Primjena logističkog modela u analizi marketinških odnosa u turističkim agencijama

A concept of relationship marketing in tourism implies creating quality relations among all participants in the tourist supply chain. Analyzing the assumptions of the development of relations and their impact on the overall performance of companies in tourism is especially important. In this regard, the subject matter of this research is the application of relationship marketing in travel agencies in Serbia and the identification of key factors of loyalty of users of tourist services. This paper aims to investigate the influence of relationship marketing assumptions (such as trust, customer complaint management, investment in internal marketing, implementation of information technology in agencies, business image and tradition of agencies, as well as socio-demographic characteristics of clients) on the choice of travel agency through which clients will travel. The contribution of the paper is in the application of the logistics model in the research of relationship marketing in agencies. The results of this research have confirmed that investing in relational determinants in tourism leads both to the development of a long-term relationship with customers and to business performance improvement. Also, the results showed that customer profiles are important in the implementation of relationship marketing to increase the number of loyal customers in tourism. The importance of the paper is in proposing an efficient model for the application of relationship marketing in order to increase the level of customer loyalty in travel agencies operating on the Serbian market.Primjena koncepta relacijskog marketinga u turizmu podrazumijeva izgradnju kvalitetnih odnosa između svih sudionika u turističkom lancu ponude. Osobito je važna analiza pretpostavki za razvoj odnosa i njihov utjecaj na ukupnu uspješnost tvrtki u turizmu. S tim u vezi, predmet rada je istraživanje primjene marketinških odnosa u turističkim agencijama u Srbiji koji posluju na tradicionalan način i putem interneta, te identifikacija ključnih čimbenika lojalnosti korisnika turističkih usluga. Cilj ovog rada je istražiti utjecaj pretpostavki relacijskog marketinga (poput povjerenja, upravljanja pritužbama kupaca, ulaganja u interni marketing, primjene informacijske tehnologije u agencijama, poslovnog imidža i tradicije, kao i socio-demografskih karakteristika klijenata) na izbor putničke agencije preko koje će klijenti putovati. Doprinos rada je u primjeni logističkog modela u istraživanju relacijskog marketinga u agencijama. Važnost rada ogleda se u predlaganju učinkovitog modela primjene koncepta marketinških odnosa u cilju povećanja lojalnosti kupaca u turističkim agencijama

Gender and Musculoskeletal Comorbidity Impact on Physical Functioning in Elderly after Hip Fracture: The Role of Rehabilitation

The study aim was to evaluate the effects of presence and level of musculoskeletal impairment along with gender on physical functioning outcome after the rehabilitation program in aged adults with a hip fracture. We analyzed 203 elderly people with hip fractures above 65 years of age that were treated after the hip surgery. According to the time of examination, patients were tested three times: at admission, discharge, and at three months post-discharge. Musculoskeletal impairments were analyzed, and for the estimation of severity of degree impairment, we used a cumulative index rating scale for geriatrics (CIRS-G). Regarding the gender, we separately analyzed males and females. To evaluate physical functioning of aged adults after a hip fracture, we used the physical functioning component (PFC) from the quality of life (SF-36) questionnaire. For males, on all three occasions we found non-significant differences were found in SF-36 PFC values between different degrees of CIRS-G musculoskeletal impairment. A significant difference was noticed in females three months post-discharge. Effects size of different examination periods for every CIRS-G severity degree of musculoskeletal impairment were high, where males had higher values for severity degrees 1 and 2, and females had higher values for severity degrees 0 and 3. Our findings might suggest that there is a certain degree of different rehabilitation treatment effects for males versus females. Moreover, it might be assumed that other factors could influence different degrees of functional improvement and outcome of individuals after a hip fracture with musculoskeletal impairment

Production of the protein, probable marker for linden allergy

Pollen allergies have tremendous global clinical impact. Diagnosis of allergy in a clinical setting is based on the use of purified allergens which are considered to be more accurate and sensitive than crude pollen extracts. Thus, proper identification and characterization of allergens at the molecular level and production of a recombinant counterpart are of outmost importance for the efficient use of the current diagnostic tools for allergy. Recombinant allergens are nowadays produced instead of natural, as isolation of a natural allergen is a troublesome process. Tree pollens that are most commonly associated with respiratory allergies are produced by birch in the Northern, Central, and Eastern Europe, and by olive and cypress in the Mediterranean regions. Accordingly, most research so far has focused on the allergenicity of pollens from birch, olive and cypress. Allergy to linden pollen has been known, but no allergen has been described from this source yet. Here we propose cloning and production of the first recombinant linden pollen allergen that can be used as a marker allergen of linden pollen allergenicity and complement existing diagnostic allergen-arrays. Also, production of this recombinant allergen has potential to contribute to the development of novel allergen-diagnostic tools through collaborations with biotech companies

Thermal Processing of Peanut Grains Impairs Their Mimicked Gastrointestinal Digestion While Downstream Defatting Treatments Affect Digestomic Profiles

Resistance to digestion by digestive proteases represents a critical property of many food allergens. Recently, a harmonized INFOGEST protocol was proposed for solid food digestion. The protocol proposes digestion conditions suitable for all kinds of solid and liquid foods. However, peanuts, as a lipid-rich food, represent a challenge for downstream analyses of the digestome. This is particularly reflected in the methodological difficulties in analyzing proteins and peptides in the presence of lipids. Therefore, the removal of the lipids seems to be a prerequisite for the downstream analysis of digestomes of lipid-rich foods. Here, we aimed to compare the digestomes of raw and thermally treated (boiled and roasted) peanuts, resulting from the INFOGEST digestion protocol for solid food, upon defatting the digests in two different manners. The most reproducible results of peanut digests were obtained in downstream analyses on TCA/acetone defatting. Unfortunately, defatting, even with an optimized TCA/acetone procedure, leads to the loss of proteins and peptides. The results of our study reveal that different thermal treatments of peanuts affect protein extraction and gastric/gastrointestinal digestion. Roasting of peanuts seems to enhance the extraction of proteins during intestinal digestion to a notable extent. The increased intestinal digestion is a consequence of the delayed extraction of thermally treated peanut proteins, which are poorly soluble in acidic gastric digestion juice but are easily extracted when the pH of the media is raised as in the subsequent intestinal phase of the digestion. Thermal processing of peanuts impaired the gastrointestinal digestion of the peanut proteins, especially in the case of roasted sample

Effect of Rubber Treatment on Compressive Strength and Modulus of Elasticity of Self-Compacting Rubberized Concrete

This paper investigates the effects of different treatment methods of rubber aggregates for self-compacting concrete (SCC) on compressive strength and modulus of elasticity. SCC mixtures with 10% replacement of fine aggregate with crumb rubber by total aggregate volume and with different aggregate treatment methods were investigated. The rubber aggregate was treated in three different methods: dry process, water-soaking, and NaOH treatment plus water soaking. Properties of SCC in a fresh and hardened state were tested and evaluated. Scanning electron microscope (SEM) analysis of three different SCC patches were made and discussed. It was observed that applying the proposed NaOH plus water soaking method resulted in the improvement of fresh and hardened concrete properties. It resulted in a more uniform distribution of rubber particles in the cement matrix, a better bond between rubber particles and the cement matrix, and higher compressive strength of SCC rubberized concrete

Supplementary data for the article: Prodic, I.; Stanic-Vucinic, D.; Apostolovic, D.; Mihailovic, J.; Radibratovic, M.; Radosavljevic, J.; Burazer, L.; Milcic, M.; Smiljanic, K.; van Hage, M.; et al. Influence of Peanut Matrix on Stability of Allergens in Gastric-Simulated Digesta: 2S Albumins Are Main Contributors to the IgE Reactivity of Short Digestion-Resistant Peptides. Clinical and Experimental Allergy 2018, 48 (6), 731–740. https://doi.org/10.1111/cea.13113

Supplementary material for: [https://doi.org/10.1111/cea.13113]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2155

Optimization of expression, purification and HRMS characterization of recombinant N-protein fragment from SARS-CoV-2

Nucleocapsid (N) protein is the most abundant SARS-CoV-2 virus derived protein and strong immunogen which can be used as a component of the immunological tests for the diagnosis of SARS-CoV-2 infection. Recombinant fragment of N-protein (58–419 aa) was expressed in E. coli in a soluble form using developed optimized protocol of expression (16-18h, 37 °C, 0.4 mM IPTG). After lysis of cells, N-protein from soluble fraction of lysate was purified using optimized protocol for purification by immobilized metal affinity chromatography on Ni-Sepharose in two repeated steps under different elution conditions. Obtained fraction of N-protein after the second chromatography was desalted and concentrated using phosphate buffer solution and ultrafiltration. The purity of isolated N-protein was deterrmined by SDS PAGE, while high resolution mass spectrometry was used for its characterization. Isolated N-protein was over 90% purity and identified as the most intense and abundant protein fragment, with PEAKS PTM score of 508 and sequence coverage of over 70%, including 173 unique peptides

Expression, purification and immunological characterization of recombinant protein fragment from SARS-CoV-2

Serological testing is important method for diagnosis of severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) infection. Nucleocapsid (N) protein is the most abundant virus derived protein and strong immunogen. We aimed to find its efficient, low-cost production, suitable for serological diagnosis. SARS-CoV-2 recombinant fragment of nucleocapsid protein (rfNP; 58–419 aa) was expressed in E. coli in soluble form, purified by immobilized metal ion affinity chromatography and strong cation exchange chromatography after which it was analyzed by Mass and CD spectrometry and characterized biochemically and immunologically. Purified rfNP has secondary structure of full-length recombinant N protein, with high percentage of disordered structure (34.2%) and of β-sheet (40.7%). rfNP was tested in immunoblot using sera of COVID-19 convalescent patients. ELISA was optimized with sera of RT-PCR confirmed positive symptomatic patients and healthy individuals. IgG detection sensitivity was 96% (47/50) and specificity 97% (67/68), while IgM detection was slightly lower (94% and 96.5%, respectively). Cost-effective approach for soluble recombinant N protein fragment production was developed, with reliable IgG and IgM antibodies detection of SARS-CoV-2 infection.Book of Abstract

Serological Elisa test development at the INEP Institute

The COVID-19 diagnostic tools are categorized into two main groups of Nucleic Acid (NA)- based and protein-based tests. To date, nucleic acid-based detection has been announced as the gold-standard strategy for coronavirus detection; however, protein-based tests are promising alternatives for rapid and large-scale screening of susceptible groups. During the first months, no rapid and reliable detecting tool was readily available to adequatly respond to the requirement of massive testing. The aim was to develope cost-effective, sensitive and rapid screening mechanisms for the detection of immune response to SARS-CoV2 (which causes COVID-19), based on the principle of ELISA. The institute INEP has developed tests for detection of IgM and IgG SARS-CoV-2 specific antibodies based on S and N proteins of virus intended to monitor different phases of natural infection, ELISA test for IgG detection in naturale infection based on the use of exclusively domestic components of the ELISA kit (including proteins produced in Serbia, Faculty of Chemistry) and a test specifically designed to monitor the effects of immunization (determination of IgG antibodies specific for the RBD domain of S protein). The tests were independently validated at the relevant laboratories in the country and abroad, and compared to an FDA/WHO approved tests of a major test producers. All testing for validation was carried out on samples collected before COVID19 (negative controls), PCR confirmed COVID19 samples (positive controls) and potencialy cross-reactive samples (other pathogens and autoimmune diseases). The antibody tests showed high levels of sensitivity and specificity and extremely low background noises. The kits are extremely stable, have a shelf life of 1 year and opened kits are usable up to 3 months at storing temperatures of 5°

Sandwich ELISA for the Quantification of Nucleocapsid Protein of SARS-CoV-2 Based on Polyclonal Antibodies from Two Different Species

In this study, a cost-effective sandwich ELISA test, based on polyclonal antibodies, for routine quantification SARS-CoV-2 nucleocapsid (N) protein was developed. The recombinant N protein was produced and used for the production of mice and rabbit antisera. Polyclonal N protein-specific antibodies served as capture and detection antibodies. The prototype ELISA has LOD 0.93 ng/mL and LOQ 5.3 ng/mL, with a linear range of 1.52–48.83 ng/mL. N protein heat pretreatment (56 °C, 1 h) decreased, while pretreatment with 1% Triton X-100 increased analytical ELISA sensitivity. The diagnostic specificity of ELISA was 100% (95% CI, 91.19–100.00%) and sensitivity was 52.94% (95% CI, 35.13–70.22%) compared to rtRT-PCR (Ct < 40). Profoundly higher sensitivity was obtained using patient samples mostly containing Wuhan-similar variants (Wuhan, alpha, and delta), 62.50% (95% CI, 40.59 to 81.20%), in comparison to samples mostly containing Wuhan-distant variants (Omicron) 30.00% (6.67–65.25%). The developed product has relatively high diagnostic sensitivity in relation to its analytical sensitivity due to the usage of polyclonal antibodies from two species, providing a wide repertoire of antibodies against multiple N protein epitopes. Moreover, the fast, simple, and inexpensive production of polyclonal antibodies, as the most expensive assay components, would result in affordable antigen tests