An improved tetracycline-inducible expression system for fission yeast.

The ability to manipulate gene expression is valuable for elucidating gene function. In the fission yeast Schizosaccharomyces pombe, the most widely used regulatable expression system is the nmt1 promoter and its two attenuated variants. However, these promoters have limitations, including a long lag, incompatibility with rich media and unsuitability for non-dividing cells. Here, we present a tetracycline-inducible system free of these shortcomings. Our system features the enotetS promoter, which achieves a similar induced level and a higher induction ratio compared to the nmt1 promoter, without exhibiting a lag. Additionally, our system includes four weakened enotetS variants, offering an expression range similar to that of the nmt1 series promoters but with more intermediate levels. To enhance usability, each promoter is combined with a Tet-repressor-expressing cassette in an integration plasmid. Importantly, our system can be used in non-dividing cells, enabling the development of a synchronous meiosis induction method with high spore viability. Moreover, our system allows for the shutdown of gene expression and the generation of conditional loss-of-function mutants. This system provides a versatile and powerful tool for manipulating gene expression in fission yeast.

Lightweight Authentication Mechanism for Industrial IoT Environment Combining Elliptic Curve Cryptography and Trusted Token.

With the promotion of Industry 4.0, which emphasizes interconnected and intelligent devices, several factories have introduced numerous terminal Internet of Things (IoT) devices to collect relevant data or monitor the health status of equipment. The collected data are transmitted back to the backend server through network transmission by the terminal IoT devices. However, as devices communicate with each other over a network, the entire transmission environment faces significant security issues. When an attacker connects to a factory network, they can easily steal the transmitted data and tamper with them or send false data to the backend server, causing abnormal data in the entire environment. This study focuses on investigating how to ensure that data transmission in a factory environment originates from legitimate devices and that related confidential data are encrypted and packaged. This paper proposes an authentication mechanism between terminal IoT devices and backend servers based on elliptic curve cryptography and trusted tokens with packet encryption using the TLS protocol. Before communication between terminal IoT devices and backend servers can occur, the authentication mechanism proposed in this paper must first be implemented to confirm the identity of the devices and, thus, the problem of attackers imitating terminal IoT devices transmitting false data is resolved. The packets communicated between devices are also encrypted, preventing attackers from knowing their content even if they steal the packets. The authentication mechanism proposed in this paper ensures the source and correctness of the data. In terms of security analysis, the proposed mechanism in this paper effectively withstands replay attacks, eavesdropping attacks, man-in-the-middle attacks, and simulated attacks. Additionally, the mechanism supports mutual authentication and forward secrecy. In the experimental results, the proposed mechanism demonstrates approximately 73% improvement in efficiency through the lightweight characteristics of elliptic curve cryptography. Moreover, in the analysis of time complexity, the proposed mechanism exhibits significant effectiveness.

TTAS: Trusted Token Authentication Service of Securing SCADA Network in Energy Management System for Industrial Internet of Things.

The vigorous development of the Industrial Internet of Things brings the advanced connection function of the new generation of industrial automation and control systems. The Supervisory Control and Data Acquisition (SCADA) network is converted into an open and highly interconnected network, where the equipment connections between industrial electronic devices are integrated with a SCADA system through a Modbus protocol. As SCADA and Modbus are easily used for control and monitoring, the interconnection and operational efficiency between systems are highly improved; however, such connectivity inevitably exposes the system to the open network environment. There are many network security threats and vulnerabilities in a SCADA network system. Especially in the era of the Industrial Internet of Things, any security vulnerability of an industrial system may cause serious property losses. Therefore, this paper proposes an encryption and verification mechanism based on the trusted token authentication service and Transport Layer Security (TLS) protocol to prevent attackers from physical attacks. Experimentally, this paper deployed and verified the system in an actual field of energy management system. According to the experimental results, the security defense architecture proposed in this paper can effectively improve security and is compatible with the actual field system.

Prognostic Factors for Survival in Patients with Clear Cell Sarcoma: An Analysis of the Surveillance, Epidemiology, and End Results (SEER) Database.

BACKGROUND Clear cell sarcoma (CCS) of soft tissue, or malignant melanoma of soft parts, is a rare disease. We aimed to identify prognostic factors linked to patient survival in CCS by analyzing demographic and clinical features using the Surveillance, Epidemiology, and End Results (SEER) database. This study aimed to identify prognostic factors associated with CCS that would be of clinical value. MATERIAL AND METHODS We collected data from patients diagnosed with CCS between 1973 and 2009 from the SEER database. The Kaplan-Meier method and Cox regression analysis were performed to identify prognostic factors for patient survival. RESULTS A total of 175 patients with CCS were identified from the SEER database. The 5-year survival rate was 62.9%, and the 10-year survival rate was 51.3%. Patients with CCS with local stage, and with tumor size ≤3 cm were more likely to have good survival rates. CONCLUSIONS The findings from this study showed that the identifiable prognostic factors in patients with CCS were stage and tumor size. Local stage and tumor size ≤3 cm were favorable prognostic factors for patient survival in CCS.

Yangxin Tongmai Formula ameliorates impaired glucose tolerance in children with Graves' disease through upregulation of the insulin receptor levels.

Graves' disease (GD) is the leading cause of hyperthyroidism, and the majority of GD patients eventually develop disorders of glucose handling, which further affects their quality of life. Yangxin Tongmai formula (YTF) is modified from a famous formula of traditional Chinese medicine for the treatment of cardiovascular diseases. In this study we investigated the potential effects of YTF in the treatment of pediatric GD patients with impaired glucose tolerance. Forty pediatric GD patients and 20 healthy children were recruited for this clinical study. Based on the glucose tolerance, the GD patients were divided into two groups: 20 patients displayed impaired glucose tolerance, while the other 20 patients displayed normal glucose tolerance. YTF was orally administered for 60 days. YTF administration significantly ameliorated the abnormal glucose tolerance and insulin sensitivity in the GD patients with impaired glucose tolerance. To determine the molecular mechanisms of this observation, the number of plasma insulin receptors was determined by ELISA. Before treatment, the fasting and postprandial levels of the insulin receptor were significantly lower in patients with impaired glucose tolerance compared with those in patients with normal glucose tolerance and healthy children. After YTF treatment, both the fasting and the postprandial circulating insulin receptor levels were upregulated, and close to those in healthy children. Therefore, YTF is a potential effective treatment to enhance glucose handling in GD children with impaired glucose tolerance.

Nitrogen Source Stabilization of Quorum Sensing in the Pseudomonas aeruginosa Bioaugmentation Strain SD-1.

Pseudomonas aeruginosa SD-1 is efficient at degrading aromatic compounds and can therefore contribute to the bioremediation of wastewater. P. aeruginosa uses quorum sensing (QS) to regulate the production of numerous secreted "public goods." In wastewater bioaugmentation applications, there are myriad nitrogen sources, and we queried whether various nitrogen sources impact the stabilities of both QS and the bacterial populations. In a laboratory strain of P. aeruginosa, PAO1, the absence of a nitrogen source has been shown to destabilize these populations through the emergence of QS mutant "cheaters." We tested the ability of SD-1 to grow in casein broth, a condition that requires QS for growth, when the nitrogen source with either NH4Cl, NaNO3, or NaNO2 or with no added nitrogen source. There was great variability in susceptibility to invasion by QS mutant cheaters and, by extension, the stability of the SD-1 population. When grown with NH4Cl as an extra nitrogen source, no population collapse was observed; by contrast, two-thirds of cultures grown in the presence of NaNO2 collapsed. In the populations that collapsed, the frequency of social cheaters exceeded 40%. NaNO3 and NaNO2 directly favor QS mutants of P. aeruginosa SD-1. Although the mechanism by which these nitrogen sources act is not clear, these data indicate that the metabolism of nitrogen can affect the stability of bacterial populations, an important observation for continuing industrial applications with this species.IMPORTANCE Bioaugmentation as a method to help remediate wastewater pollutant streams holds significant potential to enhance traditional methods of treatment. Addition of microbes that can catabolize organic pollutants can be an effective method to remove several toxic compounds. Such bioaugmented strains of bacteria have been shown to be susceptible to competition from the microbiota that are present in wastewater streams, limiting their potential effectiveness. Here, we show that bioaugmentation strains of bacteria might also be susceptible to invasion by social cheaters and that the nitrogen sources available in the wastewater might influence the ability of cheaters to overtake the bioaugmentation strains. Our results imply that control over the nitrogen sources in a wastewater stream or selective addition of certain nitrogen sources could help stabilize bioaugmentation strains of bacteria.

Syntheses of nickel (II) complexes from novel semicarbazone ligands with chloroformylarylhydrazine, benzimidazole and salicylaldehyde moieties.

This study addressed the design and syntheses of diverse ligands, which were then successfully treated with Ni (II) ion to afford a series of nickel complexes. α-Chloroformylarylhydrazine hydrochlorides contain two different functional groups. One is a strong nucleophile, and the other is a good electrophile. Therefore, it can be designed to react with several reagents to obtain diverse derivatives which can be used as ligands for metal complexes. Furthermore, benzimidazole and salicylaldehyde can provide electron donor sites, N and O electron donors, separately. Hence, the starting materials α-chloroformylarylhydrazine hydrochlorides were first treated with 2-(aminomethyl)-benzimidazole (7) to give the corresponding semicarbazides. Then, the semicarbazides 8 reacted with various substituted salicylaldehydes to afford the desired substituted-salicylaldehyde 2-aryl-4-substituted semicarbazones, which could coordinate with nickel (II) ion to give the corresponding nickel complexes.

A facile synthesis and antimicrobial activity evaluation of sydnonyl-substituted thiazolidine derivatives.

Some new sydnonyl-substituted thiazolidine derivatives were synthesized in high yields by the modified Knoevenagel condensation of 3-aryl-4-formylsydnones with thiazolidine-2,4-dione and 2-thioxo-thiazolidine-4-one, respectively. All the synthesized thiazolidine derivatives were screened by paper-disc method to identify their antimicrobial activities against three bacteria viz. Staphylococcus aureus, Proteus vulgaris and Escherichia coli, and two fungal cultures viz. Aspergillus niger and Penicillium citrinum. The reference drugs were Norfloxacin and Griseofulvin, respectively. The screening data indicated that the tested sydnonyl-substituted thiazolidine derivatives exhibited no obvious antibacterial activity compared with the standard drug Norfloxacin. However, thiazolidine derivatives displayed significant antifungal activities against Penicillium citrinum and Aspergillus niger. Notably, all of the tested compounds showed growth inhibitory activity 1.5-4.4 times higher than that of the standard drug Griseofulvin against the two fungi.

Effect of a Wheelie Training Method With the Front Wheels on a Ramp in Novice Able-Bodied Participants: A Randomized Controlled Trial.

The objective of this study was to determine if wheelie training that begins with learning how to balance with the front wheels on a ramp would increase the success rate, reduce the training time, and improve retention rates. A randomized controlled trial design was used to evaluate the effectiveness of wheelie training on a ramp setting (ramp group, n = 26) and conventional training (conventional group, n = 26). The main outcome measures were success rates in achieving wheelie competence, training time, and the retention rate in 7 and 30 days respectively. The results showed that the success rate for each training group both reached 100%. The mean training times for the conventional group and the ramp group were 86.0 ± 35.7 and 76.0 ± 25.8 minutes. Training time was not significantly affected by the training method (p = 0.23), but it was affected by gender, with women requiring an average of 92.0 ± 31.4 minutes in comparison with 70.0 ± 27.5 minutes for men (p = 0.01). The skill retention rate after 7 and 30 days was 100% for both groups. Neither success rate nor training time for wheelie skill acquisition by learners were improved by learning wheelie balance on a ramp. However, a high retention rate of wheelie skills for both training groups was found, which implies that success can be achieved by training on a ramp used in this study.

Differentiation of Enhanced Green Fluorescent Protein-Labeled Mouse Amniotic Fluid-Derived Stem Cells into Cardiomyocyte-Like Beating Cells.

BACKGROUND: Amniotic fluid-derived stem cells (AFSCs) possess optimal differentiation potential and are a promising resource for cell therapy and tissue engineering. Mouse is a good model to be studied for pre-clinical research. METHODS: In this study, we successfully established enhanced green fluorescent protein mouse-derived amniotic fluid stem cells (EGFP-mAFSCs) and investigated whether EGFP-mAFSCs possess the ability to differentiate into cardiomyocytes by in vitro culture. We evaluated stem-cell differentiation using immunofluorescence. RESULTS: This study showed that EGFP-mAFSCs can give rise to spontaneously beating cardiomyocyte-like cells expressing the specific markers c-kit, myosin heavy chain, and cardiac troponin I. CONCLUSIONS: We demonstrated that mAFSCs have the in vitro propensity to acquire a cardiomyogenic phenotype and to a certain extent cardiomyocytes; however the process efficiency which gives rise to cardiomyocyte-like cells remains quite low (2 out of 10 were found). KEY WORDS: Amniotic fluid; Cardiomyocytes; In vitro differentiation; Stem cells.

Diverse modes of chromosome terminal deletion in spontaneous canavanine-resistant Schizosaccharomyces pombe mutants.

Canavanine resistance has been used to analyze mutation rates in the fission yeast Schizosaccharomyces pombe . However, the genetic basis of canavanine resistance in this organism remains incompletely understood. Here, we performed whole genome sequencing on five spontaneously arising canavanine-resistant S. pombe mutants, including the can2-1 mutant isolated in the 1970s. This analysis revealed that three mutants, including can2-1 , experienced terminal deletions of the left arm of chromosome II, leading to the loss of multiple amino acid transporter genes. Interestingly, these three mutants underwent chromosome terminal deletion through distinct mechanisms, including homology-driven translocation, homology-independent chromosome fusion, and de novo telomere addition. Our findings shed new light on the genetic basis of canavanine resistance and mechanisms underlying chromosome terminal deletions in fission yeast.

Squamous cell carcinoma arising from chronic osteomyelitis of the femur: A case report.

Although chronic osteomyelitis (COM) affecting the extremities is a frequently occurring disease, the incidence of squamous cell carcinoma (SCC) arising from COM is rare. Consequently, understanding the diagnosis, treatment and prognosis of such a disorder remains limited. In the present study, a case of COM-associated SCC was demonstrated. A 65-year-old woman arrived to the Southern Medical University Nanfang Hospital (Guangzhou, China) with multiple sinus tracts and skin ulcers in the distal part of her left thigh, persisting for over 50 years following an open pierce injury by an ox horn. A local biopsy confirmed the diagnosis of COM-related SCC. Although limb amputation was recommended, the female patient declined initially. Instead, the female patient underwent focused debridement and wide resection of the tumor, followed by local implantation of calcium sulfate beads loaded with vancomycin and gentamycin, and application of a rail fixator. A total of 10 months later, the cancer recurred, affecting the osseous tissue. Subsequently, the patient underwent amputation of the thigh. At the one-year follow-up, the patient showed satisfactory recovery without signs of local recurrence. Despite its rarity, the severity of this disorder should not be underestimated. Personalized treatment strategies must be tailored to individual circumstances.

[Characterizations of soil enzyme activities and stoichiometry in three subtropical forest stands]. / äºšçƒ­å¸¦ä¸‰ç§æž—åˆ†åœŸå£¤é ¶æ´»æ€§å’Œé ¶åŒ–å­¦è®¡é‡æ¯”ç‰¹å¾.

We conducted in a common garden experiment to explore the differences in soil enzyme activity, stoichiometry, and their influencing factors among a secondary Castanopsis carlesii forest, 10-year-old C. carlesii plantation, and Cunninghamia lanceolata plantation. The results showed that compared to the secondary forest, the soil organic carbon, total nitrogen, and dissolved organic carbon significantly decreased by 42.6%, 47.4%, and 60.9% in C. carlesii plantation, and by 42.9%, 36.7%, and 61.1% in C. lanceolata plantation. Soil microbial biomass C, microbial biomass N (MBN), and microbial biomass phosphorus decreased significantly by 40.6%, 35.5%, and 45.9% in C. carlesii plantation, and by 53.7%、56.4%, and 61.7% in C. lanceolata plantation. Compared to the secondary forest, soil enzymes activities in C. carlesii plantation did not change significantly, but in C. lanceolata plantation, the activities of ß-1,4-glucosidase and cellobiohydrolase significantly decreased by 51.2% and 59.8%, ß-N-acetyl glucosaminidase and acid phosphatase decreased significantly by 41.0% and 29.8%, and enzymatic C:N acquisition ratio and enzymatic C:P acquisition ratio significantly decreased by 11.3% and 7.7%, respectively. Results of redundancy analysis indicated that MBN and NO3--N were the primary factors influencing soil enzyme activity and enzymic stoichiometry. Collectively, there were significant differences in soil enzyme activity and microbial nutrient demands among different forest stands. Compared to secondary forests, the establishment of C. lanceolata plantations would intensify nutrient competition between plants and microbes, and exacerbate the N and P limitations for microbes.

Clinical pathological characteristics of "crawling-type" gastric adenocarcinoma cancer: A case report.

BACKGROUND: Gastric cancer (GC) is a significant health problem worldwide, and early detection and accurate diagnosis are crucial for improving patient outcomes. Crawling-type gastric adenocarcinoma is a rare subtype of GC that has unique histopathological and clinical characteristics, and its diagnosis and management can be challenging. This pathological type of GC is also rare. CASE SUMMARY: Here, we report the case of a patient who underwent ordinary endoscopy, narrow-band imaging, and endoscopic ultrasonography intending to determine the extent of tumor invasion and upper abdominal enhanced computed tomography and whether there was tumor metastasis. Then, endoscopic submucosal dissection was performed. After pathological and immunohistochemical examination, the pathological diagnosis was crawling-type gastric adenocarcinoma. This is a very rare and special pathological type of tumor. This case highlights the importance of using advanced endoscopic techniques and pathological examination in diagnosing and managing gastric crawling-type adenocarcinoma. Moreover, the findings underscore the need for continued research and clinical experience in this rare subtype of GC to improve patient outcomes. CONCLUSION: The "crawling-type" GC is a rare and specific tumor pathology. It is difficult to identify and diagnose gliomas via endoscopy. The tumor is ill-defined, with a flat appearance and indistinct borders due to the lack of contrast against the background mucosa. Pathology revealed that the tumor cells were hand-like, so the patient has diagnosed with "crawling-type" gastric adenocarcinoma.

Expression of bone-morphogenetic protein 2 and tumor necrosis factor α correlates with bone metastases in bladder urothelial carcinoma.

We have investigated the role of bone-morphogenetic protein (BMP) 2 and tumor necrosis factor α (TNF-α) in 33 patients with bladder cancer (BCa) with bone metastasis. Thirty nonmetastatic BCas were included as controls. Immunohistochemical staining with BMP-2 and TNF-α was performed. Expressions of the factors were quantified and studied statistically. As a result, a trend showing higher expression of BMP-2 and TNF-α was associated with advanced disease. Expressions of BMP-2 and TNF-α were significantly higher in BCa with bone metastases (P = .0002 and P = .0172, respectively). The expression of BMP-2 and TNF-α showed a direct correlation in metastatic and muscle-invasive cases (P = .0202 and P = .0004, respectively) but not in nonmetastatic or noninvasive BCa (P = .1834 and P = .9215, respectively). It is postulated that BMP-2 can be responsible for the mechanism involved in triggering bone metastasis in BCa. The correlation with TNF-α indicates that the interaction of the 2 factors may promote local invasion and distant metastasis, especially to bone.

Simultaneous Single-Position Lateral Lumbar Interbody Fusion Surgery and Unilateral Percutaneous Pedicle Screw Fixation for Spondylolisthesis.

OBJECTIVE: To evaluate the clinical and radiological efficacy of a combine of lateral single screw-rod and unilateral percutaneous pedicle screw fixation (LSUP) for lateral lumbar interbody fusion (LLIF) in the treatment of spondylolisthesis. METHODS: Sixty-two consecutive patients with lumbar spondylolisthesis who underwent minimally invasive (MIS)-TLIF with bilateral pedicle screw (BPS) or LLIF-LSUP were retrospectively studied. Segmental lordosis angle (SLA), lumbar lordosis angle (LLA), disc height (DH), slipping percentage, the cross-sectional areas (CSA) of the thecal sac, screw placement accuracy, fusion rate and foraminal height (FH) were used to evaluate radiographic changes postoperatively. Visual analogue scale (VAS) and Oswestry Disability Index (ODI) were used to evaluate the clinical efficacy. RESULTS: Patients who underwent LLIF-LSUP showed shorter operating time, less length of hospital stay and lower blood loss than MIS-TLIF. No statistical difference was found between the 2 groups in screw placement accuracy, overall complications, VAS, and ODI. Compared with MIS-TLIF-BPS, LLIF-LSUP had a significant improvement in sagittal parameters including DH, FH, LLA, and SLA. The CSA of MIS-TLIF-BPS was significantly increased than that of LLIF-LSUP. The fusion rate of LLIF-LSUP was significantly higher than that of MIS-TLIF-BPS at the follow-up of 3 months postoperatively, but there was no statistical difference between the 2 groups at the follow-up of 6 months, 9 months, and 12 months. CONCLUSION: The overall clinical outcomes and complications of LLIF-LSUP were comparable to that of MIS-TLIF-BPS in this series. Compared with MIS-TLIF-BPS, LLIF-LSUP for lumbar spondylolisthesis represents a significantly shorter operating time, hospital stay and lower blood loss, and demonstrates better radiological outcomes to maintain lumbar lordosis, and reveal an overwhelming superiority in the early fusion rate.

Effects of oxygen content on gaseous and solid products during molten salt oxidation of cation exchange resins.

Molten salt oxidation (MSO) is an advanced method for waste resins treatment; nevertheless, the research about gas product variations of resins under different stoichiometric air feed coefficient (α) is rare. The optimal working condition of hazardous waste disposal is obtained through thermodynamic equilibrium calculation, and the method to improve the treatment efficiency is found to guide the optimization of the actual experiment. In this paper, Fact Sage was used to calculate the oxidation products of cation exchange resins (CERs) at different temperatures and α, focusing on the similarities and differences through the contents of CO, CH4, CO2, and SO2 during the oxidation of CERs, the MSO of CERs, and the theoretical calculation. The results indicated that the gas products of the calculation and reality of the oxidation process of CERs are quite different, while the CO contents of CERs during MSO are close to the calculated values. The main reason for this consequence is that in the oxidation process of CERs, the S in the sulfonic acid group will form thermally stable C-S with the styrene-divinylbenzene skeleton. Moreover, the introduction of carbonate can promote the destruction of C-S and absorb SO2 as sulfate, weakening the influence of C-S on the oxidation products of CERs. The gas chromatograph results indicated that the SO2 content is reduced from 0.66% in the process of CERs oxidation to 0.28% in MSO of CERs. When 1.25 times stoichiometric air feed coefficient is fed, the sulfate content in the carbonate is the highest at 900 °C, which is 23.4%.

Evaluation of Xpert MTB/RIF assay for the diagnosis of extrapulmonary tuberculosis in Southwest China.

The purpose of this study was to determine the diagnostic efficacy of Xpert MTB/RIF assay for rapid diagnosis of Tuberculosis (TB) and detection of rifampicin (RIF) resistance in patients suspected of having EPTB, assessing it against traditional culture and drug susceptibility test (DST) by proportional method, and the ability to predict multidrug resistance TB by Xpert MTB/RIF assay. In this study, the Xpert MTB/RIF assay was applied to 1,614 extrapulmonary specimens. Compared with TB culture and Composite Reference Standard (CRS), the Xpert MTB/RIF assay had a high sensitivity and specificity for detection of EPTB. Depending on the culture method or CRS as the standard, sensitivity of the Xpert MTB/RIF assay for detection of MTB in pleural effusion, cerebrospinal fluid, thoracic drainage fluid and throat swabs specimens were lower than that of other specimens. According to the experimental results, we have reason to believe that Xpert MTB/RIF assay is a rapid and simple technique with high sensitivity and specificity for diagnosing EPTB and detecting drug resistance in variety of specimens. Xpert MTB/RIF assay combined with DST maybe identify more cases of multi-drug resistant tuberculosis (MDR-TB).

Effect of backrest height on wheelchair propulsion biomechanics for level and uphill conditions.

OBJECTIVE: To evaluate the effect of backrest height on wheelchair propulsion kinematics and kinetics. DESIGN: An intervention study with repeated measures. SETTING: University laboratory. PARTICIPANTS: Convenience sample included manual wheelchair users (N=36; 26 men and 10 women) with spinal cord injuries ranging from T8 to L2. INTERVENTION: Participants propelled on a motor-driven treadmill for 2 conditions (level and slope of 3°) at a constant speed of 0.9 m/s while using in turn a sling backrest fixed at 40.6 cm (16 in) high (high backrest) and a lower height set at 50% trunk length (low backrest). MAIN OUTCOME MEASURES: Cadence, stroke angle, peak shoulder extension angle, shoulder flexion/extension range of motion, and mechanical effective force. RESULTS: Pushing with the low backrest height enabled greater range of shoulder motion (P<.01), increased stroke angle (P<.01), push time (P<.01), and reduced cadence (P=.01) regardless of whether the treadmill was level or sloped. CONCLUSIONS: A lower cadence can be achieved when pushing with a lower backrest, which decreases the risk of developing upper-limb overuse related injuries. However, postural support, comfort, and other activities of daily living must also be considered when selecting a backrest height for active, long-term wheelchair users. The improvements found when using the low backrest were found regardless of slope type. Pushing uphill demanded significantly higher resultant and tangential force, torque, mechanical effective force, and cadence.

Arthroscopic excision of ganglion cysts of the posterior cruciate ligaments using posterior trans-septal portal.

PURPOSE: To evaluate clinical outcomes of arthroscopic excision of ganglion cysts involving the posterior cruciate ligament (PCL) using the posterior trans-septal portal in the knee. METHODS: A retrospective study was performed of 15 cases of ganglion cyst involving the PCL treated at our institution over a period of 4 years. All the cysts were diagnosed and had their location confirmed preoperatively by magnetic resonance imaging (MRI). All the cysts were excised arthroscopically through the posterior trans-septal portal. All patients were followed up with MRI evaluation at a mean of 36 months after surgery. In addition, International Knee Documentation Committee (IKDC) scores and range of motion (ROM) were obtained preoperatively and postoperatively simultaneously with MRI to assess the surgical outcomes. RESULTS: Most of the patients were male patients, and the mean age was 32 years. The most common presenting complaint was pain and difficulty in knee flexion. Preoperatively, the mean ROM was 3° to 110° and the mean IKDC score was 53 (range, 38 to 67; SD, 7.9). The location of the main cystic component was posterior to the PCL in 14 patients (93%) and anterior to the PCL in 1 patient (7%). After surgery, MRI evaluation at a mean follow-up time of 36 months showed no cyst recurrence. Postoperatively, the mean IKDC score was 91 (range, 70 to 99; SD, 9.3) and the mean ROM was 3° to 128°. CONCLUSIONS: Ganglion cysts associated with the PCL can cause knee pain and limitation of knee flexion. MRI evaluation is a noninvasive method of diagnosing PCL ganglion cysts. Arthroscopic excision through the posterior trans-septal portal is a good option for relieving pain and preventing cyst recurrence. LEVEL OF EVIDENCE: Level IV, therapeutic case series.