model showed that shell resistance to gas permeation was highest for microbubbles subjected to a combined treatment of TC & CC.