New 1'-homocarbanucleoside analogs with an optically active substituted bicyclo2.2.1heptane skeleton as sugar moiety were synthesized. The pyrimidine analogs with uracil, 5-fluorouracil, thymine and ...cytosine and key intermediate with 6-chloropurine (
) as nucleobases were synthesized by a selective Mitsunobu reaction on the primary hydroxymethyl group in the presence of 5-endo-hydroxyl group. Adenine and 6-substituted adenine homonucleosides were obtained by the substitution of the 6-chlorine atom of the key intermediate
with ammonia and selected amines, and 6-methoxy- and 6-ethoxy substituted purine homonucleosides by reaction with the corresponding alkoxides. No derivatives appeared active against entero, yellow fever, chikungunya, and adeno type 1viruses. Two compounds (
and
) had lower IC
(15 ± 2 and 21 ± 4 µM) and compound
had an identical value of IC
(28 ± 4 µM) to that of acyclovir, suggesting that the bicyclo2.2.1heptane skeleton could be further studied to find a candidate for sugar moiety of the nucleosides.
β-Ketophosphonates with pentalenofurane fragments linked to the keto group were synthesized. The bulky pentalenofurane skeleton is expected to introduce more hindrance in the prostaglandin analogues ...of type
, greater than that obtained with the bicyclo3.3.0oct(a)ene fragments of prostaglandin analogues
and
, to slow down (retard) the inactivation of the prostaglandin analogues by oxidation of 15α-OH to the 15-keto group via the 15-PGDH pathway. Their synthesis was performed by a sequence of three high yield reactions, starting from the pentalenofurane alcohols
, oxidation of alcohols to acids
, esterification of acids
to methyl esters
and reaction of the esters
with lithium salt of dimethyl methanephosphonate at low temperature. The secondary compounds
and
were formed in small amounts in the oxidation reactions of
and
, and the NMR spectroscopy showed that their structure is that of an ester of the acid with the starting alcohol. Their molecular structures were confirmed by single crystal X-ray determination method for
and XRPD powder method for
.
Hydroboration-oxidation of 2α,4α-dimethanol-1β,5β-bicyclo3.3.0oct-6-en dibenzoate (
) gave alcohols
(symmetric) and
(unsymmetric) in ~60% yield, together with the monobenzoate diol
(37%), resulting ...from the reduction of the closer benzoate by the intermediate alkylborane. The corresponding alkene and dialdehyde gave only the triols
and
in ~1:1 ratio. By increasing the reaction time and the temperature, the isomerization of alkylboranes favours the un-symmetrical triol
. The PDC oxidation of the alcohols gave cleanly the corresponding ketones
and
and the deprotection of the benzoate groups gave the symmetrical ketone
, and the cyclic hemiketal
, all in high yields. The ethylene ketals of the symmetrical ketones
and
were also obtained. The compounds
,
,
,
,
could be used for synthesis of new (iso)carbacyclin analogues. The structure of the compounds was established by NMR spectroscopy and confirmed by X-ray crystallography.
An amine group was synthesized starting from an optically active bicyclo2.2.1heptane compound, which was then used to build the 5 atoms ring of a key 6-chloropurine intermediate. This was then ...reacted with ammonia and selected amines obtaining new adenine- and 6-substituted adenine conformationally constrained carbocyclic nucleoside analogues with a bicyclo2.2.1heptane skeleton in the sugar moiety. X-ray crystallography confirmed an exo-coupling of base to the ring and a L configuration of the nucleoside analogues. The compounds were tested for anticancer activity.
Iodo-, bromo-, chloro-etherification and oxymercuration–demercuration of hexahydropentalene 1,3-dimethanol were regioselectively realized with formation of pentalenofurane compounds in good yields. ...The corresponding hexahydropentaleno diacid and its monoester react regioselectively with MCPBA to give two γ-lactones. Haloetherification of the diacid also regioselectively gives halogenolactones in good yield. A new method for synthesis of a bislactone was developed in better yield (79%) than that presented in the literature (58%).
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The treatment of hexahydro-1.3-pentalenedimethanol 1 with MCPB acid gave a pentalenofurane compound 7 instead of an epoxide, in >90% yield by participation of the closer hydroxymethyl group in ...epoxidation. Acyl-protected derivatives 1a–1e gave a mixture of exo- and endo-epoxides 5/6 as expected, with exo-epoxides representing the major compound in all cases. The best yield for exo-epoxide was obtained for diacetate 1a. Basic hydrolysis of exo-epoxides gave the pentalenofurane compound 7, while that of the endo-epoxide 6c gave the unsubstituted endo-epoxide 6. The structure of the compounds was confirmed by IR, MS, 1H and 13C NMR spectra and also by extensive X-ray crystallography of compounds 7c, 7d, 5a, 6c and 7.
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Introduction: Motion analysis, the study of movement patterns to evaluate performance, plays a crucial role in surgical training. It provides objective data that can be used to assess and improve ...trainee's precision, efficiency, and overall surgical technique. The primary aim of this study is to employ accelerometer-based sensors placed on the wrist to analyze hand motions during endoscopic sinus surgery training using the sheep's head. By capturing detailed movement data, the study seeks to quantify the motion characteristics that distinguish different levels of surgical expertise. This approach seeks to quantify motion characteristics indicative of surgical expertise and enhance the objectivity and effectiveness of surgical training feedback mechanisms.Materials and methods: Twenty-four participants were divided into three groups based on their experience with endoscopic endonasal surgery. Each participant was tasked with performing specified procedures on an individual sheep's head, concentrating on exploring both nasal passages. A single Bluetooth Accelerometer WitMotion sensor was mounted on the dorsal surface of each hand. This facilitates the evaluation of efficiency parameters such as time, path length, and acceleration during the training procedures. Accelerometer data were collected and imported in CSV format (comma-separated values) for each group of surgeons-senior, specialist, and resident-mean values and standard deviations were computed. The Shapiro-Wilk Test assessed the normality of the distribution. The Kruskal-Wallis test was employed to compare procedural time, acceleration, and path length differences across the three surgeon experience levels.Results: For the procedural time, statistical significance appears in all surgical steps (p<0.001), with the biggest difference in the septoplasty group in favor of the senior group. A clear difference can be observed between the resulting acceleration of the dominant hands (instrument hand) and the non-dominant hand (endoscopic hand) and between the study groups. The difference between groups reaches statistical significance with a p-value <0.001. A statistically significant difference can be seen between the paths covered by each hand of every participant (p<0.001). Also, senior doctors covered significantly less movement with both hands than the specialists and the resident doctors (p<0.001).Conclusions: The data show a clear learning curve from resident to senior, with residents taking more time and using more hand movements to complete the same tasks. Specialists are in the intermediate phase, showing signs of honing their technique towards efficiency. This comprehensive data set can help tailor training programs to focus on both efficiency (quicker procedures) and economy of motion (reduced path length and acceleration), especially in more complex procedures where the difference in performance is more pronounced.
Training young doctors in functional endoscopic sinus surgery requires dedicated centers for cadaveric dissections. However, ethical constraints have limited cadaver availability. Alternative ...anatomical models, like the ovine model, are being explored for effective training, offering easier procurement and resembling human head anatomy. This study aims to demonstrate that the ovine model is useful for endoscopic sinus surgery training, highlighting the anatomical, imaging, histological, and endoscopic aspects.
Three adult Native Romanian Turcana sheep's heads were obtained fresh and frozen from a local slaughterhouse. Using a helical scanner, CT scans were performed, and anatomical structures in the images were carefully labeled. Two heads frozen at -20°C were serially sectioned, with one cut sagittally, dividing the skull, and the other head sectioned transversely with 2.5 cm thickness. Sectional photographs were taken. The third sheep's head underwent endoscopy, and samples from the septal mucosa and inferior turbinate were collected for histopathology examination. The specimens were processed, stained, and examined by a pathologist.
The study successfully highlighted the gross anatomy, CT imaging aspects, histological characteristics of sheep nasal mucosa, and endoscopic features, demonstrating the similarity of the sheep's head to human anatomy, making it a suitable anatomical training model for endoscopic sinus surgery.
The use of sheep's heads as substitutes for human cadaver heads in nasal surgery simulations presents a promising avenue for research. The anatomical similarities and cost-effectiveness make sheep's heads a practical choice for certain aspects of nasal surgery investigation. However, researchers must approach this methodology with a thorough understanding of its limitations, including anatomical and biomechanical differences. Validation studies comparing outcomes with human models are crucial to establishing reliability. The sheep's head anatomical model provides a highly valuable experience for young trainees in endoscopic sinus surgery. Despite encountering several challenges, including some anatomical differences, considering its advantageous attributes renders it an ideal material for mimicking surgical procedures in functional endoscopic sinus surgery.
In the context of climate changes, knowing the low-flow trends is very important for establishing appropriate measures for water resources management, in order to ensure their sustainability. This ...paper focuses on Romanian rivers and aims to identify the recent trends (during the period 1980-2013) in the low-flow variability. The analysis is based on discharges data series (daily and monthly) recorded at 54 gauging stations, with a quasi-natural flow regime. The significance of trends for annual, monthly and seasonal low-flow in the analyzed period has been established using the nonparametric Mann-Kendall test.
The variability of the lowest annual values of the mean daily and monthly discharges showed positive trends at gauging stations located mainly in the Carpathian area, while negative trends were found in lowland regions (plains and tablelands). During the winter there were identified positive low-flow trends, while negative trends were found in summer and spring. Increases in the minimum monthly flow were particularly evident in February, March and December, and negative trends were identified especially in the summer (July, June and August) and the autumn months (September and October).
Associated with the Western diet and life style,diverticular disease is affecting more and more developing countries worldwide. Recent studies show an increase in incidence of the disease at young ...age, that raises the risk of complications, along with major consequences for the patient but also for the healthcare system.
Systematic review of the literature with US National Library of Medicine and National Institutes of Health International PubMed Medline, using abstracts and articles available in PubMed Medline, Cochrane databases searching for ("Diverticulosis, Colonic epidemiology" MeSH OR"Diverticulosis, Colonic etiology" MeSH OR "Diverticulosis,Colonic genetics" MeSH OR "Diverticulosis, Colonic history" MeSH).
Even from the rise of diverticular disease as a public healthcare problem, at the end of the previous century, it was associated with a diet rich in refined sugars, lacking vegetable fibres. The higher incidence in countries like U.S.A., Canada, United Kingdom and the northern states compared with its rare occurrence in the sub-Saharan African continent, strengthen the anterior assumptions. In regions like Asia, the disease pattern is characterized by are latively low incidence of colonic diverticular disease, with distribution of diverticula mainly on the right colon. The different incidence by sex and age show the possible existence of hormonal protective factors. Studies from countries with a rich ethnic diversity, bring into question the probable genetic predisposition to diverticular disease, fact backed-up by the few studies on twins and 1st degree relatives available in the literature.
The rising incidence of colonic diverticular disease in Romania makes our country adhere the epidemiologic model existing in countries with a close socio-economic status.Although with a lower incidence than countries that have adopted a Western diet, Romania is likely to encounter a public health problem, if certain measures to identify and minimise the population exposure to risk factors are not taken.
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