The effect of spent coffee ground (SCG) loading, matrix ratio and biological treatment of SCG on poly(hydroxybutyrate) (PHB)/poly(lactic acid) (PLA) polymer blend

This study investigates the effects of SCG embedded into biodegradable polymer blends and aimed to formulate and characterise biomass-reinforced biocomposites using spent coffee ground (SCG) as reinforcement in PHB/PLA polymer blend. The effect of SCG filler loading and varying PHB/PLA ratios on the tensile properties and morphological characteristics of the biocomposites were examined. The results indicated that tensile properties reduction could be due to its incompatibility with the PHB/PLA matrixSCG aggregation at 40 wt% content resulted in higher void formation compared to lower content at 10 wt%. A PHB/PLA ratio of 50/50 with SCG loading 20 wt% was chosen for biocomposites with treated SCG. Biological treatment of SCG using Phanerochaete chrysosporium CK01 and Aspergillus niger DWA8 indicated P. chrysosporium CK01 necessitated a higher moisture content for optimum growth and enzyme production, whereas the optimal conditions for enzyme production (50-55 %, w/w) differed from those promoting A. niger DWA8 growth (40 %, w/w). SEM micrographs highlighted uniform distribution and effective wetting of treated SCG, resulting in improvements of tensile strength and modulus of biocomposites, respectively. The study demonstrated the effectiveness of sustainable fungal treatment in enhancing the interfacial adhesion between treated SCG and the PHB/PLA matrix.

X-ray polarization evidence for a 200-year-old flare of Sgr A. Nature 2023:10.1038/s41586-023-06064-x. [PMID: 37344593 DOI: 10.1038/s41586-023-06064-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

The centre of the Milky Way Galaxy hosts a black hole with a solar mass of about 4 million (Sagittarius A^* (Sgr A)) that is very quiescent at present with a luminosity many orders of magnitude below those of active galactic nuclei¹. Reflection of X-rays from Sgr A^* by dense gas in the Galactic Centre region offers a means to study its past flaring activity on timescales of hundreds and thousands of years². The shape of the X-ray continuum and the strong fluorescent iron line observed from giant molecular clouds in the vicinity of Sgr A^* are consistent with the reflection scenario^3-5. If this interpretation is correct, the reflected continuum emission should be polarized⁶. Here we report observations of polarized X-ray emission in the direction of the molecular clouds in the Galactic Centre using the Imaging X-ray Polarimetry Explorer. We measure a polarization degree of 31% ± 11%, and a polarization angle of -48° ± 11°. The polarization angle is consistent with Sgr A^* being the primary source of the emission, and the polarization degree implies that some 200 years ago, the X-ray luminosity of Sgr A^* was briefly comparable to that of a Seyfert galaxy.

A review of 100 iatrogenic nerve injuries: delays in referrals remain significant

INTRODUCTION

This is a retrospective study of 100 consecutive patients with iatrogenic nerve injuries, as seen in a tertiary referral centre over a six-year period.

MATERIALS AND METHODS

Patients who presented with new-onset nerve palsy involving a motor or mixed motor/sensory nerve following an operation were studied.

RESULTS

There were 44 male and 56 female patients with a mean age of 53 years (range 5-87 years). The median duration from the index procedures to referral was six months (range 0 days to 12 years). Approximately one third of referrals were made over 12 months since the index procedures. Twenty patients recovered spontaneously and were managed expectantly. Eighty patients underwent secondary interventions.

DISCUSSION

There remains a significant delay in referring postoperative nerve palsy to a nerve specialist. The majority of these cases will warrant secondary reconstructive surgery and delay in treatment may have a negative effect on the ultimate outcomes.

Infected pancreatic pseudocyst following severe dengue infection

Severe dengue infection is life threatening as it can result in fatal complications such as intractable bleeding from coagulopathy, multiorgan failure from shock and haemophagocytic syndrome. There have been case reports of atypical manifestation of severe dengue infection such as pancreatitis, Guillian-Barre's syndrome, perforated viscus and myocarditis. However, to our knowledge, pancreatic pseudocyst from dengue-related pancreatitis has never been reported in the literature. We hereby report a case of infected pancreatic pseudocyst in a patient with persistent pyrexia, abdominal pain and raised inflammatory markers 10 weeks from the onset of severe dengue infection. Endoscopic ultrasound (EUS) guided transluminal drainage of the infected pancreatic pseudocyst with lumen-apposing metallic stent (LAMS) was performed with good clinical and radiological outcome.

Endothelial-T cell crosstalk contributes to vascular injury in fatty liver disease

 

Cardiovascular complications are often the fundamental causes of death in non-alcoholic fatty liver disease (NAFLD) patients. While there are known systemic mediators in NAFLD that may induce vascular inflammation, the mechanism of endothelial dysfunction remain understudied. In this work, we harnessed the replicative potential of blood outgrowth endothelial cells (BOECs) to develop personalized cell lines from NAFLD patients and healthy controls. Our transcriptomic analysis showed that the top interactome network enriched in NAFLD BOECs comprised of several C-C and C-X-C chemokine ligands involved in immune cell chemotaxis. We previously reported T cell infiltration in mouse model of non-alcoholic steatohepatitis, and here, we confirmed enhanced endothelial chemokine signatures in arterial histological sections. To elucidate endothelial-immune crosstalk, we performed single-cell analysis on human peripheral blood mononuclear cells and found T cell intensification in NAFLD patients compared to healthy controls. Our immunoprofiling by flow cytometry further revealed that NAFLD patients possessed higher levels CD8+ memory cells. Functionally, T cells, instead of monocytes, adhered more pronouncedly to NAFLD BOECs. In evaluating the CXCL12-CXCR4 axis in chemotaxis, CXCR4 antagonist (AMD3100) substantially modulated the migration of patient-derived CD8+ T cells towards NAFLD BOECs, which was not observed in healthy endothelial-T cell chemotaxis coculture. Finally, we validated NAFLD-associated endothelial dysfunction by enumerating two folds more circulating endothelial cells, a biomarker of vascular injury, in the blood samples of NAFLD patients than healthy controls. Our work provides insights for translation to restore blood vessel health and potentially mitigate adverse vascular events in NAFLD.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Industrial Alignment Fund Pre-Positioning grant from the Agency for Science, Technology and Research, Singapore Endothelial-T cell crosstalk in NAFLD

Strong geometry dependence of the Casimir force between interpenetrated rectangular gratings

Quantum fluctuations give rise to Casimir forces between two parallel conducting plates, the magnitude of which increases monotonically as the separation decreases. By introducing nanoscale gratings to the surfaces, recent advances have opened opportunities for controlling the Casimir force in complex geometries. Here, we measure the Casimir force between two rectangular silicon gratings. Using an on-chip detection platform, we achieve accurate alignment between the two gratings so that they interpenetrate as the separation is reduced. Just before interpenetration occurs, the measured Casimir force is found to have a geometry dependence that is much stronger than previous experiments, with deviations from the proximity force approximation reaching a factor of ~500. After the gratings interpenetrate each other, the Casimir force becomes non-zero and independent of displacement. This work shows that the presence of gratings can strongly modify the Casimir force to control the interaction between nanomechanical components.

The geometry dependence of the Casimir force could enable applications in nanomechanical systems if the effects can be enhanced. Here, the authors demonstrate that the Casimir force between two interpenetrating nanoscale gratings can exceed the proximity force approximation by a factor of 500.

COVID-19: Initial experience of an international group of hand surgeons

The emergence of the COVID-19 pandemic has severely affected medical treatment protocols throughout the world. While the pandemic does not affect hand surgeons at first glance, they have a role to play. The purpose of this study was to describe the different measures that have been put in place in response to the COVID-19 pandemic by hand surgeons throughout the world. The survey comprised 47 surgeons working in 34 countries who responded to an online questionnaire. We found that the protocols varied in terms of visitors, health professionals in the operating room, patient waiting areas, wards and emergency rooms. Based on these preliminary findings, an international consensus on hand surgery practices for the current viral pandemic, and future ones, needs to be built rapidly.

Effects of backpack and double pack loads on postural stability

Measurement of postural stability is crucial for identifying predictors of performance, determining the efficacy of physical training and rehabilitation techniques and evaluating and preventing injuries, particularly for heavy load carriage in hikers, mountain search and rescue personnel and soldiers. This study investigated the effect of load distribution on postural stability in an upright stance using backpack and double pack loads under conflicting or impaired somatosensory, visual and vestibular conditions. The sensory organisation tests were conducted on 20 young adults before and after a 10-min level walking exercise. Young adults' ability to use inputs from somatosensory and visual systems to maintain postural stability was significantly reduced following a 10-min walking exercise with a heavy backpack (30% of body weight), whereas no significant changes were observed for double pack carriage. Thus, the distribution of heavy loads to the front and back provides superior balance control compared with back-only loading. Practitioner summary: This study investigated the effects of heavy (30% of body weight) load distribution on postural stability after a 10-min walking exercise. Backpack carriage significantly reduced postural stability, whereas there was no significant effect under double pack loads. Distribution of heavy loads on the front-and-back is desirable for superior balance control.

Gender Differences in Energy Expenditure During Walking With Backpack and Double-Pack Loads

OBJECTIVE

To investigate gender differences in energy expenditure during walking with backpack and double-pack loads.

BACKGROUND

Studies have reported that energy expenditure during walking with double-pack loads is lower compared with backpack carriage. However, the effect of gender on energy expenditure while walking with these two load distribution systems has not been investigated.

METHOD

Thirty healthy young adults (15 female and 15 male participants) walked on a treadmill with backpack and double-pack loads weighing 30% of their body weight at a speed of 0.89 m/s for 10 min. The energy expenditure in terms of oxygen consumption (VO2) and respiratory exchange ratio (RER) were continuously monitored using a portable gas analyzer throughout each walking exercise. A mixed-design analysis of variance model was adopted to test the effects of gender, pack, and time on VO2 and RER.

RESULTS

No time effect was observed on VO2. However, significant gender, pack, and interaction effects were observed. The lowest VO2 was found in female participants under double-pack carriage. No significant gender or pack differences existed in RER. However, RER significantly and incrementally increased in time from the 4th through 6th, 8th, and 10th min.

CONCLUSION

This study revealed that heavy double-pack load carriage for healthy young female participants had significantly lower energy expenditure (normalized by the entire system weight, i.e., the participant's weight plus the weight of the pack) than that of the male participants in a 10-min walking exercise.

APPLICATION

The findings of this study indicated that healthy young female participants carried a heavy double-pack with less energy cost (normalized by the entire system weight, i.e., the participant's weight plus the weight of the pack) compared with their male counterparts during a 10-min walking exercise.

Periorbital erythema and swelling as a presenting sign of lupus erythematosus in tertiary referral centers and literature review

Background Cutaneous lupus erythematosus (CLE) includes a broad range of dermatologic manifestations. Periorbital involvement, however, is a relatively rare clinical presentation of CLE. Objectives This clinical study aimed to investigate the characteristics of this unique presentation of CLE in tertiary medical centers. Methods We enrolled patients with periorbital erythema and swelling as the presenting sign of lupus erythematosus, from January 2003 to November 2017, using the data of 553 pathologically proven CLE cases from the registration database of the Chang Gung Memorial Hospitals in Taiwan. Results We enrolled a total of 25 patients. The mean age was 46.7 years and 68% of the patients were female. Most of the patients (84.0%) presented with unilateral involvement, with the left orbit involved in 15 patients (60%); the upper eyelid was the most frequently involved (72%). Mean duration between the onset of clinical manifestations and the diagnosis of CLE was approximately 59 weeks. Nineteen patients had been previously misdiagnosed. All patients had features compatible with CLE on histopathological examination. In contrast, laboratory analysis of the autoimmune profile often revealed negative results, including those for antinuclear antibodies (25%). Notably, anti-SSA/SSB (45.5%) showed the highest positive rate. During follow-up, six patients developed systemic lupus erythematosus (SLE) and two patients developed Sjögren syndrome. Conclusions The diagnosis of CLE presenting as periorbital erythema and swelling is often delayed because of clinical mimicry and the high proportion of negative results on autoantibody tests. Increased clinical suspicion and prompt histopathological examination are crucial for early diagnosis. Moreover, one-fourth of the patients ultimately developed SLE, which highlights the importance of clinical awareness.

Risks for Staphylococcus aureus colonization in patients with psoriasis: a systematic review and meta-analysis

Evidence on whether patients with psoriasis have a higher risk for staphylococcal colonization than healthy controls remains controversial. To synthesize the current literature, we performed a systematic review on the prevalence and relative risk (RR) of Staphylococcus aureus colonization in patients with psoriasis. We modified the QUADAS-2 instrument to assess the reporting quality of individual studies and applied random-effects models in meta-analysis. Overall we identified 21 eligible studies, of which 15 enrolled one or more comparison groups. The pooled prevalence of staphylococcal colonization in patients with psoriasis was 35·3% [95% confidence interval (CI) 25·0-45·6] on lesional skin and 39·2% (95% CI 33·7-44·8) in the nares. Patients with psoriasis were 4·5 times more likely to be colonized by S. aureus than healthy controls were on the skin (RR 5·54, 95% CI 3·21-9·57) and 60% more in the nares (RR 1·60, 95% CI 1·11-2·32). Cutaneous and nasal colonization by meticillin-resistant S. aureus also appeared higher in patients with psoriasis (pooled prevalence 8·6%) than in healthy controls (2·6%), yet the difference was not statistically significant (P = 0·74). In contrast, despite of a similar risk for nasal staphylococcal colonization (RR 0·67, 95% CI 0·38-1·18), patients with psoriasis were less likely to carry S. aureus on lesional skin than atopic patients (RR 0·64, 95% CI 0·40-1·02). In summarizing the current literature, we found that patients with psoriasis were at an increased risk for staphylococcal colonization compared with healthy individuals. Prospective studies on how bacterial loads correlate with disease activity can guide the clinical management of bacterial colonization while preventing the emergence of drug-resistant strains.

Perforated gastric ulcer in severe dengue infection: A case report

Abdominal pain is one of the common presentations in severe dengue infection. We report a rare case of perforated gastric ulcer in a young man diagnosed with severe dengue infection and the challenges we faced in managing this patient. Perforated gastric ulcer need to be considered if there are signs of peritonitis and persistent abdominal pain that does not conform to the natural history of dengue. Proper imaging and early surgical intervention in perforated gastric ulcer is vital in preventing further complication and reducing the risk of mortality.

A quantum-rovibrational-state-selected study of the reaction in the collision energy range of 0.05-10.00 eV: translational, rotational, and vibrational energy effects

We report detailed absolute integral cross sections (σ's) for the quantum-rovibrational-state-selected ion-molecule reaction in the center-of-mass collision energy (E_cm) range of 0.05-10.00 eV, where (vvv) = (000), (100), and (020), and . Three product channels, HCO⁺ + OH, HOCO⁺ + H, and CO⁺ + H₂O, are identified. The measured σ(HCO⁺) curve [σ(HCO⁺) versus E_cm plot] supports the hypothesis that the formation of the HCO⁺ + OH channel follows an exothermic pathway with no potential energy barriers. Although the HOCO⁺ + H channel is the most exothermic, the σ(HOCO⁺) is found to be significantly lower than the σ(HCO⁺). The σ(HOCO⁺) curve is bimodal, indicating two distinct mechanisms for the formation of HOCO⁺. The σ(HOCO⁺) is strongly inhibited at E_cm < 0.4 eV, but is enhanced at E_cm > 0.4 eV by (100) vibrational excitation. The E_cm onsets of σ(CO⁺) determined for the (000) and (100) vibrational states are in excellent agreement with the known thermochemical thresholds. This observation, along with the comparison of the σ(CO⁺) curves for the (100) and (000) states, shows that kinetic and vibrational energies are equally effective in promoting the CO⁺ channel. We have also performed high-level ab initio quantum calculations on the potential energy surface, intermediates, and transition state structures for the titled reaction. The calculations reveal potential barriers of ≈0.5-0.6 eV for the formation of HOCO⁺, and thus account for the low σ(HOCO⁺) and its bimodal profile observed. The E_cm enhancement for σ(HOCO⁺) at E_cm ≈ 0.5-5.0 eV can be attributed to the direct collision mechanism, whereas the formation of HOCO⁺ at low E_cm < 0.4 eV may involve a complex mechanism, which is mediated by the formation of a loosely sticking complex between HCO⁺ and OH. The direct collision and complex mechanisms proposed also allow the rationalization of the vibrational inhibition at low E_cm and the vibrational enhancement at high E_cm observed for the σ(HOCO⁺).

Isotopic and quantum-rovibrational-state effects for the ion-molecule reaction in the collision energy range of 0.03-10.00 eV

We report detailed quantum-rovibrational-state-selected integral cross sections for the formation of H₃O⁺via H-transfer (σ_HT) and H₂DO⁺via D-transfer (σ_DT) from the reaction in the center-of-mass collision energy (E_cm) range of 0.03-10.00 eV, where (vvv) = (000), (100), and (020) and . The E_cm inhibition and rotational enhancement observed for these reactions at E_cm < 0.5 eV are generally consistent with those reported previously for H₂O⁺ + H₂(D₂) reactions. However, in contrast to the vibrational inhibition observed for the latter reactions at low E_cm < 0.5 eV, both the σ_HT and σ_DT for the H₂O⁺ + HD reaction are found to be enhanced by (100) vibrational excitation, which is not predicted by the current state-of-the-art theoretical dynamics calculations. Furthermore, the (100) vibrational enhancement for the H₂O⁺ + HD reaction is observed in the full E_cm range of 0.03-10.00 eV. The fact that vibrational enhancement is only observed for the reaction of H₂O⁺ + HD, and not for H₂O⁺ + H₂(D₂) reactions suggests that the asymmetry of HD may play a role in the reaction dynamics. In addition to the strong isotopic effect favoring the σ_HT channel of the H₂O⁺ + HD reaction at low E_cm < 0.5 eV, competition between the σ_HT and σ_DT of the H₂O⁺ + HD reaction is also observed at E_cm = 0.3-10.0 eV. The present state-selected study of the H₂O⁺ + HD reaction, along with the previous studies of the H₂O⁺ + H₂(D₂) reactions, clearly shows that the chemical reactivity of H₂O⁺ toward H₂ (HD, D₂) depends not only on E_cm, but also on the rotational and vibrational states of H₂O⁺(X²B₁). The detailed σ_HT and σ_DT values obtained here with single rovibrational-state selections of the reactant H₂O⁺ are expected to be valuable benchmarks for state-of-the-art theoretical calculations on the chemical dynamics of the title reaction.

Cross-sectional study on knowledge of chronic kidney disease among medical outpatient clinic patients

BACKGROUND

Chronic kidney disease (CKD) is a major health concern worldwide. There are limited studies which look into the actual knowledge level of CKD among the general population both locally and internationally. This study aims to assess the knowledge level of CKD among patients in a secondary hospital in Malaysia.

METHODS

Consecutive sampling of patients attending the Medical Outpatient Clinic was performed in this crosssectional study. Respondents were given self-administered questionnaires which contain questions on demographic characteristics and knowledge on CKD.

RESULTS

Out of 300 respondents, 78.6% (n=236) of the respondents completed the questionnaire. Majority of respondents (73.7%, n=174) scored less than 4 out of 7 marks on knowledge on CKD. Respondents who were younger, males, having higher education status, professionals/executives and earned higher monthly income were more likely to have a higher mean knowledge score of CKD. Respondents who have heard of CKD were also significantly associated with higher mean knowledge score of CKD.

CONCLUSION

The study findings suggest that our Malaysian population is still inadequately informed on CKD, especially those who are at risk of developing CKD and its complications, and also among those of the lower socioeconomic group. In order for successful primary and secondary prevention of CKD, more importance should be placed on increasing awareness on CKD among these atrisk groups.

Febuxostat-associated drug reaction with eosinophilia and systemic symptoms (DRESS)

WHAT IS KNOWN AND OBJECTIVE

Febuxostat is recommended as an alternative drug for gouty patients with a history of allopurinol hypersensitivity or carrying the HLA-B*5801 allele.

CASE SUMMARY

An 81-year-old man with the medical history of gout presented to our clinic with generalized rashes for 2 days. After taking febuxostat for 2 days, he developed generalized skin rash with high fever. Laboratory tests showed elevated liver enzymes and acute kidney injury.

WHAT IS KNOWN AND OBJECTIVE

This is the first identified case of febuxostat-associated DRESS. Febuxostat should be withdrawn immediately when DRESS is observed to avoid further serious complications.

Photochemistry. Evidence for direct molecular oxygen production in CO₂ photodissociation

Photodissociation of carbon dioxide (CO2) has long been assumed to proceed exclusively to carbon monoxide (CO) and oxygen atom (O) primary products. However, recent theoretical calculations suggested that an exit channel to produce C + O2 should also be energetically accessible. Here we report the direct experimental evidence for the C + O2 channel in CO2 photodissociation near the energetic threshold of the C((3)P) + O2(X(3)Σ(g)(-)) channel with a yield of 5 ± 2% using vacuum ultraviolet laser pump-probe spectroscopy and velocity-map imaging detection of the C((3)PJ) product between 101.5 and 107.2 nanometers. Our results may have implications for nonbiological oxygen production in CO2-heavy atmospheres.

Communication: direct measurements of nascent O((3)P0,1,2) fine-structure distributions and branching ratios of correlated spin-orbit resolved product channels CO(ã(3)Π; v) + O((3)P0,1,2) and CO(X̃(1)Σ(+); v) + O((3)P0,1,2) in VUV photodissociation of CO2

We present a generally applicable experimental method for the direct measurement of nascent spin-orbit state distributions of atomic photofragments based on the detection of vacuum ultraviolet (VUV)-excited autoionizing-Rydberg (VUV-EAR) states. The incorporation of this VUV-EAR method in the application of the newly established VUV-VUV laser velocity-map-imaging-photoion (VMI-PI) apparatus has made possible the branching ratio measurement for correlated spin-orbit state resolved product channels, CO(ã(3)Π; v) + O((3)P0,1,2) and CO(X̃(1)Σ(+); v) + O((3)P0,1,2), formed by VUV photoexcitation of CO2 to the 4s(10 (1)) Rydberg state at 97,955.7 cm(-1). The total kinetic energy release (TKER) spectra obtained from the O(+) VMI-PI images of O((3)P0,1,2) reveal the formation of correlated CO(ã(3)Π; v = 0-2) with well-resolved v = 0-2 vibrational bands. This observation shows that the dissociation of CO2 to form the spin-allowed CO(ã(3)Π; v = 0-2) + O((3)P0,1,2) channel has no potential energy barrier. The TKER spectra for the spin-forbidden CO(X̃(1)Σ(+); v) + O((3)P0,1,2) channel were found to exhibit broad profiles, indicative of the formation of a broad range of rovibrational states of CO(X̃(1)Σ(+)) with significant vibrational populations for v = 18-26. While the VMI-PI images for the CO(ã(3)Π; v = 0-2) + O((3)P0,1,2) channel are anisotropic, indicating that the predissociation of CO2 4s(10 (1)) occurs via a near linear configuration in a time scale shorter than the rotational period, the angular distributions for the CO(X̃(1)Σ(+); v) + O((3)P0,1,2) channel are close to isotropic, revealing a slower predissociation process, which possibly occurs on a triplet surface via an intersystem crossing mechanism.

The Manchester short splint: A change to splinting practice in the rehabilitation of zone II flexor tendon repairs

Introduction

The results of patients with primary zone II flexor tendon repairs rehabilitated using a traditional forearm-based splint were audited and compared with those who were managed in the Manchester short splint.

Method

The short splint was fabricated to permit maximal wrist flexion and up to 45° of wrist extension with a block to 30° of metacarpophalangeal joint extension. A rehabilitation regimen consisting of early combined passive flexion exercises and active motion was employed. In 2011, 62 patients (76 digits) with a mean age of 34 years (range 14–58) were rehabilitated using the forearm-based splint (group A). In 2012, 40 patients (45 digits) with a mean age of 31 years (range 15–71) were rehabilitated using the Manchester short splint (group B).

Results

Group B had significantly less flexion contracture at their proximal interphalangeal joints than group A at 6 weeks (median 15° versus 28°; p = 0.003) and 12 weeks (median 6° versus 18°; p = 0.024) postoperatively. At the final review, group B had a significantly greater arc of flexion at their distal interphalangeal joints (median 59° versus 30°; p < 0.001) and a greater proportion of patients with excellent/good Strickland’s grades. There were three (3.9%) ruptures in group A and two (4.4%) ruptures in group B (p > 0.999).

Conclusion

The use of a shorter splint would appear to enhance the outcomes whilst preserving repair integrity.

Branching ratio measurements for vacuum ultraviolet photodissociation of 12C16O

The branching ratios for the spin-forbidden photodissociation channels of (12)C(16)O in the vacuum ultraviolet (VUV) photon energy region from 102,500 (12.709 eV) to 106,300 cm(-1) (13.180 eV) have been investigated using the VUV laser time-slice velocity-map imaging photoion technique. The excitations to three (1)Σ(+) and six (1)Π Rydberg-type states, including the progression of W(3sσ) (1)Π(v' = 0, 1, and 2) vibrational levels of CO, have been identified and investigated. The branching ratios for the product channels C((3)P) + O((3)P), C((1)D) + O((3)P), and C((3)P) + O((1)D) of these predissociative states are found to depend on the electronic, vibrational, and rotational states of CO being excited. Rotation and e/f-symmetry dependences of the branching ratios into the spin-forbidden channels have been confirmed for several of the (1)Π states, which can be explained using the heterogeneous interaction with the repulsive D'(1)Σ(+) state. The percentage of the photodissociation into the spin-forbidden channels is found to increase with increasing the rotational quantum number for the K(4pσ) (1)Σ(+) (v' = 0) state. This has been rationalized using a (1)Σ(+) to (1)Π to (3)Π coupling scheme, where the final (3)Π state is a repulsive valence state correlating to the spin-forbidden channel.

The use of non-vascularised osteochondral autograft for reconstruction of articular surfaces in the hand and wrist

Bone loss involving articular surface is a challenging problem faced by the orthopaedic surgeon. In the hand and wrist, there are articular defects that are amenable to autograft reconstruction when primary fixation is not possible. In this article, the surgical techniques and clinical outcomes of articular reconstructions in the hand and wrist using non-vascularised osteochondral autografts are reviewed.

Communication: A vibrational study of titanium dioxide cation using the vacuum ultraviolet laser pulsed field ionization-photoelectron method

We have successfully measured the vacuum ultraviolet (VUV) laser photoionization efficiency and pulsed field ionization-photoelectron (PFI-PE) spectra of cold titanium dioxide (TiO(2)) prepared by a supersonically cooled laser ablation source. The VUV-PFI-PE spectrum thus obtained exhibits long progressions of the v(2)(+)(a(1)) bending and the combination of v(1)(+)(a(1)) stretching and v(2)(+)(a(1)) bending vibrational modes of the TiO(2)(+)(X(2)B(2)) ion. The pattern of Franck-Condon factors observed indicates that the O-Ti-O bond angle of the TiO(2)(+)(X(2)B(2)) ion is significantly different from that of the TiO(2)(X(1)A(1)) neutral, whereas the change of the Ti-O bond distance is very minor upon the photoionization transition. The analysis of the PFI-PE bands has made possible the determination of the adiabatic ionization energy for TiO(2), IE(TiO(2)) = 77215.9 ± 1.2 cm(-1) (9.57355 ± 0.00015 eV), the harmonic vibrational frequencies, ω(1)(+) = 829.1 ± 2.0 cm(-1) and ω(2)(+) = 248.7 ± 0.6 cm(-1), and the anharmonic coefficients, χ(11)(+) = 5.57 ± 0.65 cm(-1), χ(22)(+) = 0.08 ± 0.06 cm(-1), and χ(12)(+) = -4.51 ± 0.30 cm(-1) for the TiO(2)(+)(X(2)B(2)) ground state.

Communication: A vibrational study of propargyl cation using the vacuum ultraviolet laser velocity-map imaging photoelectron method

By employing the vacuum ultraviolet (VUV) laser velocity-map imaging photoelectron (VUV-VMI-PE) method, we have obtained a vibrationally resolved photoelectron spectrum of gaseous propargyl radical [C(3)H(3)(X(2)B(1))] in the energy range of 0-4600 cm(-1) above its ionization energy. The cold C(3)H(3) radicals were produced from a supersonically cooled radical beam source based on 193 nm ArF photodissociation of C(3)H(3)Cl. The VUV-VMI-PE spectrum of C(3)H(3) thus obtained reveals a Franck-Condon factor (FCF) pattern with a highly dominant origin band along with weak vibrational progressions associated with excitations of the C-C ν(5)(+)(a(1)) and C≡C ν(3)(+)(a(1)) symmetric stretching modes and the CCH ν(7)(+)(b(1)) out-of-plane bending mode of C(3)H(3)(+)(X(1)A(1)). The ν(5)(+)(a(1)) vibrational frequency of 1120 cm(-1) determined in the present study is lower than the value deduced from the recent Ar-tagged infrared photodissociation study by 102 cm(-1), confirming the highly accurate vibrational frequency predictions obtained by the most recent state-of-the-art ab initio quantum calculations. The observation of the FCF disallowed ν(7)(+)(b(1)) mode is indicative of vibronic interactions. The discrepancy observed between the FCF pattern determined in the present study and that predicted by a recent high-level quantum theoretical investigation can be taken as evidence that the potential energy surfaces used in the latter theoretical study are in need of improvement in order to provide a reliable FCF prediction for the C(3)H(3)/C(3)H(3)(+) photoionization system.

Characterization of GCY1 in Saccharomyces cerevisiae by metabolic profiling

AIMS

The analytical study of intracellular (IC) metabolites has developed with advances in chromatography-linked mass spectrometry and fast sampling procedures. We applied the IC metabolite analysis to characterize the role of GCY1 in the glycerol (GLY) catabolic pathway in Saccharomyces cerevisiae.

METHODS AND RESULTS

Strains with disrupted or overexpressing GLY catabolic genes such as GCY1, DAK1 and DAK2 were constructed. The strains were cultivated under different aeration conditions and quickly quenched using a novel rapid sampling port. IC concentrations of GLY, dihydroxyacetone (DHA), glycerol 3-phosphate and dihydroxyacetone phosphate were analysed in the strains by gas chromatography/mass spectrometry. DHA was not detected in the gcy1 gene-disrupted strain but accumulated 225.91 μmol g DCW(-1) in a DHA kinase gene-deficient strain under micro-aerobic conditions. Additionally, a 16.1% increase in DHA occurred by overexpressing GCY1 in the DHA kinase-deficient strain.

CONCLUSIONS

Metabolic profiling showed that the GCY1 gene product functions as a GLY dehydrogenase in S. cerevisiae, particularly under micro-aerobic conditions.

SIGNIFICANCE AND IMPACT OF THE STUDY

Metabolic profiling of the GLY dissimilation pathway was successfully demonstrated in S. cerevisiae, and the function of GCY1 was explained by the results.

Branching ratio measurements of the predissociation of 12C16O by time-slice velocity-map ion imaging in the energy region from 108,000 to 110,500 cm(-1)

Direct branching ratio measurements of the three lowest dissociation channels of (12)C(16)O that produce C((3)P) + O((3)P), C((1)D) + O((3)P), and C((3)P) + O((1)D) are reported in the vacuum ultraviolet region from 108,000 cm(-1) (92.59 nm) to 110,500 cm(-1) (90.50 nm) using the time-slice velocity-map ion imaging and nonlinear resonant four-wave mixing techniques. Rotationally, resolved carbon ion yield spectra for both (1)Σ(+) and (1)Π bands of CO in this region have been obtained. Our measurements using this technique show that the branching ratio in this energy region, especially the relative percentages of the two spin-forbidden channels, is strongly dependent on the particular electronic and vibrational energy levels of CO that are excited.

Communication: branching ratio measurements in the predissociation of 12C16O by time-slice velocity-map ion imaging in the vacuum ultraviolet region

The first direct branching ratio measurement of the three lowest energy dissociation channels of CO that produce C((3)P) + O((3)P), C((1)D) + O((3)P), and C((3)P) + O((1)D) is reported. Rotational resolved carbon ion yield spectra for two Π bands (W(3sσ)(1)Π (v(') = 3) at 108,012.6 cm(-1) and (1)Π(v(') = 2) at 109,017 cm(-1)) and two Σ bands ((4sσ)(1)Σ(+)(v(') = 4) at 109,452 cm(-1) and (4pσ)(1)Σ(+)(v(') = 3) at 109,485 cm(-1)) of CO were obtained. Our measurements show that the branching ratio in this energy region is strongly dependent on the electronic and vibrational energy but it is independent or just weakly dependent on the parity and rotational energy levels. To our knowledge, this is the first time that the triplet channel producing O((1)D) has been experimentally observed and this is also the first time that a direct measurement of the branching ratio for the different channels in the predissociation of CO in this energy region has been made.

Time-sliced velocity-mapped imaging studies of the predissociation of single ro-vibronic energy levels of N2 in the extreme ultraviolet region using vacuum ultraviolet photoionization

The predissociation of N(2) from the rotational levels in the o(1)∏(u) (v(') = 2) and b(') (1)Σ(u) (v(') = 8) bands has been studied in the wavenumber (or energy) range from 109 350 cm(-1) (13.5577 eV) to 109 580 cm(-1) (13.5862 eV) by time-sliced velocity-mapped imaging technique with VUV photoionization detection of the fragments. These levels were excited from the ground state of N(2) (X(1)Σ(g) (+), v(") = 0) levels using an unfocused vacuum ultraviolet (VUV) laser via a one-photon process. The same VUV laser is used to ionize the metastable N ((2)D(o)) produced from the predissociation process and the time-sliced velocity-mapped imaging technique is used to determine their velocity and angular distributions. Two different theoretical methods developed, respectively, by Kim et al. [J. Chem. Phys. 125, 133316 (2006) and Zande [J. Chem. Phys. 107, 9447 (1997)] were used to calculate the anisotropic parameters for the predissociation to the channel N((4)S(o)) + N((2)D(o)) to compare with the observed value for each of the rotational levels. Very good agreement with the experimental results was obtained for both methods. Possible predissociation mechanisms were predicted from the measurements and calculations.

What are the radiological predictors of functional outcome following fractures of the distal radius?

The fracture most commonly treated by orthopaedic surgeons is that of the distal radius. However, as yet there is no consensus on what constitutes an 'acceptable' radiological position before or after treatment. This should be defined as the position that will predict good function in the majority of cases. In this paper we review the radiological indices that can be measured in fractures of the distal radius and try to identify potential predictors of functional outcome. In patients likely to have high functional demands, we recommend that the articular reconstruction be achieved with less than 2 mm of gap or step-off, the radius be restored to within 2 mm of its normal length, and that carpal alignment be restored. The ultimate aim of treatment is a pain-free, mobile wrist joint without functional limitation.

Si-based light-emitting structure synthesized with low-energy ion implantation at a low dosage

In this work, Si-based light-emitting structures were synthesized by Si+ implantation into 30 nm thermally grown SiO2 films with a low dosage (< or =1 x 10(16)/cm2). The emission band of electroluminescence (EL) extends from 300 nm to 700 nm with a peak at around 500 nm. The onset voltage for the EL is around 5 V for the 8 keV implanted sample which is low enough for many device applications. The light emission mechanism is studied in this work. It is believed that the defects in the Si+ implanted SiO2 films are the luminescent centers responsible for the EL. In addition, it is found the light emission intensity can be affected by charge trapping in nc-Si.

Manipulation Under Anaesthesia and Early Physiotherapy Facilitate Recovery of Patients with Frozen Shoulder Syndrome

Aim

The aim of this study was to examine the efficacy of manipulation under anaesthesia (MUA) followed by early physiotherapy in treating frozen shoulder syndrome.

Methods

In a prospective trial conducted between 26th August 2002 and 25th June 2004 in 86 patients with frozen shoulder syndrome, MUA was performed as a day procedure. Main outcomes were Disabilities of the Arm, Shoulder and Hand (DASH) score, a visual analogue score (VAS) for pain and range of movement, which were measured preoperatively and at six weeks postprocedure.

Results

Fifty (58.1%) patients had complete data. The average age was 54.5 years. The mean duration of symptoms until MUA was 13 months. The mean DASH score decreased from 48.07 to 15.84 (p<0.0005). The mean VAS reduced from 6.07 to 1.88 (p<0.0005). Flexion improved from 104.18 to 157.56 (p<0.0005); abduction from 70.48 to 150.00 (p<0.0005); and external rotation from 13.88 to 45.62 (p<0.0005).

Conclusion

MUA combined with early physiotherapy alleviates pain and facilitates recovery of function in patients with frozen shoulder syndrome.

High-resolution Rydberg tagging time-of-flight measurements of atomic photofragments by single-photon vacuum ultraviolet laser excitation

By coupling a comprehensive tunable vacuum ultraviolet (VUV) laser system to a velocity-mapped ion imaging apparatus, we show that high-resolution high-n Rydberg tagging time-of-flight (TOF) measurements of nascent atomic photofragments formed by laser photodissociation can be made using single-photon VUV laser photoexcitation. To illustrate this single-photon Rydberg tagging TOF method, we present here the results of the VUV laser high-n Rydberg tagging TOF measurements of O((3)P(2)) and S((3)P(2)) formed in the photodissociation of SO(2) and CS(2) at 193.3 and 202.3 nm, respectively. These results are compared to those obtained by employing the VUV laser photoionization time-sliced velocity-mapped ion imaging technique. The fact that the kinetic energy resolutions achieved in the VUV laser high-n Rydberg tagging TOF measurements of O and S atoms are found to be higher than those observed in the VUV laser photoionization, time-sliced velocity-mapped ion imaging studies show that the single-photon VUV laser high-n Rydberg tagging TOF method is useful and complementary to state-of-the-art time-sliced velocity-mapped ion imaging measurements of heavier atomic photofragments, such as O and S atoms. Furthermore, the general agreement observed between the VUV laser high-n Rydberg tagging TOF and velocity-mapped ion imaging experiments supports the conclusion that the lifetimes of the tagged Rydberg states of O and S atoms are sufficiently long to allow the reliable determination of state-resolved UV photodissociation cross sections of SO(2) and CS(2) by using the VUV laser high-n Rydberg tagging TOF method.

Amyloidoma: A Rare Cause of Soft Tissue Swelling in the Thigh

Soft tissue amyloidoma of the extremities is extremely rare and there are only 12 reported cases in the English literature to date. We present a case of soft tissue amyloidoma of the thigh in a 74-year-old lady.

Evolution of photoluminescence mechanisms of Si(+)-implanted SiO2 films with thermal annealing

The information of band structure of silicon nanocrystal (nc-Si) embedded in SiO2 thin films synthesized by Si ion implantation and subsequent thermal annealing at various temperatures has been obtained from spectroscopy ellipsometric (SE) analysis. The indirect band structure and the energy gap of the nc-Si are not affected by the annealing. In contrast, the photoluminescence (PL) spectra show a continuous evolution with the annealing. Six PL bands located at 415, 460, 520, 630, 760, and 845 nm, respectively, have been observed depending on the annealing temperature. The annealing at 1100 degrees C yields the strongest PL band at 760 nm (approximately 1.63 eV) with the intensity much higher than that of all the other PL bands. Based on the knowledge of the band structure, the 760 nm-PL band could be attributed to the indirect band-to-band transition of the nc-Si assisted by the Si-O vibration of the nc-Si/SiO2 interface with the stretching frequency of approximately 1083 cm(-1) (approximately 0.13 eV). On the other hand, the first four PL bands mentioned above could originate from different extended defects in the oxide matrix, while the 845-nm PL band could be related to the interface luminescent centers.

Quality of life and functional outcome after primary total hip replacement. A five-year follow-up

We have evaluated the quality of life and functional outcome after unilateral primary total hip replacement (THR). Between 5 January 1998 and 31 July 2000, we recruited a consecutive series of 627 patients undergoing this procedure and investigated them prospectively. Each was assessed before operation and reviewed after six months, 18 months, three years and five years. The Short Form-36 Health Survey (SF-36) and Harris Hip scores were evaluated at each appointment. All dimensions of the SF-36 except for mental health and general health perception, improved significantly after operation and this was maintained throughout the follow-up. The greatest improvement was seen at the six-month assessment. On average, women reported lower SF-36 scores pre-operatively, but the gender difference did not continue post-operatively. The Harris Hip scores improved significantly after operation, reaching a plateau after 18 months. The improved quality of life was sustained five years after THR.

Assignment of rovibrational transitions of propyne in the region of 2934–2952cm−1 measured by two-color IR–vacuum ultraviolet laser photoion-photoelectron methods

The infrared (IR) spectrum of propyne in the region of 2934-2952 cm(-1) has been recorded by the IR-vacuum ultraviolet (VUV)-photoion method. The spectrum is shown to consist of two near-resonant, but noncoupled vibrational bands: the nu2 symmetric methyl C-H stretching vibrational band and a combination vibrational band nucs. The previously unobserved Q line of the nucs band is observed. The rotational transition lines of the nu2=1 band produces IR-VUV-pulsed field ionization-photoelectron (IR-VUV-PFI-PE) signal at the C3H4+ (nu2+=1) photoionization threshold. The rotational transition lines associated with the nucs band do not produce IR-VUV-PFI-PE signal. Rotational transition lines of both vibrational bands are assigned and simulated; and ab initio calculations further confirm the assignment.

Direct identification of propargyl radical in combustion flames by vacuum ultraviolet photoionization mass spectrometry

We have developed an effusive laser photodissociation radical source, aiming for the production of vibrationally relaxed radicals. Employing this radical source, we have measured the vacuum ultraviolet (VUV) photoionization efficiency (PIE) spectrum of the propargyl radical (C(3)H(3)) formed by the 193 nm excimer laser photodissociation of propargyl chloride in the energy range of 8.5-9.9 eV using high-resolution (energy bandwidth = 1 meV) multibunch synchrotron radiation. The VUV-PIE spectrum of C(3)H(3) thus obtained is found to exhibit pronounced autoionization features, which are tentatively assigned as members of two vibrational progressions of C(3)H(3) in excited autoionizing Rydberg states. The ionization energy (IE = 8.674 +/- 0.001 eV) of C(3)H(3) determined by a small steplike feature resolved at the photoionization onset of the VUV-PIE spectrum is in excellent agreement with the IE value reported in a previous pulsed field ionization-photoelectron study. We have also calculated the Franck-Condon factors (FCFs) for the photoionization transitions C(3)H(3) (+)(X;nu(i),i = 1-12)<--C(3)H(3)(X). The comparison between the pattern of FCFs and the autoionization peaks resolved in the VUV-PIE spectrum of C(3)H(3) points to the conclusion that the resonance-enhanced autoionization mechanism is most likely responsible for the observation of pronounced autoionization features. We also present here the VUV-PIE spectra for the mass 39 ions observed in the VUV synchrotron-based photoionization mass spectrometric sampling of several premixed flames. The excellent agreement of the IE value and the pattern of autoionizing features of the VUV-PIE spectra observed in the photodissociation and flames studies has provided an unambiguous identification of the propargyl radical as an important intermediate in the premixed combustion flames. The discrepancy found between the PIE spectra obtained in flames and photodissociation at energies above the IE(C(3)H(3)) suggests that the PIE spectra obtained in flames might have contributions from the photoionization of vibrationally excited C(3)H(3) and/or the dissociative photoionization processes involving larger hydrocarbon species formed in flames.

An experimental and quasiclassical trajectory study of the rovibrationally state-selected reactions: HD+(v=0–15,j=1)+He→HeH+(HeD+)+D(H)

The absolute integral cross sections for the formation of HeH+ and HeD+ from the collisions of HD+(v,j=1)+He have been examined over a broad range of vibrational energy levels v=0-13 at the center-of-mass collision energies (ET) of 0.6 and 1.4 eV using the vacuum ultraviolet (VUV) pulsed field ionization photoelectron secondary ion coincidence method. The ET dependencies of the integral cross sections for products HeH+ and HeD+ from HD+(v=0-4)+He collisions in the ET range of 0-3 eV have also been measured using the VUV photoionization guided ion beam mass spectrometric technique, in which vibrationally selected HD+(v) reactant ions were prepared via excitation of selected autoionization resonances of HD. At low total energies, a pronounced isotope effect is observed in absolute integral cross sections for the HeH++D and HeD++H channels with significant favoring of the deuteron transfer channel. As v is increased in the range of v=0-9, the integral cross sections of the HeH++D channel are found to approach those of HeD++H. The observed velocity distributions of products HeD+ and HeH+ are consistent with an impulsive or spectator-stripping mechanism. Detailed quasiclassical trajectory (QCT) calculations are also presented for HD+(v,j=1)+He collisions at the same energies of the experiment. The QCT calculations were performed on the most accurate ab initio potential energy surface available. If the zero-point energy of the reaction products is taken into account, the QCT cross sections for products HeH+ and HeD+ from HD+(v)+He are found to be significantly lower than the experimental results at ET values near the reaction thresholds. The agreement between the experimental and QCT cross sections improves with translational energy. Except for prethreshold reactivity, QCT calculations ignoring the zero-point energy in the products are generally in good agreement with experimental absolute cross sections. The experimental HeH+/HeD+ branching ratios for the HD+(v=0-9)+He collisions are generally consistent with QCT predictions. The observed isotope effects can be rationalized on the basis of differences in thermochemical thresholds and angular momentum conservation constraints.

Combined vacuum ultraviolet laser and synchrotron pulsed field ionization study of CH2BrCl

The pulsed field ionization-photoelectron (PFI-PE) spectrum of bromochloromethane (CH2BrCl) in the region of 85,320-88,200 cm-1 has been measured using vacuum ultraviolet laser. The vibrational structure resolved in the PFI-PE spectrum was assigned based on ab initio quantum chemical calculations and Franck-Condon factor predictions. At energies 0-1400 cm-1 above the adiabatic ionization energy (IE) of CH2BrCl, the Br-C-Cl bending vibration progression (nu1+=0-8) of CH2BrCl+ is well resolved and constitutes the major structure in the PFI-PE spectrum, whereas the spectrum at energies 1400-2600 cm-1 above the IE(CH2BrCl) is found to exhibit complex vibrational features, suggesting perturbation by the low lying excited CH2BrCl+(A 2A") state. The assignment of the PFI-PE vibrational bands gives the IE(CH2BrCl)=85,612.4+/-2.0 cm-1 (10.6146+/-0.0003 eV) and the bending frequencies nu1+(a1')=209.7+/-2.0 cm-1 for CH2BrCl+(X2A'). We have also examined the dissociative photoionization process, CH2BrCl+hnu-->CH2Cl++Br+e-, in the energy range of 11.36-11.57 eV using the synchrotron based PFI-PE-photoion coincidence method, yielding the 0 K threshold or appearance energy AE(CH2Cl+)=11.509+/-0.002 eV. Combining the 0 K AE(CH2Cl+) and IE(CH2BrCl) values obtained in this study, together with the known IE(CH2Cl), we have determined the 0 K bond dissociation energies (D0) for CH2Cl+-Br (0.894+/-0.002 eV) and CH2Cl-Br (2.76+/-0.01 eV). We have also performed CCSD(T, full)/complete basis set (CBS) calculations with high-level corrections for the predictions of the IE(CH2BrCl), AE(CH2Cl+), IE(CH2Cl), D0(CH2Cl+-Br), and D0(CH2Cl-Br). The comparison between the theoretical predictions and experimental determinations indicates that the CCSD(T, full)/CBS calculations with high-level corrections are highly reliable with estimated error limits of <17 meV.

Vacuum ultraviolet laser pulsed field ionization-photoelectron study of allyl radical CH2CHCH2

The pulsed field ionization-photoelectron (PFI-PE) spectrum of allyl radical CH2CHCH2 (C3H5) in the energy range of 65 200-66 600 cm-1 has been measured using vacuum ultraviolet laser. Based on the simulation of the rotational structures resolved in the vibrational PFI-PE bands of C3H5+(X 1A1;0(0+) and nu7+=1), the ionization energies (IEs) of C3H5(X 2A2;0(0)) to form C3H5+(X 1A1;0(0+) and nu7+=1) are determined to be 65 584.6+/-2.0 cm-1 (8.131 46+/-0.000 25 eV) and 66 020.9+/-2.0 cm-1 (8.185 56+/-0.000 25 eV), respectively, where nu7+(a1) is the symmetric C-C-C bending mode of C3H5+(X 1A1). These values are compared to IE(C3H5) values obtained in previous experimental and high-level ab initio quantum theoretical studies.

Thymectomy does not abrogate long-term acceptance of MHC class I-disparate lung allografts in miniature Swine

We have previously reported that tolerance to class I disparate lung allografts in miniature swine could be induced using an intensive 12-day course of tacrolimus and that pretransplant sensitization with immunogenic MHC class I allopeptides failed to block the induction of tolerance. We also have previously reported the importance of the presence of the thymus in the induction of tolerance to isolated heart, kidney, and combined heart-kidney transplants. In this study, we examined the impact of thymectomy on tolerance induction in lung transplantation.

METHODS

Orthotopic left lung transplantation was performed using MHC class I-disparate donors. The recipients received a 12-day course of high-dose tacrolimus (n = 6). Total thymectomies were performed in three of the swine 21 days prior to transplantation. Lung grafts were monitored by chest radiography and serial open lung biopsy.

RESULTS

All euthymic recipients maintained their grafts for over 1 year. None of the thymectomized recipients has experienced graft loss in the 6 to 10 months following transplantation. Although isolated lesions of obliterative bronchiolitis were occasionally seen in one thymectomized animal on biopsy, donor-specific unresponsiveness has been observed on assays of cell-mediated lymphocytotoxicity in all recipients. Moreover, co-culture assays have shown that recipient lymphocytes can strongly inhibit the normally robust response of naïve recipient-matched lymphocytes to donor antigen. This inhibition was not seen when using stimulators primed with third-party antigens against appropriate targets.

CONCLUSIONS

These data suggest that thymus-independent peripheral regulatory mechanisms may be sufficient to induce and maintain long-term acceptance of the lung allografts.

The role of indirect recognition of MHC class I and II allopeptides in a fully mismatched miniature swine model of lung transplantation

Considerable evidence suggests that indirect recognition of MHC allopeptides plays an important role in solid-organ rejection. Here, we examine whether immunization with class I or class II allopeptides accelerates rejection in a fully MHC-mismatched lung transplant model in miniature swine.

METHODS

Recipients were immunized with either donor-derived class I or class II peptides. Sensitization to the peptides was confirmed by DTH testing and in vitro proliferation assays. Nonimmunized control (n = 6), class I peptide-immunized (n = 3), and class II peptide-immunized (n = 3) swine were transplanted with fully mismatched lungs using only a 12-day course of tacrolimus.

RESULTS

One control animal rejected its graft on postoperative day 103, while the others maintained their grafts for over 1 year. In the class I peptide-immunized group, two recipients rejected their grafts (days 14 and 52). The third animal has not rejected the graft (day 120, experiment is ongoing). In contrast, in the class II-peptide immunized group, only one animal rejected its graft on day 52, while the others maintained their grafts over 1 year. Both anti-donor IgM and IgG antibodies were detectable in all acute rejectors, although no alloantibody was detectable in long-term acceptors. Regardless of the fate of the graft, all animals have maintained their proliferative responses to the peptides. However, only acceptors maintained donor-specific hyporesponsiveness in cell-mediated lymphocytotoxity and mixed lymphocyte reaction assays.

CONCLUSIONS

Pretransplant sensitization of lung allograft recipients to donor allopeptides accelerates graft rejection. This appears particularly true for class I-derived allopeptides, suggesting that class II molecules may be less antigenic when presented indirectly.

Rotationally resolved vacuum ultraviolet pulsed field ionization-photoelectron vibrational bands for HD+(X 2Sigmag+,v+=0-20)

The authors have obtained rotationally resolved vacuum ultraviolet pulsed field ionization-photoelectron (vuv-PFI-PE) spectrum of HD in the photon energy range of 15.29-18.11 eV, covering the ionization transitions HD+(X 2Sigmag+,v+=0-21,N+)<--HD(X 1Sigmag+,v"=0,J"). The assignment of rotational transitions resolved in the vuv-PFI-PE vibrational bands for HD+(X 2Sigmag+,v+=0-20) and their simulation using the Buckingham-Orr-Sichel (BOS) model are presented. Rotational branches corresponding to the DeltaN=N+-J"=0, +/-1, +/-2, +/-3, and +/-4 transitions are observed in the vuv-PFI-PE spectrum of HD. The BOS simulation shows that the perturbation of vuv-PFI-PE rotational line intensities due to near resonance autoionization is very minor at v+>or=5 and decreases as v+ is increased. Thus, the rotationally resolved PFI-PE bands for HD+(v+>or=5) presented here provide reliable estimates of state-to-state cross sections for direct photoionization of HD, while the rotationally resolved PFI-PE bands for HD+(v+<5) are useful data for fundamental understanding of the near resonance autoionizing mechanism. On the basis of the rovibrational assignment of the vuv-PFI-PE bands, the ionization energies for the formation of HD+(X 2Sigmag+,v+=0-20,N+) from HD(X 1Sigmag+,v"=0,J") and the vibrational constants (omegae, omegaechie, omegaeye, and omegaeze), the rotational constants (Be and alphae), the vibrational energy spacings, and the dissociation energy for HD+(X 2Sigmag+) are determined. As expected, these values are found to be in excellent agreement with high level theoretical predictions.

Acute abdomen as a cause of death in sudden, unexpected deaths in the elderly

AIMS

This study profiles patients aged 70 years or above dying suddenly of an 'acute abdomen' and investigates the specific features associated with the conditions and their diagnoses.

METHODS

A retrospective study using data obtained from autopsy and police reports held in the Forensic Medicine Section of the University of Edinburgh.

RESULTS

From 1997 to 2000, out of 2121 autopsies of patients aged 70 or above, an 'acute abdomen' was considered as a primary cause of death in 111 cases. The number of cases increased over the period of study. Peptic ulcer disease was the commonest underlying cause of death. Twenty-nine (26.1%) cases were due to its complications, namely gastrointestinal haemorrhage and perforation. Sixty-nine (62.2%) patients were seen by a medical practitioner in circumstances arising from the onset of acute abdomen. In 27 (39.1%) cases a provisional diagnosis was recorded.

CONCLUSION

The 'acute abdomen' is still an appreciably frequent cause of death in sudden, unexpected deaths in the older age group. Some of the deaths may have been preventable with an early diagnosis. A high level of vigilance and early attention to an 'acute abdomen' by medical practitioners is therefore advocated.

Performance of silicon nanocrystal non-volatile memory devices under various programming mechanisms

Non-volatile memory devices based on silicon nanocrystal synthesized with very low energy Si+ implantation are fabricated. Memory performance under various programming mechanisms including Fowler-Nordheim (FN), drain-bias channel-hot-electron (DCHE), and source-bias channel-hot-electron (SCHE) has been investigated. It is observed that the DCHE yields the largest memory window among the three programming mechanisms. The DCHE and SCHE have similar endurance characteristics, but the SCHE has a longer retention time than the DCHE. Both the DCHE and SCHE have a larger memory window, a better endurance and a longer retention time as compared to the FN. Explanations to the phenomena are given.

Rovibrationally selected and resolved state-to-state photoionization of ethylene using the infrared-vacuum ultraviolet pulsed field ionization-photoelectron method

By preparing ethylene [C2H4(X1Ag)] in selected rotational levels of the nu11(b1u), nu2+nu12(b1u), or nu9(b2u) vibrational state with infrared (IR) laser photoexcitation prior to vacuum ultraviolet (VUV) laser photoionization, we have recorded rotationally resolved pulsed field ionization-photoelectron (PFI-PE) spectra for C2H4+(X2B3u) in the energy region of 0-3000 cm(-1) above the ionization energy (IE) of C2H4(X1Ag). Here, nu2(ag), nu9(b2u), nu11(b1u), and nu12(b1u) represent the C-C stretching, CH2 stretching, CH2 stretching, and CH2 bending modes of C2H4(X1Ag), respectively. The fully rovibrationally resolved spectra have allowed unambiguous symmetry assignments of the observed vibrational bands, which in turn have provided valuable information on the photoionization dynamics of C2H4. The IR-VUV photoionization of C2H4(X1Ag) via the nu11(b1u) or nu2+nu12(b1u) vibrational states is found to predominantly produce vibrational states of C2H4+(X2B3u) with b1u symmetry, which cannot be observed in single-photon VUV-PFI-PE measurements of C2H4(X1Ag). The analysis of the observed IR-VUV-PFI-PE bands has provided the IE(C2H4) = 84,790.2(2) cm(-1) and accurate vibrational frequencies for the nu4+(au)[84.1(2) cm(-1)], nu12+(b1u)[1411.7(2) cm(-1)], nu4+ +nu12+(b1g)[1482.5(2) cm(-1)], nu2+(ag)[1488.3(2) cm(-1)], nu2+ + nu4+(au)[1559.2(2) cm(-1)], 2nu4+ + nu12 +(b1u)[1848.5(2) cm(-1)], 4nu4+ + nu12 +(b1u)[2558.8(2) cm(-1)], nu2+ + nu12 +(b1u)[2872.7(2) cm(-1)], and nu11+(b1u)[2978.7(2) cm(-1)] vibrational states of C2H4+(X2B3u), where nu4+ is the ion torsional state. The IE(C2H4) and the nu4+(au), nu2+(ag), and nu2+ + nu4+ (au) frequencies are in excellent accord with those obtained in previous single-photon VUV-PFI-PE measurements. The other ion vibrational frequencies represent new experimental determinations. We have also performed high-level ab initio anharmonic vibrational frequency calculations for C2H4(X1Ag) and C2H4+(X2B3u) at the CCSD(T)/aug-cc-pVQZ level for guidance in the assignment of the IR-VUV-PFI-PE spectra. All theoretical vibrational frequencies for the neutral and ion, except the ion torsional frequency, are found to agree with experimental vibrational frequencies to better than 1%.

Vacuum ultraviolet pulsed field ionization study of ND3: accurate thermochemistry for the ND2-ND2+ and ND3-ND3+ system

The dissociation of energy-selected ND(3) (+) to form ND(2) (+)+D near its threshold has been investigated using the pulsed field ionization-photoelectron (PFI-PE)-photoion coincidence method. The breakdown curves for ND(3) (+) and ND(2) (+) give a value of 15.891+/-0.001 eV for the 0 K dissociation threshold or appearance energy (AE) for ND(2) (+) from ND(3). We have also measured the PFI-PE vibrational bands for ND(3) (+)(X;v(2) (+)=0, 1, 2, and 3), revealing partially resolved rotational structures. The simulation of these bands yields precise ionization energies (IEs) for ND(3) (+) X(0,v(2) (+)=0-3,0,0)<--ND(3) X(0,0,0,0). Using the 0 K AE (ND(2) (+)) and IE(ND(3))=10.200+/-0.001 eV determined in the present study, together with the known 0 K bond dissociation energy for ND(3) [D(0)(D-ND(2))=4.7126+/-0.0025 eV], we have determined the D(0)(ND(2) (+)-D), IE(ND(2)), and 0 K heat of formation for ND(2) (+) to be 5.691+/-0.001 eV, 11.1784+/-0.0025 eV, and 1261.82+/-0.4 kJ/mol, respectively. The PFI-PE spectrum is found to exhibit a steplike feature near the AE(ND(2) (+)), indicating that the dissociation of excited ND(3) (+) at energies slightly above the dissociation threshold is prompt, occurring in the time scale </=10(-7) s, as observed for the NH(3) system. The available energetic data for the NH(2)-NH(2) (+) and NH(3)-NH(3) (+) system are found to be in excellent accord with those for the ND(2)-ND(2) (+) and ND(3)-ND(3) (+) system after taking into account the zero-point vibrational energy corrections. This finding indicates that the thermochemical data for these two systems are reliable with well-founded error limits.

Depth Profiling of Charging Effect of Si Nanocrystals Embedded in SiO2: A Study of Charge Diffusion among Si Nanocrystals

Si nanocrystal (nc-Si) embedded in SiO2 thin film is synthesized with low-energy Si ion implantation. Depth profiling of the charging effect of the nc-Si is determined from X-ray photoemission measurement. It is observed that there is a strong correlation between the depth profile of the charging effect and the nc-Si depth distribution. The charging effect is found to decrease with the increase of nc-Si concentration and to vanish when a densely stacked nanocrystal layer is formed. The phenomenon is attributed to the charge diffusion among the nanocrystals. The charge diffusion in the nanocrystal layer may have an important implication for nanocrystal flash memory. When such a layer is used as the charge-storage layer in the memory cells, the stored charges could be lost due to the rapid charge diffusion among the nc-Si if a single defect exists in the tunneling oxide, causing a reliability problem in data retention.