Drusen and RPE atrophy automated quantification by optical coherence tomography in an elderly population

PURPOSE

Correlate OCT-derived measures of drusen and retinal pigment epithelium (RPE) atrophy areas (RAs) with demographic features in an elderly population.

PATIENTS AND METHODS

Subjects aged 50 years and older underwent Cirrus OCT scanning. Drusen area and volume were obtained from the macula within a central circle (CC) of 3 mm and a surrounding perifoveal ring (PR) of 3-5 mm, using the RPE analysis software (6.0). RA measurements were generated for the 6 × 6 mm(2) retinal area. Gender, age, smoking status, and systolic blood pressure (SBP) were considered.

RESULTS

A total of 434 eyes were included. RA was larger in women (0.63±0.16 vs 0.26±0.08 mm(2), P=0.05) and with increasing age. The PR drusen area increased with increasing age (P<0.001), whereas the CC drusen area remained stable after the age of 70 years (0.25±0.06 mm(2) for ages 70-79 years and 0.25±0.07 mm(2) for ages >80 years). Drusen volume in the CC was smaller after the age of 80 years (0.009±0.003 mm(3)) compared with the 70- to 79-year-old group (0.02±0.008 mm(3)). Drusen measurements were similar between smokers and nonsmokers, but the PR drusen area (0.29 mm(2), P=0.05) and volume (0.40 mm(3), P=0.005) were correlated with years smoked. RA (0.24 mm(2), P=0.10), PR drusen area (0.29 mm(2), P=0.05), and volume (0.40 mm(3), P=0.005) were found to be directly associated with SBP. There was a high correlation between the eyes of the same subject.

CONCLUSION

OCT-based automated algorithms can be used to analyze and describe drusen and geographic atrophy burden in such population-based studies of elderly patients.

TNF-α and LPS activate angiogenesis via VEGF and SIRT1 signalling in human dental pulp cells

AIM

To assess whether SIRT1 and VEGF are responsible for tumour necrosis factor-α (TNF-α) and lipopolysaccharide (LPS)-induced angiogenesis and to examine the molecular mechanism(s) of action in human dental pulp cells (HDPCs).

METHODOLOGY

Immortalized HDPCs obtained from Prof. Takashi Takata (Hiroshima University, Japan) were treated with LPS (1 μg mL(-1) ) and TNF-α (10 ng mL(-1) ) for 24 h. mRNA and protein levels were examined by RT-PCR and Western blotting, respectively. Migration and tube formation were examined in human umbilical vein endothelial cells (HUVECs). The data were analysed by one-way anova. Statistical analysis was performed at α = 0.05.

RESULTS

LPS and TNF-α upregulated VEGF and SIRT1 mRNA and protein levels. Inhibition of SIRT1 activity by sirtinol and SIRT1 siRNA or inhibition of the VEGF receptor by CBO-P11 significantly attenuated LPS + TNF-α-stimulated MMPs production in HDPCs, as well as migration and tube formation in HUVECs (P < 0.05). Furthermore, sirtinol, SIRT1 siRNA and CBO-P11 attenuated phosphorylation of Akt, extracellular signal-regulated kinase (ERK), p38 and c-Jun N-terminal kinase (JNK) and the nuclear translocation of NF-κB p65. Pre-treatment with inhibitors of p38, ERK, JNK, PI3K and NF-κB decreased LPS + TNF-α-induced VEGF and SIRT1 expression, MMPs activity in HDPCs and angiogenesis (P < 0.05) in HUVECs.

CONCLUSIONS

TNF-α and LPS led to upregulation of VEGF and SIRT1, and subsequent upregulation of MMP-2 and MMP-9 production, and promote angiogenesis via pathways involving PI3K, p38, ERK, JNK and NF-κB. The results suggest that inhibition of SIRT1 and VEGF might attenuate pro-inflammatory mediator-induced pulpal disease.

GNAS mutation as an alternative mechanism of activation of the Wnt/β-catenin signaling pathway in gastric adenocarcinoma of the fundic gland type

Gastric adenocarcinoma of the fundic gland type (GAFG) is a rare variant of gastric tumor. We have recently reported the frequent accumulation of β-catenin in GAFGs and showed that approximately half of the cases studied harbored at least 1 mutation in CTNNB1/AXINs/APC, leading to the constitutive activation of the Wnt/β-catenin pathway. However, the mechanisms of Wnt signaling activation in the remaining cases are unknown. Accumulating evidence showed that the activating mutation in GNAS promotes tumorigenesis via the activation of the Wnt/β-catenin pathway or the ERK1/2 MAPK pathway. Therefore, we analyzed the mutations in GNAS (exons 8 and 9) and in KRAS (exon 2) in 26 GAFGs. Immunohistochemistry revealed nuclear β-catenin expression in 22 of 26 GAFGs, and 10 (38.5%) of 26 cases harbored at least 1 mutation in CTNNB1/AXINs/APC. Activating mutations in GNAS were found in 5 (19.2%) of 26 GAFGs, all of which harbored R201C mutations. Activating mutations in KRAS were found in 2 (7.7%) of 26 GAFGs, and both of these also contained GNAS activating mutations. Four of 5 cases with GNAS mutation showed nuclear β-catenin expression, and presence of GNAS mutation was associated with β-catenin nuclear expression (P = .01). Furthermore, 3 of these 4 cases did not harbor mutations in CTNNB1, APC, or AXINs, suggesting that mutations in the Wnt component genes and those in GNAS occur almost exclusively. These results suggest that GNAS mutation might occur in a small subset of GAFG as an alternative mechanism of activating the Wnt/β-catenin signaling pathway.

The influence of surgical factors on dislocation of the meniscal bearing after Oxford medial unicompartmental knee replacement: a case-control study

The aim of this study was to evaluate the risk factors for dislocation of the bearing after a mobile-bearing Oxford medial unicompartmental knee replacement (UKR) and to test the hypothesis that surgical factors, as measured from post-operative radiographs, are associated with its dislocation From a total of 480 UKRs performed between 2001 and 2012, in 391 patients with a mean age of 66.5 years (45 to 82) (316 female, 75 male), we identified 17 UKRs where bearing dislocation occurred. The post-operative radiological measurements of the 17 UKRs and 51 matched controls were analysed using conditional logistic regression analysis. The post-operative radiological measurements included post-operative change in limb alignment, the position of the femoral and tibial components, the resection depth of the proximal tibia, and the femoral component-posterior condyle classification. We concluded that a post-operative decrease in the posterior tibial slope relative to the pre-operative value was the only significant determinant of dislocation of the bearing after medial Oxford UKR (odds ratio 1.881; 95% confidence interval 1.272 to 2.779). A post-operative posterior tibial slope < 8.45° and a difference between the pre-operative and post-operative posterior tibial slope of > 2.19° may increase the risk of dislocation.

Complete traumatic backout of the blade of proximal femoral nail antirotation: a case report

This article presents a rare case of traumatic complete expulsion of the helical blade after successful treatment of an intertrochanteric fracture with proximal femoral nail antirotation (PFNA). A 94-year-old woman sustained an intertrochanteric fracture of the left femur. Fracture fixation was performed by using PFNA-II. At six months FU, the patient presented with pain at the proximal lateral left thigh after she had fallen. A protrusion was noted. Radiographs showed a complete expulsion of the helical blade with a healed intertrochanteric fracture. The PFNA-II was removed and a cemented bipolar hemiarthroplasty was performed. At 5 months after surgery, the patient was able to walk with a walker without pain. Traumatic complete expulsion of the blade should be considered as a possible complication of PFNA/PFNA-II.

Comparison of the incidence between tuberculosis and nontuberculous mycobacterial disease after gastrectomy

PURPOSE

Gastrectomy is a well-known risk factor for tuberculosis (TB). However, little data are available regarding the relationship between gastrectomy and the risk of nontuberculous mycobacterial (NTM) disease. Here, we investigated the incidence of TB and NTM lung disease in gastrectomized patients.

METHOD

New cases of TB and NTM lung infection or disease were examined among patients who had undergone gastrectomy due to gastric cancer from 2003 to 2009 at a tertiary referral hospital in South Korea. Annualized incidence rates for cases were compared with those of the general population.

RESULTS

This study included a total of 2,684 patients. New mycobacterial cases were found in 41 patients. Cases of TB and NTM lung infection were 35 (85 %) and 6 (15 %) including 2 NTM lung disease cases, respectively. Annualized crude incidence rates for TB, NTM lung infection, and NTM lung disease were 327/100,000, 56/100,000, and 19/100,000, respectively. The age-standardized incidence rate of TB was significantly higher in gastrectomized patients than in the general population. However, the standardized incidences of NTM lung infection and disease were not significantly different from those of non-gastrectomized patients. Patients with NTM lung infection frequently exhibited comorbid chronic lung disease, while those with TB were more frequently found to have fibronodular lesions on preoperative chest radiography.

CONCLUSIONS

Gastrectomy does not appear to increase the risk of NTM lung disease. However, NTM lung infection or disease should be considered as a differential diagnosis of pulmonary TB in gastrectomized patients accompanying chronic lung disease.

Validation of international consensus guidelines for the resection of branch duct-type intraductal papillary mucinous neoplasms

Background

Classifications of intraductal papillary mucinous neoplasm (IPMN) remain ambiguous, especially for the mixed type. Factors predicting malignancy remain unclear. The aim of this study was to evaluate the usefulness of factors predicting malignancy in the new international consensus guidelines for resection of branch duct-type (BD)-IPMN and to compare them with those in the previous version.

Methods

A prospectively collected database of patients with biopsy-proven BD-IPMN was analysed to compare factors between the first and second consensus guidelines, particularly as predictors of malignancy.

Results

Of 350 patients with BD-IPMN, sensitivity (0·724) and balanced accuracy (0·751) of the second guidelines were superior to those (0·639 and 0·730) in the first version at the expense of slightly reduced specificity (0·779 versus 0·822 for the first version) by random forest models. Multiple logistic regression analysis showed that main pancreatic duct dilatation greater than 5 mm (hazard ratio (HR) 4·54, 95 per cent confidence interval 2·45 to 8·41; P &lt; 0·001), mural nodules (HR 6·27, 3·27 to 12·01; P &lt; 0·001) and carbohydrate antigen 19–9 level above 37 units/ml (HR 4·03, 1·83 to 8·90; P = 0·001) were independent predictors of BD-IPMN malignancy.

Conclusion

The new consensus guidelines provide better sensitivity, performance of factors predicting malignancy, and balanced accuracy in the diagnosis of BD-IPMN malignancy. Size alone was limited in predicting malignancy. Variability in clinical significance of the individual factors associated with a risk of malignancy indicates the need for a tailored approach in the management of patients with BD-IPMN.

Dopaminergic manipulations and its effects on neurogenesis and motor function in a transgenic mouse model of Huntington's disease

Huntington's disease (HD) is an inherited neurodegenerative disorder that is classically defined by a triad of movement and cognitive and psychiatric abnormalities with a well-established pathology that affects the dopaminergic systems of the brain. This has classically been described in terms of an early loss of dopamine D2 receptors (D2R), although interestingly the treatments most effectively used to treat patients with HD block these same receptors. We therefore sought to examine the dopaminergic system in HD not only in terms of striatal function but also at extrastriatal sites especially the hippocampus, given that transgenic (Tg) mice also exhibit deficits in hippocampal-dependent cognitive tests and a reduction in adult hippocampal neurogenesis. We showed that there was an early reduction of D2R in both the striatum and dentate gyrus (DG) of the hippocampus in the R6/1 transgenic HD mouse ahead of any overt motor signs and before striatal neuronal loss. Despite downregulation of D2Rs in these sites, further reduction of the dopaminergic input to these sites by either medial forebrain bundle lesions or receptor blockade using sulpiride was able to improve both deficits in motor performance and adult hippocampal neurogenesis. In contrast, a reduction in dopaminergic innervation of the neurogenic niches resulted in impaired neurogenesis in healthy WT mice. This study therefore provides evidence that D2R blockade improves hippocampal and striatal deficits in HD mice although the underlying mechanism for this is unclear, and suggests that agents working within this network may have greater effects than previously thought.

Biosorption of uranium(VI) from aqueous solution by biomass of brown algae Laminaria japonica

The uranium(VI) adsorption efficiency of non-living biomass of brown algae was evaluated in various adsorption experimental conditions. Several different sizes of biomass were prepared using pretreatment and surface-modification steps. The kinetics of uranium uptake were mainly dependent on the particle size of the prepared Laminaria japonica biosorbent. The optimal particle size, contact time, and injection amount for the stable operation of the wastewater treatment process were determined. Spectroscopic analyses showed that uranium was adsorbed in the porous inside structure of the biosorbent. The ionic diffusivity in the biomass was the dominant rate-limiting factor; therefore, the adsorption rate was significantly increased with decrease of particle size. From the results of comparative experiments using the biosorbents and other chemical adsorbents/precipitants, such as activated carbons, zeolites, and limes, it was demonstrated that the brown algae biosorbent could replace the conventional chemicals for uranium removal. As a post-treatment for the final solid waste reduction, the ignition treatment could significantly reduce the weight of waste biosorbents. In conclusion, the brown algae biosorbent is shown to be a favorable adsorbent for uranium(VI) removal from radioactive wastewater.

Gender and age differences in the impact of overweight on obesity-related quality of life among Korean adults

SUMMARY

OBJECTIVE

To investigate gender and age difference in impact of overweight on health-related quality of life (HRQOL) among Korean adults.

METHODS

Cross-sectional obesity-related quality of life (QOL) scores were measured by a Korean obesity-related QOL scale (KOQOL) from 448 Korean adults aged 20-80 years. A body mass index (BMI) was categorized with normal-weight as BMI < 23 kg/m(2), overweight as BMI ≥ 23 kg/m(2) based on the alternative cutoff points for Asians. Each gender was respectively stratified by median age, 45 years for men and 50 years for women, to examine the obesity-related QOL by age groups.

RESULTS

Women had a poorer obesity-related QOL compared to men (p < 0.001). In the younger age group, overweight women had a poorer obesity-related QOL compared with normal-weight women (p < 0.001), however normal-weight and overweight men showed no difference in obesity-related QOL. In the older age group, overweight men showed better QOL on the domains of work-related and psychosocial health than those for normal-weight men, but overweight women still suffered from work-related and routine life QOL.

CONCLUSIONS

This study showed the impact of overweight on obesity-related QOL was different for gender and age group. We should consider the results to manage weight in overweight persons.

Abstract P1-01-19: Role of axillary clearance with tumor positive sentinel node in mastectomy group: Is the results of ACOSOG Z0011 trial adaptable to mastectomy patient?

Background: Recent data from ACOSOG Z0011 trial or AMAROS trial suggest that axillary lymph node dissection(ALND) may be unnecessary for patients with positive sentinel lymph node biopsy(SLNB) receiving breast conserving surgery(BCS) with irradiation. However, consensus statements and guidelines until recently recommended that patients with mastectomy and tumor positive sentinel node undergo completion ALND. In this preliminary study, we compared these patients who did not undergo ALND with the patients who received BCS with SLNB only and irradiation and we analyzed the locoregional recurrence rate to show no differences of outcomes between two groups.

Method: We identified 6,163 women with invasive breast cancer who underwent surgical resection at the National Cancer Center (Goyang,Gyeonggi-do,Korea) between January 2000 to December 2011. Clinico-pathological data obtained from prospective collecting medical database of our institution were analyzed retrospectively. The mastectomy with positive SLNB group was 47 patients and BCS with positive SLNB and irradiation group was 172 patients. The primary end point was loco-regional recurrence rate.

Result : Clinical and tumor characteristics were similar between two groups except T stage and receptor status. The mean tumor size was 5.5cm with mastectomy group and 3.5cm with BCS group. The median number of nodes removed was three. There was not a single case of locoregional recurrence in both groups. At a median follow-up of 53.5 months (last follow-up, May 2013), 5-year overall survival was 85.7% with mastectomy and 97.3% with BCS group.

Conclusion : In our study, there was no case of locoregional recurrence as above. This results lend weight to the argument that SLNB without ALND may be reasonable management for selected patients with appropriate surgery and adjuvant systemic therapy. This study can be regarded as a preliminary study with a sufficient value despite of the prognosis showed some statistical differences between two groups. It resides in the difference of initial stage of patients of two groups. We will present additional data compared with the mastectomy with axillary clearance group at the meeting.

Acknowledgement This work was supported by grant from the National Cancer Center Korea (1210331-2).

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-01-19.

Afamin stimulates osteoclastogenesis and bone resorption via Gi-coupled receptor and Ca2+/calmodulin-dependent protein kinase (CaMK) pathways

BACKGROUND

Afamin was recently identified as a novel osteoclast-derived coupling factor that can stimulate the in vitro and in vivo migration of preosteoblasts.

AIM

In order to understand in more detail the biological roles of afamin in bone metabolism, we investigated its effects on osteoclastic differentiation and bone resorption.

METHODS

Osteoclasts were differentiated from mouse bone marrow cells. Tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells were considered as osteoclasts, and the resorption area was determined by incubating the cells on dentine discs. The intracellular cAMP level was determined using a direct enzyme immunoassay. Signaling pathways were investigated using western blot and RT-PCR. Recombinant afamin was administered exogenously to bone cell cultures.

RESULTS

Afamin stimulated both osteoclastogenesis and in vitro bone resorption. Consistently, the expressions of osteoclast differentiation markers were significantly increased by afamin. Although afamin mainly affected the late-differentiation stages of osteoclastogenesis, the expression levels of receptor activator of nuclear factor-κB ligand (RANKL)-dependent signals were not changed. Afamin markedly decreased the levels of intracellular cAMP with reversal by pretreatment with pertussis toxin (PTX), a specific inhibitor of Gi-coupled receptor signaling. In addition, PTX almost completely blocked afamin-stimulated osteoclastogenesis. Furthermore, pretreatment with KN93 and STO609 - Ca2+/cal - mo dulin-dependent protein kinase (CaMK) and CaMK kinase inhibitors, respectively - significantly prevented decreases in the intracellular cAMP level by afamin while attenuating afamin-stimulated osteoclastogenesis.

CONCLUSION

Afamin enhances osteoclastogenesis by decreasing intracellular cAMP levels via Gi-coupled receptor and CaMK pathways.

Ankle fractures have features of an osteoporotic fracture

We report the bone attenuation of ankle joint measured on computed tomography (CT) and the cause of injury in patients with ankle fractures. The results showed age- and gender-dependent low bone attenuation and low-energy trauma in elderly females, which suggest the osteoporotic features of ankle fractures.

INTRODUCTION

This study was performed to investigate the osteoporotic features of ankle fracture in terms of bone attenuation and cause of injury.

METHODS

One hundred ninety-four patients (mean age 51.0 years, standard deviation 15.8 years; 98 males and 96 females) with ankle fracture were included. All patients underwent CT examination, and causes of injury (high/low-energy trauma) were recorded. Mean bone attenuations of the talus, medial malleolus, lateral malleolus, and distal tibial metaphysis were measured on CT images. Patients were divided into younger age (<50 years) and older age (≥50 years) groups, and mean bone attenuation and causes of injury were compared between the two groups in each gender.

RESULTS

Proportion of low-energy trauma was higher in the older age group than in the younger age group, but the difference was only significant in female gender (p = 0.011). The older age group showed significantly lower bone attenuation in the talus, medial malleolus, lateral malleolus, and distal tibial metaphysis than the younger age group in both genders. The older age group showed more complex pattern of fractures than the younger age group. With increasing age, bone attenuations tended to decrease and the difference of bone attenuation between the genders tended to increase in the talus, medial malleolus, lateral malleolus, and distal tibial metaphysis.

CONCLUSIONS

Ankle fracture had features of osteoporotic fracture that is characterized by age- and gender-dependent low bone attenuation. Ankle fracture should not be excluded from the clinical and research interest as well as from the benefit of osteoporosis management.

The novel allele HLA-C*03:04:36 identified by sequence-based typing

The new allele, HLA-C*03:04:36, differs from C*03:04:01:01 by one nucleotide substitution at codon 207 (GGC→GGT).

A phase-1b study of everolimus plus paclitaxel in patients with small-cell lung cancer

BACKGROUND

The mammalian target of rapamycin (mTOR) pathway is dysregulated in small-cell lung cancer (SCLC) and everolimus is an oral mTOR inhibitor.

METHODS

This phase-1b study assessed everolimus safety at the levels of 2.5, 5, or 10 mg once daily in combination with paclitaxel (175 mg m(-2)) once every 3 weeks in previously treated SCLC patients. The primary end point was to determine the maximum tolerated dose of everolimus.

RESULTS

Among 21 enrolled patients, common drug-related adverse events were anaemia, neutropenia, thrombocytopenia, pain, hyperglycemia, and stomatitis. Out of 11 evaluable patients treated with everolimus at the level of 5 mg, 1 patient experienced dose-limiting toxicity (DLT) of grade 4 febrile neutropenia and grade 3 thrombocytopenia. The other two DLTs (grade 4 thrombocytopenia and grade 3 hyperglycemia) occurred in two out of three patients receiving everolimus 10 mg. The overall objective response rate was 28%.

CONCLUSION

Everolimus showed an acceptable safety profile and preliminary antitumour activity at the dose of 5 mg once daily when combined with 3-weekly paclitaxel 175 mg m(-2) in patients with SCLC.

Whitening and antioxidant activities of bornyl acetate and nezukol fractionated from Cryptomeria japonica essential oil

OBJECTIVES

The aim of this study was to investigate the whitening and antioxidant activities of essential oils from Cryptomeria japonica by determining their tyrosinase inhibition, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and superoxide dismutase (SOD)-like activities.

METHODS

Essential oils of C. japonica leaves were extracted with distilled water, and after condensation of volatile constituents, the condensates were extracted with ethyl acetate. Crude essential oils of C. japonica were divided into six fractions by thin layer chromatography and open column chromatography, and their chemical analysis was performed by GC/MS. Major compounds of fractions were composed of kaurene, bornyl acetate, nezukol, (-)-4-terpineol, δ-cadinene, α-terpineol, γ-eudesmol, α-eudesmol and elemol.

RESULTS

For tyrosinase inhibitory activity using two substrates, l-tyrosine and 3,4-dihydroxyphenylalanine (l-DOPA), kaurene, bornyl acetate and nezukol were highly effective. In antioxidant activity, (-)-4-terpinenol and δ-cadinene showed high DPPH radical scavenging activity, and bornyl acetate and nezukol indicated extremely high SOD-like activity.

CONCLUSION

Therefore, bornyl acetate and nezukol fractionated from C. japonica essential oil, which showed highly active whitening and antioxidant activities, have potential applications in cosmeceutical materials.

Evaluation of the efficacy of low-level light therapy using 1072 nm infrared light for the treatment of herpes simplex labialis

BACKGROUND

Recent research has shown that low-level light therapy (LLLT) using 1072 nm infrared light is effective in reducing the duration of herpes simplex labialis (HSL) episodes and enhancing the healing process.

METHODS

This was a prospective, randomized, placebo-controlled, clinical trial to evaluate the efficacy of a 1072 nm light-emitting diode device for the treatment of HSL. In total, 87 patients with recurrent HSL were recruited and randomly divided into two groups. Subjects received a 3-min treatment with either 1072 nm infrared light therapy or placebo (sham) light therapy three times/day for 2 days. The devices used for both groups were identical in appearance and could not be differentiated by volunteers or researchers, and 1072 nm light is invisible to the human eye. The primary endpoint was healing time, which was taken as the time for the HSL lesions to resolve fully and for the underlying skin to become completely re-epithelialized, and the secondary endpoint was lesion crusting.

RESULTS

The median time to healing for the active group was 129 h, compared with 177 h for the control group, which was significant (P = 0.01). There was no difference between the two groups for median time to lesion crusting (P = 0.66).

CONCLUSIONS

Compared with placebo treatment, the treatment of HSL lesions with 1072 nm infrared light significantly reduced healing time.

Analysis of flicker noise for improved data retention characteristics in silicon-oxide-high-k-oxide-silicon flash memory using N2 implantation

In this paper, we fabricate planar-type Silicon-Oxide-High-k-Oxide-Silicon (SOHOS) and the planar-type SOHOS devices with N2 implantation of 3 x 10(15) dose in a tunneling oxide to determine the impact of N2 implantation in the tunneling oxide of a memory device. The N2 implantation device has better retention characteristics than the device with no implantation. In order establish the correlation between N2 implantation and retention characteristic improvement, the low frequency noise (1/f noise) characteristic is investigated. The normalized drain current noise (S(ID)/I(D)2) level of the N2 implantation device is higher than that of the device with no implantation, which means that N2 implantation causes more trap formation near the interface. Considering that N2 implantation does not affect the DC transfer characteristics, such as mobility and sub-threshold slope, this finding indicates that the increase in the 1/f noise level is due to oxide traps rather than to interface traps. Therefore, the retention characteristic improvement in the N2 implantation device can be explained by the generation of higher number of oxide traps and an increase in the potential barrier blocking the leakage path in the tunneling oxide.

Evolution of beam distribution in crossing a Walkinshaw resonance

The third-integer coupling resonance at ν(x)-2ν(z)=ℓ, known as the Walkinshaw resonance, is important in high-power accelerators. We find that, when the betatron tunes ramp through a Walkinshaw resonance the fractional emittance growth (FEG) is a universal function of the effective resonance strength: G(1,-2,ℓ)√[ε(xi)]|Δ(ν(x)-2ν(z))/Δn|(-1/2), where G(1,-2,ℓ) is the resonance strength; ε(xi) and ε(zi) are the initial horizontal and vertical emittances, respectively; and |Δ(ν(x)-2ν(z))/Δn| is the resonance crossing rate per revolution. At large effective resonance strengths, the FEG reaches an asymptotic maximum value (FEG)(max)~2ε(xi)/ε(zi) for ε(xi)>>1/2ε(zi) or ε(zi)/(2ε(xi)) for ε(xi)<<1/2ε(zi). There is little emittance exchange at ε(xi)=1/2ε(z), which can be used to minimize emittance growth in crossing a Walkinshaw resonance.