Temporal and spatial differences in human activities performed in Urban Green Spaces of Vilnius(Lithuania)

Urban green spaces(UGS)are relevant to city well-being,as recognized by the United Nations’Sustainable Development Goals(SDGs).However,few studies have studied the temporal use of UGS.This work assessed the seasonal,weekly,and daily use of three urban green spaces(Vingis Park,Bernardino Garden,and Jomantas Park)in Vilnius(Lithuania).The study is based on an on-site observation-based survey,which recorded users’characteristics,activities,and weather conditions during summer and winter.The results showed that UGS’s seasonal,weekly,and daily use differed according to park and users’characteristics.Parks with a higher diversity of facilities had a high seasonal difference in the number of observed activities.User numbers were higher in the summer for activities with children,social activities,sports,and water activities than in the winter.Jomantas Park had the lowest variability in user characteristics.Weather variables were linked to changes in users’activities.Higher precipitation and lower temperature were associated with reducing the number of users and the diversity of registered activities.Most of the stationary activities were observed during summer.The diversity of the observed activities was associated with the available facilities rather than the park size.The distribution of stationary activities was spatially correlated with facility/equipment(benches,playgrounds,sports,and fitness equipment)and proximity to water features.The results of this study are relevant for UGS design,planning,and management.

Urban green spaces accessibility in two European cities:Vilnius(Lithuania)and Coimbra(Portugal)

Urban green spaces(UGS)are essential for human well-being,contributing towards quality of life and promoting social interactions and inclusion.Accessibility to recreational UGS is key to human well-being in urban areas.However,there is a lack of works focused on recreational UGS accessibility in cities from different countries,using different types of transport.In this work,we studied the accessibility to recreational UGS in Vilnius(Lithuania)and Coimbra(Portugal)through four transport modes(foot,bike,bus and car)within 5-and 10-minute distance.The results showed important differences between cities.Vilnius had higher accessibility to recreational UGS than Coimbra in all transport modes.In both cities,the accessibility was highest by car and lowest by bus.Also,the percentage of population covered by 5-and 10-minute distance UGS accessibility in Vilnius is higher than in Coimbra,despite the lower population density in Vilnius.A large number of recreational UGS,their geographic distribution,the dispersed population pattern,and the location of several urbanizations near recreational UGS increased the inhabitant’s accessibility to recreational UGS in Vilnius.The differences in accessibility between cities were mainly attributed to the large number of recreational UGS and higher road network density,cycleways and footways density,and bus lines in Vilnius,compared to Coimbra.This work identified the areas where recreational UGS accessibility is difficult in using different transport modes and need to be improved in study areas.This is essential to support urban planners and increase cities’well-being.The findings of this work will be important for the management of the studied urban areas.

Direct Marketing and Consumer Trust in Organic Food Products： Vilnius （Lithuania） Case

The market of organic food products has a continuous upward trend though the growth rate and sale channels in individual countries are rather different. This research aims to identify the key factors that influence consumers＇ choice to buy organic food products in Lithuania focusing on the consumer trust in the quality and the most acceptable marketing channels. In order to get the necessary information, the residents of Vilnius （the capital of Lithuania）, as having the greatest potential for the organic food market in the country, were interviewed. The analysis of collected data was done using the methods of mathematical statistics and comparison of relative frequencies. The results of this research prove the increasing consumers＇ interest in organic food products. The majority of consumers consider these products to be healthier, better-tasting and fresher. Only about a third of the purchasers （usually buying frequently） can see differences between organic and non-organic products, therefore, there is a problem to distinguish organic food from conventional products and, consequently, remains a possibility to cheat the consumer. An additional quality control and direct sales from known and familiar farmers might increase trust in the quality of organic food products. So far, supermarkets are the most important place to buy organic foods, however, the greater consumer confidence in the quality of organic products bought at farmers＇ markets and the acceptance of the majority of purchasers to buy organic food products directly from the farmers suppose the need to develop a direct marketing system.

The patients’ opinion on the use of information technologies at the Seskine Outpatient Clinic and “Centro poliklinika” Outpatient Clinic of the city of Vilnius according to the age of patients

Objectives: The objective of this study is to assess patients’ opinion of the information technologies (IT) electronic registration systems at the “Centro poliklinika” and Seskine outpatient clinics in Vilnius City. Material and Methods: The survey was conducted in May-June, 2012. In the course of the primary survey, one questionnaire was handed out to one in tenth of the newly arrived patients. Total number of 650 questionnaires was distributed. 563 respondents participated in the survey (feedback rate—86.6%). Statistical analysis of data was performed by means of personal computer using SPSS software package. Results: 54.7% of respondents state that they make use of the possibility of online registration with the family doctor. 85.05% of respondents indicate that a doctor, when making the next appointment or referring to the medical specialist, registers a patient on site by means of computer. Upon arrival of a respondent to the reception desk of the medical establishment, 90.3% of respondents are registered by means of computer. 72.4% of respondents say that they have a choice to telephone and inquire about the time of visit if they have forgotten the visit time or lost the appointment sheet. Majority of respondents using the online registration option belong to the age group between 21 and 40 years—35.3%. Conclusions: Answers by the respondents and the breakdown between “Centro poliklinika” and Seskine outpatient clinics are very similar and no essential differences have been determined.

Potential risk factors of food allergy in children: EuroPrevall project results in Vilnius, Lithuania

Objectives: In recent decades, the prevalence of allergic diseases, including food allergy, has been increasing. This is becoming an important health problem. Many risk factors of food allergy were identified recently, and many of them still are controversial. The aim of this study was to evaluate the potential risk factors of food allergy in child population following the methodology of the EuroPrevall project. Methods: Vilnius University was a partner in the EuroPrevall integrated project “The prevalence cost and basis of food allergy in Europe”, which is an EU-funded multi-disciplinary research study. A case-control study design was used to address the study question. All subjects were assessed by means of questionnaire and blood sample test for specific immunoglobulin E. Possible risk factors like mother’s addictions (smoking, alcohol drinking during pregnancy), infant low birth weight and nursing duration, gender, treatment with antibiotics during first two years of life were analysed. Multiple logistic regression was used for risk factor analysis. Results: No statistically significant associations were found between risk factors and food allergy. Only gender (male) (ORa = 3.36, 95% CI 1.17-9.63) and mother’s food allergy (ORa = 5.44, 95% CI 1.19-24.97) were directly associated with child’s food allergy. Because of the presence of those both two factors (gender (male) + mother’s allergy), the risk for food allergy increased particularly—OR was 18.31 (95% CI 2.01-166.07). Conclusion: Gender (male) and mother’s food allergy are the most important risk factors directly associated with children’s food allergy.

Decline and fall of aging astrocytes:the human perspective

“Last scene of all that ends this strange,eventful history,is second childishness and mere oblivion.I am sans teeth,sans eyes,sans taste,sans everything.”William Shakespeare‘As You Like It'Act 2,Sc.7,l.139Aging of the human brain is characterized by a progressive decline of its functional capacity;this decline however varies widely,and cognitive longevity differs substantially between individuals.

Global Alliance against Chronic Respiratory Diseases demonstration project:aerosol pollution and its seasonal peculiarities in primary schools of Vilnius

Background:The growing public health concern caused by non-communicable diseases in urban surroundings cannot be solved by health care alone;therefore a multidisciplinary approach is mandatory.This study aimed to evaluate the airborne aerosol pollution level in primary schools as possible factor influencing origin and course of the diseases in children.Methods:Seasonal aerosol particle number concentration(PNC)and mass concentration(PMC)were studied in the randomly selected eleven primary schools in the Lithuanian capital,Vilnius,as model of a middle-size Eastern European city.Total PNC in the size range from 0.01 to>1.0μm in diameter was measured using a condensation particle counter.Using an optical particle sizer,PNC was measured and PMC estimated for particles from 0.3 to 10.0μm.A descriptive statistics was used to estimate the aerosol pollution levels.Results:During all seasons,local cafeterias in the absence of ventilation were the main sources of the elevated levels of indoor PMC and PNC(up to 97,500 particles/cm3).The other sources of airborne particulates were the children’s activity during the lesson breaks with PMC up to 586μg/m3.Soft furniture,carpets in the classrooms and corridors were responsible for PMC up to 200μg/m3.Outdoor aerosol pollution(up to 18,170 particles/cm3)was higher for schools in city center.Elevated air pollution in classrooms also resulted from intermittent sources,such as construction work during classes(200-1000μg/m3)and petrol-powered lawn trimmers(up to 66,400 particles/cm3).Conclusion:The results of our survey show that even in a relatively low polluted region of Eastern Europe there are big differences in aerosol pollution within middle-sized city.Additional efforts are needed to improve air quality in schools:more frequent wet cleaning,monitoring the operation of ventilation systems,a ban on construction works during school year,on a use of sandblasting mechanisms in the neighborhood of schools.

黄河流域生态保护迈向高质量发展的特征——植被绿度、生产力和降水利用效率的差异性变化

Globally,vegetation has been changing dramatically.The vegetation-water dynamic is key to understanding ecosystem structure and functioning in water-limited ecosystems.Continual satellite monitoring has detected global vegetation greening.However,a vegetation greenness increase does not mean that ecosystem functions increase.The intricate interplays resulting from the relationships between vegetation and precipitation must be more adequately comprehended.In this study,satellite data,for example,leaf area index(LAI),net primary production(NPP),and rainfall use efficiency(RUE),were used to quantify vegetation dynamics and their relationship with rainfall in different reaches of the Yellow River Basin(YRB).A sequential regression method was used to detect trends of NPP sensitivity to rainfall.The results showed that 34.53%of the YRB exhibited a significant greening trend since 2000.Among them,20.54%,53.37%,and 16.73%of upper,middle,and lower reach areas showed a significant positive trend,respectively.NPP showed a similar trend to LAI in the YRB upper,middle,and lower reaches.A notable difference was noted in the distributions and trends of RUE across the upper,middle,and lower reaches.Moreover,there were significant trends in vegetation-rainfall sensitivity in 16.86%of the YRB’s middle reaches—14.08%showed negative trends and 2.78%positive trends.A total of 8.41%of the YRB exhibited a marked increase in LAI,NPP,and RUE.Subsequently,strategic locations reliant on the correlation between vegetation and rainfall were identified and designated for restoration planning purposes to propose future ecological restoration efforts.Our analysis indicates that the middle reach of the YRB exhibited the most significant variation in vegetation greenness and productivity.The present study underscores the significance of examining the correlation between vegetation and rainfall within the context of the high-quality development strategy of the YRB.The outcomes of our analysis and the proposed ecological restoration framework can provide decision-makers with valuable insights for executing rational basin pattern optimization and sustainable management.

Astrocytes dynamically regulate the blood-brain barrier in the healthy brain

The blood-brain barrier(BBB)(discovered and defined by Max Lewandowsky and Lina Stern,and not,as it is universally,and yet erroneously believed,by Paul Ehrlich(Verkhratsky and Pivoriunas,2023))that separates the nervous system from the circulation is evolutionarily conserved from arthropods to man.The primeval BBB of the invertebrates and some early vertebrates was made solely by glial cells and secured(in invertebrates)by septate junctions.

An Evidence-Based CoCoSo Framework with Double Hierarchy Linguistic Data for Viable Selection of Hydrogen Storage Methods

Hydrogen is the new age alternative energy source to combat energy demand and climate change.Storage of hydrogen is vital for a nation’s growth.Works of literature provide different methods for storing the produced hydrogen,and the rational selection of a viable method is crucial for promoting sustainability and green practices.Typically,hydrogen storage is associated with diverse sustainable and circular economy(SCE)criteria.As a result,the authors consider the situation a multi-criteria decision-making(MCDM)problem.Studies infer that previous models for hydrogen storage method(HSM)selection(i)do not consider preferences in the natural language form;(ii)weights of experts are not methodically determined;(iii)hesitation of experts during criteria weight assessment is not effectively explored;and(iv)three-stage solution of a suitable selection of HSM is unexplored.Driven by these gaps,in this paper,authors put forward a new integrated framework,which considers double hierarchy linguistic information for rating,criteria importance through inter-criteria correlation(CRITIC)for expert weight calculation,evidence-based Bayesian method for criteria weight estimation,and combined compromise solution(CoCoSo)for ranking HSMs.The applicability of the developed framework is testified by using a case example of HSM selection in India.Sensitivity and comparative analysis reveal the merits and limitations of the developed framework.

Enhanced thermal emission from metal-free,fully epitaxial structures with epsilon-near-zero InAs layers

We introduce a novel method to create mid-infrared(MIR)thermal emitters using fully epitaxial,metal-free structures.Through the strategic use of epsilon-near-zero(ENZ)thin films in InAs layers,we achieve a narrow-band,wide-angle,and p-polarized thermal emission spectra.This approach,employing molecular beam epitaxy,circumvents the complexities associated with current layered structures and yields temperature-resistant emission wavelengths.Our findings contribute a promising route towards simpler,more efficient MIR optoelectronic devices.

Epinephrine also acts on beta cells and insulin secretion

In a recent review examining neurotransmitter modulation of insulin secretion,the significant impact of epinephrine was not addressed.Its primary action involves inhibiting insulin release via alpha-adrenergic receptors,thereby reducing the response to insulin secretion stimulators,through the activation of K+channels and resulting in membrane hyperpolarization in beta cells.

Mapping ecosystem services in urban and peri-urban areas.A systematic review

Urban and peri-urban ecosystems are subjected to an intense impact.The demand for ecosystem services(ES)is higher in these areas.Nevertheless,despite the anthropogenic pressures,urban and peri-urban ecosystems supply important ES.Mapping is a crucial exercise to understand ES dynamics in these environments better.This work aims to systematically review mapping ES in urban and peri-urban areas studies,following the Preferred Reporting Items for Systematic Reviews and Meta-alpha Methods.A total of 207 studies were selected.The results show increased work between 2011 and 2023,mainly conducted in Europe and China.Most work were developed in urban areas and did not follow an established ES classification.Most studies focused on the ES supply dimension,the regulation and maintenance section.Regarding provisioning ES,most studies focused on Cultivating terrestrial plants for nutrition,regulating and maintainin g Atmospheric composition and conditions,and for cultural ES on Physical and experiential interactions with the natural environment.Quantitative methods were mostly applied following Indicator-based(secondary data:biophysical,socio-economic)models.Very few work validated the outputs.Several studies forecasted ES,primarily based on land use changes using CA-Markov approaches.This study provides an overview of the most mapped urban and peri-urban ES globally,the areas where more studies need to be conducted,and the methods developed.

Alterations of protein homeostasis in Alzheimer's disease:beyond Procrustean bed of endoplasmic reticulum stress and unfolded protein response

Alzheimer’s disease(AD)is a major age-related form of dementia with a number of cases exponentially growing,causing enormous social and economic impact on individuals and society.Neuropathological hallmarks of AD,evident in postmortem AD brains,include a massive loss of the grey matter in the neocortex,extracellular deposition of amyloid-β(Aβ)in the form of senile plaques and cerebrovascular amyloid angiopathy,and intra-neuronal accumulation of neurofibrillary tangles,formed by hyper-phosphorylated tau protein.

Artificial night light and thyroid cancer

BACKGROUND The occurrence of thyroid cancer(TC)has increased in recent decades.Exposure to outdoor artificial light at night(ALN)is associated with an increased risk of cancer.AIM To investigated the impact of ALN,as a significant environmental pollutant,on TC incidence worldwide.METHODS The assessment involved analyzing satellite ALN data in conjunction with TC incidence data[adjusted standardized rate(ASR)],while considering the quality of cancer registries(QCR),gross domestic product(GDP)per person,and health expenditure per person(HEP)for each country.RESULTS Results indicated a correlation between higher ASR and ALN exposure percentages,particularly in countries with higher GDP or HEP quartiles(all P<0.05).Significant differences in ASR were observed across QCR levels,both high and low quality(all P<0.05),but not in countries without registry activity.However,when evaluating ASR against ALN exposure percentages while considering GDP/HEP quartiles or QCR levels,no significant associations were found(all P>0.10).CONCLUSION The findings suggest a potential link between higher GDP and adverse health conditions,serving as possible risk factors for TC,rather than a direct association with ALN.Limitations include the use of cross-sectional data,temporal misalign ment,and reliance on ALN as a socioeconomic proxy.It is proposed that light pollution might be connected to a lifestyle conducive to carcinogenesis.Additionally,the presence of higher GDP/HEP could enhance access to diagnostic resources,potentially facilitating TC diagnosis and inclusion in cancer registries.

Value of adipokines in predicting the severity of acute pancreatitis:Comprehensive review

AIM:To analyze the prognostic value of adipokines in predicting the course,complications and fatal outcome of acute pancreatitis(AP).METHODS:We performed the search of PubMed database and the systemic analysis of the literature for both experimental and human studies on prognostic value of adipokines in AP for period 2002-2012.Only the papers that described the use of adipokines for prediction of severity and/or complications of AP were selected for further analysis.Each article had to contain information about the levels of measured adipokines,diagnosis and verification of AP,to specify presence of pancreatic necrosis,organ dysfunction and/or mortality rates.From the very beginning,study was carried out adhering to the PRISMA checklist and flowchart for systemic reviews.To assess quality of all included human studies,the Quality Assessment of Diagnostic Accuracy Studies tool was used.Because of the high heterogeneity between the studies,it was decided to refrain from the statistical processing or meta-analysis of the available data.RESULTS:Nine human and three experimental studies were included into review.In experimental studies significant differences between leptin concentrations at 24 and 48 h in control,acute edematous and acute necrotizing pancreatitis groups were found(P = 0.027 and P < 0.001).In human studies significant differences between leptin and resitin concentrations in control and acute pancreatitis groups were found.1-3 d serum adiponectin threshold of 4.5 μg/mL correctly classified the severity of 81% of patients with AP.This threshold yielded a sensitivity of 70%,specificity 85%,positive predictive value 64%,negative predictive value88%(area under curve 0.75).Resistin and visfatin concentrations differ significantly between mild and severe acute pancreatitis groups,they correlate with severity of disease,need for interventions and outcome.Both adipokines are good markers for parapancreatic necrosis and the cut-off values of 11.9 ng/mL and 1.8 ng/mL respectively predict the high ranges of radiological scores.However,the review revealed that all nine human studies with adipokines are very different in terms of methodology and objectives,so it is difficult to generalize their results.It seems that concentrations of the leptin and resistin increases significantly in patients with acute pancreatitis compared with controls.Serum levels of adiponectin,visfatin and especially resitin(positive correlation with Acute Physiology and Chronic Health Evaluation Ⅱ,Ranson and C-reactive protein) are significantly different in mild acute pancreatitis and severe acute pancreatitis patients,so,they can serve as a markers for the disease severity prediction.Resistin and visfatin can also be used for pancreatic and parapancreatic necrosis prediction,interventions needs and possible,outcome.CONCLUSION:High levels of adipokines could allow for prediction of a severe disease course and outcome even in small pancreatic lesions on computed tomography scans.

Liver cirrhosis and left ventricle diastolic dysfunction: Systematic review

BACKGROUND Liver cirrhosis is a chronic hepatic disease which is associated with cardiovascular abnormalities.Hyperdynamic circulation in liver cirrhosis causes functional and structural cardiac alterations.The prevalence of left ventricle diastolic dysfunction(LVDD)in cirrhotic patients ranges from 25.7%to as high as 81.4%as reported in different studies.In several studies the severity of diastolic dysfunction(DD)correlated with a degree of liver failure and the rate of dysfunction was higher in patients with decompensated cirrhosis compared with compensated.Future directions of comprehensive assessment of cardiac function in cirrhotic patients might provide a better prognosis for these patients.AIM To clarify the correlation between the severity of liver cirrhosis and left ventricle diastolic dysfunction in the existing literature.METHODS Through January and February of 2019 at Vilnius University we conducted a systematic review of the global existing literature on the prevalence of left ventricle diastolic dysfunction in patients with liver cirrhosis.We searched for articles in PubMed,Medline and Web of science databases.Articles were selected by using adequate inclusion and exclusion criteria.Our interest was the outcome of likely correlation between the severity of cirrhosis[evaluated by Child-Pugh classes,Model For End-Stage Liver Disease(MELD)scores]and left ventricle diastolic dysfunction[classified according to American Society of Echocardiography(ASE)guidelines(2009,2016)],as well as relative risk of dysfunction in cirrhotic patients.Subgroup analyses were performed to evaluate the ratio and grades of left ventricle diastolic dysfunction with respect to cirrhosis severity.RESULTS A total of 1149 articles and abstracts met the initial search criteria.Sixteen articles which met the predefined eligibility criteria were included in the final analysis.Overall,1067 patients(out of them 723 men)with liver cirrhosis were evaluated for left ventricle diastolic dysfunction.In our systemic analysis we have found that 51.2%of cirrhotic patients had left ventricle diastolic dysfunction diagnosed and the grade 1 was the most prevalent(59.2%,P<0.001)among them,the grade 3 had been rarely diagnosed-only 5.1%.The data about the prevalence of diastolic dysfunction in cirrhotic patients depending on Child-Pugh Classes was available from 5 studies(365 patients overall)and only in 1 research diastolic dysfunction was found being associated with severity of liver cirrhosis(P<0.005).We established that diastolic dysfunction was diagnosed in 44.6%of Child-Pugh A class patients,in 62%of Child B class and in 63.3%of Child C patients(P=0.028).The proportion of patients with higher diastolic dysfunction grades increases in more severe cirrhosis presentation(P<0.001).There was no difference between mean MELD scores in patients with and without diastolic dysfunction and in different diastolic dysfunction groups.In all studies diastolic dysfunction was more frequent in patients with ascites.CONCLUSION This systemic analysis suggests that left ventricle diastolic dysfunction is an attribute of liver cirrhosis which has not received sufficient attention from clinicians so far.Future suggestions of a comprehensive assessment of cardiac function in cirrhotic patients might provide a better prognosis for these patients and give hint for better understanding of the left ventricle diastolic dysfunction pathogenesis in liver cirrhosis.

How severe is moderately severe acute pancreatitis? Clinical validation of revised 2012 Atlanta Classification

AIM To explore the outcomes and the appropriate treatment for patients with moderately severe acute pancreatitis(AP).METHODS Statistical analysis was performed on data from the prospectively collected database of 103 AP patients admitted to the Department of Surgery,Hospital of Lithuanian University of Health Sciences in 2008-2013. All patients were confirmed to have the diagnosis of AP during the first 24 h following admission. The severity of pancreatitis was assessed by MODS and APACHE Ⅱ scale. Clinical course was re-evaluated after 24,48 and 72 h. All patients were categorized into 3 groups based on Atlanta 2012 classification: Mild,moderately severe,and severe.Outcomes and management in moderately severe group were also compared to mild and severe cases according to Atlanta 1992 and 2012 classification.RESULTS Fifty-three-point four percent of patients had edematous while 46.6 % were diagnosed with necrotic AP. The most common cause of AP was alcohol(42.7%) followed by alimentary(26.2%),biliary(26.2%) and idiopathic(4.9%). Under Atlanta 1992 classification 56(54.4%) cases were classified as "mild" and 47(45.6%) as "severe". Using the revised classification(Atlanta 2012),the patient stratification was different: 49(47.6%) mild,27(26.2%) moderately severe and 27(26.2%) severe AP cases. The two severe groups(Atlanta 1992 and Revised Atlanta 2012) did not show statistically significant differences in clinical parameters,including ICU stay,need for interventional treatment,infected pancreatic necrosis or mortality rates. The moderately severe group of 27 patients(according to Atlanta 2012) had significantly better outcomes when compared to those 47 patients classified as severe form of AP(according to Atlanta 1992) with lower incidence of necrosis and sepsis,lower APACHE Ⅱ(P = 0.002) and MODS(P = 0.001) scores,shorter ICU stay,decreased need for interventional and surgical treatment.CONCLUSION Study shows that Atlanta 2012 criteria are more accurate,reduce unnecessary treatments for patients with mild and moderate severe pancreatitis,potentially resulting in health costs savings.

Modified graphene‐based materials as effective catalysts for transesterification of rapeseed oil to biodiesel fuel

Production of biodiesel by the transesterification process using different modified graphene‐based materials as catalysts was studied.Solid acid graphene‐based samples were prepared by grafting sulfonic or phosphate groups on the surface of thermally reduced graphene oxide.The obtained materials were thoroughly characterized using scanning electron microscopy,X‐ray diffraction,thermogravimetric analysis,X‐ray photoelectron spectroscopy,N2 adsorption‐desorption measurements,potentiometric titration,elemental analysis,and Fourier transform infrared spectroscopy.The prepared catalysts were tested in the transesterification of rapeseed oil with methanol at 130°C under pressure,and their activities were compared to the performance of a commercially available heterogeneous acidic catalyst,Amberlyst‐15.All modified samples were active in the transesterification process;however,significant differences were observed in the yield of biodiesel,depending on the method of catalyst preparation and strength of the acidic sites.The highest yield of fatty acid methyl esters of 70%was obtained for thermally reduced graphene oxide functionalized with 4‐benzenediazonium sulfonate after 6 h of processing,and this result was much higher than that obtained for the commercial catalyst Amberlyst‐15.The results of the reusability test were also promising.

Laser additive manufacturing of Si/ZrO_(2)tunable crystalline phase 3D nanostructures

The current study is directed to the rapidly developing field of inorganic material 3D object production at nano-/micro scale.The fabrication method includes laser lithography of hybrid organic-inorganic materials with subsequent heat treatment leading to a variety of crystalline phases in 3D structures.In this work,it was examined a series of organometallic polymer precursors with different silicon(Si)and zirconium(Zr)molar ratios,ranging from 9:1 to 5:5,prepared via sol-gel method.All mixtures were examined for perspective to be used in 3D laser manufacturing by fabricating nano-and micro-feature sized structures.Their spatial downscaling and surface morphology were evaluated depending on chemical composition and crystallographic phase.The appearance of a crystalline phase was proven using single-crystal X-ray diffraction analysis,which revealed a lower crystallization temperature for microstructures compared to bulk materials.Fabricated 3D objects retained a complex geometry without any distortion after heat treatment up to 1400℃.Under the proper conditions,a wide variety of crystalline phases as well as zircon(ZrSiO_(4)-a highly stable material)can be observed.In addition,the highest new record of achieved resolution below 60 nm has been reached.The proposed preparation protocol can be used to manufacture micro/nano-devices with high precision and resistance to high temperature and aggressive environment.