Biomedical subjects

M Frey

Publications and source records attributed to M Frey.

At least 19 recordsLinked to original sources

PubMed2006

Bronchial hyperresponsiveness and the development of asthma and COPD in asymptomatic individuals: SAPALDIA cohort study.

BACKGROUND: Bronchial hyperresponsiveness (BHR) is a common feature of asthma. However, BHR is also present in asymptomatic individuals and its clinical and prognostic significance is unclear. We hypothesised that BHR might play a role in the development of chronic obstructive pulmonary disease (COPD) as well as asthma. METHODS: In 1991 respiratory symptoms and BHR to methacholine were evaluated in 7126 of the 9651 participants in the SAPALDIA cohort study. Eleven years later 5825 of these participants were re-evaluated, of whom 4852 performed spirometric tests. COPD was defined as an FEV1/FVC ratio of <0.70. RESULTS: In 1991 17% of participants had BHR, of whom 51% were asymptomatic. Eleven years later the prevalence of asthma, wheeze, and shortness of breath in formerly asymptomatic subjects with or without BHR was, respectively, 5.7% v 2.0%, 8.3% v 3.4%, and 19.1% v 11.9% (all p<0.001). Similar differences were observed for chronic cough (5.9% v 2.3%; p = 0.002) and COPD (37.9% v 14.3%; p<0.001). BHR conferred an adjusted odds ratio (OR) of 2.9 (95% CI 1.8 to 4.5) for wheezing at follow up among asymptomatic participants. The adjusted OR for COPD was 4.5 (95% CI 3.3 to 6.0). Silent BHR was associated with a significantly accelerated decline in FEV1 by 12 (5-18), 11 (5-16), and 4 (2-8) ml/year in current smokers, former smokers and never smokers, respectively, at SAPALDIA 2. CONCLUSIONS: BHR is a risk factor for an accelerated decline in FEV1 and the development of asthma and COPD, irrespective of atopic status. Current smokers with BHR have a particularly high loss of FEV1.

Adult↗

PubMed2006

[Spontaneous pneumomediastinum in asthma].

A pneumomediastinum is characterized by free air within the mediastinum. In most cases it is caused by an injury of the thorax. A spontaneous pneumomediastinum (sPM) occurred without any recognizable cause. By a sudden intraalveolar hypertension (caused by cough or physical exertion) a damage of alveoli is followed by diffusion of air along the bronchovascular sheats to the mediastinal soft tissue. sPM is a rare complication of asthma especially in young men. We demonstrate a young asthmatic patient with sPM first diagnosed as an allergic reaction to draw the attention to this rare but differential diagnostic important entity. sPM is reported in connection with drug inhalation abuse as a more frequent problem within the last years.

Adult↗

PubMed2006

Intra-individual comparison between open and 2-portal endoscopic release in clinically matched bilateral carpal syndrome.

Based upon bilateral carpal tunnel syndrome (CTS) we undertook a prospective randomised intra-individual comparison between open (OR) and 2-portal endoscopic release (2-PER) to establish if there is any demonstrable advantage in undertaking either technique in a 1 year follow-up. Ten patients with bilateral CTS were enrolled in this study and underwent a 2-PER on the one and an OR with two minimised incisions on the contralateral hand. Both hands were examined pre- and postoperatively after 2, 4, 6 and 12 weeks and after 6 and 12 months, respectively. Preoperatively both hands revealed statistically no significant differences in all the parameters recorded. Comparing both techniques no significant differences could be detected in the follow-up period. Nevertheless, both techniques showed significant improvements in the severity of symptoms and pain, in sensory nerve testing and in electro-diagnostic parameters, when comparing pre- with postoperative data after 1 year. The endoscopic approach revealed no distinct advantages over the open technique not only in the late but also in the early postoperative follow-up period when performing intra-individual comparison. Considering the higher complication rate and costs when performing 2-PER the OR with two minimised incisions seems to be a good alternative in order to keep the recovery period as short as possible.

Carpal Bones↗

PubMed2006

Free functional muscle transplantation for facial reanimation: experimental comparison between the one- and two-stage approach.

To investigate functional results of either one- or two-staged free muscle transplantation the scutuloauricularis model in the New Zealand white rabbit was used. Thirty rabbits were allocated to two groups with 15 animals each. In Group 1 (one-stage approach) peroneus brevis (PB) was harvested as a free muscle graft with a 7cm long motor branch. The graft was positioned instead of right scutuloauricularis (SCUT) and its vascular supply microsurgically re-established. The motor branch was transferred to the contralateral side and its proximal end coapted to the cut facial motor branch to left SCUT. Before nerve coaptation biopsies were harvested from the cut motor branch for morphological analysis. In Group 2 (two-stage approach) a 7cm long saphenous nerve graft was taken and coapted to the cut motor branch of SCUT and crossed over to the contralateral side. Nerve specimens from the cut motor branch were taken. Eight months later the free transplantation of PB was performed and its motor branch coapted to the distal end of the cross-over nerve graft. After a total time period of 13 months the final experiments were carried out in each group. Maximal tetanic tensions in reinnervated PB were measured and biopsies of muscle grafts together with nerve biopsies from the distal part of the motor branch were harvested for morphological analysis. Muscle grafts of Group 1 revealed tetanic tension values of 12.5N (SD 3.1) in comparison to 10.6N (SD 3.5) obtained in Group 2. This difference was not statistically significant (p=0.303). In Group 1, the amount of regenerated nerve fibers counted at the distal motor branch site (mean: 2798, SD 1242) was significantly higher (p=0.008) than in Group 2 (mean: 1138, SD 1004). Muscle graft morphology revealed significantly less Type I fibers (p=0.016) and more Type IIb/d fibers (p=0.011) in Group 1 compared to Group 2. However, the overall amount of perimysial connective tissue showed no significant difference in both groups (p=0.478). Free muscle transplantation in a one-stage approach offers similar functional results in comparison to the two-stage approach. Although muscle grafts of the one-stage transplantation underwent a longer period of denervation similar contents of perimysial connective tissue could be observed.

Animals↗

PubMed2006

Evaluation of a single-locus real-time polymerase chain reaction as a screening test for specific detection of methicillin-resistant Staphylococcus aureus in ICU patients.

The aim of the present study was to determine the diagnostic value of a single-locus real-time polymerase chain reaction (PCR) recently proposed for rapid detection of methicillin-resistant Staphylococcus aureus (MRSA) from clinical samples (IDI-MRSA; Infectio Diagnostic, Sainte-Foy, Québec, Canada). This test, which was developed on the basis of studies of the sequence analysis of the mecA gene carried by staphylococcal cassette chromosome mec (SCCmec), was used to screen nasal swabs of 320 intensive care unit (ICU) patients at admission. The results were compared with those of conventional culture of swabs from several body sites. When compared with culture of swabs from the nose, throat, and wounds, the diagnostic values of the real-time PCR test from nasal swabs were as follows: 92.3% sensitivity, 98.6% specificity, 75.0% positive predictive value, and 99.6% negative predictive value. Fifteen (4.7%) samples could not be evaluated because the PCR reaction was inhibited, even after the samples were frozen and thawed for retesting. Culture of nasal swabs showed that 78 of the patients were colonized with methicillin-susceptible S. aureus. Unexpectedly, 4 (5.1%) of these samples gave false-positive results in the IDI-MRSA. These isolates were all single clones, as shown by pulsed-field gel electrophoresis and spa typing. Reliable results were obtained with the IDI-MRSA assay, even in a patient population with a low prevalence (approximately 4%) of MRSA and even when compared with swabs of different body sites. Nevertheless, further work is needed to reduce the inhibition rate of the PCR and to explain why false-positive results were obtained with methicillin-susceptible S. aureus.

Bacterial Proteins↗

PubMed2006

[Is a differentiated treatment depending on the degree of severity justified in cubital tunnel syndrome?].

BACKGROUND: Cubital tunnel syndrome is the second most common chronic nerve entrapment of the upper extremity, yet both diagnosis and staging of the severity of the progression of the disease rely mostly on the keen observation and interpretation of clinical signs and symptoms. To be valid, a staging system must correlate well with the known pathophysiological mechanisms of chronic nerve compression, have objective parameters available to quantify differing degrees of sensory and motor dysfunction, and finally must allow different therapeutic consequences. PATIENTS AND METHODS: In this study we have prospectively evaluated 44 patients who presented with the clinical diagnosis of cubital tunnel syndrome. Quantitative Sensory Testing was performed using a computer-assisted testing system (Sensory-Management Services L. L. C., Baltimore). Classic two-point discrimination, one point pressure threshold, pinch and grip strength were measured. Progression of disease was staged according to the gradual loss of sensory and motor function. After an average of 15 months postoperatively, ulnar nerve function was re-evaluated using the same parameters and outcome measured with the modified Bishop rating scale. RESULTS: The results of this study indicate that 100 % of patients in the moderate group had a good and excellent outcome, whereas only 74 % of the severe group were rated as good and excellent with 17 % moderate and 9 % poor outcome.

Adult↗

PubMed2006

Transtheoretical Model and substance use in HIV-positive youth.

The purpose of the study was to test constructs of the Transtheoretical Model (TTM) for predicting alcohol and other drug use in HIV-positive youth (ages 16-25). Questionnaires and interviews about alcohol and other drug use, stage of change, self-efficacy, emotional distress and social support were obtained from 64 HIV-positive youth. Structural equation modeling with standard errors determined by methods appropriate to small samples, demonstrated that self-efficacy mediated the relationship between stage of change and alcohol use and between social support and alcohol use. The same pattern of results emerged for marijuana use. The models predicted 47% of the variance in alcohol use and 69% of the variance in marijuana use. Results supported the TTM and highlight the potential of interventions that seek to boost self-efficacy and social support specific to reducing substance use.

Adolescent↗

PubMed2006

Psychosocial factors and treatment adherence in paediatric HIV/AIDS.

A social ecological model provides a promising framework for understanding the individual, family, and societal factors contributing to non-adherence to treatment of paediatric HIV. This study explored which factors relevant to this model are associated with caregivers' adherence and child health outcomes. A cross-sectional design was utilized to assess relationships among current individual, familial, extra-familial factors, caregiver adherence, and viral load. Data were collected from 43 caregivers, and viral load data were obtained from the medical records of their HIV+ children. Caregiver drug and alcohol use and HIV+ status were associated with non-adherence and elevated viral load. Negative outcome expectancy was associated with lower adherence but was not significant in the multivariate analyses. Family factors were not significant, but these measures had low reliability in this sample. Extra-familial factors such as dissatisfaction with medical specialty care and more stressful life events were not directly associated with adherence but were related to increased caregiver substance use. Results of this first study to explore multiple predictors of adherence and health outcomes in paediatric HIV require replication with larger samples, but findings suggest caregiver characteristics that place children at risk for disease progression due to poor adherence to treatment.

Adolescent↗

PubMed2005

Lactate: early predictor of morbidity and mortality in patients with severe burns.

A severe burn results in a devastating and unique derangement called burn shock. Historically, resuscitation has been guided by a combination of basic laboratory values, invasive monitoring and clinical findings, but the optimal guide to the endpoint of resuscitation remains controversial. One-hundred sixty-six patients, who were admitted to our Burn Unit, were enrolled in this prospective study. Resuscitation of these patients was undertaken according to the current standard of care. Parkland formula was used as a first approximation of acquired fluid administration rates and fluid administration was adapted in order to meet clinical needs. The aim of this study was to evaluate if plasma lactate is a useful parameter to estimate the severity of a burn shock. One of the main objectives was to evaluate, if the lactate clearance adds additional information. The results of this study indicate that the initial lactate level (Day 0) is a useful parameter to separate survivors from non-survivors. Moreover, a significant marker of shock and resuscitation was observed in evaluating the lactate clearance on Day 1. A better chance of survival occurs when resuscitation results in a lactate clearance to normal values within 24h (survival was 68% if the lactate reached normal values, compared to 32% if the lactate level remained supra-normal). In summary, we believe that measuring lactate and lactate clearance may help to detect critically injured patients either for adequacy of treatment, or selection of other therapeutic options.

Biomarkers↗

PubMed2005

Inflammatory cytokines interleukin-6 and oncostatin m induce plasminogen activator inhibitor-1 in human adipose tissue.

BACKGROUND: Adipose tissue is a prominent source of plasminogen activator inhibitor-1 (PAI-1), the primary physiological inhibitor of plasminogen activation. Increased PAI-1 expression acts as a cardiovascular risk factor, and plasma levels of PAI-1 strongly correlate with body mass index (BMI). Elevated serum levels of interleukin-6 (IL-6), an inflammatory cytokine and a member of the glycoprotein 130 (gp130) ligand family, are found in obese patients and might indicate low-grade systemic inflammation. Another gp130 ligand, oncostatin M (OSM), upregulates PAI-1 in cardiac myocytes, astrocytes, and endothelial cells. We used tissue explants and primary cultures of preadipocytes and adipocytes from human subcutaneous and visceral adipose tissue to investigate whether IL-6 and OSM affect PAI-1 expression in fat. METHODS AND RESULTS: Human subcutaneous and visceral adipose tissue responded to treatment with IL-6 and OSM with a significant increase in PAI-1 production. Human preadipocytes were isolated from subcutaneous and visceral adipose tissue. Adipocyte differentiation was induced by hormone supplementation. All cell types expressed receptors for IL-6 and OSM and produced up to 12-fold increased levels of PAI-1 protein and up to 9-fold increased levels of PAI-1 mRNA on stimulation with IL-6 and OSM. AG-490, a janus kinase/signal transducer and activator of transcription inhibitor, abolished the OSM-dependent PAI-1 induction almost completely. CONCLUSIONS: We have for the first time established a link between the gp130 ligands, the proinflammatory mediators IL-6 and OSM, and the expression of PAI-1 in human adipose tissue. Thus, we speculate that IL-6 and OSM, by upregulating PAI-1 in adipose tissue, can contribute to the increased cardiovascular risk of obese patients.

Adipose Tissue↗

PubMed2005

Are there ethnic differences of facial movements between Europeans and Asians?

PURPOSE: Due to the widespread use of Free Functional Muscle Transplant (FFMT) around the world to reanimate the paralysed face, it is important to be aware of ethnic differences in facial movements. METHODS AND MATERIAL: Participants in this study were born in Taiwan (n=24) and Austria (n=24). Analyses were conducted applying the digitised three-dimensional video-analysis system. All 48 subjects have never undergone any treatments in the face nor did they have previous histories of craniofacial anomalies. RESULTS: In general, Europeans were observed to have larger facial movements than Asians, from 0.4 mm (e.g. 5.7%) up to 3.9 mm (e.g. 30.3%), on average 1.3 mm+/-0.82 SD (e.g. 20.6%). Particularly the eyebrow, nose and mouth regions show statistically significant larger excursions on average 1.4 mm (e.g. 19.9%), 1.3 mm (e.g. 34.6%) and 3.0 mm (e.g. 30.3%). One exception is in the eye region, where Asians have a larger excursion (1.4 mm, e.g. 15.8%) of the eyelids, due to the larger distances between the upper and lower eyelids in the rest position. CONCLUSION: Europeans have generally larger facial movements than Asians. Particularly the eyebrow, nose and mouth regions show statistically significant larger excursions; exception must be made to the eye region, where Asians have a larger excursion of the eyelids. This is the first step to gather essential information about the ethnical differences in facial movements, a factor that should be considered as FFMT is becoming more popular worldwide.

Adult↗

PubMed2005

The Viennese culture method: cultured human epithelium obtained on a dermal matrix based on fibroblast containing fibrin glue gels.

The aim of this study was to develop a new keratinocyte culture system on a dermal equivalent suitable for skin wound closure. Our dermal matrix is based on a fibrin glue gel containing live human fibroblast (from human foreskin). Keratinocytes obtained from primary culture according to the Rheinwald and Green method, were seeded on to the gel. In all cases, the keratinocytes plated on the dermal equivalent grew to confluence and stratified epithelium was obtained. After 10 days an irregular multilayer could be observed. The cells showed active interaction with the fibrin support, presenting as cell formations projecting into the matrix. After 15 days a regular epithelial sheet consisting of three to four layers of cells was formed. A limiting membrane demarcating the keratinocytes from the fibrin matrix was discernible. Squamous differentiation similar to Strata reticulare and corneum found in vivo could be observed. Nuclei of basal cells were regularly spaced from each other and the chromatin was of homogeneous appearance without prominent nucleoli. The last time point (20 days) showed signs of disintegration of the epithelial sheet. A basement membrane-like structure could not be seen any more. Detachment of the basal cells was associated with subepithelial vacuoles. Basal cells contained irregular nuclei. Therefore, we conclude that 15 days of culture were optimal for the generation of a keratinocyte layers with signs of differentiation; this new culture system could be an important step forward in covering severely burned patients due to a number of advantages, as for example a large expansion factor, the shortening of the optimal culture time to 15 days, the usage of commercially available fibrin glue gels and the versatile manipulation of composite cultures.

Adult↗

PubMed2005

[Significance of electroneurographic parameters in the diagnosis of chronic neuropathy of the ulnar nerve at the elbow].

PURPOSE: Ulnar neuropathy at the elbow (UNE) is the second most common compressive neuropathy of the upper limb. Besides clinical evaluation, electrodiagnostic studies are usually applied to confirm the diagnosis. However, there are certain limitations to the diagnosis of UNE by electrodiagnostic studies. In a prospectively performed study we compared the diagnostic value of the electrodiagnostic parameters to the symptoms and the clinical parameters for different degrees of sensory and motor dysfunctions. METHODS AND MATERIALS: Between 2001 and 2003, 38 patients (mean age 53.9 +/- 8.8 years, 19 men and 19 women) were treated at our institution for UNE. For 34 (89%) patients complete electrodiagnostic studies were performed and for 25 patients there was also an electrodiagnostic evaluation of the asymptomatic contralateral arm. According to the symptoms and clinical parameters (grip and pinch grip, two-point discrimination), the patients were assigned to three stages (mild, moderate, and severe). Electrophysiological measurements for each stage were compared with one another. The diagnostic value for each electrophysiological parameter was evaluated in comparison to the normal limits of the "Deutsche Gesellschaft für Neurologie (DGN)" and the "American Association of Electrodiagnostic Medicine (AAEM)". RESULTS: In the 34 symptomatic arms the mean values for motor nerve conduction were: conduction velocity (MNCV) = 41.2 +/- 11.6 m/s; velocity change above-to-below-elbow segment = 12.8 +/- 7.7 m/s; CMAP = 9224 +/- 5514 microV; dL = 3.24 +/- 0.82 mg. For the moderate stages of nerve compression (n = 11) the mean values are: MNCV = 42.5 +/- 12.7; velocity change MNCV = 13.2 +/- 6.8; CMAP = 11 890 +/- 4750; dL = 2.97 +/- 0.57; for severe nerve compression (n = 23): MNCV = 40.6 +/- 11.0; change MNCV = 12.7 +/- 8.3; CMAP = 7948 +/- 5358; dL = 3.37 +/- 0.8. The difference for each parameter between the symptomatic and asymptomatic contralateral arm was statistically significant (p < 0.05) as it was for the difference of the parameters of the group with severe nerve compression in comparison to the asymptomatic arm. In the comparison of the moderate stage group with the asymptomatic arm there was only a significant difference for MNCV and there was no significant difference between the moderate and the severe group. In our study the calculated sensitivities for the electrodiagnostic studies were 76% for all symptomatic arms, 64% for the moderate group, and 83% for the severe nerve compression group. In all patients the MNCV was the most sensitive parameter. CONCLUSION: Electrodiagnostic studies were only able to reveal 3/4 of all patients with an affection of the ulnar nerve and only 2/3 of the patients with a moderate stage of ulnar nerve compression. Although important for the further therapy, a differentiation between a moderate and severe degree of nerve compression was not possible.

Chronic Disease↗

PubMed2005

Intraoperative imaging of the brachial plexus by high-resolution ultrasound.

The authors attempted to perform direct high resolution ultrasound imaging of the intraneural ultrastructure of the brachial plexus for intraoperative image guidance in brachial plexus surgery. The brachial plexuses of four fresh-frozen cadaver specimens were surgically exposed in a standard approach used in routine brachial plexus surgery to undergo direct ultrasound examination using a 15 MHz SonoCT scanhead. By placing the scanhead directly onto the epineurium, all components of the brachial plexus were directly visualized in an axial plane and compared with histologic findings. The internal neural structure at different levels could be visualized in high resolution, showing the specific fascicular pattern. The histologic processing revealed good correlation with the intraneural topography demonstrated on ultrasound. In the study, high resolution ultrasound examination of the brachial plexus showed substantial details of the ultrastructure of neural tissue, which may play a role in intraoperative image guidance in the surgical treatment of patients with brachial plexopathy.

Brachial Plexus↗

PubMed2005

Measuring adherence to treatment of paediatric HIV/AIDS.

Parent, child, physician report and pill counts were used to measure adherence in paediatric HIV. Relationships to viral load were assessed. Pill counts were considered invalid. Adherence measures did not correlate with one another. Physicians reported lower adherence than parents, but parent and physician report correlated with viral load. The clinical and research utility of the various measures are discussed.

Adolescent↗

PubMed2005

How should COPD patients exercise during respiratory rehabilitation? Comparison of exercise modalities and intensities to treat skeletal muscle dysfunction.

BACKGROUND: Physical exercise is an important component of respiratory rehabilitation because it reverses skeletal muscle dysfunction, a clinically important manifestation of COPD associated with reduced health-related quality of life (HRQL) and survival. However, there is controversy regarding the components of the optimal exercise protocol. A study was undertaken to systematically evaluate and summarise randomised controlled trials (RCTs) comparing different exercise protocols for COPD patients. METHODS: Six electronic databases, congress proceedings and bibliographies of included studies were searched without imposing language restrictions. Two reviewers independently screened all records and extracted data on study samples, interventions and methodological characteristics of included studies. RESULTS: The methodological quality of the 15 included RCTs was low to moderate. Strength exercise led to larger improvements of HRQL than endurance exercise (weighted mean difference for Chronic Respiratory Questionnaire 0.27, 95% CI 0.02 to 0.52). Interval exercise seems to be of similar effectiveness as continuous exercise, but there are few data on clinically relevant outcomes. One small RCT which included patients with mild COPD compared the effect of high and low intensity exercise (at 80% and 40% of the maximum exercise capacity, respectively) and found larger physiological training effects from high intensity exercise. CONCLUSIONS: Strength exercise should be routinely incorporated in respiratory rehabilitation. There is insufficient evidence to recommend high intensity exercise for COPD patients and investigators should conduct larger high quality trials to evaluate exercise intensities in patients with moderate to severe COPD.

Exercise Therapy↗

PubMed2005

Value of smear and PCR in bronchoalveolar lavage fluid in culture positive pulmonary tuberculosis.

At present, further investigations are needed in patients with suspected pulmonary tuberculosis (TB) and either negative sputum smear or without sputum. The aim of the present study was to analyse the yield of bronchoalveolar lavage fluid (BALF) smear and PCR in patients with confirmed pulmonary TB. Patients with a positive culture for Mycobacterium tuberculosis complex in sputum or BALF were analysed over 5 yrs. In total, 90 out of 230 (39%) patients with culture-positive pulmonary TB had a positive sputum smear, and 120 patients underwent bronchoscopy. BALF smear was positive in 56 (47%), BALF PCR in 93 (78%) patients, and BALF smear and/or PCR was positive in 83%. In total, 71 patients who underwent bronchoscopy and had complete clinical records were further analysed. BALF (smear or Mycobacterium tuberculosis complex-PCR) allowed a rapid diagnosis in 10 (59%) out of 17 patients who had a negative sputum smear, and 49 (91%) out of 54 patients without sputum production. Of these 71 patients, 12 (17%) were only culture positive. Rapid diagnosis of pulmonary TB by smear and/or PCR was made in 190 out of 210 patients (90%) in sputum or BALF. In conclusion, combined use of bronchoalveolar lavage fluid smear and Mycobacterium tuberculosis complex-PCR has a good diagnostic yield in patients with sputum smear-negative tuberculosis or without sputum production.

Adult↗

PubMed2004

Bulk glasses and ultrahard nanoceramics based on alumina and rare-earth oxides.

Although often regarded as a network-former in conventional silicate glasses, Al(2)O(3) alone cannot be obtained as a bulk glass. Until now, glasses comprising continuously linked [AlO(x)] polyhedra have been prepared in only a few systems under very fast cooling conditions, which limits their dimensions to a few millimetres. Yet it is desirable to prepare bulk, or monolithic, alumina-rich glasses, with the prospect of superior mechanical, chemical and optical properties. Here we report a novel process for preparing very-high-alumina glasses and nanoscale glass-ceramics. Fully dense bulk articles in net shape are obtained through viscous sintering of glass microbeads. Additional heat treatment of the consolidated glasses leads to fully crystallized transparent glass-converted nanoceramics with a hardness similar to that of alumina. This method avoids the impracticably high applied pressures (more than 1 GPa) that have been required in most cases to prepare nanocrystalline ceramics by sintering, owing to the concurrent nature of densification and grain growth under pressureless conditions. The reported techniques can be extended to form glasses and nanoceramics in other oxide systems that do not include a conventional glass-forming component.

Journal Article↗