Abstract The article presents an experimental method of determining the geometric properties of jet engine rotor airfoils based on modal vibration testing. The procedure is based on adjusting the ...results of analytical calculations to the laboratory outcomes. Experimental tests were carried out on a set of 20 jet engine fan blades made of AL7022-t6 aluminium alloy. Each blade differed in weight and geometric dimensions within the accepted design tolerance. Numerical analysis of five airfoils that differed in thickness was performed. Modal vibration test results were summarised and compared with the results obtained by the numerical method. The comparison revealed a high similarity of the frequency and form of vibrations acquired by numerical simulation for each of the blades in relation to the executed vibration testing. Based on the verification of the theoretical model with the results obtained through experimental testing, conclusions were drawn about the object’s dynamic behaviour and its technological quality and geometric properties, whereby each of airfoil was probably thinned.
Background
Pseudomeningoceles (PMCs) as abnormal collections of cerebrospinal fluid are quite common findings on follow-up MRI after Chiari decompression surgery (CDS). However, the importance of ...their identification has not been truly determined, especially when PMCs are described occasionally in the process of radiological follow-up. We retrospectively analyzed surgical outcomes and imaging findings after CDS depending upon the occurrence and thickness of PMCs.
Methods
A total of 76 adult patients who underwent CDS were analyzed. The clinical and radiological outcomes of patients with a pseudomeningocele (wPMC) were evaluated and compared to those of patients without a pseudomeningocele (w/oPMC). Radiological morphometric measurements were performed and compared between groups. Comparisons of the maximal PMC thickness were made within the wPMC group.
Results
PMCs were recognized in 27 (35.5%) patients, of whom 3 (11.1%) required reoperation. Differences in satisfactory result rates regarding gestalt assessment and Chicago Chiari Outcome Scale were statistically insignificant between the w/oPMC and wPMC groups (
p
= 1 and
p
= 0.56, respectively). The postoperative syringomyelia decrease and cerebellar tonsil elevation were similar between the groups (
p
= 1 and
p
= 0.74, respectively) in the long-term follow-up. Additionally, the clinical or radiological outcomes with radiological details were not related to PMC thickness in the long-term follow-up. However, radiological details showed the cooccurrence of PMCs with a postsurgical of cerebello-tentorial distance increase (
p
< 0.05), basion-pontomedullary sulcus distance decrease (
p
< 0.05) and tonsillo-graft distance decrease (
p
< 0.05).
Conclusions
We found no significant relationships between PMC presence or thickness and clinical or radiological outcomes. However, postoperative changes within the posterior fossa associated with PMCs resemble brain sagging, which occurs in intracranial hypotension. Therefore, extradural cerebrospinal fluid escape may also be responsible for symptoms in some patients with PMCs after CDS.
The cortical bone trajectory screws technique (CBTT) is a popular minimally invasive spine surgery. Few studies have reported long-term outcomes. We aimed to evaluate the complication profile and ...long-term follow-up results of patients with lumbar degenerative disease treated with the CBTT.This retrospective analysis included the first 40 consecutive patients that underwent the CBTT. The indication for surgery was critical stenosis of the intervertebral foramen, which required removal of the entire intervertebral joint, on at least 1 side, during decompression.The last follow-up showed minimal clinically important differences in the numerical rating scale of leg pain, the numerical rating scale of back pain, and the Oswestry Disability Index, in 97%, 95%, and 95% of patients, respectively. Thirty-nine patients completed long-term radiological follow-up. Computed tomography demonstrated solid bone union on 47 (92%) operated levels, collapsed union on 2 (4%) levels, nonunion on 1 (2%) level, and 1 (2%) patient was lost to follow-up. Seven patients experienced complications (4 hardware-related). Three patients required 4 revision surgeries.The CBTT effectively achieved spinal fusion; over 90% of patients achieved clinical improvement at a mean follow-up of 4.4 years (range: 3-5.75 years).
In lateral cervical disc herniations, posterior foraminotomy (PF) provides direct nerve root decompression and maintains segmental mobility. However, partial facetectomy can cause instability. This ...study evaluated long-term clinical outcomes related to cervical sagittal alignment after PF.
The study included 48 consecutive patients with lateral cervical disc herniations who underwent PF. Pain and mobility were evaluated using the Numeric Rating Scale and Neck Disability Index (NDI), respectively. Sagittal alignment was evaluated using the modified Toyama method.
Median Numeric Rating Scale arm, Numeric Rating Scale neck, and NDI scores improved by 7, 4.5, and 24 points, respectively. Corresponding mean minimal clinically important differences were achieved in 94%, 77%, and 98% of patients at a mean follow-up of 8.4 years. Of patients, 82% showed favorable radiological results (i.e., retained or developed lordosis or had straight spine), while 18% showed unfavorable radiological results (i.e., retained or changed toward kyphosis). The latter group had multilevel cervical degenerative disc disease (mcDDD) before PF. Nevertheless, the risk of developing kyphosis was only 2.6%, and the potential for improving sagittal balance was 43%. Follow-up median NDI scores, but not minimal clinically important differences, were significantly worse in patients with preoperative kyphosis (21 vs. 8; P = 0.03) or mcDDD (20 vs. 8; P = 0.024) compared with other patients.
Patients with preoperative kyphosis or mcDDD had worse NDI outcomes but also benefited from PF. Sagittal alignment improved in >40% of patients, but coexisting mcDDD was a main risk factor for kyphosis persistence.
Mechanical thrombectomy (MT) is not reimbursed by the Polish public health system. We present a description of 5 years of experience with MT in acute stroke in Comprehensive Stroke Centers (CSCs) in ...Poland.
We retrospectively analyzed the results of a structured questionnaire from 23 out of 25 identified CSCs and 22 data sets that include 61 clinical, radiological and outcome measures.
Most of the CSCs (74%) were founded at University Hospitals and most (65.2%) work round the clock. In 78.3% of them, the working teams are composed of neurologists and neuro-radiologists. All CSCs perform CT and angio-CT before MT. In total 586 patients were subjected to MT and data from 531 of them were analyzed. Mean time laps from stroke onset to groin puncture was 250±99min. 90.3% of the studied patients had MT within 6h from stroke onset; 59.3% of them were treated with IV rt-PA prior to MT; 15.1% had IA rt-PA during MT and 4.7% – emergent stenting of a large vessel. M1 of MCA was occluded in 47.8% of cases. The Solitaire device was used in 53% of cases. Successful recanalization (TICI2b–TICI3) was achieved in 64.6% of cases and 53.4% of patients did not experience hemorrhagic transformation. Clinical improvement on discharge was noticed in 53.7% of cases, futile recanalization – in 30.7%, mRS of 0–2 – in 31.4% and mRS of 6 in 22% of cases.
Our results can help harmonize standards for MT in Poland according to international guidelines.
Reconstruction is the method of choice in the treatment of ACL rupture. Postoperative rehabilitation is a very important aspect of therapeutic management. One of priority elements is to regain proper ...strength and function of the quadriceps muscle in a short time. The aim of this study was to estimate the dynamics of the increase in strength and girth of quadriceps after ACL reconstruction.
The examined group consisted of 30 patients who had undergone arthroscopic assisted quadruple bundle dual channel ACL reconstruction surgery in years 2010-2011. The average age of the patients at the time of operation was 31.7 years (range 17-53). Each patient was examined 4 times: before the surgery as well as in the second, sixth and twelfth week after the reconstruction.
Examination revealed a significant increase in quadriceps girth, with peak increase rate observed within the two first weeks after the surgery. Between weeks 2 and 6, a decrease in quadriceps girth was observed followed by repeated increase worm week 6 on. The greatest increase in the girth at the thickest point of the muscle was observed in rehabilitation weeks 6 through 12. A significant decrease in muscle strength was observed in the first 2 weeks after the surgery. In the remaining periods, the strength of the quadriceps muscle continued to grow. The average KSS score increased from 109.1 at week 2 to 162.3 at week 12 after the surgery.
Rehabilitation results in a dynamic increase in the strength of quadriceps between weeks 6 and 12 following reconstruction of anterior cruciate ligament. However, the 12-week rehabilitation period is not sufficient to regain full functionality.
•Taxonomic resources of the pristine rivers in the Biebrza National Park.•Five groups of organisms examined: benthic diatoms, phytoplankton, macrophytes, macrozoobenthos, and ichthyofauna.•Documented ...pool of taxa and estimated the predicted richness.•Valuable biodiversity resources, including protected plant and animal species.•High alpha diversity (within-site diversity) but relatively low gamma diversity (total diversity across all sites).
The study focuses on the pristine rivers of the Biebrza National Park (BNP), an extensive area of wetlands, which holds significant biodiversity importance on a European scale. The aim of this work was to identify the taxonomic resources of the river network of this area and to compare the biodiversity of various aquatic organisms, and moreover, evaluate the field sampling effort required to identify the whole pool of taxa inhabiting the survey area. Fieldwork was carried out in 2021 at 25 survey sites, where the taxonomic compositions of five groups of organisms were identified: benthic diatoms, phytoplankton, macrophytes, benthic macroinvertebrates, and ichthyofauna and identified taxa have been presented in the appendix. The biodiversity indices of these groups were calculated, i.e. the species richness, and the Shannon and Simpson indices. The entire predicted biodiversity of these groups of organisms was also estimated. The Chao2 asymptotic taxonomic richness estimator for incidence data was used to calculate the additional number of survey sites that would be required to discover 80%, 90% and 100% of the anticipated taxonomic richness in each of the five groups of organisms. With the information on the species inhabiting the Biebrza Valley that this survey yielded, the biodiversity at a single site (alpha diversity) and within the entire area surveyed (gamma diversity) was estimated. The phytoplankton (475 taxa) and the benthic macroinvertebrates (308) showed the greatest diversity in taxonomic richness. In addition, there were 151 species in the benthic diatom group, 72 macrophyte taxa, and 24 fish species. The analysis showed, moreover, that if the fieldwork were continued, another 110 phytoplankton and 104 benthic macroinvertebrates taxa would be recorded for BNP, along with 40 further species of benthic diatoms, 9 more macrophyte species, and 2 more fish species. Alpha diversity was found to be high but gamma diversity was relatively low due to the homogeneous nature of the rivers surveyed (low beta diversity), effective conservation measures, and minimal human disturbances.
Nitric oxide in preterm labor Bielecki, Marian; Tomasiak, Marian; Jarocki, Sławomir ...
Ginekologia polska
74, Številka:
5
Journal Article
Recenzirano
Synthesis of nitric oxide proceeds in the human myometrium. Decrease of its concentrations can play an essential part in the initiation of uterine contractions in term. Authors suppose, that ...inhibition of the synthesis of nitric oxide plays a role in premature labour. Concentrations of nitric oxide in women with threatening premature labour were marked. Group I consisted of women with premature departure of amniotic fluid, group II--woman with retained amniotic fluid and with idiopathic contractile activity, group III--woman with departure of amniotic fluid and with idiopathic contractile activity. Concentration of nitric oxide was lower in the group of women with a premature contractile activity in comparison with healthy pregnant women in the same period of pregnancy. Higher concentrations of nitric oxide were observed in the group of patients without contractile activity after departure of amniotic fluid.
The aim of the study was to determine the concentrations of TGF-beta, PDGF and VEGF growth factors in peripheral blood. The examinations were carried out in the group of pregnant women with ...preeclampsia. The results were compared to those obtained in a control group of healthy pregnant women. The statistically significant increase in all examined growth factors was observed in women with preeclampsia in comparison to healthy women. The results suggest that growth factors may play an important role in etiology and pathophysiology of preeclampsia.
In accordance with presented results and clinical observation it should be assumed that basic phenomena resulting in clinical sign of preeclampsia take place already in implantation and ...embryogenesis. Abnormal trophoblastic infiltrations and changes in vascular endothelium functioning occur due to disturbed interaction of cytokines and growth factors. Pathologies present in endothelial cells (EC) become the cause of blood overcoagulation and hypertension and promote other clinical symptoms of preeclampsia.
PDF
