Experimental evaluation of particle exposure at different seats in a single-aisle aircraft cabin.

During the COVID-19 pandemic, exposure to particles exhaled by infected passengers in commercial aircraft cabins has been a great concern. Currently, aircraft cabins adopt mixing ventilation. However, complete mixing may not be achieved, and thus the particle concentration in the respiratory zone may vary from seat to seat in a cabin. To evaluate the particle exposure in a typical single-aisle aircraft cabin, this investigation constructed an aircraft cabin mockup for experimental tests. Particles were released from a single source or dual sources at different seats to represent particles exhaled by infected passengers. The particle concentrations in the respiratory zones at various seats were measured and compared. The particle exposure was evaluated in both a cross section and a longitudinal section. Leaving the middle seat vacant to reduce particle exposure was also addressed. In addition, the velocity fields and air temperatures were measured to provide a better understanding of particle transport. It was found that the particle exposure at the window seat is always the lowest, regardless of the particle release locations. If the passenger seated in the middle does not release particles, his/her presence enhances the particle dispersion and thereby reduces the particle exposure for adjacent passengers. In the cabin mockup, the released particles can be transported across at least four rows of seats in the longitudinal direction.

Continuous wave and ReS2 passively Q-switched Er : SrF2 laser at ∼3 µm.

We report on an efficient Er:SrF2 laser at 2.79 µm. A continuous wave output power of 1.06 W was obtained with a slope efficiency of 41%, significantly exceeding the Stokes efficiency of 35%. Stable Q-switched laser operation was realized by using an ReS2 saturable absorber, generating an average output power of 0.58 W with a pulse duration of 508 ns at a repetition rate of 49 kHz, corresponding to a pulse energy of 12.1 µJ.

Passively Q-switched Ho,Pr:LiLuF4 laser with graphitic carbon nitride nanosheet film.

A few-layer graphitic carbon nitride (g-CN) nanosheet film on an yttrium aluminum garnet substrate was fabricated and employed as saturable absorber for a passively Q-switched Ho,Pr:LiLuF4 laser at 2.95 µm. Under an absorbed pump power of 3.89 W at a pump wavelength of 1.15 µm, a maximum average output power of 101 mW was realized with a pulse duration of 420 ns and a repetition rate of 93 kHz. Even shorter pulse durations of 385 ns were obtained at a reduced output coupler transmission.

Graphitic C3N4 as a new saturable absorber for the mid-infrared spectral range.

The saturable absorption properties of few-layer graphitic carbon nitride (g-C3N4) nanosheets near 3 µm were investigated. A stable Q-switched Er:Lu2O3 laser at 2.84 µm was realized by using a home-made g-C3N4 saturable absorber (SA), generating a pulse duration of 351 ns and an average output power of 1.09 W at a repetition rate of 99 kHz, corresponding to a pulse energy of 11.1 µJ. Our result indicates a great potential of g-C3N4 as a new SA in the 3 µm wavelength range.

Watt-level passively Q-switched Er:Lu2O3 laser at 2.84 µm using MoS2.

Efficient diode-pumped passively Q-switched Er:Lu2O3 laser operation at 2.84 µm was realized. A few-layer MoS2 nanosheet film on a YAG substrate, was fabricated and employed as saturable absorber (SA) in a short plane-plane cavity. Under an absorbed diode laser pump power of 7.61 W, an average output power of 1.03 W was generated with a pulse duration of 335 ns and a repetition rate of 121 kHz, resulting in a pulse energy of 8.5 µJ.

Long-Term Outcomes of Simultaneous Liver-Kidney Transplant Patients with Hepatitis B Compared to with Liver Transplant Alone.

BACKGROUND: The number and survival rate of simultaneous liver-kidney transplant (SLKT) recipients have increased dramatically since 2002. However, the long-term effectiveness of SLKT in patients with hepatitis B is unknown. MATERIAL/METHODS: Forty-six patients who visited the Organ Transplant Center of the Shanghai First People's Hospital between January 2001 and May 2005 had hepatitis B virus infection and renal failure (any degree), and underwent organ transplantation: 21 patients underwent SLKT and 25 patients underwent liver transplant (LT) alone. RESULTS: The 1-, 3-, and 5-year survival rates of SLKT recipients were 90.5%, 81.0%, and 81.0%, respectively. Incidence of acute hepatic allograft rejection between SLKT recipients and LT recipients (33% vs. 16%) did not reach significance (P=0.170). Despite higher infection rate, more prevalent hepatitis B relapse, and longer stay in the intensive care unit, SLKT recipients experienced significantly higher 1-year survival rate (90.5%) compared with LT recipients (60%, P=0.019). Multivariate regression analysis revealed that postoperative renal failure (odds ratio (OR)=48, P=0.003) and Risk/Injury/Failure/Loss/End-stage (RIFLE) stage (OR=8, P=0.012) were independent risk factors for postoperative death after LT. CONCLUSIONS: SLKT in patients with hepatitis B had higher early-stage infection rate, but had a higher long-term survival rate compared with the LT group. Although the incidence of postoperative hepatitis B relapse in SLKT recipients was higher, timely and reasonable treatment can ensure long-term survival of patients. Worsening RIFLE stage of recipients can predict high mortality when only given LT. SLKT might be a better choice for RIFLE stage 2 or 3 patients than LT alone.

Experimental and theoretical investigation on passively Q-switched laser action in c-cut Nd:MgO:LiNbO3.

The performance of a diode-pumped c-cut Nd:MgO:LiNbO3 laser at 1093 nm was demonstrated. Under an absorbed pump power of 7.450 W, a maximum continuous wave output power of 1.570 W was obtained, corresponding to a slope efficiency of 26.0%. For passive Q-switching operation, 24 ns pulses were observed with a repetition rate of 17.1 kHz, resulting in a peak power of 1357 W. The experimental results were theoretically analyzed by a rate equation model, in which the Gaussian spatial distribution of the intracavity photon density was taken into account.

Preclinical evaluation of a newly designed ureteral stent and magnetic retrieval catheter for minimally invasive stent removal.

OBJECTIVE: To develop a simple minimally invasive method for ureteral stent removal that does not require cystoscopy or fluoroscopic guidance. MATERIALS AND METHODS: We developed a novel ureteral stent comprising the main body of a stent and an iron oxide-coated net that was woven of processed polyester sutures. The ureteral stent was retrieved by a magnetic retrieval catheter with small hooks on the neck surface. Detailed analysis of the necessary mechanical and magnetic properties was performed, and we conducted retrieval tests of the ureteral stent from a specially designed urinary system model. RESULTS: The breaking strength and Young modulus of the processed polyester sutures were 10.12 ± 0.30 N and 9143 ± 7 N/tex, respectively. Thermogravimetric tests showed that the iron (III) oxide powders on the processed sutures accounted for 23% of the total weight. The magnetization value of the magnetic retrieval catheter was 578 emu/g. The dissolution times of polyvinyl alcohol wrapped the net in saline or urine were 24.2 ± 2.0 and 23.6 ± 3.1 hours, respectively. All stents in both the experimental and the control groups were successfully removed from the specially designed urinary model. However, the retrieval time in the experimental group was significantly shorter than that in the control group (38.6 ± 12.6 vs 59 ± 15.7 seconds; P <.05). CONCLUSION: Ureteral stent removal using a magnetic retrieval catheter with small capture devices is considered feasible. This technique is easy to learn and should be considered as suitable for use on an outpatient basis.

Decrease expression of microRNA-20a promotes cancer cell proliferation and predicts poor survival of hepatocellular carcinoma.

BACKGROUND: Growing evidences indicate microRNAs play important roles in cancer development, progression, metastasis and may constitute robust biomarkers for cancer prognosis. The aim of this study was to identify the clinical and functional association of microRNA-20a (miR-20a) in hepatocellular carcinoma (HCC). METHODS: MiR-20a was detected using Taqman real-time polymerase chain reaction. Kaplan-Meier and Cox proportional regression analyses were utilized to determine the association of miR-20a with survival of patients. The potential functions of miR-20a on proliferation were evaluated by proliferation and flow cytometry analysis. The direct target gene of miR-20a was also identified by luciferase reporter assays. RESULTS: MiR-20a was lower in primary HCC than normal liver, and were further decreased in those with post-liver transplantation (LT) HCC recurrence compared with those with non-recurrence (p = 0.001). Patients with lower miR-20a expression had significantly poorer recurrence-free survival (RFS, Log rank p < 0.001) and overall survival (OS, Log rank p < 0.001). Multivariate analysis revealed that lower miR-20a was an independent predictor of poor prognosis. MiR-20a restoration could suppress HepG2 and SMMC-7721 cells proliferation and induce cell cycle G1 arrest and apoptosis. Subsequent investigations revealed that miR-20a directly targeted myeloid cell leukemia sequence 1 (Mcl-1) and reduced the endogenous protein level of Mcl-1 in HCC cells. CONCLUSIONS: MiR-20a is decreased in HCCs and correlates with HCC recurrence and prognosis. Down-regulation of miR-20a increases the proliferation abilities of HCC cells. Our findings suggest miR-20a may represent a novel potential therapeutic target and biomarker for survival of HCC patients.

The unusual mycobacterial chaperonins: evidence for in vivo oligomerization and specialization of function.

The pathogen Mycobacterium tuberculosis expresses two chaperonins, one (Cpn60.1) dispensable and one (Cpn60.2) essential. These proteins have been reported not to form oligomers despite the fact that oligomerization of chaperonins is regarded as essential for their function. We show here that the Cpn60.2 homologue from Mycobacterium smegmatis also fails to oligomerize under standard conditions. However, we also show that the Cpn60.2 proteins from both organisms can replace the essential groEL gene of Escherichia coli, and that they can function with E. coli GroES cochaperonin, as well as with their cognate cochaperonin proteins, strongly implying that they form oligomers in vivo. We show that the Cpn60.1 proteins, but not the Cpn60.2 proteins, can complement for loss of the M. smegmatis cpn60.1 gene. We investigated the oligomerization of the Cpn60.2 proteins using analytical ultracentrifugation and mass spectroscopy. Both form monomers under standard conditions, but they form higher order oligomers in the presence of kosmotropes and ADP or ATP. Under these conditions, their ATPase activity is significantly enhanced. We conclude that the essential mycobacterial chaperonins, while unstable compared to many other bacterial chaperonins, do act as oligomers in vivo, and that there has been specialization of function of the mycobacterial chaperonins following gene duplication.

[Effect of modified Badenoch operation on the treatment of posterior urethral stricture].

OBJECTIVE: To determine the effects of modified pull-through operation (Badenoch operation) on the treatment of posterior urethral stricture. METHODS: From September 2001 to December 2010 traditional pull-through operation was Modified for two times in our center. A total of 129 patients with posttraumatic posterior urethral stricture resulting from pelvic fracture injury underwent the modified urethral pull-through operation. Stricture length was 1.5 to 5.3 cm (mean 2.9 cm). Of the patients 43 had undergone at least 1 previous failed management for stricture. In phase 1 (from September 2001 to January 2008), the improving items include: (1) The distal urethral end was stitched and tied to the catheter. (2) As catheter was inserted into bladder and 20 ml water was injected into catheter balloon, the distal urethral end was fixed in the proximal urethra and an overlaying of 1.5 cm was formed between the two ends. (3) Three weeks later, it was tried to insert the catheter to bladder. After the urethral stump necrosis and the catheter separating from the urethra, the catheter was removed. In phase 2 (from February 2008 to December 2010), based on the above, irrigating catheter was used. After the surgery, urethra was irrigated with 0.02% furacillin solution through the catheter 3 times a day. All patients were followed up for at least 6 months. If patients had no conscious dysuria and maximum urinary flow rate (Qmax) > 15 ml/s, the treatment was considered successful. All complications were recorded. RESULTS: In phase 1, the 96 patients (101 times) underwent the procedure. The treatment was successful in 88 patients (success rate 92%). Within 1 to 13 days after removal of the catheter, urethral stricture was recurred in 8 patients. They had to undergo cystostomy once more for 3 to 11 months before reoperation (the 3 patients' reoperation was in phase 2). The 8 cases were treated successfully. In phase 2, 33 patients (total 36 times) underwent the procedure. One patient was failed (success rate 97%). The actual follow-up time is 7 to 93 months (An average of 37.6 months). Qmax is (22 ± 5) ml/s. No complications such as urinary incontinence, erectile pain, urinary shortening happened. CONCLUSIONS: The modified urethral pull-through operation is effective for the surgical treatment of posttraumatic posterior urethral stricture. It has a high success rate with durable long-term results. Complications are few. The procedure is simple, less demanding and especially suitable in patients who had previously undergone failed surgical treatments.

Renal vein lengthening using gonadal vein reduces surgical difficulty in living-donor kidney transplantation.

BACKGROUND: During living-donor kidney transplantation, to maximally decrease donor injury, the right kidney with lower glomerular filtration rate often is selected as the donor kidney. However, the renal vein of the right kidney is relatively short for transplantation. The gonadal vein is essentially useless and is easily accessed during the donor nephrectomy. METHODS: Seventeen live kidney donors received right kidney nephrectomy for living-donor kidney transplantation. Short renal veins were lengthened by circular anastomosis or spiral anastomosis of longitudinally cut gonadal veins. The renal function of receivers was evaluated using creatinine clearance. RESULTS: The renal veins were extended by 2.0-2.7 cm with circular anastomosis and 4.1-4.5 cm with spiral anastomosis with an average of 2.5 ± 0.7 cm. Lengthening of renal veins averaged 20.4 ± 4.2 min. All surgeries were successful, significantly reducing difficulty of vascular anastomosis during transplantation. No poor early graft function occurred. No side effects were observed in donors. CONCLUSIONS: When donor renal veins are too short for effective kidney transplantation and may affect reliability of vascular anastomosis, they can be lengthened by using gonadal veins without increasing injury to the donor. Successful extension of donor kidney renal veins expands the indication for right donor kidneys.

Modified urethral pull-through operation for posterior urethral stricture and long-term outcome.

PURPOSE: We present our experience, technique and long-term results of the modified urethral pull-through operation for posttraumatic posterior urethral stricture. MATERIALS AND METHODS: A total of 113 patients with posttraumatic posterior urethral stricture resulting from pelvic fracture injury underwent the modified urethral pull-through operation at our department from August 1999 to March 2007. Patient age was 17 to 69 years (mean 35.2). Stricture length was 1.5 to 4.7 cm (mean 2.6). Of the patients 52 (46.0%) had undergone at least 1 previous failed management for stricture, including urethroplasty in 29 (25.7%). Followup included symptomatic and urinary flow rate evaluation, which was performed 6 and 12 months after the modified urethral pull-through operation in all patients and thereafter when needed, and urethrography and/or urethroscopy in patients with voiding symptoms. Clinical outcomes were considered a success when no postoperative procedure was needed. RESULTS: Patients were followed for 12 to 86 months (mean 48.5). During that period 109 patients were symptom-free and required no further procedures. The maximal flow rate in each case was greater than 15 ml per second. Recurrent stricture developed in 4 patients. All treatment failures occurred within the first 8 months postoperatively. Failed repairs were successfully managed endoscopically in 1 patient by urethral dilation in 1 and by repeating the pull-through operation in the remaining 2 for a primary success rate of 96.5% and a final success rate of 100%. All patients were continent. Erectile dysfunction was noted postoperatively in 5 patients (3.7%). There was no chordee, penile shortening or urethral diverticula. CONCLUSIONS: The modified urethral pull-through operation is effective for the surgical treatment of posttraumatic posterior urethral stricture. It has a high success rate with durable long-term results. Complications are few. The procedure is simple, less demanding and especially suitable in patients who had previously undergone failed surgical treatments.

[Influence of transforming growth factor beta1 on long-term renal allograft function].

OBJECTIVE: To determine the association between urine transforming growth factor beta(1) (TGF-beta(1)) concentration and long-term renal allograft function. METHODS: Patients undergoing kidney transplantation between August 1, 1999 and June 30, 2001 and survived for one year with normal renal functions were investigated. The blood and urine TGF-beta(1) concentrations were tested at an interval of at least 6 months. Totally 134 patients completed the 3-year follow up investigation. Correlation between their renal functions (creatinine clearance rates) and their urine relative TGF-beta(1) concentrations 1 year after renal transplantation were determined. Of the 134 renal recipients, 16 were diagnosed to have chronic allograft nephropathy (CAN), and their blood and urine TGF-beta(1) concentrations 1 year after renal transplantation were compared with those of the recipients free of CAN. RESULTS: There was a positive correlation between long-term renal functions (loss of creatinine clearance rates) and in relative concentration of TGF-beta(1) urine 1 year after renal transplantation. The urine TGF-beta(1) concentrations of CAN and CAN-free recipients 1 year after transplantation were 182.7-/+40.2 and 398-/+33.5 pg/mg.Cr, respectively, showing significant differences. The blood TGF-beta(1) concentrations of CAN and CAN-free recipients were comparable (32.1-/+4.7 and 31.9-/+4.8 ng/ml, respectively). CONCLUSION: Urine TGF-beta(1) is significantly elevated even before the onset of renal dysfunction in patients with CAN, and urine TGF-beta(1) level in early stage after renal transplantation can help predict long-term renal function.

[Association between TGF-Beta1 in allograft and chronic allograft nephropathy].

OBJECTIVE: To investigate the relation between TGF-beta1 in allograft and chronic allograft nephropathy (CAN). METHODS: The levels of urine TGF-beta1 were tested in 146 recipients whose renal function were normal from September 1, 2000 to January 31, 2001. Twenty recipients with the highest level of urine TGF-beta1 were classified in group A, while 20 other recipients with the lowest level of urine TGF-beta1 were classified in group B. In these two groups biopsies were carried out in 14 cases and 12 cases respectively, and TGF-beta1 mRNA in the biopsies was measured by RT-PCR. The levels of TGF-beta1 in the blood were also measured in the two groups. Three years later, the renal function was compared between the two groups. Biopsies were carried out in renal recipients whose creatinine is higher than normal. RESULTS: The level of TGF-beta1 in the blood showed no significant difference between the two groups; 3 years after transplantation, the loss of renal function in group A was severer than that in group B. The number levels of CAN cases in group A was larger than that in group B. The expression levels of TGF-beta1 and TGF-beta1 mRNA of the allografts were higher in group A than in group B; there were statistically significant differences between the two groups. CONCLUSION: The findings suggest that there is an association between TGF-beta1 in kidneys and CAN. The level of urine TGF-beta1 after renal transplantation may predict future renal function.

Effect of losartan on slowing progression of chronic allograft nephropathy.

OBJECTIVE: To investigate the effects of losartan, a specific angiotensin II receptor blocker, on slowing progression of renal insufficiency in patients with biopsy-proven chronic allograft nephropathy (CAN) and the molecular mechanism of the therapy. METHODS: Twenty-two renal transplant recipients with biopsy-proven CAN (group A) were treated with losartan within two months after renal dysfunction for at least one year. Losartan was administered at a dose of 50 mg/d. Twenty-four recipients in the same fashion (group B) who never received angiotensin II receptor antagonist were studied as control. The investigation time for each patient lasted one year. Renal functions and concentrations of plasma and urine transforming growth factor-beta1 (TGF-beta1) were compared between the two groups at the initiation and end of the study. In group A, expressions of TGF-betal mRNA and immunofluorescence intensity of TGF-betal protein and pathological alterations in renal biopsy specimens were compared between before losartan therapy and after one year of the therapy. RESULTS: At the initiation of the investigation, no significant differences were found between group A and group B in clinical data such as donor age, cold-ischemia time, HLA mismatch, levels of creatinine clearance (Ccr), plasma and urine TGF-beta1 concentrations. One year later, 14 of 22 (63.6%) patients showed stable or improved graft functions in group A, and 4 of 24 (16.7%) in group B. The difference was significant (P < 0.05). At the end of the study, urine TGF-betal concentration was 273.8 +/- 84.1 pg/mg x Cr in group A and 457.2 +/- 78.9 pg/mg x Cr in group B. During one year study period, loss of Ccr was 6.6 +/- 5.4 mL/min in group A and 16.2 +/- 9.1 mL/min in group B. Both of the differences were significant between the two groups (P < 0.01). No significant differences were found in plasma TGF-betal concentrations between the four values determined at the initiation and end of the study in the two groups (F = 2.56, P > 0.05). After one year losartan therapy, group A showed a significant decrease in expressions of TGF-beta1 mRNA and TGF-betal protein in renal biopsy specimens [from 1.59 +/- 0.35 to 0.96 +/- 0.27 and from (10.83 +/- 2.33) x l0(6) to (6.41 +/- 1.53) x 10(6), respectively; both P < 0.01], but in light microscopy the histological changes were similar to the first renal biopsy. Losartan was excellently tolerated in all patients in group A. No cases with losartan therapy showed too low blood pressure and other side effects. CONCLUSION: This study suggests that losartan have an effect on slowing progression of CAN. Reducing production of intrarenal TGF-betal may play a decisive role in the efficacy of losartan.

[Sildenafil citrate for erectile dysfunction in male kidney transplant recipients].

OBJECTIVE: To evaluate the efficacy and safety of sildenafil citrate in man kidney transplant recipients with erectile dysfunction. METHODS: One hundred and seventy married males, aged 26 approximately 50 years, who had received kidney transplantations at least half a year before and whose serum creatinine was under 133 umol/l, were selected randomly in the study. Their sexual function was investigated according to the International Index of Erectile Function-5 (IIEF-5), and those with erectile dysfunction (ED) were treated with oral sildenafil citrate for 6 months. The efficacy was assessed by IIEF-5. RESULTS: Fifty-three men with ED received oral sildenafil citrate for 6 months. At the end of the treatment, each index in IIEF-5 increased significantly. There were no interactions between sildenafil and cyclosporine and there was no significant adverse effect of sildenafil on the graft function. CONCLUSION: Sildenafil is an effective and safe agent for the treatment of ED in kidney transplant recipients.

[TGF-beta1 in allograft and long-term renal function].

OBJECTIVE: To determine the relation between transforming growth factor beta1 (TGF-beta1) in allograft and long-term renal function. METHODS: Urine TGF-beta1 relative concentration (divided by urine creatinine) was tested in 168 recipients whose renal function was normal between August 1, 2000 and March 31, 2001. Twenty patients with higher urine TGF-beta1 relative concentrations formed Group A, and another 20 patients with lower urine TGF-beta1 formed Group B. In both groups biopsies were carried out in 15 cases and 12 cases respectively, and TGF-beta1 in the biopsis was tested by immunofluorescence. Blood TGF-beta1 concentrations in the 2 groups were also tested. Three years later, the renal function was compared between the 2 groups. Biopsies were carried out in renal recipients whose creatinine was higher than that of the normal. RESULTS: Blood TGF-beta1 concentrations in the 2 groups were not different significantly; 3 years after the transplantation, there was more loss of renal function and more chronic allograft nephropathy (CAN) cases in Group A than in Group B. Expression of TGF-beta1 in the allografts was higher in Group A than in Group B. The differences in the 2 groups were significant. CONCLUSION: The findings suggest that the higher expression of TGF-beta1 in the allografts is associated with the lower long-term survival rate of kidney graft. The level of urine TGF-beta1 after the renal transplantation can predict the long-term renal function.

[Investigation of sexual function in male kidney transplant recipients].

OBJECTIVE: To observe the change of sexual function in male kidney transplant recipients. METHODS: Sixty married males, aged 26 to 45 years, who had received kidney transplantations at least half a year before and whose serum creatinine (Scr) was under 200 mumol/L, were selected randomly in the study. Sexual functions were reviewed before and after the patients' renal failure and after kidney transplantations. The results were analyzed in Chi-Square test methods. RESULTS: Their sexual functions, significantly aggravated after renal failure, were improved after kidney transplantations, but failed to return to normal. The recipients had a common worry that their sex lives might affect the renal grafts. CONCLUSIONS: Kidney transplantations significantly improve the sexual functions of these renal failure patients. It is quite necessary to provide sexological guidance to kidney transplant recipients and their spouses.