Pengaruh Konsentrasi Polivinil Alkohol (PVA) terhadap Performa Elektrokimia LiTi2(PO4)3 Hasil Proses Sol-Gel sebagai Anoda untuk Baterai Ion Lithium Tipe Aqueous Elektrolit

Penelitian tentang baterai ion lithium sebagai sistem penyimpanan energi berkembang begitu pesat. Pada baterai ion lithium, salah satu bagian utama adalah anoda yang terdiri atas material LiTi2(PO4)3. Maka, penelitian ini bertujuan untuk mengetahui pengaruh konsentarsi polivinil alkohol (PVA) terhadap performa elektrokimia LiTi2(PO4)3 sebagai anoda baterai ion lithium. Proses sintesis material LiTi2(PO4)3 dilakukan dengan proses sol-gel menggunakan Li2CO3, TiO2, NH4H2PO4, dan variasi penambahan konsentrasi 5 wt%, 10 wt%, 15 wt% polivinil alkohol (PVA). Pada pengujian XRD dari ketiga sampel, teridentifikasi LiTi2(PO4)3 sesuai dengan JCPDS 35-074 meskipun masih ada fasa lain dalam intensitas yang kecil. Pengujian SEM menunjukkan bahwa material LiTi2(PO4)3 5wt% PVA memiliki ukuran partikel yang lebih kecil dibandingkan dengan lainnya. Namun demikian, ukuran partikel tidak merata dan masih ada sedikit aglomerasi karena proses kalsinasi pada temperatur tinggi. Pengujian performa elektrokimia Cyclic Voltammetry (CV) menunjukkan bahwa anoda LiTi2(PO4)3 5wt% PVA menunjukkan nilai kinetik ion yang tinggi, karena pada anoda tersebut memiliki ukuran partikel yang paling kecil dibandingkan yang lainnya sehingga meningkatkan difusivitas ion Li+. Adapun pengujian Galvanostat Charge-Discharge menunjukkan bahwa anoda LiTi2(PO4)3 5wt% PVA memiliki stabilitas yang lebih baik karena pada anoda LiTi2(PO4)3 5wt% PVA memiliki sebaran ukuran partikel yang lebih kecil sehingga transfer ion saat proses interkalasi/de-interkalasi dapat berlangsung secara stabil

Dolomitization of the Lower Ordovician Aguathuna Formation carbonates, Port au Port Peninsula, western Newfoundland, Canada: implications for a hydrocarbon reservoir

The Lower Ordovician Aguathuna Formation (∼100 m thick) is formed of shallow-marine carbonates, which constitute the uppermost part of the St. George Group of western Newfoundland. Sedimentation was paused by a major subaerial exposure (St. George Unconformity), which likely developed a significant pore system in the underlying carbonates by meteoric dissolution. The sequence has been affected by multiphase dolomitization that caused complex changes in the rock porosity. The Aguathuna dolomites are classified into three main generations ranging in crystal size between ∼4 µm and 2 mm. The occurrence of fabric-retentive dolomicrites implies that dolomitization likely started during the early stages of diagenesis. Although dolomitization is pervasive in the upper part of the formation and significantly occludes the pores, some intervals in the lower part have higher porosity. The development of lower permeable layers overlain by an impermeable (seal) cap suggests a possible potential diagenetic trap. Unlike sabkha deposits, the Aguathuna carbonates do not have evaporite interlayers. Furthermore, the low Sr contents (∼96 ppm) and the δ18O values of earlier dolomites (–3.3‰ to –6.9‰ VPDB (Vienna Pee Dee Belemnite)) are also difficult to reconcile with a brine origin. The Sr/Ca molar ratios (0.0067–0.0009), calculated for the earliest dolomitizing fluid, suggest a modified seawater origin, likely mixed sea and meteoric waters. The least radiogenic 87Sr/86Sr values of the earliest dolomite are consistent with those of early Ordovician seawater, which supports an early-stage diagenesis. Petrography, geochemistry, and fluid inclusions of the late dolomites suggest precipitation at higher temperatures (∼73–95 °C) in deeper burial environments from hydrothermal solutions

Low platelet to lymphocyte ratio and high platelet distribution width have an inferior outcome in chronic lymphocytic leukaemia patients

Introduction.  Chronic lymphocytic leukaemia (CLL) is an incurable disease of the elderly, characterised by gradual accu­mulation of small mature B lymphocytes which escape apoptosis through inflammatory signals from the microenviron­ment. Elevated inflammatory markers are associated with very poor prognosis in different types of cancer. Therefore, we examined retrospectively the impact of platelet lymphocyte ratio (PLR) and platelet distribution width (PDW) on 180 CLL patients’ outcome. Materials and methods.  This retrospective study included 180 patients with CLL who were diagnosed and selected among cases referred to the Oncology Center Mansoura University between January 1st, 2008 and June 30th, 2016. All the relevant information was collected from the electronic medical records of the selected patients. Results.  Our results revealed that low PLR (<2.5) was more frequently observed in patients with stage C (p < 0.001), with 17p deletion (p = 0.017), and CD38 expression (p = 0.08), but not with seropositive HCV patients (p = 0.2). High PDW (≥18.5 fl) was more frequently associated with intention to treat population (p = 0.038), and CD38 expression (p = 0.068), but not with 17p deletion (p = 0.25) and seropositive HCV patients (p = 0.4). Multivariate analysis for overall survival showed that stage A and low PDW were independent factors for overall survival (p = 0.014 and 0.04 respectively), while high PLR (p = 0.05), and seronegative HCV patients (p = 0.1) lost their significance. Conclusion.  Our data showed that low PLR and high PDW were associated with poor prognostic markers. Stage C-CLL and high PDW were independent predictors of survival

Giant Spontaneous Femoral Artery Pseudoaneurysm Treated with Covered Stents : Report of a rare presentation and review of literature

We report the case of a 62-year-old woman who presented with a one-month history of a pulsatile mass, with no antecedent trauma or intervention. Imaging showed a large pseudoaneurysm (PSA) of the distal portion of the left superficial femoral artery. The PSA was treated successfully with endovascular placement of covered stents

Variation in the provision and practice of implant-based breast reconstruction in the UK: Results from the iBRA national practice questionnaire

Introduction The introduction of biological and synthetic meshes has revolutionised the practice of implant-based breast reconstruction (IBBR) but evidence for effectiveness is lacking. The iBRA (implant Breast Reconstruction evAluation) study is a national trainee-led project that aims to explore the practice and outcomes of IBBR to inform the design of a future trial. We report the results of the iBRA National Practice Questionnaire (NPQ) which aimed to comprehensively describe the provision and practice of IBBR across the UK. Methods A questionnaire investigating local practice and service provision of IBBR developed by the iBRA Steering Group was completed by trainee and consultant leads at breast and plastic surgical units across the UK. Summary data for each survey item were calculated and variation between centres and overall provision of care examined. Results 81 units within 79 NHS-hospitals completed the questionnaire. Units offered a range of reconstructive techniques, with IBBR accounting for 70% (IQR:50–80%) of participating units' immediate procedures. Units on average were staffed by 2.5 breast surgeons (IQR:2.0–3.0) and 2.0 plastic surgeons (IQR:1.0–3.0) performing 35 IBBR cases per year (IQR:20-50). Variation was demonstrated in the provision of novel different techniques for IBBR especially the use of biological (n = 62) and synthetic (n = 25) meshes and in patient selection for these procedures. Conclusions The iBRA-NPQ has demonstrated marked variation in the provision and practice of IBBR in the UK. The prospective audit phase of the iBRA study will determine the safety and effectiveness of different approaches to IBBR and allow evidence-based best practice to be explored

The impact of immediate breast reconstruction on the time to delivery of adjuvant therapy: the iBRA-2 study

Background: Immediate breast reconstruction (IBR) is routinely offered to improve quality-of-life for women requiring mastectomy, but there are concerns that more complex surgery may delay adjuvant oncological treatments and compromise long-term outcomes. High-quality evidence is lacking. The iBRA-2 study aimed to investigate the impact of IBR on time to adjuvant therapy. Methods: Consecutive women undergoing mastectomy ± IBR for breast cancer July–December, 2016 were included. Patient demographics, operative, oncological and complication data were collected. Time from last definitive cancer surgery to first adjuvant treatment for patients undergoing mastectomy ± IBR were compared and risk factors associated with delays explored. Results: A total of 2540 patients were recruited from 76 centres; 1008 (39.7%) underwent IBR (implant-only [n = 675, 26.6%]; pedicled flaps [n = 105,4.1%] and free-flaps [n = 228, 8.9%]). Complications requiring re-admission or re-operation were significantly more common in patients undergoing IBR than those receiving mastectomy. Adjuvant chemotherapy or radiotherapy was required by 1235 (48.6%) patients. No clinically significant differences were seen in time to adjuvant therapy between patient groups but major complications irrespective of surgery received were significantly associated with treatment delays. Conclusions: IBR does not result in clinically significant delays to adjuvant therapy, but post-operative complications are associated with treatment delays. Strategies to minimise complications, including careful patient selection, are required to improve outcomes for patients

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Exercise versus usual care after non-reconstructive breast cancer surgery (UK PROSPER): multicentre randomised controlled trial and economic evaluation

Objective To evaluate whether a structured exercise programme improved functional and health related quality of life outcomes compared with usual care for women at high risk of upper limb disability after breast cancer surgery. Design Multicentre, pragmatic, superiority, randomised controlled trial with economic evaluation. Setting 17 UK National Health Service cancer centres. Participants 392 women undergoing breast cancer surgery, at risk of postoperative upper limb morbidity, randomised (1:1) to usual care with structured exercise (n=196) or usual care alone (n=196). Interventions Usual care (information leaflets) only or usual care plus a physiotherapy led exercise programme, incorporating stretching, strengthening, physical activity, and behavioural change techniques to support adherence to exercise, introduced at 7-10 days postoperatively, with two further appointments at one and three months. Main outcome measures Disability of Arm, Hand and Shoulder (DASH) questionnaire at 12 months, analysed by intention to treat. Secondary outcomes included DASH subscales, pain, complications, health related quality of life, and resource use, from a health and personal social services perspective. Results Between 26 January 2016 and 31 July 2017, 951 patients were screened and 392 (mean age 58.1 years) were randomly allocated, with 382 (97%) eligible for intention to treat analysis. 181 (95%) of 191 participants allocated to exercise attended at least one appointment. Upper limb function improved after exercise compared with usual care (mean DASH 16.3 (SD 17.6) for exercise (n=132); 23.7 (22.9) usual care (n=138); adjusted mean difference 7.81, 95% confidence interval 3.17 to 12.44; P=0.001). Secondary outcomes favoured exercise over usual care, with lower pain intensity at 12 months (adjusted mean difference on numerical rating scale −0.68, −1.23 to −0.12; P=0.02) and fewer arm disability symptoms at 12 months (adjusted mean difference on Functional Assessment of Cancer Therapy-Breast+4 (FACT-B+4) −2.02, −3.11 to −0.93; P=0.001). No increase in complications, lymphoedema, or adverse events was noted in participants allocated to exercise. Exercise accrued lower costs per patient (on average −£387 (€457; $533) (95% confidence interval −£2491 to £1718; 2015 pricing) and was cost effective compared with usual care. Conclusions The PROSPER exercise programme was clinically effective and cost effective and reduced upper limb disability one year after breast cancer treatment in patients at risk of treatment related postoperative complications