理学最新文献

As early as about 2400 years ago, Mozi (original name Mo Di, Latinized as Micius), an ancient Chinese scientist, proposed the theory of pinhole imaging that demonstrates the fundamental principle of light behavior. About 700 years ago, Marco Polo, an Italian explorer, traveled to China along the Silk Road, marveled at the economic prosperity and the advanced technology of Hangzhou City in China, and described Hangzhou as “the most beautiful and splendid city in the world”. About 5 years ago, with the support of the China-proposed Belt-and-Road Initiative, it was in Hangzhou City that Professor Pavlos Savvidis, an Armenian-born Greek physicist, chose to work with more of his Chinese counterparts and took on the challenge of building a new research laboratory on quantum optoelectronics. He used to study and work in the UK, the USA, and Greece, but now in New China’s first new type of research university supported by the society—Westlake University. Traveling from West to East, traversing from one civilization to another, Professor Pavlos Savvidis delves into his unwavering quest for light in this issue of “Light People”, and discusses his tireless pursuit of excellence in the field of optoelectronics, which has garnered him widespread citation, recognition, and contribution to the global scientific community.

Laser-sustained plasma (LSP) source featuring high brightness and broadband spectral coverage is found to be powerful in various fields of scientific and industrial applications. However, the fundamental limit of low conversion efficiency constrains the system compactness and widespread applications of such broadband light sources. In this paper, we propose an innovative orthogonal LSP to break through the conversion efficiency limitation. Driven by the elevated conversion efficiency from absorbed laser power to ultraviolet (UV) emission, a compact broadband source (250–1650 nm) with UV spectral radiance exceeding 210 ({mW}/({{mm}}^{2},cdot, {sr},cdot, {nm})) is achieved with >100 W pump laser. With the plot of a two-dimensional refractive index model, we report an important conceptual advance that the orthogonal design eliminates the influence of the negative lensing effect on laser power density. Experimental results unambiguously demonstrate that we achieve a bright compact UV-VIS-NIR source with negligible thermal loss and the highest conversion efficiency to our knowledge. Significant enhancement of 4 dB contrast-to-noise ratio (CNR) in spectral single-pixel imaging has been demonstrated using the proposed ultrabroadband source. By establishing the quantitative link between pumping optics design and plasma absorption, this work presents a compact broadband source that combines superior conversion efficiency and unprecedented brightness, which is essential to high-speed inspection and spectroscopy applications.

An original form of photonic force microscope has been developed. Operating with a trapped lanthanide-doped crystal of nanometric dimensions, a minimum detected force of the order of 110 aN and a force sensitivity down to 1.8 fN/(sqrt{{rm{Hz}}}) have been realised. This opens up new prospects for force sensing in the physical sciences.

Single-particle tracking (SPT) is an immensely valuable technique for studying a variety of processes in the life sciences and physics. It can help researchers better understand the positions, paths, and interactions of single objects in systems that are highly dynamic or require imaging over an extended time. Here, we propose an all-dielectric one-dimensional photonic crystal (1D PC) that enhances spin-to-orbital angular momentum conversion for three-dimensional (3D) SPTs. This well-designed 1D PC can work as a substrate for optical microscopy. We introduce this effect into the interferometric scattering (iSCAT) technique, resulting in a double-helix point spread function (DH-PSF). DH-PSF provides more uniform Fisher information for 3D position estimation than the PSFs of conventional microscopy, such as encoding the axial position of a single particle in the angular orientation of DH-PSF lobes, thus providing a means for 3D SPT. This approach can address the challenge of iSCAT in 3D SPT because DH-PSF iSCAT will not experience multiple contrast inversions when a single particle travels along the axial direction. DH-PSF iSCAT microscopy was used to record the 3D trajectory of a single microbead attached to the flagellum, facilitating precise analysis of fluctuations in motor dynamics. Its ability to track single nanoparticles, such as 3D diffusion trajectories of 20 nm gold nanoparticles in glycerol solution, was also demonstrated. The DH-PSF iSCAT technique enabled by a 1D PC holds potential promise for future applications in physical, biological, and chemical science.

The traditional vaccines against hepatitis have been instrumental in reducing the incidence of some types of viral hepatitis; however, the need for cost-effective, easily distributable, and needle-free vaccine alternatives has led to the exploration of plant-based vaccines. Plant-based techniques offer a promising avenue for producing viral hepatitis vaccines due to their low-cost cultivation, scalability, and the potential for oral administration. This review highlights the successful expression of hepatitis B surface antigens in plants and the subsequent formation of virus-like particles, which have shown immunogenicity in preclinical and clinical trials. The challenges such as achieving sufficient antigen expression levels, ensuring consistent dosing, and navigating regulatory frameworks, are addressed. The review considers the potential of plant-based vaccines to meet the demands of rapid vaccine deployment in response to outbreaks and their role in global immunization strategies, particularly in resource-limited settings. This review underscores the significant strides made in plant molecular farming and the potential of plant-based vaccines to complement existing immunization methods against viral hepatitis.

Background: Viral and bacterial infections may be complicated by rhabdomyolysis, which has a spectrum of clinical presentations ranging from asymptomatic laboratory abnormalities to life-threatening conditions such as renal failure. Direct viral injury as well as inflammatory responses may cause rhabdomyolysis in the course of coronavirus disease 2019 (COVID-19). When presented with acute kidney injury (AKI), rhabdomyolysis may be related to higher morbidity and mortality.

Aim: To compare rhabdomyolysis-related AKI with other AKIs during COVID-19.

Methods: A total of 115 patients with COVID-19 who had AKI were evaluated retrospectively. Fifteen patients had a definite diagnosis of rhabdomyolysis (i.e., creatine kinase levels increased to > 5 times the upper normal range with a concomitant increase in transaminases and lactate dehydrogenase). These patients were aged 61.0 ± 19.1 years and their baseline creatinine levels were 0.87 ± 0.13 mg/dL. Patients were treated according to national COVID-19 treatment guidelines. They were compared with patients with COVID-19 who had AKI due to other reasons.

Results: For patients with rhabdomyolysis, creatinine reached 2.47 ± 1.17 mg/dL during follow-up in hospital. Of these patients, 13.3% had AKI upon hospital admission, and 86.4% developed AKI during hospital follow-up. Their peak C-reactive protein reached as high as 253.2 ± 80.6 mg/L and was higher than in patients with AKI due to other reasons (P < 0.01). Peak ferritin and procalcitonin levels were also higher for patients with rhabdomyolysis (P = 0.02 and P = 0.002, respectively). The mortality of patients with rhabdomyolysis was calculated as 73.3%, which was higher than in other patients with AKI (18.1%) (P = 0.001).

Conclusion: Rhabdomyolysis was present in 13.0% of the patients who had AKI during COVID-19 infection. Rhabdomyolysis-related AKI is more proinflammatory and has a more mortal clinical course.

Background: Varicella (chickenpox) and herpes zoster (shingles) are outcomes of varicella-zoster virus (VZV) infection, and understanding their incidence trends is vital for public health planning.

Aim: To conduct an ambispective epidemiological study by analyzing the main epidemiological characteristics of VZV infection during an 18 year-period (2000-2018).

Methods: We used descriptive and epidemiological methods to characterize chickenpox in Bulgaria, the city of Plovdiv and the region for a period of 18 years (2000-2018).

Results: The average incidence of varicella-zoster infection for the period 2000-2018 in the Plovdiv region was estimated at 449.58‰. The highest relative share of the infection was assessed in the month of January at 13.6%, and the lowest in the months of August and September at 2.9% (both months). The age group most affected by the infection was 1-4 years, followed by 5-9 years. This corresponds to the so-called "pro-epidemic population" - a phenomenon typical for airborne infections, confirming their mass impact on the perpetuation of VZV infection.

Conclusion: Our findings reveal significant insights into VZV epidemiology, including age-specific incidence rates, clinical manifestations, and vaccination impact. This comprehensive analysis contributes to the broader understanding of VZV infection dynamics and may inform evidence-based preventive measures.

Acute liver failure (ALF) is a rare cause of liver-related mortality worldwide, with an estimated annual global incidence of more than one million cases. While drug-induced liver injury, including acetaminophen toxicity, is the leading cause of ALF in the Western world, viral infections remain a significant cause of ALF and the most common cause in many developing nations. Given the high mortality rates associated with ALF, healthcare providers should be aware of the broad range of viral infections that have been implicated to enable early diagnosis, rapid treatment initiation when possible, and optimal management, which may include liver transplantation. This review aims to provide a summary of viral causes of ALF, diagnostic approaches, treatment options, and expected outcomes.

Background: Chronic hepatitis C virus (HCV) has been associated with hepatic and extrahepatic malignancies. Limited studies have shown an association between colorectal adenomas and HCV populations.

Aim: To study the prevalence of colorectal adenomas in patients with HCV compared to the general population and to evaluate if it is an independent risk factor for colorectal adenomas.

Methods: Patients were divided into HCV and non-HCV based on their HCV RNA titers. Patients with alcoholic liver disease, hepatitis B infection, and inflammatory bowel disease were excluded. Continuous variables were analyzed using the Mann-Whitney U test, and categorical variables using χ ² with P < 0.05 were considered statistically significant. The significant covariates (independent variables) were matched in both groups by propensity score matching, followed by multivariate regression analysis.

Results: Of the 415 patients screened, 109 HCV patients and 97 non-HCV patients with colonoscopy results were included in the study. HCV patients were older, had a smoking history, had less frequent aspirin use, and had a lower body mass index (BMI) (P < 0.05). The HCV cohort had a significantly increased number of patients with adenomas (adenoma detection rate of 53.2% vs 34%. P = 0.006). We performed a propensity-matched multivariate analysis where HCV infection was significantly associated with colorectal adenoma (OR: 2.070, P = 0.019).

Conclusion: Our study shows a significantly higher rate of adenomas in HCV patients compared to the general population. Prospective studies would help determine if the increase in adenoma detection lowers the risk for colorectal cancer.

Background: The severe respiratory manifestations observed in severe coronavirus disease 2019 (COVID-19) cases are often associated with an excessive inflammatory response. Dexamethasone, a synthetic glucocorticoid, exerts its anti-inflammatory effects by inhibiting the transcription of pro-inflammatory genes and suppressing the activity of various immune cells. This mechanism has implications for mitigating the cytokine storm observed in severe COVID-19 cases. Early on in the pandemic, the Recovery Collaborative working group showed a mortality benefit of using dexamethasone in decreasing mortality in patients with COVID-19 requiring respiratory support. However, the optimal dosage of corticosteroids remains debatable. Several studies that compare different doses of dexamethasone in COVID-19 exist, but the results are conflicting.

Aim: To review the latest evidence regarding dosage, safety, and efficacy of dexamethasone in severe COVID-19.

Methods: We followed preferred reporting items for systematic reviews and meta-analysis guidelines. A detailed literature search was conducted across PubMed, Google Scholar, and Medline to include publications up to March 2024. Our keywords included "COVID-19" "SARS-CoV-2" "dexamethasone" "corticosteroid" "steroid" and "glucocorticoid"-along with their combinations. We employed the Cochrane Risk of Bias Tool and the Newcastle-Ottawa scale to evaluate the integrity and potential of bias in the included studies. A meta-analysis was conducted using a random-effects model, assessing pooled odds ratios and mean differences, with heterogeneity gauged by the I ² statistic and the χ ² tests.

Results: No statistical differences were found in 28-day all-cause mortality [pooled odds ratio (OR) = 1.109, 95%CI: 0.918-1.340], 60-day all-cause mortality (OR = 0.873, 95%CI: 0.744-1.024; I ² = 47.29%), mean length of hospital stay (mean difference = -0.08 days, 95%CI: -0.001 to 0.161) and adverse events (OR = 0.877, 95%CI: 0.707-1.087).

Conclusion: Differing doses of corticosteroids have no clinical implications on mortality, mean length of hospital stay, and adverse events in COVID-19 patients. Additional research is required in patients requiring invasive or non-invasive ventilation.