The sensitivity of vertical-channel 3-D NAND Flash memories to wide-energy spectrum neutrons is investigated as a function of cell depth in the pillars. Errors are found to be less numerous at the ...center of the pillar, mainly due to the impact of top-to-bottom tapering on the electrical characteristics of the floating gate (FG) cells and, to a smaller extent, to a different generation of neutron secondaries as a function of depth.
Electronic switching in phase-change memories Pirovano, A.; Lacaita, A.L.; Benvenuti, A. ...
IEEE transactions on electron devices,
03/2004, Letnik:
51, Številka:
3
Journal Article
Recenzirano
A detailed investigation of electronic switching in chalcogenide-based phase-change memory devices is presented. An original bandgap model consistent with the microscopic structure of both ...crystalline and amorphous chalcogenide is described, and a physical picture of the switching mechanism is proposed. Numerical simulations provide, for the first time, a quantitative description of the peculiar current-voltage curve of a Ge/sub 2/Sb/sub 2/Te/sub 5/ resistor, in good agreement with measurements performed on test devices.
Complications following total knee arthroplasty (TKA) lead to patient morbidity and cost. While acute phase reactants, such as c-reactive protein (CRP) and fibrinogen, have been used to predict ...complications following TKA, the extent and duration of changes in albumin levels following TKA are unknown. It is hypothesized that like CRP and fibrinogen, albumin, and the fibrinogen/albumin ratio (FAR) represent useful measures of the acute phase response (APR) following TKA. The purpose of this study was to describe the longitudinal course of albumin and FAR in healthy patients following TKA, relative to established biomarkers, and examine if the variance in albumin or FAR correlates with patient comorbidities.
This retrospective cohort study of patients undergoing TKA at a tertiary medical center. CRP, fibrinogen, and albumin values were collected pre- and post-operatively. An age-adjusted Charlson comorbidity index (CCI) was utilized as a measure of patient comorbidity status.
The median preoperative albumin value was 4.3 g/dL, which dropped to 3.6 g/dL on postoperative day 1 following TKA. The albumin value returned to 93% of the baseline by postoperative week 2. The course of albumin inversely mirrored the course of CRP (r = -0.41). Median preoperative FAR was 0.087 g/L, which rose to 0.130 g/L by postoperative week 2 and returned to baseline by postoperative week 6. While preoperative FAR strongly correlated with postoperative week 2 values (r = 0.74), there was a weak positive correlation between age-adjusted CCI and pre-operative FAR (r = 0.24) in patients undergoing primary TKA.
Albumin levels follow a predictable postoperative decline that inversely correlates with CRP in healthy patients following TKA. Given the low cost and abundance of laboratories offering albumin levels, direct albumin levels and/or albumin ratios such as FAR may be underutilized biomarkers for monitoring the APR following TKA.
Immediately following a fracture, a fibrin laden hematoma is formed to prevent bleeding and infection. Subsequently, the organized removal of fibrin, via the protease plasmin, is essential to permit ...fracture repair through angiogenesis and ossification. Yet, when plasmin activity is lost, the depletion of fibrin alone is insufficient to fully restore fracture repair, suggesting the existence of additional plasmin targets important for fracture repair. Previously, activated matrix metalloproteinase 9 (MMP-9) was demonstrated to function in fracture repair by promoting angiogenesis. Given that MMP-9 is a defined plasmin target, it was hypothesized that pro-MMP-9, following plasmin activation, promotes fracture repair. This hypothesis was tested in a fixed murine femur fracture model with serial assessment of fracture healing. Contrary to previous findings, a complete loss of MMP-9 failed to affect fracture healing and union through 28 days post injury. Therefore, these results demonstrated that MMP-9 is dispensable for timely fracture union and cartilage transition to bone in fixed femur fractures. Pro-MMP-9 is therefore not a significant target of plasmin in fracture repair and future studies assessing additional plasmin targets associated with angiogenesis are warranted.
A detailed investigation of the time evolution for the low-field resistance R/sub off/ and the threshold voltage V/sub th/ in chalcogenide-based phase-change memory devices is presented. It is ...observed that both R/sub off/ and V/sub th/ increase and become stable with time and temperature, thus improving the cell readout window. Relying on a microscopic model, the drift of R/sub off/ and V/sub th/ is linked to the dynamic of the intrinsic traps typical of amorphous chalcogenides, thus providing for the first time a unified framework for the comprehension of chalcogenide materials transient behavior.
Objective
Describe features unique to head and neck (H&N) necrotizing fasciitis (NF) compared to other anatomic regions and specify a prognostic score associated with death and descending necrotizing ...mediastinitis (DNM).
Study Design
Retrospective cohort.
Setting
Tertiary care, level 1 trauma center.
Methods
A single‐institution database identified 399 confirmed cases of NF between 2006 and 2021, 33 of which involved the H&N. Patients with confirmed H&N NF were sorted into cohorts based on clinical outcomes, with the “poor” outcomes group defined by death and/or DNM.
Results
Thirty‐three patients with H&N NF were included. Compared to NF of other regions, patients with H&N NF had a significantly lower mortality rate (6.06% vs 20.8%, p = .041) and significantly lower rates of obesity (27.3% vs 63.7%, p < .001) and hypertension (42.4% vs 60.9%, p = .038). Within the H&N group, there were 2 deaths (6.06%) and 8 cases of DNM (24.2%). Diabetes was associated with poor outcomes (p = .047), as was an abbreviated sequential organ failure assessment score for necrotizing fasciitis (nfSOFA) of 2 or greater (p = .015).
Conclusion
H&N NF is unique among other forms of NF, with a lower mortality rate and lower rates of obesity and hypertension in affected patients. Within the H&N cohort, worse outcomes were associated with diabetes as well as a nfSOFA score of 2 or greater. Timely surgical debridement alongside broad‐spectrum antibiotics remains the mainstay of treatment for NF; however, this simple prognostic score may play a role during the early stages of care for patients with H&N NF.
Abstract Background During surgery, trauma to musculoskeletal tissue induces a systemic reaction known as the acute phase response (APR). When excessive or prolonged, the APR has been implicated as ...an underlying cause of surgical complications. The purpose of this study was to determine the typical APR following total joint arthroplasty in a healthy population defined by the Charlson Comorbidity Index (CCI). Methods This retrospective study identified 180 healthy patients (CCI < 2) who underwent total joint arthroplasty by a single surgeon for primary osteoarthritis from 2013 to 2015. Serial measurements of C-reactive protein (CRP) and fibrinogen were obtained preoperative, perioperative, and at 2 and 6 weeks postoperative. Results Postoperative CRP peaked during the inpatient period and returned to baseline by 2 weeks. Fibrinogen peaked after CRP and returned to baseline by 6 weeks. Elevated preoperative CRP correlated with a more robust postoperative APR for both total hip arthroplasty and total knee arthroplasty, suggesting that a patient's preoperative inflammatory state correlates with the magnitude of the postoperative APR. Conclusion Measurement of preoperative acute phase reactants may provide an objective means to predict a patient's risk of postoperative dysregulation of the APR and complications.
Abstract Clinical features and treatment outcome were compared in depressed outpatients with and without a history of emotional and physical abuse (EPA), including childhood maltreatment. Patients ...were initially randomized to IPT or SSRI and then augmented with the second treatment if they did not remit with monotherapy. Assessments included the SCID-I, the SCID-II for DSM-IV diagnoses, the HRSD, the QIDS and the Mood Spectrum Self-Report (MOODS-SR). Seventy-eight (25%) patients reported a history of EPA; 60 (76.9%) were women. Patients with a history of EPA did not differ from those without on HRSD scores at baseline, but showed an earlier age at onset of depression and a longer duration of illness. The two groups differed on several mood spectrum factors, namely: ‘ depressive mood ’ (15.6 ± 4.9 vs. 13.5 ± 5.4; p < 0.004), ‘ psychomotor retardation ’ (11.7 ± 4.5 vs. 9.6 ± 4.7; p < 0.001), ‘ drug and illness-related depression ’ (1.3 ± 1.3 vs. 0.6 ± 1.0; p < 0.0001), and ‘ neurovegetative symptoms ’ (8.3 ± 2.6 vs. 6.9 ± 2.9; p < 0.0001). Patients with EPA had also a significantly longer time to remission (89 vs. 67 days, log-rank test, p = 0.035). The need for augmentation treatment was significantly more frequent among patients with EPA than in those without. The present study suggests that patients with a history of EPA show a subtype of depression characterized by poor treatment response and more severe neurovegetative and psychomotor symptoms.
In this letter, we show a compact model that describes the main electrical features of phase change memory (PCM) devices. The model coherently reproduces the behavior of both SET and RESET states ...with the description of the physics of involved phenomena for different bias and temperature conditions. For arbitrary programming pulses, the model is able to generate intermediate states with mixed phase distributions and, thus, with resistance values between the SET and RESET ones. The proposed model is therefore a precious tool for the design of multilevel PCM applications.
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