Carbon nanostructure-reinforced SiCw/Si3N4 composite with enhanced thermal conductivity and mechanical properties

Carbon nanostructures (CNS) as a kind of reinforcement material can remarkably enhance the mechanical and thermal properties of ceramics. This research presents an analysis of the influence of CNS on the thermal conductivity and mechanical properties of SiC_w/Si₃N₄ composites. The SiC_w/Si₃N₄ composites containing various types of CNS e.g. carbon nanofibers (CNF), multi-walled carbon nanotubes (MWCNT) and graphene nano-platelets (GNP) were fabricated by hot-press sintering. XRD analysis confirmed a complete transformation of α-Si₃N₄ to β-Si₃N₄ and microstructural analysis shows a uniform distribution, as well as a pullout and bridging mechanism of CNS. The results revealed that the thermal conductivity and mechanical properties of SiC_w/Si₃N₄ composites increased with the addition of CNS. Maximum values of fracture toughness (9.70 ± 0.8 MPa m^1/2) and flexural strength (765 ± 58 MPa) have been achieved for the MWCNT-containing SiC_w/Si₃N₄ composite, whereas the maximum values of Young''s modulus (250 ± 3.8 GPa) and hardness (27.2 ± 0.9 GPa) have been achieved for the CNF-containing SiC_w/Si₃N₄ composite. Moreover, thermal conductivity also improved with the addition of CNS and reached a maximum value of 110.6 W m⁻¹ K⁻¹ for the CNF-containing SiC_w/Si₃N₄ composite. This work provides a useful approach for the fabrication of high-performance multifunctional composites for emerging engineering applications.

Carbon nanostructures (CNS) as a kind of reinforcement material can remarkably enhance the mechanical and thermal properties of ceramics.     

The impact of lymph node status and features on oncological outcomes in urothelial carcinoma of the upper urinary tract (UTUC) treated by nephroureterectomy

Purpose

Prognostic impact of lymphadenectomy during radical nephroureterectomy (RNU) for urothelial carcinoma of the upper urinary tract (UTUC) is controversial. Our aim was to assess the impact of lymph node status (LNS) on survival in patients treated by RNU.

Methods

In our multi-institutional, retrospective database, 714 patients with non-metastatic UTUC had undergone RNU between 1995 and 2010. LNS was tested as prognostic factor for survivals through univariate and multivariable Cox regression analysis.

Results

Median age was 70 years [interquartile range (IQR), 60–75] with median follow-up of 27 months (IQR, 10–50). Overall, lymphadenectomy was performed in 254 patients (35.5 %). Among these patients, 204 (80 %) had negative lymph nodes (pN0) and 50 (20 %) had positive lymph nodes (pN1/2). The 5-year cancer-specific survival (CSS) was 81 % [95 % confidence interval (CI), 73–88 %] for pN0 patients, 85 % (95 % CI, 80–90 %) for pNx patients and 47 % (95 % CI, 24–69 %) for pN1/2 patients (p < 0.001). Metastasis-free survival (MFS) and overall survival (OS) rates were significantly lower in pN1/2 patients than in pN0 and pNx patients (p < 0.05). On multivariable analysis, LNS did not appear as an independent prognostic factor for CSS, OS or MFS (p > 0.05). In case of lymph node involvement, extra-nodal extension was marginally associated with worse CSS (log rank p = 0.07). The retrospective design was the main limitation.

Conclusion

LNS is helpful for survival stratification in patients treated with RNU for UTUC. However, LNS did not appear as an independent predictor of survival in this retrospective series and needs to be investigated in a large multicentre, prospective evaluation.     

Is there a relationship between attention deficit/hyperactivity disorder and Osgood–Schlatter disease?

Purpose

The purpose of this prospective study is to investigate the relationship between Osgood–Schlatter disease (OSD) and attention deficit/hyperactivity disorder (ADHD).

Methods

Seventy-four children with a diagnosis of OSD were referred to child and adolescent psychiatry department for the evaluation of ADHD. Diagnostic and Statistical Manual of Mental Disorders was used for diagnostic criteria.

Results

Diagnosis of ADHD was made in 56 (75.6 %) out of 74 children.

Conclusions

Results of this study suggest that ADHD is a significant risk factor for OSD. During the evaluation of a patient with OSD, a thorough history should be obtained about the behavioral symptoms that indicate underlying ADHD. In case of suspicion, these patients should be referred for an additional evaluation by a child psychiatrist.

Level of evidence

II.     

Unexpectedly ease surgery for a worrisome abdominal mass: Pedunculated GISTs

INTRODUCTIONDiscovery of abdominal masses often poses significant diagnostic difficulties. GISTs are mesenchymal masses, with specific histological features. Dimensions may vary from millimeters to giant tumours. We would like to present our case, which had an unexpectedly easy operative course which was easily handled with a simple surgical excision with a short operative duration.PRESENTATION OF CASEA 38 years old female patient was diagnosed to have an abdominal heterogen mass of 15 cm × 12 cm × 10 cm in dimension. Abdominal computed tomography revealed the solid mass between the stomach and pancreas corpus and tail, possibly orginating from the pancreas. With the preoperative diagnosis of locally invasive distal pancreas cancer the patient underwent laparotomy, following the dissection, the mass was observed to be originating from the posterior gastric Wall, extending exophytically with a peduncle of 5 cm in width, without any visual evidence for peritoneal invasion and metastasis. The tumour and the peduncle was resected with stapler device. Total operation time was 30 min. Postoperative course was uneventful. Pathologic diagnosis was gastrointestinal stromal tumour (GIST).DISCUSSIONPedunculated large GISTs are not frequent and they can enlarge as 15 cm in diameter and compress the neighbouring organs. When they were huge, it is difficult to differentiate the origin of the masses. GISTs should be considered in differential diagnosis of giant abdominal masses.CONCLUSIONWhen GISTs are huge and pedunculated, it can be difficult to differentiate the origin of the masses. This case report presents unexpectedly ease surgery for a worrysome abdominal mass.     

Assessing the Validity of Western Measurement of Online Risks to Children in an Asian Context

Before the advent of the Internet, television and film was the only audio-visual medium to which most children were exposed. The risks were primarily limited to children being exposed to sexual and violent materials, the nature of which were known and easy to control. Nowadays, children are surrounded by a variety of digital media and are exposed to different risks, many of which are still unknown. The Internet is fully integrated into children’s daily lives, along with the potential risks. The present study aimed to (i) describe the level of risks children are exposed to, and (ii) test the measurement validity of a total of 45 items assessing nine scales of online risk to children that were adapted from studies carried out in Europe and the United States. The study comprised 420 schoolchildren. The results showed that children were more exposed to ‘unwanted exposure to pornography’ and less to ‘conduct risk’ (e.g., accidental illegal downloading; creating profiles on inappropriate websites). Boys and older children were more exposed to the risks compared to girls and younger children. The study validated five dimensions (inappropriate materials, sexting, contact-related risks, risky online sexual behavior, and bullying/being bullied) assessing online risk to children by using exploratory and confirmatory factor analyses. The study found that scales developed in Europe and the United States are not wholly suitable to an Asian context and needed to be modified. Further investigation to classify online risks to children and offer a solutions to reducing the online risks.     

Development and validation of a short-form, rapid estimate of adult literacy in medicine

BACKGROUND: Although prior studies used the 66-item Rapid Estimate of Adult Literacy in Medicine (REALM instrument) for literacy assessment, researchers may require a shorter, validated instrument when designing interventions for clinical contexts. OBJECTIVE: To develop and validate a very brief literacy assessment tool, the REALM-Short Form (REALM-SF). PATIENTS: The model development, validation, and field testing validation samples included 1336, 164, and 50 patients, respectively. SETTING: General medicine and subspecialty clinics and medicine inpatient wards. DESIGN: For development and validation samples, indicator variables for REALM instrument items were evaluated as potential predictors of REALM instrument score by stepwise multiple regression analysis with subsequent bootstrap and confirmatory factor analysis of selected items. Pearson correlations compared REALM-SF and REALM instrument scores and kappa analyses compared grade level assignments. For the field testing validation sample, Pearson correlations compared Wide Range Achievement Test and REALM-SF scores. RESULTS: The REALM-SF included 7 items with stable model coefficients and 1 underlying linear factor. REALM-SF and REALM instrument scores were highly correlated in development (r = 0.95, P < 0.001) and validation (r = 0.94, P < 0.001) samples. There was excellent agreement between REALM-SF and REALM instrument grade-level assignments when dichotomized at the 6th grade (development: 97% agreement, K = 0.88, P < 0.001; validation: 88% agreement, K = 0.75, P < 0.001) and 8th grade levels (development: 94% agreement, K = 0.78, P < 0.001; validation: 84% agreement, K = 0.67, P < 0.001). REALM-SF and Wide Range Achievement Test scores were highly correlated (r = 0.83, P < 0.001) in field testing validation. CONCLUSIONS: The REALM-SF provides researchers a brief, validated instrument for assessing patient literacy in diverse research settings.