Topsoil Nutrients Drive Leaf Carbon and Nitrogen Concentrations of a Desert Phreatophyte in Habitats with Different Shallow Groundwater Depths

Phreatophytes are deep-rooted plants that reach groundwater and are widely distributed in arid and semiarid areas around the world. Multiple environmental factors affect the growth of phreatophytes in desert ecosystems. However, the key factor determining the leaf nutrients of phreatophytes in arid regions remains elusive. This study aimed to reveal the key factors affecting the ecological stoichiometry of desert phreatophytes in the shallow groundwater of three oases at the southern rim of the Taklimakan Desert in Central Asia. Groundwater depth; groundwater pH and the degree of mineralization of groundwater; topsoil pH and salt concentration; topsoil and leaf carbon, nitrogen, and phosphorus concentrations of phreatophytic Alhagi sparsifolia grown at groundwater depths of 1.3–2.2 m in the saturated aquifer zone in a desert–oasis ecotone in northwestern China were investigated. Groundwater depth was closely related to the mineralization degree of groundwater, topsoil C and P concentrations, and topsoil salt content and pH. The ecological stoichiometry of A. sparsifolia was influenced by depth, pH and the degree of mineralization of groundwater, soil nutrients and salt concentration. However, the effects of soil C and P concentrations on the leaf C and N concentrations of A. sparsifolia were higher than those of groundwater depth and pH and soil salt concentration. Moreover, A. sparsifolia absorbed more N in the soil than in the groundwater and atmosphere. This quantitative study provides new insights into the nutrient utilization of a desert phreatophyte grown at shallow groundwater depths in extremely arid desert ecosystems.

Removal of Ampicillin by Heterogeneous Photocatalysis: Combined Experimental and DFT Study

A long-term exposition of antibiotics represents a serious problem for the environment, especially for human health. Heterogeneous photocatalysis opens a green way for their removal. Here, we correlated the structural-textural properties of TiO2 photocatalysts with their photocatalytic performance in ampicillin abatement. The tested nanoparticles included anatase and rutile and their defined mixtures. The nominal size range varied from 5 to 800 nm, Aeroxide P25 serving as an industrial benchmark reference. The degradation mechanism of photocatalytic ampicillin abatement was studied by employing both experimental (UPLC/MS/MS, hydroxyl radical scavenger) and theoretical (quantum calculations) approaches. Photocatalytic activity increased with the increasing particle size, generally, anatase being more active than rutile. Interestingly, in the dark, the ampicillin concentration decreased as well, especially in the presence of very small nanoparticles. Even if the photolysis of ampicillin was negligible, a very high degree of mineralization of antibiotic was achieved photocatalytically using the smallest nanoparticles of both allotropes and their mixtures. Furthermore, for anatase samples, the reaction rate constant increases with increasing crystallite size, while the degree of mineralization decreases. Importantly, the suggested degradation pathway mechanism determined by DFT modeling was in very good agreement with experimentally detected reaction products.

Examination of explants by electron microscopy and correlations with the biomechanical score of prosthetic restorations with implant support

Objectives. The objective of our study was to evaluate the bone-implant interface in 10 cases of failure of fixed implant-prosthetic treatment by electron microscopy and spectrophotometry, in correlation with the evolution of Renouard-Rangert biomechanical scoring. Material and method. The study material was represented by 10 dental implants of 3 different morphological types (A, B, C), from the Biomat © collection, Polytechnic University of Bucharest, which were examined under the Phenom ProX electron microscope. The studied samples had a file in which there was noted the biomechanical score Renouard-Rangert from the treatment planning phase, but also from the patient dispensary phase. The survival time of the analyzed samples at the level of the maxillary bones was 7-24 months. Results. Following the examination at the electron microscope, the presence of an adherent neoformation bone tissue was detected on every implant, which covered each implant relatively uniform, with different degrees of mineralization depending on the type of implant, the duration of bone implantation and evolution of biomechanical scoring in red or yellow. Discussions. The use in our study only of standard size implants is an important advantage over other studies using mini-implants or temporary implants. The cases in which the biomechanical scoring reached "red" showed a lower degree of mineralization, and those that reached "yellow" had a higher degree of mineralization. Among the cases with biomechanical soring "in yellow" were samples collected from the posterior maxillary region, generally considered a risk area in implantology. Conclusions. In our study we found a correspondence between the modification of the Renouard-Rangert biomechanical scoring and the degree of mineralization of the bone deposited on the surface of the explants. Regardless of the evolution of biomechanical scoring, on all 10 analyzed samples we found a close contact between the neoformation tissue and the implanted devices, which indicates the high biocompatibility of the three types of implants. The relatively small number of samples analyzed is a limitation of our study. In the future, we recommend, in order to validate the results, to extend the study to a greater number of cases.

RAMAN-FLUORESCENT CHARACTERISTICS OF DIFFERENT ANATOMICAL AND TOPOGRAPHIC ZONES OF TEETH OF DIFFERENT FUNCTIONAL GROUPS

The aim of the study is to study the state of mineralization of various anatomical and topraphic zones of teeth for different functiona I groups and to justify its clinical feasibility. In a preclinical in vitro study on 20 model test objects of teeth (incisors, canines, premolars and painters), removed according to clinical indications, Raman-fluorescent study of the degree of mineralization of various anatomical and topographic zones of the tooth in different functional groups of teeth was carried out. Used APC Inspector M with a wavelength of532 nm probing radiation. The advantages of Raman fluorescence spectroscopy for determining the degree of mineralization of hard tooth tissues are objectivity (digital technology), expressiveness, non-invasiveness, simple and non-destructive control of the degree of mineralization/remineralization of hard tooth tissues, the ability to document and store information. In th e course of the study, a qualitative and quantitative analysis of the mineralization of various anatomical and topraphic zones of teeth for different functional groups of teeth was carried out. High sensitivity and reproducibility of the method allowed to reveal significant differences in mineralization of tooth enamel in the area of the cutting edge, equator and neck of the tooth. It is shown that these differences are manifested in other functional groups of teeth (p < 0.05).

Effects of diet consistency on mandibular growth. A review

This article is a review that focuses on the diet consistency and how this affects mandibular morphology. Various published studies focused on the relationship between mastication and growth of the mandible because it is considered that mandibular growth is dependent on the loads exerted by the function of the masticatory muscles. Moreover it has been pointed out that the increase of orthodontic anomalies is due to the modern softer diet. Even in rats, soft diet is one of the factors causing malocclusions. All of the studies have been experimental, mainly in rodents, since this research is impossible to be applied on humans in a short period of time. Most experimental studies suggested that occlusal loading affects bone mass, bone amount, bone density, the length and the width of the bone, the degree of mineralization, the genetic expression, the collagen immunoreaction and the chondrocytes action on the cartilage. It is stated that bone volumes and thickness of the mandible of rats fed with soft diet were smaller when compared to animals fed with hard diet. Also the mandibles and condyles were smaller and less dense in the rats of soft diet as compared to controls. Furthermore the length and the width of the condyle in the soft diet group of animals were smaller as compared to the condyle of the hard diet group of animals. Soft diets affect also the degree of mineralization, and the action of the chondrocytes on the cartilage.

RESEARCH OF INFLUENCE OF SALIVARY AND Oral CLEANING HYGIENE ON INDICATORS OF MINERALIZATION OF HARD TOOTH TISSUES OF DIFFERENT FUNCTIONAL GROUPS

In vitro, investigate by the method of Raman fluorescence spectroscopy the effect of saliva and oral hygiene products on the mineralization indices of various anatomical and topographic areas of teeth for their various functional groups, to substantiate its clinical feasibility and effectiveness. Methods: in a preclinical in vitro study on 90 model test objects of teeth (incisors, premolars, and molars) removed according to clinical indications, a Raman fluorescence study of the degree of mineralization (Raman spectrum characteristics), dental hygiene conditions (plaque and intensity fluorescence) and evaluation of the effectiveness of remineralizing agents (films, suspensions) in various functional groups of teeth. For registration of the studied parameters, InSpektr M agro-industrial complex was used with a probe wavelength of 532 nm. The advantages of Raman fluorescence spectroscopy for determining the degree of mineralization and the hygienic state of tooth hard tissues are objectivity (digital technology), expressivity, non-invasiveness, simple and non-invasive control the degree of mineralization / demineralization of the hard tissues of the tooth and its hygienic state, the possibility of documenting and storing information (creating a database). Results: In the course of the study, a qualitative and quantitative analysis of the influence of saliva and oral hygiene products on the mineralization and hygienic condition of various functional groups of teeth was carried out.

RAMAN FLUORESCENCE CHARACTERISTICS OF HARD DENTAL TISSUES AND THEIR CLINICAL SIGNIFICANCE

The aim of the study is to study the spectral characteristics of the hard tissues of the tooth, their Raman-fluorescent components (RFS) and to determine the possibility of using the method to assess the degree of mineralization of hard tissues of the tooth. In a preclinical study on model test objects of different functional groups of teeth (incisors, premolars, molars), remote by clinical indications, Raman-fluorescence spectroscopy was performed using the laser hardware-software complex “Inspector M” with a wavelength of probing radiation 514 nm. In the course of the study, a qualitative and quantitative analysis of the content and distribution of hydroxyapatite in the structures of hard dental tissues (enamel, dentin, cement) in normal and pathological conditions was performed. The high sensitivity and expressiveness of the method, the possibility of quantitative processing of the results of the study, which allows us to recommend it for assessing the degree of mineralization/demineralization of the tooth, the effectiveness of remineralizing drugs and methods of their use in the clinic of therapeutic dentistry.