A life cycle assessment of cardboard waste in low stress grade concrete applications

Utilising cardboard waste for the partial substitution of cement within concrete has the potential to yield significant sustainability benefits. Cardboard waste is abundantly available, and a significant proportion of this material is disposed of in landfill. However, conversion of waste cardboard into kraft fibres (KFs) for concrete implementation can be utilised in the building and construction industry. Therefore, identification of sustainability variables associated with cardboard waste in concrete is vital. In this study, two KF composites satisfied the criteria for low stress grade concrete and were subsequently evaluated. SFKF5 mix design contained 5% KFs and SFKF105 contained 10% KFs with 5% metakaolin (MK). Both composites had silica fume (SF) as a fibre modification technique for durability purposes. A life cycle assessment (LCA) determined the environmental effect of waste cardboard integration. A Monte-Carlo simulation was utilised as the sensitivity analysis to investigate transportation and energy manufacturing greenhouse gas (GHG) emission variables. LCA results of SFKF105 had a savings of 11%, 8%, 4% and 1% for terrestrial acidification potential, global warming potential (GWP), terrestrial ecotoxicity potential (TEP) and human toxicity potential, respectively. SFKF5 revealed savings of 3%, 2% and 4% for GWP, TEP and marine eutrophication potential, respectively. The additional travel requirements of KFs and MK to the cement batching plant for composite production did not surpass the embodied energy and travel emissions of the control. However, this was negated due to the additional energy requirements to manufacture KFs. The control, SFKF5, and SFKF105 had an average total of 572, 1023 and 997 kgCO2-eq/m3, respectively.

Thermal Characterizations of Waste Cardboard Kraft Fibres in the Context of Their Use as a Partial Cement Substitute within Concrete Composites

The building and construction industry consumes a significant amount of virgin resources and minimizing the demand with alternative waste materials can provide a contemporary solution. In this study, thermal components of kraft fibres (KFs) derived from waste cardboard are investigated. The mechanical properties containing KFs within concrete composites are evaluated. Metakaolin (MK) and KFs were integrated into concrete samples as a partial substitute for cement. Silica Fume (SF) was applied to the KF (SFKFs) with a view to enhancing the fibre durability. The results indicated that there was a reduction in compressive strength of 44 and 56% when 10% raw and modified KFs were integrated, respectively. Raw, fibre and matrix-modified samples demonstrated a 35, 4 and 24% flexural strength reduction, respectively; however, the tensile strength improved by 8% when the matrix was modified using MK and SFKF. The morphology of the fibres was illustrated using a scanning electron microscope (SEM), with an energy dispersion X-ray spectroscopy (EDS) provision and Fourier transform infrared spectroscopy (FT-IR) employed to gain insights into their chemical nature. The thermal, calorimetric and combustion attributes of the fibres were measured using thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and pyrolysis combustion flow calorimetry (PCFC). SFKFs showed a lower heat release capacity (HRC), demonstrating a lower combustion propensity compared to raw KFs. Furthermore, the 45% decreased peak heat release rate (pHRR) of SFKFs highlighted the overall reduction in the fire hazards associated with these materials. TGA results also confirmed a lower mass weight loss of SFKFs at elevated temperatures, thus corroborating the results from the PCFC runs.

[Surgical treatment in De Quervain's tenosynovitis. About 20 cases]

INTRODUCTION

The De Quervain's tenosynovitis is an inadequacy into the first extensor compartment between the osteo-fibrous tunnel and the tendons. This mechanical conflict generates a tenosynovitis of the extensor pollicis brevis and the abductor pollicis longus tendons in first dorsal extensor compartment of the wrist.

PATIENTS AND METHODS

The authors report a retrospective study of 20 patients who have been treated by a longitudinal surgical approach. The mean age was 49 years old with a net female predominance. The Finkelstein's test was positive in all cases. All patients were treated operatively by incision of the sheath, which was sufficient to unwind the dorsal compartment tendons. The sheath palmar flap has been sutured with skin (Le Viet plasty) to avoid a further tendons luxation.

RESULTS

At three years follow-up, the functional results were good in all the patients. However, non-aesthetic scars were noticed in three patients. We did not notice neither a case of anesthesia of the radial nerve nor a tendinous luxation in our series.

DISCUSSION

The stenosing tenosynovitis of the first dorsal extensor compartment of the wrist is a relatively frequent pathology in the young woman. We use a longitudinal surgical approach to avoid the radial nerve lesions. Le Viet procedure using the palmar flap of the pulley fixed to the dermis works as a barrier and maintains the tendons sliding on the radial styloid groove.

[Efficacy and safety of thrombolytic therapy in the elderly with severe pulmonary embolism]

Thrombolytic therapy leads to more rapid dissolution of thrombi in severe pulmonary embolism than conventional heparin therapy but is considered with much reserve in elderly patients because of the risk of haemorrhage, which is thought to be potentially greater in these subjects. The object of this study was to assess the efficacy and safety of thrombolytic therapy in patients over 70 years of age with severe pulmonary embolism, compared with patients under 70 years of age with the same condition. Eighty-nine patients with severe pulmonary embolism (Miller score > 17/34) were prescribed thrombolytic therapy in the absence of a contraindication without taking age into consideration. Fifty-three were under 70 years of age (54 +/- 15; range: 18 to 70 years) and 36 were over 70 years of age (78 +/- 5; range: 71 to 88 years). Apart from age, there was no difference in the clinical presentation of the two groups. Thrombolytic therapy was initiated with streptokinase 100,000 IU/hr for twelve hours after an initial bolus of 250,000 IU or with urokinase or plasminogen tissue activator in cases with a contraindication to streptokinase. An uncomplicated course was observed in the same percentage of cases in the two groups. The Miller score and mean pulmonary pressures fell in the same way in the two groups. Three patients died during the hospital period, two aged under 70 (3.7%) and one over 7 years of age (2.7%). Major bleeding occurred in 3 subjects under 70 (5.6%) and 5 subjects over 70 (13.8%) (p = 0.29).(ABSTRACT TRUNCATED AT 250 WORDS)

Safety of thrombolytic therapy in elderly patients with massive pulmonary embolism: a comparison with nonelderly patients

OBJECTIVES

The aim of the study was to prospectively estimate the safety of thrombolytic therapy in elderly patients with massive pulmonary embolism in comparison with that in nonelderly patients.

BACKGROUND

In massive pulmonary embolism, lysis of thrombi can be achieved faster with thrombolytic therapy than with conventional heparin therapy, but it is administered with great caution in elderly patients because the risk of bleeding is thought to be higher than in nonelderly patients. Yet, thrombolytic therapy might be of value in elderly patients also, in allowing potentially more rapid improvement than is achieved with conventional heparin therapy.

METHODS

Eighty-nine patients with massive pulmonary embolism defined as Miller score > or = 17/34 underwent thrombolytic therapy without consideration of age if they had no contraindication for such treatment. Fifty-three patients were < or = 70 years old (mean age +/- SD 54 +/- 15 years; range 18 to 70), and 36 patients were > or = 71 years old (78 +/- 5 years; range 71 to 88). Except for mean age, there were no significant differences between the two treatment groups, particularly in terms of clinical presentation, average Miller score and pulmonary artery pressure regimen. Thrombolytic therapy was administered in the form of streptokinase at a dose of 100,000 IU/h over 12 h, with an initial injection of 250,000 IU over 15 min. Heparin was introduced 12 h after initiation of thrombolytic therapy. Urokinase or tissue-type plasminogen activator was used only in case of contraindication to streptokinase.

RESULTS

The frequency of uncomplicated clinical course was the same in both treatment groups. Surgical embolectomy was necessary in three nonelderly patients (5.6%) and one elderly patient (2.7%). Changes in pulmonary pressure regimen and Miller score were identical in both groups. Three patients died during the in-hospital course: two nonelderly patients (3.7%) and one elderly patient (2.7%). Minor bleeding occurred in five nonelderly (9.4%) and five elderly (13.8%) patients (p = 0.74). Major bleeding was observed in three nonelderly (5.6%) and five elderly (13.8%) patients (p = 0.29). Bleeding subsequent to early invasive procedure accounted for six (75%) of eight patients with major bleeding: two nonelderly patients (one of whom died) and four elderly patients. No intracranial hemorrhage was observed. No predisposing factor for bleeding was identified, except the need for early vascular access for pulmonary angiography through the femoral approach or for percutaneous insertion of an intracaval device for partial interruption of the inferior vena cava.

CONCLUSIONS

Thrombolytic therapy administered for massive pulmonary embolism in patients free of contraindication yields similar results and carries a similar risk for bleeding complications in elderly compared with nonelderly patients. Limiting early invasive procedures may result in less frequent major bleeding complications.